/* @internal */
namespace ts {
const ambientModuleSymbolRegex = /^".+"$/;
let nextSymbolId = 1;
let nextNodeId = 1;
let nextMergeId = 1;
let nextFlowId = 1;
export function getNodeId(node: Node): number {
if (!node.id) {
node.id = nextNodeId;
nextNodeId++;
}
return node.id;
}
export function getSymbolId(symbol: Symbol): number {
if (!symbol.id) {
symbol.id = nextSymbolId;
nextSymbolId++;
}
return symbol.id;
}
export function isInstantiatedModule(node: ModuleDeclaration, preserveConstEnums: boolean) {
const moduleState = getModuleInstanceState(node);
return moduleState === ModuleInstanceState.Instantiated ||
(preserveConstEnums && moduleState === ModuleInstanceState.ConstEnumOnly);
}
export function createTypeChecker(host: TypeCheckerHost, produceDiagnostics: boolean): TypeChecker {
const getPackagesSet: () => Map<true> = memoize(() => {
const set = createMap<true>();
host.getSourceFiles().forEach(sf => {
if (!sf.resolvedModules) return;
forEachEntry(sf.resolvedModules, r => {
if (r && r.packageId) set.set(r.packageId.name, true);
});
});
return set;
});
// Cancellation that controls whether or not we can cancel in the middle of type checking.
// In general cancelling is *not* safe for the type checker. We might be in the middle of
// computing something, and we will leave our internals in an inconsistent state. Callers
// who set the cancellation token should catch if a cancellation exception occurs, and
// should throw away and create a new TypeChecker.
//
// Currently we only support setting the cancellation token when getting diagnostics. This
// is because diagnostics can be quite expensive, and we want to allow hosts to bail out if
// they no longer need the information (for example, if the user started editing again).
let cancellationToken: CancellationToken | undefined;
let requestedExternalEmitHelpers: ExternalEmitHelpers;
let externalHelpersModule: Symbol;
// tslint:disable variable-name
const Symbol = objectAllocator.getSymbolConstructor();
const Type = objectAllocator.getTypeConstructor();
const Signature = objectAllocator.getSignatureConstructor();
// tslint:enable variable-name
let typeCount = 0;
let symbolCount = 0;
let enumCount = 0;
let instantiationDepth = 0;
let constraintDepth = 0;
let currentNode: Node | undefined;
const emptySymbols = createSymbolTable();
const identityMapper: (type: Type) => Type = identity;
const compilerOptions = host.getCompilerOptions();
const languageVersion = getEmitScriptTarget(compilerOptions);
const moduleKind = getEmitModuleKind(compilerOptions);
const allowSyntheticDefaultImports = getAllowSyntheticDefaultImports(compilerOptions);
const strictNullChecks = getStrictOptionValue(compilerOptions, "strictNullChecks");
const strictFunctionTypes = getStrictOptionValue(compilerOptions, "strictFunctionTypes");
const strictBindCallApply = getStrictOptionValue(compilerOptions, "strictBindCallApply");
const strictPropertyInitialization = getStrictOptionValue(compilerOptions, "strictPropertyInitialization");
const noImplicitAny = getStrictOptionValue(compilerOptions, "noImplicitAny");
const noImplicitThis = getStrictOptionValue(compilerOptions, "noImplicitThis");
const keyofStringsOnly = !!compilerOptions.keyofStringsOnly;
const freshObjectLiteralFlag = compilerOptions.suppressExcessPropertyErrors ? 0 : ObjectFlags.FreshLiteral;
const emitResolver = createResolver();
const nodeBuilder = createNodeBuilder();
const globals = createSymbolTable();
const undefinedSymbol = createSymbol(SymbolFlags.Property, "undefined" as __String);
undefinedSymbol.declarations = [];
const globalThisSymbol = createSymbol(SymbolFlags.Module, "globalThis" as __String, CheckFlags.Readonly);
globalThisSymbol.exports = globals;
globalThisSymbol.valueDeclaration = createNode(SyntaxKind.Identifier) as Identifier;
(globalThisSymbol.valueDeclaration as Identifier).escapedText = "globalThis" as __String;
globals.set(globalThisSymbol.escapedName, globalThisSymbol);
const argumentsSymbol = createSymbol(SymbolFlags.Property, "arguments" as __String);
const requireSymbol = createSymbol(SymbolFlags.Property, "require" as __String);
/** This will be set during calls to `getResolvedSignature` where services determines an apparent number of arguments greater than what is actually provided. */
let apparentArgumentCount: number | undefined;
// for public members that accept a Node or one of its subtypes, we must guard against
// synthetic nodes created during transformations by calling `getParseTreeNode`.
// for most of these, we perform the guard only on `checker` to avoid any possible
// extra cost of calling `getParseTreeNode` when calling these functions from inside the
// checker.
const checker: TypeChecker = {
getNodeCount: () => sum(host.getSourceFiles(), "nodeCount"),
getIdentifierCount: () => sum(host.getSourceFiles(), "identifierCount"),
getSymbolCount: () => sum(host.getSourceFiles(), "symbolCount") + symbolCount,
getTypeCount: () => typeCount,
isUndefinedSymbol: symbol => symbol === undefinedSymbol,
isArgumentsSymbol: symbol => symbol === argumentsSymbol,
isUnknownSymbol: symbol => symbol === unknownSymbol,
getMergedSymbol,
getDiagnostics,
getGlobalDiagnostics,
getTypeOfSymbolAtLocation: (symbol, location) => {
location = getParseTreeNode(location);
return location ? getTypeOfSymbolAtLocation(symbol, location) : errorType;
},
getSymbolsOfParameterPropertyDeclaration: (parameterIn, parameterName) => {
const parameter = getParseTreeNode(parameterIn, isParameter);
if (parameter === undefined) return Debug.fail("Cannot get symbols of a synthetic parameter that cannot be resolved to a parse-tree node.");
return getSymbolsOfParameterPropertyDeclaration(parameter, escapeLeadingUnderscores(parameterName));
},
getDeclaredTypeOfSymbol,
getPropertiesOfType,
getPropertyOfType: (type, name) => getPropertyOfType(type, escapeLeadingUnderscores(name)),
getTypeOfPropertyOfType: (type, name) => getTypeOfPropertyOfType(type, escapeLeadingUnderscores(name)),
getIndexInfoOfType,
getSignaturesOfType,
getIndexTypeOfType,
getBaseTypes,
getBaseTypeOfLiteralType,
getWidenedType,
getTypeFromTypeNode: nodeIn => {
const node = getParseTreeNode(nodeIn, isTypeNode);
return node ? getTypeFromTypeNode(node) : errorType;
},
getParameterType: getTypeAtPosition,
getPromisedTypeOfPromise,
getReturnTypeOfSignature,
getNullableType,
getNonNullableType,
typeToTypeNode: nodeBuilder.typeToTypeNode,
indexInfoToIndexSignatureDeclaration: nodeBuilder.indexInfoToIndexSignatureDeclaration,
signatureToSignatureDeclaration: nodeBuilder.signatureToSignatureDeclaration,
symbolToEntityName: nodeBuilder.symbolToEntityName as (symbol: Symbol, meaning: SymbolFlags, enclosingDeclaration?: Node, flags?: NodeBuilderFlags) => EntityName, // TODO: GH#18217
symbolToExpression: nodeBuilder.symbolToExpression as (symbol: Symbol, meaning: SymbolFlags, enclosingDeclaration?: Node, flags?: NodeBuilderFlags) => Expression, // TODO: GH#18217
symbolToTypeParameterDeclarations: nodeBuilder.symbolToTypeParameterDeclarations,
symbolToParameterDeclaration: nodeBuilder.symbolToParameterDeclaration as (symbol: Symbol, enclosingDeclaration?: Node, flags?: NodeBuilderFlags) => ParameterDeclaration, // TODO: GH#18217
typeParameterToDeclaration: nodeBuilder.typeParameterToDeclaration as (parameter: TypeParameter, enclosingDeclaration?: Node, flags?: NodeBuilderFlags) => TypeParameterDeclaration, // TODO: GH#18217
getSymbolsInScope: (location, meaning) => {
location = getParseTreeNode(location);
return location ? getSymbolsInScope(location, meaning) : [];
},
getSymbolAtLocation: node => {
node = getParseTreeNode(node);
return node ? getSymbolAtLocation(node) : undefined;
},
getShorthandAssignmentValueSymbol: node => {
node = getParseTreeNode(node);
return node ? getShorthandAssignmentValueSymbol(node) : undefined;
},
getExportSpecifierLocalTargetSymbol: nodeIn => {
const node = getParseTreeNode(nodeIn, isExportSpecifier);
return node ? getExportSpecifierLocalTargetSymbol(node) : undefined;
},
getExportSymbolOfSymbol(symbol) {
return getMergedSymbol(symbol.exportSymbol || symbol);
},
getTypeAtLocation: node => {
node = getParseTreeNode(node);
return node ? getTypeOfNode(node) : errorType;
},
getPropertySymbolOfDestructuringAssignment: locationIn => {
const location = getParseTreeNode(locationIn, isIdentifier);
return location ? getPropertySymbolOfDestructuringAssignment(location) : undefined;
},
signatureToString: (signature, enclosingDeclaration, flags, kind) => {
return signatureToString(signature, getParseTreeNode(enclosingDeclaration), flags, kind);
},
typeToString: (type, enclosingDeclaration, flags) => {
return typeToString(type, getParseTreeNode(enclosingDeclaration), flags);
},
symbolToString: (symbol, enclosingDeclaration, meaning, flags) => {
return symbolToString(symbol, getParseTreeNode(enclosingDeclaration), meaning, flags);
},
typePredicateToString: (predicate, enclosingDeclaration, flags) => {
return typePredicateToString(predicate, getParseTreeNode(enclosingDeclaration), flags);
},
writeSignature: (signature, enclosingDeclaration, flags, kind, writer) => {
return signatureToString(signature, getParseTreeNode(enclosingDeclaration), flags, kind, writer);
},
writeType: (type, enclosingDeclaration, flags, writer) => {
return typeToString(type, getParseTreeNode(enclosingDeclaration), flags, writer);
},
writeSymbol: (symbol, enclosingDeclaration, meaning, flags, writer) => {
return symbolToString(symbol, getParseTreeNode(enclosingDeclaration), meaning, flags, writer);
},
writeTypePredicate: (predicate, enclosingDeclaration, flags, writer) => {
return typePredicateToString(predicate, getParseTreeNode(enclosingDeclaration), flags, writer);
},
getAugmentedPropertiesOfType,
getRootSymbols,
getContextualType: nodeIn => {
const node = getParseTreeNode(nodeIn, isExpression);
return node ? getContextualType(node) : undefined;
},
getContextualTypeForObjectLiteralElement: nodeIn => {
const node = getParseTreeNode(nodeIn, isObjectLiteralElementLike);
return node ? getContextualTypeForObjectLiteralElement(node) : undefined;
},
getContextualTypeForArgumentAtIndex: (nodeIn, argIndex) => {
const node = getParseTreeNode(nodeIn, isCallLikeExpression);
return node && getContextualTypeForArgumentAtIndex(node, argIndex);
},
getContextualTypeForJsxAttribute: (nodeIn) => {
const node = getParseTreeNode(nodeIn, isJsxAttributeLike);
return node && getContextualTypeForJsxAttribute(node);
},
isContextSensitive,
getFullyQualifiedName,
getResolvedSignature: (node, candidatesOutArray, agumentCount) =>
getResolvedSignatureWorker(node, candidatesOutArray, agumentCount, CheckMode.Normal),
getResolvedSignatureForSignatureHelp: (node, candidatesOutArray, agumentCount) =>
getResolvedSignatureWorker(node, candidatesOutArray, agumentCount, CheckMode.IsForSignatureHelp),
getConstantValue: nodeIn => {
const node = getParseTreeNode(nodeIn, canHaveConstantValue);
return node ? getConstantValue(node) : undefined;
},
isValidPropertyAccess: (nodeIn, propertyName) => {
const node = getParseTreeNode(nodeIn, isPropertyAccessOrQualifiedNameOrImportTypeNode);
return !!node && isValidPropertyAccess(node, escapeLeadingUnderscores(propertyName));
},
isValidPropertyAccessForCompletions: (nodeIn, type, property) => {
const node = getParseTreeNode(nodeIn, isPropertyAccessExpression);
return !!node && isValidPropertyAccessForCompletions(node, type, property);
},
getSignatureFromDeclaration: declarationIn => {
const declaration = getParseTreeNode(declarationIn, isFunctionLike);
return declaration ? getSignatureFromDeclaration(declaration) : undefined;
},
isImplementationOfOverload: node => {
const parsed = getParseTreeNode(node, isFunctionLike);
return parsed ? isImplementationOfOverload(parsed) : undefined;
},
getImmediateAliasedSymbol,
getAliasedSymbol: resolveAlias,
getEmitResolver,
getExportsOfModule: getExportsOfModuleAsArray,
getExportsAndPropertiesOfModule,
getSymbolWalker: createGetSymbolWalker(
getRestTypeOfSignature,
getTypePredicateOfSignature,
getReturnTypeOfSignature,
getBaseTypes,
resolveStructuredTypeMembers,
getTypeOfSymbol,
getResolvedSymbol,
getIndexTypeOfStructuredType,
getConstraintOfTypeParameter,
getFirstIdentifier,
),
getAmbientModules,
getJsxIntrinsicTagNamesAt,
isOptionalParameter: nodeIn => {
const node = getParseTreeNode(nodeIn, isParameter);
return node ? isOptionalParameter(node) : false;
},
tryGetMemberInModuleExports: (name, symbol) => tryGetMemberInModuleExports(escapeLeadingUnderscores(name), symbol),
tryGetMemberInModuleExportsAndProperties: (name, symbol) => tryGetMemberInModuleExportsAndProperties(escapeLeadingUnderscores(name), symbol),
tryFindAmbientModuleWithoutAugmentations: moduleName => {
// we deliberately exclude augmentations
// since we are only interested in declarations of the module itself
return tryFindAmbientModule(moduleName, /*withAugmentations*/ false);
},
getApparentType,
getUnionType,
createAnonymousType,
createSignature,
createSymbol,
createIndexInfo,
getAnyType: () => anyType,
getStringType: () => stringType,
getNumberType: () => numberType,
createPromiseType,
createArrayType,
getElementTypeOfArrayType,
getBooleanType: () => booleanType,
getFalseType: (fresh?) => fresh ? falseType : regularFalseType,
getTrueType: (fresh?) => fresh ? trueType : regularTrueType,
getVoidType: () => voidType,
getUndefinedType: () => undefinedType,
getNullType: () => nullType,
getESSymbolType: () => esSymbolType,
getNeverType: () => neverType,
isSymbolAccessible,
getObjectFlags,
isArrayLikeType,
isTypeInvalidDueToUnionDiscriminant,
getAllPossiblePropertiesOfTypes,
getSuggestionForNonexistentProperty: (node, type) => getSuggestionForNonexistentProperty(node, type),
getSuggestionForNonexistentSymbol: (location, name, meaning) => getSuggestionForNonexistentSymbol(location, escapeLeadingUnderscores(name), meaning),
getSuggestionForNonexistentExport: (node, target) => getSuggestionForNonexistentExport(node, target),
getBaseConstraintOfType,
getDefaultFromTypeParameter: type => type && type.flags & TypeFlags.TypeParameter ? getDefaultFromTypeParameter(type as TypeParameter) : undefined,
resolveName(name, location, meaning, excludeGlobals) {
return resolveName(location, escapeLeadingUnderscores(name), meaning, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ false, excludeGlobals);
},
getJsxNamespace: n => unescapeLeadingUnderscores(getJsxNamespace(n)),
getAccessibleSymbolChain,
getTypePredicateOfSignature: getTypePredicateOfSignature as (signature: Signature) => TypePredicate, // TODO: GH#18217
resolveExternalModuleSymbol,
tryGetThisTypeAt: (node, includeGlobalThis) => {
node = getParseTreeNode(node);
return node && tryGetThisTypeAt(node, includeGlobalThis);
},
getTypeArgumentConstraint: nodeIn => {
const node = getParseTreeNode(nodeIn, isTypeNode);
return node && getTypeArgumentConstraint(node);
},
getSuggestionDiagnostics: (file, ct) => {
if (skipTypeChecking(file, compilerOptions)) {
return emptyArray;
}
let diagnostics: DiagnosticWithLocation[] | undefined;
try {
// Record the cancellation token so it can be checked later on during checkSourceElement.
// Do this in a finally block so we can ensure that it gets reset back to nothing after
// this call is done.
cancellationToken = ct;
// Ensure file is type checked
checkSourceFile(file);
Debug.assert(!!(getNodeLinks(file).flags & NodeCheckFlags.TypeChecked));
diagnostics = addRange(diagnostics, suggestionDiagnostics.get(file.fileName));
if (!file.isDeclarationFile && (!unusedIsError(UnusedKind.Local) || !unusedIsError(UnusedKind.Parameter))) {
addUnusedDiagnostics();
}
return diagnostics || emptyArray;
}
finally {
cancellationToken = undefined;
}
function addUnusedDiagnostics() {
checkUnusedIdentifiers(getPotentiallyUnusedIdentifiers(file), (containingNode, kind, diag) => {
if (!containsParseError(containingNode) && !unusedIsError(kind)) {
(diagnostics || (diagnostics = [])).push({ ...diag, category: DiagnosticCategory.Suggestion });
}
});
}
},
runWithCancellationToken: (token, callback) => {
try {
cancellationToken = token;
return callback(checker);
}
finally {
cancellationToken = undefined;
}
},
getLocalTypeParametersOfClassOrInterfaceOrTypeAlias,
};
function getResolvedSignatureWorker(nodeIn: CallLikeExpression, candidatesOutArray: Signature[] | undefined, argumentCount: number | undefined, checkMode: CheckMode): Signature | undefined {
const node = getParseTreeNode(nodeIn, isCallLikeExpression);
apparentArgumentCount = argumentCount;
const res = node ? getResolvedSignature(node, candidatesOutArray, checkMode) : undefined;
apparentArgumentCount = undefined;
return res;
}
const tupleTypes = createMap<GenericType>();
const unionTypes = createMap<UnionType>();
const intersectionTypes = createMap<IntersectionType>();
const literalTypes = createMap<LiteralType>();
const indexedAccessTypes = createMap<IndexedAccessType>();
const evolvingArrayTypes: EvolvingArrayType[] = [];
const undefinedProperties = createMap<Symbol>() as UnderscoreEscapedMap<Symbol>;
const unknownSymbol = createSymbol(SymbolFlags.Property, "unknown" as __String);
const resolvingSymbol = createSymbol(0, InternalSymbolName.Resolving);
const anyType = createIntrinsicType(TypeFlags.Any, "any");
const autoType = createIntrinsicType(TypeFlags.Any, "any");
const wildcardType = createIntrinsicType(TypeFlags.Any, "any");
const errorType = createIntrinsicType(TypeFlags.Any, "error");
const unknownType = createIntrinsicType(TypeFlags.Unknown, "unknown");
const undefinedType = createNullableType(TypeFlags.Undefined, "undefined", 0);
const undefinedWideningType = strictNullChecks ? undefinedType : createNullableType(TypeFlags.Undefined, "undefined", ObjectFlags.ContainsWideningType);
const nullType = createNullableType(TypeFlags.Null, "null", 0);
const nullWideningType = strictNullChecks ? nullType : createNullableType(TypeFlags.Null, "null", ObjectFlags.ContainsWideningType);
const stringType = createIntrinsicType(TypeFlags.String, "string");
const numberType = createIntrinsicType(TypeFlags.Number, "number");
const bigintType = createIntrinsicType(TypeFlags.BigInt, "bigint");
const falseType = createIntrinsicType(TypeFlags.BooleanLiteral, "false") as FreshableIntrinsicType;
const regularFalseType = createIntrinsicType(TypeFlags.BooleanLiteral, "false") as FreshableIntrinsicType;
const trueType = createIntrinsicType(TypeFlags.BooleanLiteral, "true") as FreshableIntrinsicType;
const regularTrueType = createIntrinsicType(TypeFlags.BooleanLiteral, "true") as FreshableIntrinsicType;
trueType.regularType = regularTrueType;
trueType.freshType = trueType;
regularTrueType.regularType = regularTrueType;
regularTrueType.freshType = trueType;
falseType.regularType = regularFalseType;
falseType.freshType = falseType;
regularFalseType.regularType = regularFalseType;
regularFalseType.freshType = falseType;
const booleanType = createBooleanType([regularFalseType, regularTrueType]);
// Also mark all combinations of fresh/regular booleans as "Boolean" so they print as `boolean` instead of `true | false`
// (The union is cached, so simply doing the marking here is sufficient)
createBooleanType([regularFalseType, trueType]);
createBooleanType([falseType, regularTrueType]);
createBooleanType([falseType, trueType]);
const esSymbolType = createIntrinsicType(TypeFlags.ESSymbol, "symbol");
const voidType = createIntrinsicType(TypeFlags.Void, "void");
const neverType = createIntrinsicType(TypeFlags.Never, "never");
const silentNeverType = createIntrinsicType(TypeFlags.Never, "never");
const implicitNeverType = createIntrinsicType(TypeFlags.Never, "never");
const nonPrimitiveType = createIntrinsicType(TypeFlags.NonPrimitive, "object");
const stringNumberSymbolType = getUnionType([stringType, numberType, esSymbolType]);
const keyofConstraintType = keyofStringsOnly ? stringType : stringNumberSymbolType;
const numberOrBigIntType = getUnionType([numberType, bigintType]);
const emptyObjectType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
const emptyJsxObjectType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
emptyJsxObjectType.objectFlags |= ObjectFlags.JsxAttributes;
const emptyTypeLiteralSymbol = createSymbol(SymbolFlags.TypeLiteral, InternalSymbolName.Type);
emptyTypeLiteralSymbol.members = createSymbolTable();
const emptyTypeLiteralType = createAnonymousType(emptyTypeLiteralSymbol, emptySymbols, emptyArray, emptyArray, undefined, undefined);
const emptyGenericType = <GenericType><ObjectType>createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
emptyGenericType.instantiations = createMap<TypeReference>();
const anyFunctionType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
// The anyFunctionType contains the anyFunctionType by definition. The flag is further propagated
// in getPropagatingFlagsOfTypes, and it is checked in inferFromTypes.
anyFunctionType.objectFlags |= ObjectFlags.ContainsAnyFunctionType;
const noConstraintType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
const circularConstraintType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
const resolvingDefaultType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
const markerSuperType = createTypeParameter();
const markerSubType = createTypeParameter();
markerSubType.constraint = markerSuperType;
const markerOtherType = createTypeParameter();
const noTypePredicate = createIdentifierTypePredicate("<<unresolved>>", 0, anyType);
const anySignature = createSignature(undefined, undefined, undefined, emptyArray, anyType, /*resolvedTypePredicate*/ undefined, 0, /*hasRestParameter*/ false, /*hasLiteralTypes*/ false);
const unknownSignature = createSignature(undefined, undefined, undefined, emptyArray, errorType, /*resolvedTypePredicate*/ undefined, 0, /*hasRestParameter*/ false, /*hasLiteralTypes*/ false);
const resolvingSignature = createSignature(undefined, undefined, undefined, emptyArray, anyType, /*resolvedTypePredicate*/ undefined, 0, /*hasRestParameter*/ false, /*hasLiteralTypes*/ false);
const silentNeverSignature = createSignature(undefined, undefined, undefined, emptyArray, silentNeverType, /*resolvedTypePredicate*/ undefined, 0, /*hasRestParameter*/ false, /*hasLiteralTypes*/ false);
const enumNumberIndexInfo = createIndexInfo(stringType, /*isReadonly*/ true);
interface DuplicateInfoForSymbol {
readonly firstFileLocations: Node[];
readonly secondFileLocations: Node[];
readonly isBlockScoped: boolean;
}
interface DuplicateInfoForFiles {
readonly firstFile: SourceFile;
readonly secondFile: SourceFile;
/** Key is symbol name. */
readonly conflictingSymbols: Map<DuplicateInfoForSymbol>;
}
/** Key is "/path/to/a.ts|/path/to/b.ts". */
let amalgamatedDuplicates: Map<DuplicateInfoForFiles> | undefined;
const reverseMappedCache = createMap<Type | undefined>();
let ambientModulesCache: Symbol[] | undefined;
/**
* List of every ambient module with a "*" wildcard.
* Unlike other ambient modules, these can't be stored in `globals` because symbol tables only deal with exact matches.
* This is only used if there is no exact match.
*/
let patternAmbientModules: PatternAmbientModule[];
let globalObjectType: ObjectType;
let globalFunctionType: ObjectType;
let globalCallableFunctionType: ObjectType;
let globalNewableFunctionType: ObjectType;
let globalArrayType: GenericType;
let globalReadonlyArrayType: GenericType;
let globalStringType: ObjectType;
let globalNumberType: ObjectType;
let globalBooleanType: ObjectType;
let globalRegExpType: ObjectType;
let globalThisType: GenericType;
let anyArrayType: Type;
let autoArrayType: Type;
let anyReadonlyArrayType: Type;
let deferredGlobalNonNullableTypeAlias: Symbol;
// The library files are only loaded when the feature is used.
// This allows users to just specify library files they want to used through --lib
// and they will not get an error from not having unrelated library files
let deferredGlobalESSymbolConstructorSymbol: Symbol | undefined;
let deferredGlobalESSymbolType: ObjectType;
let deferredGlobalTypedPropertyDescriptorType: GenericType;
let deferredGlobalPromiseType: GenericType;
let deferredGlobalPromiseLikeType: GenericType;
let deferredGlobalPromiseConstructorSymbol: Symbol | undefined;
let deferredGlobalPromiseConstructorLikeType: ObjectType;
let deferredGlobalIterableType: GenericType;
let deferredGlobalIteratorType: GenericType;
let deferredGlobalIterableIteratorType: GenericType;
let deferredGlobalAsyncIterableType: GenericType;
let deferredGlobalAsyncIteratorType: GenericType;
let deferredGlobalAsyncIterableIteratorType: GenericType;
let deferredGlobalTemplateStringsArrayType: ObjectType;
let deferredGlobalImportMetaType: ObjectType;
let deferredGlobalExtractSymbol: Symbol;
let deferredGlobalExcludeSymbol: Symbol;
let deferredGlobalPickSymbol: Symbol;
let deferredGlobalBigIntType: ObjectType;
const allPotentiallyUnusedIdentifiers = createMap<PotentiallyUnusedIdentifier[]>(); // key is file name
let flowLoopStart = 0;
let flowLoopCount = 0;
let sharedFlowCount = 0;
let flowAnalysisDisabled = false;
const emptyStringType = getLiteralType("");
const zeroType = getLiteralType(0);
const zeroBigIntType = getLiteralType({ negative: false, base10Value: "0" });
const resolutionTargets: TypeSystemEntity[] = [];
const resolutionResults: boolean[] = [];
const resolutionPropertyNames: TypeSystemPropertyName[] = [];
let suggestionCount = 0;
const maximumSuggestionCount = 10;
const mergedSymbols: Symbol[] = [];
const symbolLinks: SymbolLinks[] = [];
const nodeLinks: NodeLinks[] = [];
const flowLoopCaches: Map<Type>[] = [];
const flowLoopNodes: FlowNode[] = [];
const flowLoopKeys: string[] = [];
const flowLoopTypes: Type[][] = [];
const sharedFlowNodes: FlowNode[] = [];
const sharedFlowTypes: FlowType[] = [];
const potentialThisCollisions: Node[] = [];
const potentialNewTargetCollisions: Node[] = [];
const awaitedTypeStack: number[] = [];
const diagnostics = createDiagnosticCollection();
// Suggestion diagnostics must have a file. Keyed by source file name.
const suggestionDiagnostics = createMultiMap<DiagnosticWithLocation>();
const enum TypeFacts {
None = 0,
TypeofEQString = 1 << 0, // typeof x === "string"
TypeofEQNumber = 1 << 1, // typeof x === "number"
TypeofEQBigInt = 1 << 2, // typeof x === "bigint"
TypeofEQBoolean = 1 << 3, // typeof x === "boolean"
TypeofEQSymbol = 1 << 4, // typeof x === "symbol"
TypeofEQObject = 1 << 5, // typeof x === "object"
TypeofEQFunction = 1 << 6, // typeof x === "function"
TypeofEQHostObject = 1 << 7, // typeof x === "xxx"
TypeofNEString = 1 << 8, // typeof x !== "string"
TypeofNENumber = 1 << 9, // typeof x !== "number"
TypeofNEBigInt = 1 << 10, // typeof x !== "bigint"
TypeofNEBoolean = 1 << 11, // typeof x !== "boolean"
TypeofNESymbol = 1 << 12, // typeof x !== "symbol"
TypeofNEObject = 1 << 13, // typeof x !== "object"
TypeofNEFunction = 1 << 14, // typeof x !== "function"
TypeofNEHostObject = 1 << 15, // typeof x !== "xxx"
EQUndefined = 1 << 16, // x === undefined
EQNull = 1 << 17, // x === null
EQUndefinedOrNull = 1 << 18, // x === undefined / x === null
NEUndefined = 1 << 19, // x !== undefined
NENull = 1 << 20, // x !== null
NEUndefinedOrNull = 1 << 21, // x != undefined / x != null
Truthy = 1 << 22, // x
Falsy = 1 << 23, // !x
All = (1 << 24) - 1,
// The following members encode facts about particular kinds of types for use in the getTypeFacts function.
// The presence of a particular fact means that the given test is true for some (and possibly all) values
// of that kind of type.
BaseStringStrictFacts = TypeofEQString | TypeofNENumber | TypeofNEBigInt | TypeofNEBoolean | TypeofNESymbol | TypeofNEObject | TypeofNEFunction | TypeofNEHostObject | NEUndefined | NENull | NEUndefinedOrNull,
BaseStringFacts = BaseStringStrictFacts | EQUndefined | EQNull | EQUndefinedOrNull | Falsy,
StringStrictFacts = BaseStringStrictFacts | Truthy | Falsy,
StringFacts = BaseStringFacts | Truthy,
EmptyStringStrictFacts = BaseStringStrictFacts | Falsy,
EmptyStringFacts = BaseStringFacts,
NonEmptyStringStrictFacts = BaseStringStrictFacts | Truthy,
NonEmptyStringFacts = BaseStringFacts | Truthy,
BaseNumberStrictFacts = TypeofEQNumber | TypeofNEString | TypeofNEBigInt | TypeofNEBoolean | TypeofNESymbol | TypeofNEObject | TypeofNEFunction | TypeofNEHostObject | NEUndefined | NENull | NEUndefinedOrNull,
BaseNumberFacts = BaseNumberStrictFacts | EQUndefined | EQNull | EQUndefinedOrNull | Falsy,
NumberStrictFacts = BaseNumberStrictFacts | Truthy | Falsy,
NumberFacts = BaseNumberFacts | Truthy,
ZeroNumberStrictFacts = BaseNumberStrictFacts | Falsy,
ZeroNumberFacts = BaseNumberFacts,
NonZeroNumberStrictFacts = BaseNumberStrictFacts | Truthy,
NonZeroNumberFacts = BaseNumberFacts | Truthy,
BaseBigIntStrictFacts = TypeofEQBigInt | TypeofNEString | TypeofNENumber | TypeofNEBoolean | TypeofNESymbol | TypeofNEObject | TypeofNEFunction | TypeofNEHostObject | NEUndefined | NENull | NEUndefinedOrNull,
BaseBigIntFacts = BaseBigIntStrictFacts | EQUndefined | EQNull | EQUndefinedOrNull | Falsy,
BigIntStrictFacts = BaseBigIntStrictFacts | Truthy | Falsy,
BigIntFacts = BaseBigIntFacts | Truthy,
ZeroBigIntStrictFacts = BaseBigIntStrictFacts | Falsy,
ZeroBigIntFacts = BaseBigIntFacts,
NonZeroBigIntStrictFacts = BaseBigIntStrictFacts | Truthy,
NonZeroBigIntFacts = BaseBigIntFacts | Truthy,
BaseBooleanStrictFacts = TypeofEQBoolean | TypeofNEString | TypeofNENumber | TypeofNEBigInt | TypeofNESymbol | TypeofNEObject | TypeofNEFunction | TypeofNEHostObject | NEUndefined | NENull | NEUndefinedOrNull,
BaseBooleanFacts = BaseBooleanStrictFacts | EQUndefined | EQNull | EQUndefinedOrNull | Falsy,
BooleanStrictFacts = BaseBooleanStrictFacts | Truthy | Falsy,
BooleanFacts = BaseBooleanFacts | Truthy,
FalseStrictFacts = BaseBooleanStrictFacts | Falsy,
FalseFacts = BaseBooleanFacts,
TrueStrictFacts = BaseBooleanStrictFacts | Truthy,
TrueFacts = BaseBooleanFacts | Truthy,
SymbolStrictFacts = TypeofEQSymbol | TypeofNEString | TypeofNENumber | TypeofNEBigInt | TypeofNEBoolean | TypeofNEObject | TypeofNEFunction | TypeofNEHostObject | NEUndefined | NENull | NEUndefinedOrNull | Truthy,
SymbolFacts = SymbolStrictFacts | EQUndefined | EQNull | EQUndefinedOrNull | Falsy,
ObjectStrictFacts = TypeofEQObject | TypeofEQHostObject | TypeofNEString | TypeofNENumber | TypeofNEBigInt | TypeofNEBoolean | TypeofNESymbol | TypeofNEFunction | NEUndefined | NENull | NEUndefinedOrNull | Truthy,
ObjectFacts = ObjectStrictFacts | EQUndefined | EQNull | EQUndefinedOrNull | Falsy,
FunctionStrictFacts = TypeofEQFunction | TypeofEQHostObject | TypeofNEString | TypeofNENumber | TypeofNEBigInt | TypeofNEBoolean | TypeofNESymbol | TypeofNEObject | NEUndefined | NENull | NEUndefinedOrNull | Truthy,
FunctionFacts = FunctionStrictFacts | EQUndefined | EQNull | EQUndefinedOrNull | Falsy,
UndefinedFacts = TypeofNEString | TypeofNENumber | TypeofNEBigInt | TypeofNEBoolean | TypeofNESymbol | TypeofNEObject | TypeofNEFunction | TypeofNEHostObject | EQUndefined | EQUndefinedOrNull | NENull | Falsy,
NullFacts = TypeofEQObject | TypeofNEString | TypeofNENumber | TypeofNEBigInt | TypeofNEBoolean | TypeofNESymbol | TypeofNEFunction | TypeofNEHostObject | EQNull | EQUndefinedOrNull | NEUndefined | Falsy,
EmptyObjectStrictFacts = All & ~(EQUndefined | EQNull | EQUndefinedOrNull),
EmptyObjectFacts = All,
}
const typeofEQFacts = createMapFromTemplate({
string: TypeFacts.TypeofEQString,
number: TypeFacts.TypeofEQNumber,
bigint: TypeFacts.TypeofEQBigInt,
boolean: TypeFacts.TypeofEQBoolean,
symbol: TypeFacts.TypeofEQSymbol,
undefined: TypeFacts.EQUndefined,
object: TypeFacts.TypeofEQObject,
function: TypeFacts.TypeofEQFunction
});
const typeofNEFacts = createMapFromTemplate({
string: TypeFacts.TypeofNEString,
number: TypeFacts.TypeofNENumber,
bigint: TypeFacts.TypeofNEBigInt,
boolean: TypeFacts.TypeofNEBoolean,
symbol: TypeFacts.TypeofNESymbol,
undefined: TypeFacts.NEUndefined,
object: TypeFacts.TypeofNEObject,
function: TypeFacts.TypeofNEFunction
});
const typeofTypesByName = createMapFromTemplate<Type>({
string: stringType,
number: numberType,
bigint: bigintType,
boolean: booleanType,
symbol: esSymbolType,
undefined: undefinedType
});
const typeofType = createTypeofType();
let _jsxNamespace: __String;
let _jsxFactoryEntity: EntityName | undefined;
const subtypeRelation = createMap<RelationComparisonResult>();
const assignableRelation = createMap<RelationComparisonResult>();
const comparableRelation = createMap<RelationComparisonResult>();
const identityRelation = createMap<RelationComparisonResult>();
const enumRelation = createMap<RelationComparisonResult>();
type TypeSystemEntity = Node | Symbol | Type | Signature;
const enum TypeSystemPropertyName {
Type,
ResolvedBaseConstructorType,
DeclaredType,
ResolvedReturnType,
ImmediateBaseConstraint,
EnumTagType,
JSDocTypeReference,
}
const enum CheckMode {
Normal = 0, // Normal type checking
Contextual = 1 << 0, // Explicitly assigned contextual type, therefore not cacheable
Inferential = 1 << 1, // Inferential typing
SkipContextSensitive = 1 << 2, // Skip context sensitive function expressions
SkipGenericFunctions = 1 << 3, // Skip single signature generic functions
IsForSignatureHelp = 1 << 4, // Call resolution for purposes of signature help
}
const enum CallbackCheck {
None,
Bivariant,
Strict,
}
const enum MappedTypeModifiers {
IncludeReadonly = 1 << 0,
ExcludeReadonly = 1 << 1,
IncludeOptional = 1 << 2,
ExcludeOptional = 1 << 3,
}
const enum ExpandingFlags {
None = 0,
Source = 1,
Target = 1 << 1,
Both = Source | Target,
}
const enum MembersOrExportsResolutionKind {
resolvedExports = "resolvedExports",
resolvedMembers = "resolvedMembers"
}
const enum UnusedKind {
Local,
Parameter,
}
/** @param containingNode Node to check for parse error */
type AddUnusedDiagnostic = (containingNode: Node, type: UnusedKind, diagnostic: DiagnosticWithLocation) => void;
const builtinGlobals = createSymbolTable();
builtinGlobals.set(undefinedSymbol.escapedName, undefinedSymbol);
const isNotOverloadAndNotAccessor = and(isNotOverload, isNotAccessor);
initializeTypeChecker();
return checker;
function getJsxNamespace(location: Node | undefined): __String {
if (location) {
const file = getSourceFileOfNode(location);
if (file) {
if (file.localJsxNamespace) {
return file.localJsxNamespace;
}
const jsxPragma = file.pragmas.get("jsx");
if (jsxPragma) {
const chosenpragma: any = isArray(jsxPragma) ? jsxPragma[0] : jsxPragma; // TODO: GH#18217
file.localJsxFactory = parseIsolatedEntityName(chosenpragma.arguments.factory, languageVersion);
if (file.localJsxFactory) {
return file.localJsxNamespace = getFirstIdentifier(file.localJsxFactory).escapedText;
}
}
}
}
if (!_jsxNamespace) {
_jsxNamespace = "React" as __String;
if (compilerOptions.jsxFactory) {
_jsxFactoryEntity = parseIsolatedEntityName(compilerOptions.jsxFactory, languageVersion);
if (_jsxFactoryEntity) {
_jsxNamespace = getFirstIdentifier(_jsxFactoryEntity).escapedText;
}
}
else if (compilerOptions.reactNamespace) {
_jsxNamespace = escapeLeadingUnderscores(compilerOptions.reactNamespace);
}
}
return _jsxNamespace;
}
function getEmitResolver(sourceFile: SourceFile, cancellationToken: CancellationToken) {
// Ensure we have all the type information in place for this file so that all the
// emitter questions of this resolver will return the right information.
getDiagnostics(sourceFile, cancellationToken);
return emitResolver;
}
function lookupOrIssueError(location: Node | undefined, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number, arg3?: string | number): Diagnostic {
const diagnostic = location
? createDiagnosticForNode(location, message, arg0, arg1, arg2, arg3)
: createCompilerDiagnostic(message, arg0, arg1, arg2, arg3);
const existing = diagnostics.lookup(diagnostic);
if (existing) {
return existing;
}
else {
diagnostics.add(diagnostic);
return diagnostic;
}
}
function addRelatedInfo(diagnostic: Diagnostic, ...relatedInformation: [DiagnosticRelatedInformation, ...DiagnosticRelatedInformation[]]) {
if (!diagnostic.relatedInformation) {
diagnostic.relatedInformation = [];
}
diagnostic.relatedInformation.push(...relatedInformation);
return diagnostic;
}
function error(location: Node | undefined, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number, arg3?: string | number): Diagnostic {
const diagnostic = location
? createDiagnosticForNode(location, message, arg0, arg1, arg2, arg3)
: createCompilerDiagnostic(message, arg0, arg1, arg2, arg3);
diagnostics.add(diagnostic);
return diagnostic;
}
function addErrorOrSuggestion(isError: boolean, diagnostic: DiagnosticWithLocation) {
if (isError) {
diagnostics.add(diagnostic);
}
else {
suggestionDiagnostics.add(diagnostic.file.fileName, { ...diagnostic, category: DiagnosticCategory.Suggestion });
}
}
function errorOrSuggestion(isError: boolean, location: Node, message: DiagnosticMessage | DiagnosticMessageChain, arg0?: string | number, arg1?: string | number, arg2?: string | number, arg3?: string | number): void {
addErrorOrSuggestion(isError, "message" in message ? createDiagnosticForNode(location, message, arg0, arg1, arg2, arg3) : createDiagnosticForNodeFromMessageChain(location, message));
}
function createSymbol(flags: SymbolFlags, name: __String, checkFlags?: CheckFlags) {
symbolCount++;
const symbol = <TransientSymbol>(new Symbol(flags | SymbolFlags.Transient, name));
symbol.checkFlags = checkFlags || 0;
return symbol;
}
function isTransientSymbol(symbol: Symbol): symbol is TransientSymbol {
return (symbol.flags & SymbolFlags.Transient) !== 0;
}
function getExcludedSymbolFlags(flags: SymbolFlags): SymbolFlags {
let result: SymbolFlags = 0;
if (flags & SymbolFlags.BlockScopedVariable) result |= SymbolFlags.BlockScopedVariableExcludes;
if (flags & SymbolFlags.FunctionScopedVariable) result |= SymbolFlags.FunctionScopedVariableExcludes;
if (flags & SymbolFlags.Property) result |= SymbolFlags.PropertyExcludes;
if (flags & SymbolFlags.EnumMember) result |= SymbolFlags.EnumMemberExcludes;
if (flags & SymbolFlags.Function) result |= SymbolFlags.FunctionExcludes;
if (flags & SymbolFlags.Class) result |= SymbolFlags.ClassExcludes;
if (flags & SymbolFlags.Interface) result |= SymbolFlags.InterfaceExcludes;
if (flags & SymbolFlags.RegularEnum) result |= SymbolFlags.RegularEnumExcludes;
if (flags & SymbolFlags.ConstEnum) result |= SymbolFlags.ConstEnumExcludes;
if (flags & SymbolFlags.ValueModule) result |= SymbolFlags.ValueModuleExcludes;
if (flags & SymbolFlags.Method) result |= SymbolFlags.MethodExcludes;
if (flags & SymbolFlags.GetAccessor) result |= SymbolFlags.GetAccessorExcludes;
if (flags & SymbolFlags.SetAccessor) result |= SymbolFlags.SetAccessorExcludes;
if (flags & SymbolFlags.TypeParameter) result |= SymbolFlags.TypeParameterExcludes;
if (flags & SymbolFlags.TypeAlias) result |= SymbolFlags.TypeAliasExcludes;
if (flags & SymbolFlags.Alias) result |= SymbolFlags.AliasExcludes;
return result;
}
function recordMergedSymbol(target: Symbol, source: Symbol) {
if (!source.mergeId) {
source.mergeId = nextMergeId;
nextMergeId++;
}
mergedSymbols[source.mergeId] = target;
}
function cloneSymbol(symbol: Symbol): Symbol {
const result = createSymbol(symbol.flags, symbol.escapedName);
result.declarations = symbol.declarations ? symbol.declarations.slice() : [];
result.parent = symbol.parent;
if (symbol.valueDeclaration) result.valueDeclaration = symbol.valueDeclaration;
if (symbol.constEnumOnlyModule) result.constEnumOnlyModule = true;
if (symbol.members) result.members = cloneMap(symbol.members);
if (symbol.exports) result.exports = cloneMap(symbol.exports);
recordMergedSymbol(result, symbol);
return result;
}
/**
* Note: if target is transient, then it is mutable, and mergeSymbol with both mutate and return it.
* If target is not transient, mergeSymbol will produce a transient clone, mutate that and return it.
*/
function mergeSymbol(target: Symbol, source: Symbol): Symbol {
if (!(target.flags & getExcludedSymbolFlags(source.flags)) ||
(source.flags | target.flags) & SymbolFlags.Assignment) {
Debug.assert(source !== target);
if (!(target.flags & SymbolFlags.Transient)) {
const resolvedTarget = resolveSymbol(target);
if (resolvedTarget === unknownSymbol) {
return source;
}
target = cloneSymbol(resolvedTarget);
}
// Javascript static-property-assignment declarations always merge, even though they are also values
if (source.flags & SymbolFlags.ValueModule && target.flags & SymbolFlags.ValueModule && target.constEnumOnlyModule && !source.constEnumOnlyModule) {
// reset flag when merging instantiated module into value module that has only const enums
target.constEnumOnlyModule = false;
}
target.flags |= source.flags;
if (source.valueDeclaration &&
(!target.valueDeclaration ||
isAssignmentDeclaration(target.valueDeclaration) && !isAssignmentDeclaration(source.valueDeclaration) ||
isEffectiveModuleDeclaration(target.valueDeclaration) && !isEffectiveModuleDeclaration(source.valueDeclaration))) {
// other kinds of value declarations take precedence over modules and assignment declarations
target.valueDeclaration = source.valueDeclaration;
}
addRange(target.declarations, source.declarations);
if (source.members) {
if (!target.members) target.members = createSymbolTable();
mergeSymbolTable(target.members, source.members);
}
if (source.exports) {
if (!target.exports) target.exports = createSymbolTable();
mergeSymbolTable(target.exports, source.exports);
}
recordMergedSymbol(target, source);
}
else if (target.flags & SymbolFlags.NamespaceModule) {
error(getNameOfDeclaration(source.declarations[0]), Diagnostics.Cannot_augment_module_0_with_value_exports_because_it_resolves_to_a_non_module_entity, symbolToString(target));
}
else { // error
const isEitherEnum = !!(target.flags & SymbolFlags.Enum || source.flags & SymbolFlags.Enum);
const isEitherBlockScoped = !!(target.flags & SymbolFlags.BlockScopedVariable || source.flags & SymbolFlags.BlockScopedVariable);
const message = isEitherEnum
? Diagnostics.Enum_declarations_can_only_merge_with_namespace_or_other_enum_declarations
: isEitherBlockScoped
? Diagnostics.Cannot_redeclare_block_scoped_variable_0
: Diagnostics.Duplicate_identifier_0;
const sourceSymbolFile = source.declarations && getSourceFileOfNode(source.declarations[0]);
const targetSymbolFile = target.declarations && getSourceFileOfNode(target.declarations[0]);
const symbolName = symbolToString(source);
// Collect top-level duplicate identifier errors into one mapping, so we can then merge their diagnostics if there are a bunch
if (sourceSymbolFile && targetSymbolFile && amalgamatedDuplicates && !isEitherEnum && sourceSymbolFile !== targetSymbolFile) {
const firstFile = comparePaths(sourceSymbolFile.path, targetSymbolFile.path) === Comparison.LessThan ? sourceSymbolFile : targetSymbolFile;
const secondFile = firstFile === sourceSymbolFile ? targetSymbolFile : sourceSymbolFile;
const filesDuplicates = getOrUpdate<DuplicateInfoForFiles>(amalgamatedDuplicates, `${firstFile.path}|${secondFile.path}`, () =>
({ firstFile, secondFile, conflictingSymbols: createMap() }));
const conflictingSymbolInfo = getOrUpdate<DuplicateInfoForSymbol>(filesDuplicates.conflictingSymbols, symbolName, () =>
({ isBlockScoped: isEitherBlockScoped, firstFileLocations: [], secondFileLocations: [] }));
addDuplicateLocations(conflictingSymbolInfo.firstFileLocations, source);
addDuplicateLocations(conflictingSymbolInfo.secondFileLocations, target);
}
else {
addDuplicateDeclarationErrorsForSymbols(source, message, symbolName, target);
addDuplicateDeclarationErrorsForSymbols(target, message, symbolName, source);
}
}
return target;
function addDuplicateLocations(locs: Node[], symbol: Symbol): void {
for (const decl of symbol.declarations) {
pushIfUnique(locs, (getExpandoInitializer(decl, /*isPrototypeAssignment*/ false) ? getNameOfExpando(decl) : getNameOfDeclaration(decl)) || decl);
}
}
}
function addDuplicateDeclarationErrorsForSymbols(target: Symbol, message: DiagnosticMessage, symbolName: string, source: Symbol) {
forEach(target.declarations, node => {
const errorNode = (getExpandoInitializer(node, /*isPrototypeAssignment*/ false) ? getNameOfExpando(node) : getNameOfDeclaration(node)) || node;
addDuplicateDeclarationError(errorNode, message, symbolName, source.declarations);
});
}
function addDuplicateDeclarationError(errorNode: Node, message: DiagnosticMessage, symbolName: string, relatedNodes: ReadonlyArray<Node> | undefined) {
const err = lookupOrIssueError(errorNode, message, symbolName);
for (const relatedNode of relatedNodes || emptyArray) {
err.relatedInformation = err.relatedInformation || [];
if (length(err.relatedInformation) >= 5) continue;
addRelatedInfo(err, !length(err.relatedInformation) ? createDiagnosticForNode(relatedNode, Diagnostics._0_was_also_declared_here, symbolName) : createDiagnosticForNode(relatedNode, Diagnostics.and_here));
}
}
function combineSymbolTables(first: SymbolTable | undefined, second: SymbolTable | undefined): SymbolTable | undefined {
if (!hasEntries(first)) return second;
if (!hasEntries(second)) return first;
const combined = createSymbolTable();
mergeSymbolTable(combined, first);
mergeSymbolTable(combined, second);
return combined;
}
function mergeSymbolTable(target: SymbolTable, source: SymbolTable) {
source.forEach((sourceSymbol, id) => {
const targetSymbol = target.get(id);
target.set(id, targetSymbol ? mergeSymbol(targetSymbol, sourceSymbol) : sourceSymbol);
});
}
function mergeModuleAugmentation(moduleName: StringLiteral | Identifier): void {
const moduleAugmentation = <ModuleDeclaration>moduleName.parent;
if (moduleAugmentation.symbol.declarations[0] !== moduleAugmentation) {
// this is a combined symbol for multiple augmentations within the same file.
// its symbol already has accumulated information for all declarations
// so we need to add it just once - do the work only for first declaration
Debug.assert(moduleAugmentation.symbol.declarations.length > 1);
return;
}
if (isGlobalScopeAugmentation(moduleAugmentation)) {
mergeSymbolTable(globals, moduleAugmentation.symbol.exports!);
}
else {
// find a module that about to be augmented
// do not validate names of augmentations that are defined in ambient context
const moduleNotFoundError = !(moduleName.parent.parent.flags & NodeFlags.Ambient)
? Diagnostics.Invalid_module_name_in_augmentation_module_0_cannot_be_found
: undefined;
let mainModule = resolveExternalModuleNameWorker(moduleName, moduleName, moduleNotFoundError, /*isForAugmentation*/ true);
if (!mainModule) {
return;
}
// obtain item referenced by 'export='
mainModule = resolveExternalModuleSymbol(mainModule);
if (mainModule.flags & SymbolFlags.Namespace) {
mainModule = mergeSymbol(mainModule, moduleAugmentation.symbol);
}
else {
// moduleName will be a StringLiteral since this is not `declare global`.
error(moduleName, Diagnostics.Cannot_augment_module_0_because_it_resolves_to_a_non_module_entity, (moduleName as StringLiteral).text);
}
}
}
function addToSymbolTable(target: SymbolTable, source: SymbolTable, message: DiagnosticMessage) {
source.forEach((sourceSymbol, id) => {
const targetSymbol = target.get(id);
if (targetSymbol) {
// Error on redeclarations
forEach(targetSymbol.declarations, addDeclarationDiagnostic(unescapeLeadingUnderscores(id), message));
}
else {
target.set(id, sourceSymbol);
}
});
function addDeclarationDiagnostic(id: string, message: DiagnosticMessage) {
return (declaration: Declaration) => diagnostics.add(createDiagnosticForNode(declaration, message, id));
}
}
function getSymbolLinks(symbol: Symbol): SymbolLinks {
if (symbol.flags & SymbolFlags.Transient) return <TransientSymbol>symbol;
const id = getSymbolId(symbol);
return symbolLinks[id] || (symbolLinks[id] = {});
}
function getNodeLinks(node: Node): NodeLinks {
const nodeId = getNodeId(node);
return nodeLinks[nodeId] || (nodeLinks[nodeId] = { flags: 0 } as NodeLinks);
}
function isGlobalSourceFile(node: Node) {
return node.kind === SyntaxKind.SourceFile && !isExternalOrCommonJsModule(<SourceFile>node);
}
function getSymbol(symbols: SymbolTable, name: __String, meaning: SymbolFlags): Symbol | undefined {
if (meaning) {
const symbol = symbols.get(name);
if (symbol) {
Debug.assert((getCheckFlags(symbol) & CheckFlags.Instantiated) === 0, "Should never get an instantiated symbol here.");
if (symbol.flags & meaning) {
return symbol;
}
if (symbol.flags & SymbolFlags.Alias) {
const target = resolveAlias(symbol);
// Unknown symbol means an error occurred in alias resolution, treat it as positive answer to avoid cascading errors
if (target === unknownSymbol || target.flags & meaning) {
return symbol;
}
}
}
}
// return undefined if we can't find a symbol.
}
/**
* Get symbols that represent parameter-property-declaration as parameter and as property declaration
* @param parameter a parameterDeclaration node
* @param parameterName a name of the parameter to get the symbols for.
* @return a tuple of two symbols
*/
function getSymbolsOfParameterPropertyDeclaration(parameter: ParameterDeclaration, parameterName: __String): [Symbol, Symbol] {
const constructorDeclaration = parameter.parent;
const classDeclaration = parameter.parent.parent;
const parameterSymbol = getSymbol(constructorDeclaration.locals!, parameterName, SymbolFlags.Value);
const propertySymbol = getSymbol(getMembersOfSymbol(classDeclaration.symbol), parameterName, SymbolFlags.Value);
if (parameterSymbol && propertySymbol) {
return [parameterSymbol, propertySymbol];
}
return Debug.fail("There should exist two symbols, one as property declaration and one as parameter declaration");
}
function isBlockScopedNameDeclaredBeforeUse(declaration: Declaration, usage: Node): boolean {
const declarationFile = getSourceFileOfNode(declaration);
const useFile = getSourceFileOfNode(usage);
if (declarationFile !== useFile) {
if ((moduleKind && (declarationFile.externalModuleIndicator || useFile.externalModuleIndicator)) ||
(!compilerOptions.outFile && !compilerOptions.out) ||
isInTypeQuery(usage) ||
declaration.flags & NodeFlags.Ambient) {
// nodes are in different files and order cannot be determined
return true;
}
// declaration is after usage
// can be legal if usage is deferred (i.e. inside function or in initializer of instance property)
if (isUsedInFunctionOrInstanceProperty(usage, declaration)) {
return true;
}
const sourceFiles = host.getSourceFiles();
return sourceFiles.indexOf(declarationFile) <= sourceFiles.indexOf(useFile);
}
if (declaration.pos <= usage.pos) {
// declaration is before usage
if (declaration.kind === SyntaxKind.BindingElement) {
// still might be illegal if declaration and usage are both binding elements (eg var [a = b, b = b] = [1, 2])
const errorBindingElement = getAncestor(usage, SyntaxKind.BindingElement) as BindingElement;
if (errorBindingElement) {
return findAncestor(errorBindingElement, isBindingElement) !== findAncestor(declaration, isBindingElement) ||
declaration.pos < errorBindingElement.pos;
}
// or it might be illegal if usage happens before parent variable is declared (eg var [a] = a)
return isBlockScopedNameDeclaredBeforeUse(getAncestor(declaration, SyntaxKind.VariableDeclaration) as Declaration, usage);
}
else if (declaration.kind === SyntaxKind.VariableDeclaration) {
// still might be illegal if usage is in the initializer of the variable declaration (eg var a = a)
return !isImmediatelyUsedInInitializerOfBlockScopedVariable(declaration as VariableDeclaration, usage);
}
else if (isClassDeclaration(declaration)) {
// still might be illegal if the usage is within a computed property name in the class (eg class A { static p = "a"; [A.p]() {} })
return !findAncestor(usage, n => isComputedPropertyName(n) && n.parent.parent === declaration);
}
return true;
}
// declaration is after usage, but it can still be legal if usage is deferred:
// 1. inside an export specifier
// 2. inside a function
// 3. inside an instance property initializer, a reference to a non-instance property
// 4. inside a static property initializer, a reference to a static method in the same class
// 5. inside a TS export= declaration (since we will move the export statement during emit to avoid TDZ)
// or if usage is in a type context:
// 1. inside a type query (typeof in type position)
// 2. inside a jsdoc comment
if (usage.parent.kind === SyntaxKind.ExportSpecifier || (usage.parent.kind === SyntaxKind.ExportAssignment && (usage.parent as ExportAssignment).isExportEquals)) {
// export specifiers do not use the variable, they only make it available for use
return true;
}
// When resolving symbols for exports, the `usage` location passed in can be the export site directly
if (usage.kind === SyntaxKind.ExportAssignment && (usage as ExportAssignment).isExportEquals) {
return true;
}
const container = getEnclosingBlockScopeContainer(declaration);
return !!(usage.flags & NodeFlags.JSDoc) || isInTypeQuery(usage) || isUsedInFunctionOrInstanceProperty(usage, declaration, container);
function isImmediatelyUsedInInitializerOfBlockScopedVariable(declaration: VariableDeclaration, usage: Node): boolean {
const container = getEnclosingBlockScopeContainer(declaration);
switch (declaration.parent.parent.kind) {
case SyntaxKind.VariableStatement:
case SyntaxKind.ForStatement:
case SyntaxKind.ForOfStatement:
// variable statement/for/for-of statement case,
// use site should not be inside variable declaration (initializer of declaration or binding element)
if (isSameScopeDescendentOf(usage, declaration, container)) {
return true;
}
break;
}
// ForIn/ForOf case - use site should not be used in expression part
const grandparent = declaration.parent.parent;
return isForInOrOfStatement(grandparent) && isSameScopeDescendentOf(usage, grandparent.expression, container);
}
function isUsedInFunctionOrInstanceProperty(usage: Node, declaration: Node, container?: Node): boolean {
return !!findAncestor(usage, current => {
if (current === container) {
return "quit";
}
if (isFunctionLike(current)) {
return true;
}
const initializerOfProperty = current.parent &&
current.parent.kind === SyntaxKind.PropertyDeclaration &&
(<PropertyDeclaration>current.parent).initializer === current;
if (initializerOfProperty) {
if (hasModifier(current.parent, ModifierFlags.Static)) {
if (declaration.kind === SyntaxKind.MethodDeclaration) {
return true;
}
}
else {
const isDeclarationInstanceProperty = declaration.kind === SyntaxKind.PropertyDeclaration && !hasModifier(declaration, ModifierFlags.Static);
if (!isDeclarationInstanceProperty || getContainingClass(usage) !== getContainingClass(declaration)) {
return true;
}
}
}
return false;
});
}
}
/**
* Resolve a given name for a given meaning at a given location. An error is reported if the name was not found and
* the nameNotFoundMessage argument is not undefined. Returns the resolved symbol, or undefined if no symbol with
* the given name can be found.
*
* @param isUse If true, this will count towards --noUnusedLocals / --noUnusedParameters.
*/
function resolveName(
location: Node | undefined,
name: __String,
meaning: SymbolFlags,
nameNotFoundMessage: DiagnosticMessage | undefined,
nameArg: __String | Identifier | undefined,
isUse: boolean,
excludeGlobals = false,
suggestedNameNotFoundMessage?: DiagnosticMessage): Symbol | undefined {
return resolveNameHelper(location, name, meaning, nameNotFoundMessage, nameArg, isUse, excludeGlobals, getSymbol, suggestedNameNotFoundMessage);
}
function resolveNameHelper(
location: Node | undefined,
name: __String,
meaning: SymbolFlags,
nameNotFoundMessage: DiagnosticMessage | undefined,
nameArg: __String | Identifier | undefined,
isUse: boolean,
excludeGlobals: boolean,
lookup: typeof getSymbol,
suggestedNameNotFoundMessage?: DiagnosticMessage): Symbol | undefined {
const originalLocation = location; // needed for did-you-mean error reporting, which gathers candidates starting from the original location
let result: Symbol | undefined;
let lastLocation: Node | undefined;
let lastSelfReferenceLocation: Node | undefined;
let propertyWithInvalidInitializer: Node | undefined;
const errorLocation = location;
let grandparent: Node;
let isInExternalModule = false;
loop: while (location) {
// Locals of a source file are not in scope (because they get merged into the global symbol table)
if (location.locals && !isGlobalSourceFile(location)) {
if (result = lookup(location.locals, name, meaning)) {
let useResult = true;
if (isFunctionLike(location) && lastLocation && lastLocation !== (<FunctionLikeDeclaration>location).body) {
// symbol lookup restrictions for function-like declarations
// - Type parameters of a function are in scope in the entire function declaration, including the parameter
// list and return type. However, local types are only in scope in the function body.
// - parameters are only in the scope of function body
// This restriction does not apply to JSDoc comment types because they are parented
// at a higher level than type parameters would normally be
if (meaning & result.flags & SymbolFlags.Type && lastLocation.kind !== SyntaxKind.JSDocComment) {
useResult = result.flags & SymbolFlags.TypeParameter
// type parameters are visible in parameter list, return type and type parameter list
? lastLocation === (<FunctionLikeDeclaration>location).type ||
lastLocation.kind === SyntaxKind.Parameter ||
lastLocation.kind === SyntaxKind.TypeParameter
// local types not visible outside the function body
: false;
}
if (meaning & result.flags & SymbolFlags.Variable) {
// expression inside parameter will lookup as normal variable scope when targeting es2015+
const functionLocation = <FunctionLikeDeclaration>location;
if (compilerOptions.target && compilerOptions.target >= ScriptTarget.ES2015 && isParameter(lastLocation) &&
functionLocation.body && result.valueDeclaration.pos >= functionLocation.body.pos && result.valueDeclaration.end <= functionLocation.body.end) {
useResult = false;
}
else if (result.flags & SymbolFlags.FunctionScopedVariable) {
// parameters are visible only inside function body, parameter list and return type
// technically for parameter list case here we might mix parameters and variables declared in function,
// however it is detected separately when checking initializers of parameters
// to make sure that they reference no variables declared after them.
useResult =
lastLocation.kind === SyntaxKind.Parameter ||
(
lastLocation === (<FunctionLikeDeclaration>location).type &&
!!findAncestor(result.valueDeclaration, isParameter)
);
}
}
}
else if (location.kind === SyntaxKind.ConditionalType) {
// A type parameter declared using 'infer T' in a conditional type is visible only in
// the true branch of the conditional type.
useResult = lastLocation === (<ConditionalTypeNode>location).trueType;
}
if (useResult) {
break loop;
}
else {
result = undefined;
}
}
}
switch (location.kind) {
case SyntaxKind.SourceFile:
if (!isExternalOrCommonJsModule(<SourceFile>location)) break;
isInExternalModule = true;
// falls through
case SyntaxKind.ModuleDeclaration:
const moduleExports = getSymbolOfNode(location as SourceFile | ModuleDeclaration).exports!;
if (location.kind === SyntaxKind.SourceFile || isAmbientModule(location)) {
// It's an external module. First see if the module has an export default and if the local
// name of that export default matches.
if (result = moduleExports.get(InternalSymbolName.Default)) {
const localSymbol = getLocalSymbolForExportDefault(result);
if (localSymbol && (result.flags & meaning) && localSymbol.escapedName === name) {
break loop;
}
result = undefined;
}
// Because of module/namespace merging, a module's exports are in scope,
// yet we never want to treat an export specifier as putting a member in scope.
// Therefore, if the name we find is purely an export specifier, it is not actually considered in scope.
// Two things to note about this:
// 1. We have to check this without calling getSymbol. The problem with calling getSymbol
// on an export specifier is that it might find the export specifier itself, and try to
// resolve it as an alias. This will cause the checker to consider the export specifier
// a circular alias reference when it might not be.
// 2. We check === SymbolFlags.Alias in order to check that the symbol is *purely*
// an alias. If we used &, we'd be throwing out symbols that have non alias aspects,
// which is not the desired behavior.
const moduleExport = moduleExports.get(name);
if (moduleExport &&
moduleExport.flags === SymbolFlags.Alias &&
getDeclarationOfKind(moduleExport, SyntaxKind.ExportSpecifier)) {
break;
}
}
// ES6 exports are also visible locally (except for 'default'), but commonjs exports are not (except typedefs)
if (name !== InternalSymbolName.Default && (result = lookup(moduleExports, name, meaning & SymbolFlags.ModuleMember))) {
if (isSourceFile(location) && location.commonJsModuleIndicator && !result.declarations.some(isJSDocTypeAlias)) {
result = undefined;
}
else {
break loop;
}
}
break;
case SyntaxKind.EnumDeclaration:
if (result = lookup(getSymbolOfNode(location)!.exports!, name, meaning & SymbolFlags.EnumMember)) {
break loop;
}
break;
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.PropertySignature:
// TypeScript 1.0 spec (April 2014): 8.4.1
// Initializer expressions for instance member variables are evaluated in the scope
// of the class constructor body but are not permitted to reference parameters or
// local variables of the constructor. This effectively means that entities from outer scopes
// by the same name as a constructor parameter or local variable are inaccessible
// in initializer expressions for instance member variables.
if (isClassLike(location.parent) && !hasModifier(location, ModifierFlags.Static)) {
const ctor = findConstructorDeclaration(location.parent);
if (ctor && ctor.locals) {
if (lookup(ctor.locals, name, meaning & SymbolFlags.Value)) {
// Remember the property node, it will be used later to report appropriate error
propertyWithInvalidInitializer = location;
}
}
}
break;
case SyntaxKind.ClassDeclaration:
case SyntaxKind.ClassExpression:
case SyntaxKind.InterfaceDeclaration:
// The below is used to lookup type parameters within a class or interface, as they are added to the class/interface locals
// These can never be latebound, so the symbol's raw members are sufficient. `getMembersOfNode` cannot be used, as it would
// trigger resolving late-bound names, which we may already be in the process of doing while we're here!
if (result = lookup(getSymbolOfNode(location as ClassLikeDeclaration | InterfaceDeclaration).members || emptySymbols, name, meaning & SymbolFlags.Type)) {
if (!isTypeParameterSymbolDeclaredInContainer(result, location)) {
// ignore type parameters not declared in this container
result = undefined;
break;
}
if (lastLocation && hasModifier(lastLocation, ModifierFlags.Static)) {
// TypeScript 1.0 spec (April 2014): 3.4.1
// The scope of a type parameter extends over the entire declaration with which the type
// parameter list is associated, with the exception of static member declarations in classes.
error(errorLocation, Diagnostics.Static_members_cannot_reference_class_type_parameters);
return undefined;
}
break loop;
}
if (location.kind === SyntaxKind.ClassExpression && meaning & SymbolFlags.Class) {
const className = (<ClassExpression>location).name;
if (className && name === className.escapedText) {
result = location.symbol;
break loop;
}
}
break;
case SyntaxKind.ExpressionWithTypeArguments:
// The type parameters of a class are not in scope in the base class expression.
if (lastLocation === (<ExpressionWithTypeArguments>location).expression && (<HeritageClause>location.parent).token === SyntaxKind.ExtendsKeyword) {
const container = location.parent.parent;
if (isClassLike(container) && (result = lookup(getSymbolOfNode(container).members!, name, meaning & SymbolFlags.Type))) {
if (nameNotFoundMessage) {
error(errorLocation, Diagnostics.Base_class_expressions_cannot_reference_class_type_parameters);
}
return undefined;
}
}
break;
// It is not legal to reference a class's own type parameters from a computed property name that
// belongs to the class. For example:
//
// function foo<T>() { return '' }
// class C<T> { // <-- Class's own type parameter T
// [foo<T>()]() { } // <-- Reference to T from class's own computed property
// }
//
case SyntaxKind.ComputedPropertyName:
grandparent = location.parent.parent;
if (isClassLike(grandparent) || grandparent.kind === SyntaxKind.InterfaceDeclaration) {
// A reference to this grandparent's type parameters would be an error
if (result = lookup(getSymbolOfNode(grandparent as ClassLikeDeclaration | InterfaceDeclaration).members!, name, meaning & SymbolFlags.Type)) {
error(errorLocation, Diagnostics.A_computed_property_name_cannot_reference_a_type_parameter_from_its_containing_type);
return undefined;
}
}
break;
case SyntaxKind.ArrowFunction:
// when targeting ES6 or higher there is no 'arguments' in an arrow function
// for lower compile targets the resolved symbol is used to emit an error
if (compilerOptions.target! >= ScriptTarget.ES2015) {
break;
}
// falls through
case SyntaxKind.MethodDeclaration:
case SyntaxKind.Constructor:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
case SyntaxKind.FunctionDeclaration:
if (meaning & SymbolFlags.Variable && name === "arguments") {
result = argumentsSymbol;
break loop;
}
break;
case SyntaxKind.FunctionExpression:
if (meaning & SymbolFlags.Variable && name === "arguments") {
result = argumentsSymbol;
break loop;
}
if (meaning & SymbolFlags.Function) {
const functionName = (<FunctionExpression>location).name;
if (functionName && name === functionName.escapedText) {
result = location.symbol;
break loop;
}
}
break;
case SyntaxKind.Decorator:
// Decorators are resolved at the class declaration. Resolving at the parameter
// or member would result in looking up locals in the method.
//
// function y() {}
// class C {
// method(@y x, y) {} // <-- decorator y should be resolved at the class declaration, not the parameter.
// }
//
if (location.parent && location.parent.kind === SyntaxKind.Parameter) {
location = location.parent;
}
//
// function y() {}
// class C {
// @y method(x, y) {} // <-- decorator y should be resolved at the class declaration, not the method.
// }
//
if (location.parent && isClassElement(location.parent)) {
location = location.parent;
}
break;
case SyntaxKind.JSDocTypedefTag:
case SyntaxKind.JSDocCallbackTag:
// js type aliases do not resolve names from their host, so skip past it
location = getJSDocHost(location);
break;
}
if (isSelfReferenceLocation(location)) {
lastSelfReferenceLocation = location;
}
lastLocation = location;
location = location.parent;
}
// We just climbed up parents looking for the name, meaning that we started in a descendant node of `lastLocation`.
// If `result === lastSelfReferenceLocation.symbol`, that means that we are somewhere inside `lastSelfReferenceLocation` looking up a name, and resolving to `lastLocation` itself.
// That means that this is a self-reference of `lastLocation`, and shouldn't count this when considering whether `lastLocation` is used.
if (isUse && result && (!lastSelfReferenceLocation || result !== lastSelfReferenceLocation.symbol)) {
result.isReferenced! |= meaning;
}
if (!result) {
if (lastLocation) {
Debug.assert(lastLocation.kind === SyntaxKind.SourceFile);
if ((lastLocation as SourceFile).commonJsModuleIndicator && name === "exports" && meaning & lastLocation.symbol.flags) {
return lastLocation.symbol;
}
}
if (!excludeGlobals) {
result = lookup(globals, name, meaning);
}
}
if (!result) {
if (originalLocation && isInJSFile(originalLocation) && originalLocation.parent) {
if (isRequireCall(originalLocation.parent, /*checkArgumentIsStringLiteralLike*/ false)) {
return requireSymbol;
}
}
}
if (!result) {
if (nameNotFoundMessage) {
if (!errorLocation ||
!checkAndReportErrorForMissingPrefix(errorLocation, name, nameArg!) && // TODO: GH#18217
!checkAndReportErrorForExtendingInterface(errorLocation) &&
!checkAndReportErrorForUsingTypeAsNamespace(errorLocation, name, meaning) &&
!checkAndReportErrorForUsingTypeAsValue(errorLocation, name, meaning) &&
!checkAndReportErrorForUsingNamespaceModuleAsValue(errorLocation, name, meaning) &&
!checkAndReportErrorForUsingValueAsType(errorLocation, name, meaning)) {
let suggestion: Symbol | undefined;
if (suggestedNameNotFoundMessage && suggestionCount < maximumSuggestionCount) {
suggestion = getSuggestedSymbolForNonexistentSymbol(originalLocation, name, meaning);
if (suggestion) {
const suggestionName = symbolToString(suggestion);
const diagnostic = error(errorLocation, suggestedNameNotFoundMessage, diagnosticName(nameArg!), suggestionName);
if (suggestion.valueDeclaration) {
addRelatedInfo(
diagnostic,
createDiagnosticForNode(suggestion.valueDeclaration, Diagnostics._0_is_declared_here, suggestionName)
);
}
}
}
if (!suggestion) {
error(errorLocation, nameNotFoundMessage, diagnosticName(nameArg!));
}
suggestionCount++;
}
}
return undefined;
}
// Perform extra checks only if error reporting was requested
if (nameNotFoundMessage) {
if (propertyWithInvalidInitializer) {
// We have a match, but the reference occurred within a property initializer and the identifier also binds
// to a local variable in the constructor where the code will be emitted.
const propertyName = (<PropertyDeclaration>propertyWithInvalidInitializer).name;
error(errorLocation, Diagnostics.Initializer_of_instance_member_variable_0_cannot_reference_identifier_1_declared_in_the_constructor,
declarationNameToString(propertyName), diagnosticName(nameArg!));
return undefined;
}
// Only check for block-scoped variable if we have an error location and are looking for the
// name with variable meaning
// For example,
// declare module foo {
// interface bar {}
// }
// const foo/*1*/: foo/*2*/.bar;
// The foo at /*1*/ and /*2*/ will share same symbol with two meanings:
// block-scoped variable and namespace module. However, only when we
// try to resolve name in /*1*/ which is used in variable position,
// we want to check for block-scoped
if (errorLocation &&
(meaning & SymbolFlags.BlockScopedVariable ||
((meaning & SymbolFlags.Class || meaning & SymbolFlags.Enum) && (meaning & SymbolFlags.Value) === SymbolFlags.Value))) {
const exportOrLocalSymbol = getExportSymbolOfValueSymbolIfExported(result);
if (exportOrLocalSymbol.flags & SymbolFlags.BlockScopedVariable || exportOrLocalSymbol.flags & SymbolFlags.Class || exportOrLocalSymbol.flags & SymbolFlags.Enum) {
checkResolvedBlockScopedVariable(exportOrLocalSymbol, errorLocation);
}
}
// If we're in an external module, we can't reference value symbols created from UMD export declarations
if (result && isInExternalModule && (meaning & SymbolFlags.Value) === SymbolFlags.Value && !(originalLocation!.flags & NodeFlags.JSDoc)) {
const merged = getMergedSymbol(result);
if (length(merged.declarations) && every(merged.declarations, d => isNamespaceExportDeclaration(d) || isSourceFile(d) && !!d.symbol.globalExports)) {
error(errorLocation!, Diagnostics._0_refers_to_a_UMD_global_but_the_current_file_is_a_module_Consider_adding_an_import_instead, unescapeLeadingUnderscores(name)); // TODO: GH#18217
}
}
}
return result;
}
function isSelfReferenceLocation(node: Node): boolean {
switch (node.kind) {
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.ClassDeclaration:
case SyntaxKind.InterfaceDeclaration:
case SyntaxKind.EnumDeclaration:
case SyntaxKind.TypeAliasDeclaration:
case SyntaxKind.ModuleDeclaration: // For `namespace N { N; }`
return true;
default:
return false;
}
}
function diagnosticName(nameArg: __String | Identifier) {
return isString(nameArg) ? unescapeLeadingUnderscores(nameArg as __String) : declarationNameToString(nameArg as Identifier);
}
function isTypeParameterSymbolDeclaredInContainer(symbol: Symbol, container: Node) {
for (const decl of symbol.declarations) {
if (decl.kind === SyntaxKind.TypeParameter) {
const parent = isJSDocTemplateTag(decl.parent) ? getJSDocHost(decl.parent) : decl.parent;
if (parent === container) {
return !(isJSDocTemplateTag(decl.parent) && find((decl.parent.parent as JSDoc).tags!, isJSDocTypeAlias)); // TODO: GH#18217
}
}
}
return false;
}
function checkAndReportErrorForMissingPrefix(errorLocation: Node, name: __String, nameArg: __String | Identifier): boolean {
if (!isIdentifier(errorLocation) || errorLocation.escapedText !== name || isTypeReferenceIdentifier(errorLocation) || isInTypeQuery(errorLocation)) {
return false;
}
const container = getThisContainer(errorLocation, /*includeArrowFunctions*/ false);
let location = container;
while (location) {
if (isClassLike(location.parent)) {
const classSymbol = getSymbolOfNode(location.parent);
if (!classSymbol) {
break;
}
// Check to see if a static member exists.
const constructorType = getTypeOfSymbol(classSymbol);
if (getPropertyOfType(constructorType, name)) {
error(errorLocation, Diagnostics.Cannot_find_name_0_Did_you_mean_the_static_member_1_0, diagnosticName(nameArg), symbolToString(classSymbol));
return true;
}
// No static member is present.
// Check if we're in an instance method and look for a relevant instance member.
if (location === container && !hasModifier(location, ModifierFlags.Static)) {
const instanceType = (<InterfaceType>getDeclaredTypeOfSymbol(classSymbol)).thisType!; // TODO: GH#18217
if (getPropertyOfType(instanceType, name)) {
error(errorLocation, Diagnostics.Cannot_find_name_0_Did_you_mean_the_instance_member_this_0, diagnosticName(nameArg));
return true;
}
}
}
location = location.parent;
}
return false;
}
function checkAndReportErrorForExtendingInterface(errorLocation: Node): boolean {
const expression = getEntityNameForExtendingInterface(errorLocation);
if (expression && resolveEntityName(expression, SymbolFlags.Interface, /*ignoreErrors*/ true)) {
error(errorLocation, Diagnostics.Cannot_extend_an_interface_0_Did_you_mean_implements, getTextOfNode(expression));
return true;
}
return false;
}
/**
* Climbs up parents to an ExpressionWithTypeArguments, and returns its expression,
* but returns undefined if that expression is not an EntityNameExpression.
*/
function getEntityNameForExtendingInterface(node: Node): EntityNameExpression | undefined {
switch (node.kind) {
case SyntaxKind.Identifier:
case SyntaxKind.PropertyAccessExpression:
return node.parent ? getEntityNameForExtendingInterface(node.parent) : undefined;
case SyntaxKind.ExpressionWithTypeArguments:
if (isEntityNameExpression((<ExpressionWithTypeArguments>node).expression)) {
return <EntityNameExpression>(<ExpressionWithTypeArguments>node).expression;
}
// falls through
default:
return undefined;
}
}
function checkAndReportErrorForUsingTypeAsNamespace(errorLocation: Node, name: __String, meaning: SymbolFlags): boolean {
const namespaceMeaning = SymbolFlags.Namespace | (isInJSFile(errorLocation) ? SymbolFlags.Value : 0);
if (meaning === namespaceMeaning) {
const symbol = resolveSymbol(resolveName(errorLocation, name, SymbolFlags.Type & ~namespaceMeaning, /*nameNotFoundMessage*/undefined, /*nameArg*/ undefined, /*isUse*/ false));
const parent = errorLocation.parent;
if (symbol) {
if (isQualifiedName(parent)) {
Debug.assert(parent.left === errorLocation, "Should only be resolving left side of qualified name as a namespace");
const propName = parent.right.escapedText;
const propType = getPropertyOfType(getDeclaredTypeOfSymbol(symbol), propName);
if (propType) {
error(
parent,
Diagnostics.Cannot_access_0_1_because_0_is_a_type_but_not_a_namespace_Did_you_mean_to_retrieve_the_type_of_the_property_1_in_0_with_0_1,
unescapeLeadingUnderscores(name),
unescapeLeadingUnderscores(propName),
);
return true;
}
}
error(errorLocation, Diagnostics._0_only_refers_to_a_type_but_is_being_used_as_a_namespace_here, unescapeLeadingUnderscores(name));
return true;
}
}
return false;
}
function checkAndReportErrorForUsingValueAsType(errorLocation: Node, name: __String, meaning: SymbolFlags): boolean {
if (meaning & (SymbolFlags.Type & ~SymbolFlags.Namespace)) {
const symbol = resolveSymbol(resolveName(errorLocation, name, ~SymbolFlags.Type & SymbolFlags.Value, /*nameNotFoundMessage*/undefined, /*nameArg*/ undefined, /*isUse*/ false));
if (symbol && !(symbol.flags & SymbolFlags.Namespace)) {
error(errorLocation, Diagnostics._0_refers_to_a_value_but_is_being_used_as_a_type_here, unescapeLeadingUnderscores(name));
return true;
}
}
return false;
}
function checkAndReportErrorForUsingTypeAsValue(errorLocation: Node, name: __String, meaning: SymbolFlags): boolean {
if (meaning & (SymbolFlags.Value & ~SymbolFlags.NamespaceModule)) {
if (name === "any" || name === "string" || name === "number" || name === "boolean" || name === "never") {
error(errorLocation, Diagnostics._0_only_refers_to_a_type_but_is_being_used_as_a_value_here, unescapeLeadingUnderscores(name));
return true;
}
const symbol = resolveSymbol(resolveName(errorLocation, name, SymbolFlags.Type & ~SymbolFlags.Value, /*nameNotFoundMessage*/undefined, /*nameArg*/ undefined, /*isUse*/ false));
if (symbol && !(symbol.flags & SymbolFlags.NamespaceModule)) {
const message = isES2015OrLaterConstructorName(name)
? Diagnostics._0_only_refers_to_a_type_but_is_being_used_as_a_value_here_Do_you_need_to_change_your_target_library_Try_changing_the_lib_compiler_option_to_es2015_or_later
: Diagnostics._0_only_refers_to_a_type_but_is_being_used_as_a_value_here;
error(errorLocation, message, unescapeLeadingUnderscores(name));
return true;
}
}
return false;
}
function isES2015OrLaterConstructorName(n: __String) {
switch (n) {
case "Promise":
case "Symbol":
case "Map":
case "WeakMap":
case "Set":
case "WeakSet":
return true;
}
return false;
}
function checkAndReportErrorForUsingNamespaceModuleAsValue(errorLocation: Node, name: __String, meaning: SymbolFlags): boolean {
if (meaning & (SymbolFlags.Value & ~SymbolFlags.NamespaceModule & ~SymbolFlags.Type)) {
const symbol = resolveSymbol(resolveName(errorLocation, name, SymbolFlags.NamespaceModule & ~SymbolFlags.Value, /*nameNotFoundMessage*/undefined, /*nameArg*/ undefined, /*isUse*/ false));
if (symbol) {
error(errorLocation, Diagnostics.Cannot_use_namespace_0_as_a_value, unescapeLeadingUnderscores(name));
return true;
}
}
else if (meaning & (SymbolFlags.Type & ~SymbolFlags.NamespaceModule & ~SymbolFlags.Value)) {
const symbol = resolveSymbol(resolveName(errorLocation, name, (SymbolFlags.ValueModule | SymbolFlags.NamespaceModule) & ~SymbolFlags.Type, /*nameNotFoundMessage*/undefined, /*nameArg*/ undefined, /*isUse*/ false));
if (symbol) {
error(errorLocation, Diagnostics.Cannot_use_namespace_0_as_a_type, unescapeLeadingUnderscores(name));
return true;
}
}
return false;
}
function checkResolvedBlockScopedVariable(result: Symbol, errorLocation: Node): void {
Debug.assert(!!(result.flags & SymbolFlags.BlockScopedVariable || result.flags & SymbolFlags.Class || result.flags & SymbolFlags.Enum));
// Block-scoped variables cannot be used before their definition
const declaration = find(
result.declarations,
d => isBlockOrCatchScoped(d) || isClassLike(d) || (d.kind === SyntaxKind.EnumDeclaration) || isInJSFile(d) && !!getJSDocEnumTag(d));
if (declaration === undefined) return Debug.fail("Declaration to checkResolvedBlockScopedVariable is undefined");
if (!(declaration.flags & NodeFlags.Ambient) && !isBlockScopedNameDeclaredBeforeUse(declaration, errorLocation)) {
let diagnosticMessage;
const declarationName = declarationNameToString(getNameOfDeclaration(declaration));
if (result.flags & SymbolFlags.BlockScopedVariable) {
diagnosticMessage = error(errorLocation, Diagnostics.Block_scoped_variable_0_used_before_its_declaration, declarationName);
}
else if (result.flags & SymbolFlags.Class) {
diagnosticMessage = error(errorLocation, Diagnostics.Class_0_used_before_its_declaration, declarationName);
}
else if (result.flags & SymbolFlags.RegularEnum) {
diagnosticMessage = error(errorLocation, Diagnostics.Enum_0_used_before_its_declaration, declarationName);
}
else {
Debug.assert(!!(result.flags & SymbolFlags.ConstEnum));
if (compilerOptions.preserveConstEnums) {
diagnosticMessage = error(errorLocation, Diagnostics.Class_0_used_before_its_declaration, declarationName);
}
}
if (diagnosticMessage) {
addRelatedInfo(diagnosticMessage,
createDiagnosticForNode(declaration, Diagnostics._0_is_declared_here, declarationName)
);
}
}
}
/* Starting from 'initial' node walk up the parent chain until 'stopAt' node is reached.
* If at any point current node is equal to 'parent' node - return true.
* Return false if 'stopAt' node is reached or isFunctionLike(current) === true.
*/
function isSameScopeDescendentOf(initial: Node, parent: Node | undefined, stopAt: Node): boolean {
return !!parent && !!findAncestor(initial, n => n === stopAt || isFunctionLike(n) ? "quit" : n === parent);
}
function getAnyImportSyntax(node: Node): AnyImportSyntax | undefined {
switch (node.kind) {
case SyntaxKind.ImportEqualsDeclaration:
return node as ImportEqualsDeclaration;
case SyntaxKind.ImportClause:
return (node as ImportClause).parent;
case SyntaxKind.NamespaceImport:
return (node as NamespaceImport).parent.parent;
case SyntaxKind.ImportSpecifier:
return (node as ImportSpecifier).parent.parent.parent;
default:
return undefined;
}
}
function getDeclarationOfAliasSymbol(symbol: Symbol): Declaration | undefined {
return find<Declaration>(symbol.declarations, isAliasSymbolDeclaration);
}
function getTargetOfImportEqualsDeclaration(node: ImportEqualsDeclaration, dontResolveAlias: boolean): Symbol | undefined {
if (node.moduleReference.kind === SyntaxKind.ExternalModuleReference) {
return resolveExternalModuleSymbol(resolveExternalModuleName(node, getExternalModuleImportEqualsDeclarationExpression(node)));
}
return getSymbolOfPartOfRightHandSideOfImportEquals(node.moduleReference, dontResolveAlias);
}
function resolveExportByName(moduleSymbol: Symbol, name: __String, dontResolveAlias: boolean) {
const exportValue = moduleSymbol.exports!.get(InternalSymbolName.ExportEquals);
return exportValue
? getPropertyOfType(getTypeOfSymbol(exportValue), name)
: resolveSymbol(moduleSymbol.exports!.get(name), dontResolveAlias);
}
function isSyntacticDefault(node: Node) {
return ((isExportAssignment(node) && !node.isExportEquals) || hasModifier(node, ModifierFlags.Default) || isExportSpecifier(node));
}
function canHaveSyntheticDefault(file: SourceFile | undefined, moduleSymbol: Symbol, dontResolveAlias: boolean) {
if (!allowSyntheticDefaultImports) {
return false;
}
// Declaration files (and ambient modules)
if (!file || file.isDeclarationFile) {
// Definitely cannot have a synthetic default if they have a syntactic default member specified
const defaultExportSymbol = resolveExportByName(moduleSymbol, InternalSymbolName.Default, /*dontResolveAlias*/ true); // Dont resolve alias because we want the immediately exported symbol's declaration
if (defaultExportSymbol && some(defaultExportSymbol.declarations, isSyntacticDefault)) {
return false;
}
// It _might_ still be incorrect to assume there is no __esModule marker on the import at runtime, even if there is no `default` member
// So we check a bit more,
if (resolveExportByName(moduleSymbol, escapeLeadingUnderscores("__esModule"), dontResolveAlias)) {
// If there is an `__esModule` specified in the declaration (meaning someone explicitly added it or wrote it in their code),
// it definitely is a module and does not have a synthetic default
return false;
}
// There are _many_ declaration files not written with esmodules in mind that still get compiled into a format with __esModule set
// Meaning there may be no default at runtime - however to be on the permissive side, we allow access to a synthetic default member
// as there is no marker to indicate if the accompanying JS has `__esModule` or not, or is even native esm
return true;
}
// TypeScript files never have a synthetic default (as they are always emitted with an __esModule marker) _unless_ they contain an export= statement
if (!isSourceFileJS(file)) {
return hasExportAssignmentSymbol(moduleSymbol);
}
// JS files have a synthetic default if they do not contain ES2015+ module syntax (export = is not valid in js) _and_ do not have an __esModule marker
return !file.externalModuleIndicator && !resolveExportByName(moduleSymbol, escapeLeadingUnderscores("__esModule"), dontResolveAlias);
}
function getTargetOfImportClause(node: ImportClause, dontResolveAlias: boolean): Symbol | undefined {
const moduleSymbol = resolveExternalModuleName(node, node.parent.moduleSpecifier);
if (moduleSymbol) {
let exportDefaultSymbol: Symbol | undefined;
if (isShorthandAmbientModuleSymbol(moduleSymbol)) {
exportDefaultSymbol = moduleSymbol;
}
else {
exportDefaultSymbol = resolveExportByName(moduleSymbol, InternalSymbolName.Default, dontResolveAlias);
}
const file = find(moduleSymbol.declarations, isSourceFile);
const hasSyntheticDefault = canHaveSyntheticDefault(file, moduleSymbol, dontResolveAlias);
if (!exportDefaultSymbol && !hasSyntheticDefault) {
error(node.name, Diagnostics.Module_0_has_no_default_export, symbolToString(moduleSymbol));
}
else if (hasSyntheticDefault) {
// per emit behavior, a synthetic default overrides a "real" .default member if `__esModule` is not present
return resolveExternalModuleSymbol(moduleSymbol, dontResolveAlias) || resolveSymbol(moduleSymbol, dontResolveAlias);
}
return exportDefaultSymbol;
}
}
function getTargetOfNamespaceImport(node: NamespaceImport, dontResolveAlias: boolean): Symbol | undefined {
const moduleSpecifier = node.parent.parent.moduleSpecifier;
return resolveESModuleSymbol(resolveExternalModuleName(node, moduleSpecifier), moduleSpecifier, dontResolveAlias);
}
// This function creates a synthetic symbol that combines the value side of one symbol with the
// type/namespace side of another symbol. Consider this example:
//
// declare module graphics {
// interface Point {
// x: number;
// y: number;
// }
// }
// declare var graphics: {
// Point: new (x: number, y: number) => graphics.Point;
// }
// declare module "graphics" {
// export = graphics;
// }
//
// An 'import { Point } from "graphics"' needs to create a symbol that combines the value side 'Point'
// property with the type/namespace side interface 'Point'.
function combineValueAndTypeSymbols(valueSymbol: Symbol, typeSymbol: Symbol): Symbol {
if (valueSymbol === unknownSymbol && typeSymbol === unknownSymbol) {
return unknownSymbol;
}
if (valueSymbol.flags & (SymbolFlags.Type | SymbolFlags.Namespace)) {
return valueSymbol;
}
const result = createSymbol(valueSymbol.flags | typeSymbol.flags, valueSymbol.escapedName);
result.declarations = deduplicate(concatenate(valueSymbol.declarations, typeSymbol.declarations), equateValues);
result.parent = valueSymbol.parent || typeSymbol.parent;
if (valueSymbol.valueDeclaration) result.valueDeclaration = valueSymbol.valueDeclaration;
if (typeSymbol.members) result.members = typeSymbol.members;
if (valueSymbol.exports) result.exports = valueSymbol.exports;
return result;
}
function getExportOfModule(symbol: Symbol, name: __String, dontResolveAlias: boolean): Symbol | undefined {
if (symbol.flags & SymbolFlags.Module) {
return resolveSymbol(getExportsOfSymbol(symbol).get(name)!, dontResolveAlias);
}
}
function getPropertyOfVariable(symbol: Symbol, name: __String): Symbol | undefined {
if (symbol.flags & SymbolFlags.Variable) {
const typeAnnotation = (<VariableDeclaration>symbol.valueDeclaration).type;
if (typeAnnotation) {
return resolveSymbol(getPropertyOfType(getTypeFromTypeNode(typeAnnotation), name));
}
}
}
function getExternalModuleMember(node: ImportDeclaration | ExportDeclaration, specifier: ImportOrExportSpecifier, dontResolveAlias = false): Symbol | undefined {
const moduleSymbol = resolveExternalModuleName(node, node.moduleSpecifier!)!; // TODO: GH#18217
const targetSymbol = resolveESModuleSymbol(moduleSymbol, node.moduleSpecifier!, dontResolveAlias);
if (targetSymbol) {
const name = specifier.propertyName || specifier.name;
if (name.escapedText) {
if (isShorthandAmbientModuleSymbol(moduleSymbol)) {
return moduleSymbol;
}
let symbolFromVariable: Symbol | undefined;
// First check if module was specified with "export=". If so, get the member from the resolved type
if (moduleSymbol && moduleSymbol.exports && moduleSymbol.exports.get(InternalSymbolName.ExportEquals)) {
symbolFromVariable = getPropertyOfType(getTypeOfSymbol(targetSymbol), name.escapedText);
}
else {
symbolFromVariable = getPropertyOfVariable(targetSymbol, name.escapedText);
}
// if symbolFromVariable is export - get its final target
symbolFromVariable = resolveSymbol(symbolFromVariable, dontResolveAlias);
let symbolFromModule = getExportOfModule(targetSymbol, name.escapedText, dontResolveAlias);
// If the export member we're looking for is default, and there is no real default but allowSyntheticDefaultImports is on, return the entire module as the default
if (!symbolFromModule && allowSyntheticDefaultImports && name.escapedText === InternalSymbolName.Default) {
symbolFromModule = resolveExternalModuleSymbol(moduleSymbol, dontResolveAlias) || resolveSymbol(moduleSymbol, dontResolveAlias);
}
const symbol = symbolFromModule && symbolFromVariable && symbolFromModule !== symbolFromVariable ?
combineValueAndTypeSymbols(symbolFromVariable, symbolFromModule) :
symbolFromModule || symbolFromVariable;
if (!symbol) {
const moduleName = getFullyQualifiedName(moduleSymbol, node);
const declarationName = declarationNameToString(name);
const suggestion = getSuggestedSymbolForNonexistentModule(name, targetSymbol);
if (suggestion !== undefined) {
const suggestionName = symbolToString(suggestion);
const diagnostic = error(name, Diagnostics.Module_0_has_no_exported_member_1_Did_you_mean_2, moduleName, declarationName, suggestionName);
if (suggestion.valueDeclaration) {
addRelatedInfo(diagnostic,
createDiagnosticForNode(suggestion.valueDeclaration, Diagnostics._0_is_declared_here, suggestionName)
);
}
}
else {
error(name, Diagnostics.Module_0_has_no_exported_member_1, moduleName, declarationName);
}
}
return symbol;
}
}
}
function getTargetOfImportSpecifier(node: ImportSpecifier, dontResolveAlias: boolean): Symbol | undefined {
return getExternalModuleMember(node.parent.parent.parent, node, dontResolveAlias);
}
function getTargetOfNamespaceExportDeclaration(node: NamespaceExportDeclaration, dontResolveAlias: boolean): Symbol {
return resolveExternalModuleSymbol(node.parent.symbol, dontResolveAlias);
}
function getTargetOfExportSpecifier(node: ExportSpecifier, meaning: SymbolFlags, dontResolveAlias?: boolean) {
return node.parent.parent.moduleSpecifier ?
getExternalModuleMember(node.parent.parent, node, dontResolveAlias) :
resolveEntityName(node.propertyName || node.name, meaning, /*ignoreErrors*/ false, dontResolveAlias);
}
function getTargetOfExportAssignment(node: ExportAssignment | BinaryExpression, dontResolveAlias: boolean): Symbol | undefined {
const expression = (isExportAssignment(node) ? node.expression : node.right) as EntityNameExpression | ClassExpression;
if (isClassExpression(expression)) {
return checkExpression(expression).symbol;
}
const aliasLike = resolveEntityName(expression, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace, /*ignoreErrors*/ true, dontResolveAlias);
if (aliasLike) {
return aliasLike;
}
checkExpression(expression);
return getNodeLinks(expression).resolvedSymbol;
}
function getTargetOfAliasDeclaration(node: Declaration, dontRecursivelyResolve = false): Symbol | undefined {
switch (node.kind) {
case SyntaxKind.ImportEqualsDeclaration:
return getTargetOfImportEqualsDeclaration(<ImportEqualsDeclaration>node, dontRecursivelyResolve);
case SyntaxKind.ImportClause:
return getTargetOfImportClause(<ImportClause>node, dontRecursivelyResolve);
case SyntaxKind.NamespaceImport:
return getTargetOfNamespaceImport(<NamespaceImport>node, dontRecursivelyResolve);
case SyntaxKind.ImportSpecifier:
return getTargetOfImportSpecifier(<ImportSpecifier>node, dontRecursivelyResolve);
case SyntaxKind.ExportSpecifier:
return getTargetOfExportSpecifier(<ExportSpecifier>node, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace, dontRecursivelyResolve);
case SyntaxKind.ExportAssignment:
case SyntaxKind.BinaryExpression:
return getTargetOfExportAssignment((<ExportAssignment | BinaryExpression>node), dontRecursivelyResolve);
case SyntaxKind.NamespaceExportDeclaration:
return getTargetOfNamespaceExportDeclaration(<NamespaceExportDeclaration>node, dontRecursivelyResolve);
default:
return Debug.fail();
}
}
/**
* Indicates that a symbol is an alias that does not merge with a local declaration.
* OR Is a JSContainer which may merge an alias with a local declaration
*/
function isNonLocalAlias(symbol: Symbol | undefined, excludes = SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace): symbol is Symbol {
if (!symbol) return false;
return (symbol.flags & (SymbolFlags.Alias | excludes)) === SymbolFlags.Alias || !!(symbol.flags & SymbolFlags.Alias && symbol.flags & SymbolFlags.Assignment);
}
function resolveSymbol(symbol: Symbol, dontResolveAlias?: boolean): Symbol;
function resolveSymbol(symbol: Symbol | undefined, dontResolveAlias?: boolean): Symbol | undefined;
function resolveSymbol(symbol: Symbol | undefined, dontResolveAlias?: boolean): Symbol | undefined {
return !dontResolveAlias && isNonLocalAlias(symbol) ? resolveAlias(symbol) : symbol;
}
function resolveAlias(symbol: Symbol): Symbol {
Debug.assert((symbol.flags & SymbolFlags.Alias) !== 0, "Should only get Alias here.");
const links = getSymbolLinks(symbol);
if (!links.target) {
links.target = resolvingSymbol;
const node = getDeclarationOfAliasSymbol(symbol);
if (!node) return Debug.fail();
const target = getTargetOfAliasDeclaration(node);
if (links.target === resolvingSymbol) {
links.target = target || unknownSymbol;
}
else {
error(node, Diagnostics.Circular_definition_of_import_alias_0, symbolToString(symbol));
}
}
else if (links.target === resolvingSymbol) {
links.target = unknownSymbol;
}
return links.target;
}
function markExportAsReferenced(node: ImportEqualsDeclaration | ExportAssignment | ExportSpecifier) {
const symbol = getSymbolOfNode(node);
const target = resolveAlias(symbol);
if (target) {
const markAlias = target === unknownSymbol ||
((target.flags & SymbolFlags.Value) && !isConstEnumOrConstEnumOnlyModule(target));
if (markAlias) {
markAliasSymbolAsReferenced(symbol);
}
}
}
// When an alias symbol is referenced, we need to mark the entity it references as referenced and in turn repeat that until
// we reach a non-alias or an exported entity (which is always considered referenced). We do this by checking the target of
// the alias as an expression (which recursively takes us back here if the target references another alias).
function markAliasSymbolAsReferenced(symbol: Symbol) {
const links = getSymbolLinks(symbol);
if (!links.referenced) {
links.referenced = true;
const node = getDeclarationOfAliasSymbol(symbol);
if (!node) return Debug.fail();
if (node.kind === SyntaxKind.ExportAssignment) {
// export default <symbol>
checkExpressionCached((<ExportAssignment>node).expression);
}
else if (node.kind === SyntaxKind.ExportSpecifier) {
// export { <symbol> } or export { <symbol> as foo }
checkExpressionCached((<ExportSpecifier>node).propertyName || (<ExportSpecifier>node).name);
}
else if (isInternalModuleImportEqualsDeclaration(node)) {
// import foo = <symbol>
checkExpressionCached(<Expression>node.moduleReference);
}
}
}
// This function is only for imports with entity names
function getSymbolOfPartOfRightHandSideOfImportEquals(entityName: EntityName, dontResolveAlias?: boolean): Symbol | undefined {
// There are three things we might try to look for. In the following examples,
// the search term is enclosed in |...|:
//
// import a = |b|; // Namespace
// import a = |b.c|; // Value, type, namespace
// import a = |b.c|.d; // Namespace
if (entityName.kind === SyntaxKind.Identifier && isRightSideOfQualifiedNameOrPropertyAccess(entityName)) {
entityName = <QualifiedName>entityName.parent;
}
// Check for case 1 and 3 in the above example
if (entityName.kind === SyntaxKind.Identifier || entityName.parent.kind === SyntaxKind.QualifiedName) {
return resolveEntityName(entityName, SymbolFlags.Namespace, /*ignoreErrors*/ false, dontResolveAlias);
}
else {
// Case 2 in above example
// entityName.kind could be a QualifiedName or a Missing identifier
Debug.assert(entityName.parent.kind === SyntaxKind.ImportEqualsDeclaration);
return resolveEntityName(entityName, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace, /*ignoreErrors*/ false, dontResolveAlias);
}
}
function getFullyQualifiedName(symbol: Symbol, containingLocation?: Node): string {
return symbol.parent ? getFullyQualifiedName(symbol.parent, containingLocation) + "." + symbolToString(symbol) : symbolToString(symbol, containingLocation, /*meaning*/ undefined, SymbolFormatFlags.DoNotIncludeSymbolChain | SymbolFormatFlags.AllowAnyNodeKind);
}
/**
* Resolves a qualified name and any involved aliases.
*/
function resolveEntityName(name: EntityNameOrEntityNameExpression, meaning: SymbolFlags, ignoreErrors?: boolean, dontResolveAlias?: boolean, location?: Node): Symbol | undefined {
if (nodeIsMissing(name)) {
return undefined;
}
const namespaceMeaning = SymbolFlags.Namespace | (isInJSFile(name) ? meaning & SymbolFlags.Value : 0);
let symbol: Symbol | undefined;
if (name.kind === SyntaxKind.Identifier) {
const message = meaning === namespaceMeaning ? Diagnostics.Cannot_find_namespace_0 : getCannotFindNameDiagnosticForName(getFirstIdentifier(name).escapedText);
const symbolFromJSPrototype = isInJSFile(name) ? resolveEntityNameFromAssignmentDeclaration(name, meaning) : undefined;
symbol = resolveName(location || name, name.escapedText, meaning, ignoreErrors || symbolFromJSPrototype ? undefined : message, name, /*isUse*/ true);
if (!symbol) {
return symbolFromJSPrototype;
}
}
else if (name.kind === SyntaxKind.QualifiedName || name.kind === SyntaxKind.PropertyAccessExpression) {
const left = name.kind === SyntaxKind.QualifiedName ? name.left : name.expression;
const right = name.kind === SyntaxKind.QualifiedName ? name.right : name.name;
let namespace = resolveEntityName(left, namespaceMeaning, ignoreErrors, /*dontResolveAlias*/ false, location);
if (!namespace || nodeIsMissing(right)) {
return undefined;
}
else if (namespace === unknownSymbol) {
return namespace;
}
if (isInJSFile(name)) {
if (namespace.valueDeclaration &&
isVariableDeclaration(namespace.valueDeclaration) &&
namespace.valueDeclaration.initializer &&
isCommonJsRequire(namespace.valueDeclaration.initializer)) {
const moduleName = (namespace.valueDeclaration.initializer as CallExpression).arguments[0] as StringLiteral;
const moduleSym = resolveExternalModuleName(moduleName, moduleName);
if (moduleSym) {
const resolvedModuleSymbol = resolveExternalModuleSymbol(moduleSym);
if (resolvedModuleSymbol) {
namespace = resolvedModuleSymbol;
}
}
}
}
symbol = getSymbol(getExportsOfSymbol(namespace), right.escapedText, meaning);
if (!symbol) {
if (!ignoreErrors) {
error(right, Diagnostics.Namespace_0_has_no_exported_member_1, getFullyQualifiedName(namespace), declarationNameToString(right));
}
return undefined;
}
}
else {
throw Debug.assertNever(name, "Unknown entity name kind.");
}
Debug.assert((getCheckFlags(symbol) & CheckFlags.Instantiated) === 0, "Should never get an instantiated symbol here.");
return (symbol.flags & meaning) || dontResolveAlias ? symbol : resolveAlias(symbol);
}
/**
* 1. For prototype-property methods like `A.prototype.m = function () ...`, try to resolve names in the scope of `A` too.
* Note that prototype-property assignment to locations outside the current file (eg globals) doesn't work, so
* name resolution won't work either.
* 2. For property assignments like `{ x: function f () { } }`, try to resolve names in the scope of `f` too.
*/
function resolveEntityNameFromAssignmentDeclaration(name: Identifier, meaning: SymbolFlags) {
if (isJSDocTypeReference(name.parent)) {
const secondaryLocation = getAssignmentDeclarationLocation(name.parent);
if (secondaryLocation) {
return resolveName(secondaryLocation, name.escapedText, meaning, /*nameNotFoundMessage*/ undefined, name, /*isUse*/ true);
}
}
}
function getAssignmentDeclarationLocation(node: TypeReferenceNode): Node | undefined {
const typeAlias = findAncestor(node, node => !(isJSDocNode(node) || node.flags & NodeFlags.JSDoc) ? "quit" : isJSDocTypeAlias(node));
if (typeAlias) {
return;
}
const host = getJSDocHost(node);
if (isExpressionStatement(host) &&
isBinaryExpression(host.expression) &&
getAssignmentDeclarationKind(host.expression) === AssignmentDeclarationKind.PrototypeProperty) {
// X.prototype.m = /** @param {K} p */ function () { } <-- look for K on X's declaration
const symbol = getSymbolOfNode(host.expression.left);
if (symbol) {
return getDeclarationOfJSPrototypeContainer(symbol);
}
}
if ((isObjectLiteralMethod(host) || isPropertyAssignment(host)) &&
isBinaryExpression(host.parent.parent) &&
getAssignmentDeclarationKind(host.parent.parent) === AssignmentDeclarationKind.Prototype) {
// X.prototype = { /** @param {K} p */m() { } } <-- look for K on X's declaration
const symbol = getSymbolOfNode(host.parent.parent.left);
if (symbol) {
return getDeclarationOfJSPrototypeContainer(symbol);
}
}
const sig = getHostSignatureFromJSDocHost(host);
if (sig) {
const symbol = getSymbolOfNode(sig);
return symbol && symbol.valueDeclaration;
}
}
function getDeclarationOfJSPrototypeContainer(symbol: Symbol) {
const decl = symbol.parent!.valueDeclaration;
if (!decl) {
return undefined;
}
const initializer = isAssignmentDeclaration(decl) ? getAssignedExpandoInitializer(decl) :
hasOnlyExpressionInitializer(decl) ? getDeclaredExpandoInitializer(decl) :
undefined;
return initializer || decl;
}
function resolveExternalModuleName(location: Node, moduleReferenceExpression: Expression, ignoreErrors?: boolean): Symbol | undefined {
return resolveExternalModuleNameWorker(location, moduleReferenceExpression, ignoreErrors ? undefined : Diagnostics.Cannot_find_module_0);
}
function resolveExternalModuleNameWorker(location: Node, moduleReferenceExpression: Expression, moduleNotFoundError: DiagnosticMessage | undefined, isForAugmentation = false): Symbol | undefined {
return isStringLiteralLike(moduleReferenceExpression)
? resolveExternalModule(location, moduleReferenceExpression.text, moduleNotFoundError, moduleReferenceExpression, isForAugmentation)
: undefined;
}
function resolveExternalModule(location: Node, moduleReference: string, moduleNotFoundError: DiagnosticMessage | undefined, errorNode: Node, isForAugmentation = false): Symbol | undefined {
if (moduleReference === undefined) {
return;
}
if (startsWith(moduleReference, "@types/")) {
const diag = Diagnostics.Cannot_import_type_declaration_files_Consider_importing_0_instead_of_1;
const withoutAtTypePrefix = removePrefix(moduleReference, "@types/");
error(errorNode, diag, withoutAtTypePrefix, moduleReference);
}
const ambientModule = tryFindAmbientModule(moduleReference, /*withAugmentations*/ true);
if (ambientModule) {
return ambientModule;
}
const currentSourceFile = getSourceFileOfNode(location);
const resolvedModule = getResolvedModule(currentSourceFile, moduleReference)!; // TODO: GH#18217
const resolutionDiagnostic = resolvedModule && getResolutionDiagnostic(compilerOptions, resolvedModule);
const sourceFile = resolvedModule && !resolutionDiagnostic && host.getSourceFile(resolvedModule.resolvedFileName);
if (sourceFile) {
if (sourceFile.symbol) {
if (resolvedModule.isExternalLibraryImport && !resolutionExtensionIsTSOrJson(resolvedModule.extension)) {
errorOnImplicitAnyModule(/*isError*/ false, errorNode, resolvedModule, moduleReference);
}
// merged symbol is module declaration symbol combined with all augmentations
return getMergedSymbol(sourceFile.symbol);
}
if (moduleNotFoundError) {
// report errors only if it was requested
error(errorNode, Diagnostics.File_0_is_not_a_module, sourceFile.fileName);
}
return undefined;
}
if (patternAmbientModules) {
const pattern = findBestPatternMatch(patternAmbientModules, _ => _.pattern, moduleReference);
if (pattern) {
return getMergedSymbol(pattern.symbol);
}
}
// May be an untyped module. If so, ignore resolutionDiagnostic.
if (resolvedModule && !resolutionExtensionIsTSOrJson(resolvedModule.extension) && resolutionDiagnostic === undefined || resolutionDiagnostic === Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type) {
if (isForAugmentation) {
const diag = Diagnostics.Invalid_module_name_in_augmentation_Module_0_resolves_to_an_untyped_module_at_1_which_cannot_be_augmented;
error(errorNode, diag, moduleReference, resolvedModule.resolvedFileName);
}
else {
errorOnImplicitAnyModule(/*isError*/ noImplicitAny && !!moduleNotFoundError, errorNode, resolvedModule, moduleReference);
}
// Failed imports and untyped modules are both treated in an untyped manner; only difference is whether we give a diagnostic first.
return undefined;
}
if (moduleNotFoundError) {
// For relative paths, see if this was possibly a projectReference redirect
if (pathIsRelative(moduleReference)) {
const sourceFile = getSourceFileOfNode(location);
const redirects = sourceFile.redirectedReferences;
if (redirects) {
const normalizedTargetPath = getNormalizedAbsolutePath(moduleReference, getDirectoryPath(sourceFile.fileName));
for (const ext of [Extension.Ts, Extension.Tsx]) {
const probePath = normalizedTargetPath + ext;
if (redirects.indexOf(probePath) >= 0) {
error(errorNode, Diagnostics.Output_file_0_has_not_been_built_from_source_file_1, moduleReference, probePath);
return undefined;
}
}
}
}
if (resolutionDiagnostic) {
error(errorNode, resolutionDiagnostic, moduleReference, resolvedModule.resolvedFileName);
}
else {
const tsExtension = tryExtractTSExtension(moduleReference);
if (tsExtension) {
const diag = Diagnostics.An_import_path_cannot_end_with_a_0_extension_Consider_importing_1_instead;
error(errorNode, diag, tsExtension, removeExtension(moduleReference, tsExtension));
}
else if (!compilerOptions.resolveJsonModule &&
fileExtensionIs(moduleReference, Extension.Json) &&
getEmitModuleResolutionKind(compilerOptions) === ModuleResolutionKind.NodeJs &&
hasJsonModuleEmitEnabled(compilerOptions)) {
error(errorNode, Diagnostics.Cannot_find_module_0_Consider_using_resolveJsonModule_to_import_module_with_json_extension, moduleReference);
}
else {
error(errorNode, moduleNotFoundError, moduleReference);
}
}
}
return undefined;
}
function errorOnImplicitAnyModule(isError: boolean, errorNode: Node, { packageId, resolvedFileName }: ResolvedModuleFull, moduleReference: string): void {
const errorInfo = !isExternalModuleNameRelative(moduleReference) && packageId
? typesPackageExists(packageId.name)
? chainDiagnosticMessages(
/*details*/ undefined,
Diagnostics.If_the_0_package_actually_exposes_this_module_consider_sending_a_pull_request_to_amend_https_Colon_Slash_Slashgithub_com_SlashDefinitelyTyped_SlashDefinitelyTyped_Slashtree_Slashmaster_Slashtypes_Slash_1,
packageId.name, mangleScopedPackageName(packageId.name))
: chainDiagnosticMessages(
/*details*/ undefined,
Diagnostics.Try_npm_install_types_Slash_1_if_it_exists_or_add_a_new_declaration_d_ts_file_containing_declare_module_0,
moduleReference,
mangleScopedPackageName(packageId.name))
: undefined;
errorOrSuggestion(isError, errorNode, chainDiagnosticMessages(
errorInfo,
Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type,
moduleReference,
resolvedFileName));
}
function typesPackageExists(packageName: string): boolean {
return getPackagesSet().has(getTypesPackageName(packageName));
}
function resolveExternalModuleSymbol(moduleSymbol: Symbol, dontResolveAlias?: boolean): Symbol;
function resolveExternalModuleSymbol(moduleSymbol: Symbol | undefined, dontResolveAlias?: boolean): Symbol | undefined;
function resolveExternalModuleSymbol(moduleSymbol: Symbol, dontResolveAlias?: boolean): Symbol {
if (moduleSymbol) {
const exportEquals = resolveSymbol(moduleSymbol.exports!.get(InternalSymbolName.ExportEquals), dontResolveAlias);
const exported = getCommonJsExportEquals(exportEquals, moduleSymbol);
return getMergedSymbol(exported) || moduleSymbol;
}
return undefined!;
}
function getCommonJsExportEquals(exported: Symbol | undefined, moduleSymbol: Symbol): Symbol | undefined {
if (!exported || exported === unknownSymbol || exported === moduleSymbol || moduleSymbol.exports!.size === 1 || exported.flags & SymbolFlags.Alias) {
return exported;
}
const merged = cloneSymbol(exported);
if (merged.exports === undefined) {
merged.flags = merged.flags | SymbolFlags.ValueModule;
merged.exports = createSymbolTable();
}
moduleSymbol.exports!.forEach((s, name) => {
if (name === InternalSymbolName.ExportEquals) return;
merged.exports!.set(name, merged.exports!.has(name) ? mergeSymbol(merged.exports!.get(name)!, s) : s);
});
return merged;
}
// An external module with an 'export =' declaration may be referenced as an ES6 module provided the 'export ='
// references a symbol that is at least declared as a module or a variable. The target of the 'export =' may
// combine other declarations with the module or variable (e.g. a class/module, function/module, interface/variable).
function resolveESModuleSymbol(moduleSymbol: Symbol | undefined, referencingLocation: Node, dontResolveAlias: boolean): Symbol | undefined {
const symbol = resolveExternalModuleSymbol(moduleSymbol, dontResolveAlias);
if (!dontResolveAlias && symbol) {
if (!(symbol.flags & (SymbolFlags.Module | SymbolFlags.Variable)) && !getDeclarationOfKind(symbol, SyntaxKind.SourceFile)) {
const compilerOptionName = moduleKind >= ModuleKind.ES2015
? "allowSyntheticDefaultImports"
: "esModuleInterop";
error(referencingLocation, Diagnostics.This_module_can_only_be_referenced_with_ECMAScript_imports_Slashexports_by_turning_on_the_0_flag_and_referencing_its_default_export, compilerOptionName);
return symbol;
}
if (compilerOptions.esModuleInterop) {
const referenceParent = referencingLocation.parent;
if (
(isImportDeclaration(referenceParent) && getNamespaceDeclarationNode(referenceParent)) ||
isImportCall(referenceParent)
) {
const type = getTypeOfSymbol(symbol);
let sigs = getSignaturesOfStructuredType(type, SignatureKind.Call);
if (!sigs || !sigs.length) {
sigs = getSignaturesOfStructuredType(type, SignatureKind.Construct);
}
if (sigs && sigs.length) {
const moduleType = getTypeWithSyntheticDefaultImportType(type, symbol, moduleSymbol!);
// Create a new symbol which has the module's type less the call and construct signatures
const result = createSymbol(symbol.flags, symbol.escapedName);
result.declarations = symbol.declarations ? symbol.declarations.slice() : [];
result.parent = symbol.parent;
result.target = symbol;
result.originatingImport = referenceParent;
if (symbol.valueDeclaration) result.valueDeclaration = symbol.valueDeclaration;
if (symbol.constEnumOnlyModule) result.constEnumOnlyModule = true;
if (symbol.members) result.members = cloneMap(symbol.members);
if (symbol.exports) result.exports = cloneMap(symbol.exports);
const resolvedModuleType = resolveStructuredTypeMembers(moduleType as StructuredType); // Should already be resolved from the signature checks above
result.type = createAnonymousType(result, resolvedModuleType.members, emptyArray, emptyArray, resolvedModuleType.stringIndexInfo, resolvedModuleType.numberIndexInfo);
return result;
}
}
}
}
return symbol;
}
function hasExportAssignmentSymbol(moduleSymbol: Symbol): boolean {
return moduleSymbol.exports!.get(InternalSymbolName.ExportEquals) !== undefined;
}
function getExportsOfModuleAsArray(moduleSymbol: Symbol): Symbol[] {
return symbolsToArray(getExportsOfModule(moduleSymbol));
}
function getExportsAndPropertiesOfModule(moduleSymbol: Symbol): Symbol[] {
const exports = getExportsOfModuleAsArray(moduleSymbol);
const exportEquals = resolveExternalModuleSymbol(moduleSymbol);
if (exportEquals !== moduleSymbol) {
addRange(exports, getPropertiesOfType(getTypeOfSymbol(exportEquals)));
}
return exports;
}
function tryGetMemberInModuleExports(memberName: __String, moduleSymbol: Symbol): Symbol | undefined {
const symbolTable = getExportsOfModule(moduleSymbol);
if (symbolTable) {
return symbolTable.get(memberName);
}
}
function tryGetMemberInModuleExportsAndProperties(memberName: __String, moduleSymbol: Symbol): Symbol | undefined {
const symbol = tryGetMemberInModuleExports(memberName, moduleSymbol);
if (symbol) {
return symbol;
}
const exportEquals = resolveExternalModuleSymbol(moduleSymbol);
if (exportEquals === moduleSymbol) {
return undefined;
}
const type = getTypeOfSymbol(exportEquals);
return type.flags & TypeFlags.Primitive ? undefined : getPropertyOfType(type, memberName);
}
function getExportsOfSymbol(symbol: Symbol): SymbolTable {
return symbol.flags & SymbolFlags.Class ? getResolvedMembersOrExportsOfSymbol(symbol, MembersOrExportsResolutionKind.resolvedExports) :
symbol.flags & SymbolFlags.Module ? getExportsOfModule(symbol) :
symbol.exports || emptySymbols;
}
function getExportsOfModule(moduleSymbol: Symbol): SymbolTable {
const links = getSymbolLinks(moduleSymbol);
return links.resolvedExports || (links.resolvedExports = getExportsOfModuleWorker(moduleSymbol));
}
interface ExportCollisionTracker {
specifierText: string;
exportsWithDuplicate: ExportDeclaration[];
}
type ExportCollisionTrackerTable = UnderscoreEscapedMap<ExportCollisionTracker>;
/**
* Extends one symbol table with another while collecting information on name collisions for error message generation into the `lookupTable` argument
* Not passing `lookupTable` and `exportNode` disables this collection, and just extends the tables
*/
function extendExportSymbols(target: SymbolTable, source: SymbolTable | undefined, lookupTable?: ExportCollisionTrackerTable, exportNode?: ExportDeclaration) {
if (!source) return;
source.forEach((sourceSymbol, id) => {
if (id === InternalSymbolName.Default) return;
const targetSymbol = target.get(id);
if (!targetSymbol) {
target.set(id, sourceSymbol);
if (lookupTable && exportNode) {
lookupTable.set(id, {
specifierText: getTextOfNode(exportNode.moduleSpecifier!)
} as ExportCollisionTracker);
}
}
else if (lookupTable && exportNode && targetSymbol && resolveSymbol(targetSymbol) !== resolveSymbol(sourceSymbol)) {
const collisionTracker = lookupTable.get(id)!;
if (!collisionTracker.exportsWithDuplicate) {
collisionTracker.exportsWithDuplicate = [exportNode];
}
else {
collisionTracker.exportsWithDuplicate.push(exportNode);
}
}
});
}
function getExportsOfModuleWorker(moduleSymbol: Symbol): SymbolTable {
const visitedSymbols: Symbol[] = [];
// A module defined by an 'export=' consists of one export that needs to be resolved
moduleSymbol = resolveExternalModuleSymbol(moduleSymbol);
return visit(moduleSymbol) || emptySymbols;
// The ES6 spec permits export * declarations in a module to circularly reference the module itself. For example,
// module 'a' can 'export * from "b"' and 'b' can 'export * from "a"' without error.
function visit(symbol: Symbol | undefined): SymbolTable | undefined {
if (!(symbol && symbol.exports && pushIfUnique(visitedSymbols, symbol))) {
return;
}
const symbols = cloneMap(symbol.exports);
// All export * declarations are collected in an __export symbol by the binder
const exportStars = symbol.exports.get(InternalSymbolName.ExportStar);
if (exportStars) {
const nestedSymbols = createSymbolTable();
const lookupTable = createMap<ExportCollisionTracker>() as ExportCollisionTrackerTable;
for (const node of exportStars.declarations) {
const resolvedModule = resolveExternalModuleName(node, (node as ExportDeclaration).moduleSpecifier!);
const exportedSymbols = visit(resolvedModule);
extendExportSymbols(
nestedSymbols,
exportedSymbols,
lookupTable,
node as ExportDeclaration
);
}
lookupTable.forEach(({ exportsWithDuplicate }, id) => {
// It's not an error if the file with multiple `export *`s with duplicate names exports a member with that name itself
if (id === "export=" || !(exportsWithDuplicate && exportsWithDuplicate.length) || symbols.has(id)) {
return;
}
for (const node of exportsWithDuplicate) {
diagnostics.add(createDiagnosticForNode(
node,
Diagnostics.Module_0_has_already_exported_a_member_named_1_Consider_explicitly_re_exporting_to_resolve_the_ambiguity,
lookupTable.get(id)!.specifierText,
unescapeLeadingUnderscores(id)
));
}
});
extendExportSymbols(symbols, nestedSymbols);
}
return symbols;
}
}
function getMergedSymbol(symbol: Symbol): Symbol;
function getMergedSymbol(symbol: Symbol | undefined): Symbol | undefined;
function getMergedSymbol(symbol: Symbol | undefined): Symbol | undefined {
let merged: Symbol;
return symbol && symbol.mergeId && (merged = mergedSymbols[symbol.mergeId]) ? merged : symbol;
}
function getSymbolOfNode(node: Declaration): Symbol;
function getSymbolOfNode(node: Node): Symbol | undefined;
function getSymbolOfNode(node: Node): Symbol | undefined {
return getMergedSymbol(node.symbol && getLateBoundSymbol(node.symbol));
}
function getParentOfSymbol(symbol: Symbol): Symbol | undefined {
return getMergedSymbol(symbol.parent && getLateBoundSymbol(symbol.parent));
}
function getAlternativeContainingModules(symbol: Symbol, enclosingDeclaration: Node): Symbol[] {
const containingFile = getSourceFileOfNode(enclosingDeclaration);
const id = "" + getNodeId(containingFile);
const links = getSymbolLinks(symbol);
let results: Symbol[] | undefined;
if (links.extendedContainersByFile && (results = links.extendedContainersByFile.get(id))) {
return results;
}
if (containingFile && containingFile.imports) {
// Try to make an import using an import already in the enclosing file, if possible
for (const importRef of containingFile.imports) {
if (nodeIsSynthesized(importRef)) continue; // Synthetic names can't be resolved by `resolveExternalModuleName` - they'll cause a debug assert if they error
const resolvedModule = resolveExternalModuleName(enclosingDeclaration, importRef, /*ignoreErrors*/ true);
if (!resolvedModule) continue;
const ref = getAliasForSymbolInContainer(resolvedModule, symbol);
if (!ref) continue;
results = append(results, resolvedModule);
}
if (length(results)) {
(links.extendedContainersByFile || (links.extendedContainersByFile = createMap())).set(id, results!);
return results!;
}
}
if (links.extendedContainers) {
return links.extendedContainers;
}
// No results from files already being imported by this file - expand search (expensive, but not location-specific, so cached)
const otherFiles = host.getSourceFiles();
for (const file of otherFiles) {
if (!isExternalModule(file)) continue;
const sym = getSymbolOfNode(file);
const ref = getAliasForSymbolInContainer(sym, symbol);
if (!ref) continue;
results = append(results, sym);
}
return links.extendedContainers = results || emptyArray;
}
/**
* Attempts to find the symbol corresponding to the container a symbol is in - usually this
* is just its' `.parent`, but for locals, this value is `undefined`
*/
function getContainersOfSymbol(symbol: Symbol, enclosingDeclaration: Node | undefined): Symbol[] | undefined {
const container = getParentOfSymbol(symbol);
if (container) {
const additionalContainers = mapDefined(container.declarations, fileSymbolIfFileSymbolExportEqualsContainer);
const reexportContainers = enclosingDeclaration && getAlternativeContainingModules(symbol, enclosingDeclaration);
if (enclosingDeclaration && getAccessibleSymbolChain(container, enclosingDeclaration, SymbolFlags.Namespace, /*externalOnly*/ false)) {
return concatenate(concatenate([container], additionalContainers), reexportContainers); // This order expresses a preference for the real container if it is in scope
}
const res = append(additionalContainers, container);
return concatenate(res, reexportContainers);
}
const candidates = mapDefined(symbol.declarations, d => !isAmbientModule(d) && d.parent && hasNonGlobalAugmentationExternalModuleSymbol(d.parent) ? getSymbolOfNode(d.parent) : undefined);
if (!length(candidates)) {
return undefined;
}
return mapDefined(candidates, candidate => getAliasForSymbolInContainer(candidate, symbol) ? candidate : undefined);
function fileSymbolIfFileSymbolExportEqualsContainer(d: Declaration) {
const fileSymbol = getExternalModuleContainer(d);
const exported = fileSymbol && fileSymbol.exports && fileSymbol.exports.get(InternalSymbolName.ExportEquals);
return resolveSymbol(exported) === resolveSymbol(container) ? fileSymbol : undefined;
}
}
function getAliasForSymbolInContainer(container: Symbol, symbol: Symbol) {
if (container === getParentOfSymbol(symbol)) {
// fast path, `symbol` is either already the alias or isn't aliased
return symbol;
}
const exports = getExportsOfSymbol(container);
const quick = exports.get(symbol.escapedName);
if (quick && symbolRefersToTarget(quick)) {
return quick;
}
return forEachEntry(exports, exported => {
if (symbolRefersToTarget(exported)) {
return exported;
}
});
function symbolRefersToTarget(s: Symbol) {
if (s === symbol || resolveSymbol(s) === symbol || resolveSymbol(s) === resolveSymbol(symbol)) {
return s;
}
}
}
function getExportSymbolOfValueSymbolIfExported(symbol: Symbol): Symbol;
function getExportSymbolOfValueSymbolIfExported(symbol: Symbol | undefined): Symbol | undefined;
function getExportSymbolOfValueSymbolIfExported(symbol: Symbol | undefined): Symbol | undefined {
return getMergedSymbol(symbol && (symbol.flags & SymbolFlags.ExportValue) !== 0 ? symbol.exportSymbol : symbol);
}
function symbolIsValue(symbol: Symbol): boolean {
return !!(symbol.flags & SymbolFlags.Value || symbol.flags & SymbolFlags.Alias && resolveAlias(symbol).flags & SymbolFlags.Value);
}
function findConstructorDeclaration(node: ClassLikeDeclaration): ConstructorDeclaration | undefined {
const members = node.members;
for (const member of members) {
if (member.kind === SyntaxKind.Constructor && nodeIsPresent((<ConstructorDeclaration>member).body)) {
return <ConstructorDeclaration>member;
}
}
}
function createType(flags: TypeFlags): Type {
const result = new Type(checker, flags);
typeCount++;
result.id = typeCount;
return result;
}
function createIntrinsicType(kind: TypeFlags, intrinsicName: string): IntrinsicType {
const type = <IntrinsicType>createType(kind);
type.intrinsicName = intrinsicName;
return type;
}
function createNullableType(kind: TypeFlags, intrinsicName: string, objectFlags: ObjectFlags): NullableType {
const type = createIntrinsicType(kind, intrinsicName);
type.objectFlags = objectFlags;
return type;
}
function createBooleanType(trueFalseTypes: ReadonlyArray<Type>): IntrinsicType & UnionType {
const type = <IntrinsicType & UnionType>getUnionType(trueFalseTypes);
type.flags |= TypeFlags.Boolean;
type.intrinsicName = "boolean";
return type;
}
function createObjectType(objectFlags: ObjectFlags, symbol?: Symbol): ObjectType {
const type = <ObjectType>createType(TypeFlags.Object);
type.objectFlags = objectFlags;
type.symbol = symbol!;
type.members = undefined;
type.properties = undefined;
type.callSignatures = undefined;
type.constructSignatures = undefined;
type.stringIndexInfo = undefined;
type.numberIndexInfo = undefined;
return type;
}
function createTypeofType() {
return getUnionType(arrayFrom(typeofEQFacts.keys(), getLiteralType));
}
function createTypeParameter(symbol?: Symbol) {
const type = <TypeParameter>createType(TypeFlags.TypeParameter);
if (symbol) type.symbol = symbol;
return type;
}
// A reserved member name starts with two underscores, but the third character cannot be an underscore
// or the @ symbol. A third underscore indicates an escaped form of an identifer that started
// with at least two underscores. The @ character indicates that the name is denoted by a well known ES
// Symbol instance.
function isReservedMemberName(name: __String) {
return (name as string).charCodeAt(0) === CharacterCodes._ &&
(name as string).charCodeAt(1) === CharacterCodes._ &&
(name as string).charCodeAt(2) !== CharacterCodes._ &&
(name as string).charCodeAt(2) !== CharacterCodes.at;
}
function getNamedMembers(members: SymbolTable): Symbol[] {
let result: Symbol[] | undefined;
members.forEach((symbol, id) => {
if (!isReservedMemberName(id) && symbolIsValue(symbol)) {
(result || (result = [])).push(symbol);
}
});
return result || emptyArray;
}
function setStructuredTypeMembers(type: StructuredType, members: SymbolTable, callSignatures: ReadonlyArray<Signature>, constructSignatures: ReadonlyArray<Signature>, stringIndexInfo: IndexInfo | undefined, numberIndexInfo: IndexInfo | undefined): ResolvedType {
(<ResolvedType>type).members = members;
(<ResolvedType>type).properties = members === emptySymbols ? emptyArray : getNamedMembers(members);
(<ResolvedType>type).callSignatures = callSignatures;
(<ResolvedType>type).constructSignatures = constructSignatures;
(<ResolvedType>type).stringIndexInfo = stringIndexInfo;
(<ResolvedType>type).numberIndexInfo = numberIndexInfo;
return <ResolvedType>type;
}
function createAnonymousType(symbol: Symbol | undefined, members: SymbolTable, callSignatures: ReadonlyArray<Signature>, constructSignatures: ReadonlyArray<Signature>, stringIndexInfo: IndexInfo | undefined, numberIndexInfo: IndexInfo | undefined): ResolvedType {
return setStructuredTypeMembers(createObjectType(ObjectFlags.Anonymous, symbol),
members, callSignatures, constructSignatures, stringIndexInfo, numberIndexInfo);
}
function forEachSymbolTableInScope<T>(enclosingDeclaration: Node | undefined, callback: (symbolTable: SymbolTable) => T): T {
let result: T;
for (let location = enclosingDeclaration; location; location = location.parent) {
// Locals of a source file are not in scope (because they get merged into the global symbol table)
if (location.locals && !isGlobalSourceFile(location)) {
if (result = callback(location.locals)) {
return result;
}
}
switch (location.kind) {
case SyntaxKind.SourceFile:
if (!isExternalOrCommonJsModule(<SourceFile>location)) {
break;
}
// falls through
case SyntaxKind.ModuleDeclaration:
if (result = callback(getSymbolOfNode(location as ModuleDeclaration).exports!)) {
return result;
}
break;
}
}
return callback(globals);
}
function getQualifiedLeftMeaning(rightMeaning: SymbolFlags) {
// If we are looking in value space, the parent meaning is value, other wise it is namespace
return rightMeaning === SymbolFlags.Value ? SymbolFlags.Value : SymbolFlags.Namespace;
}
function getAccessibleSymbolChain(symbol: Symbol | undefined, enclosingDeclaration: Node | undefined, meaning: SymbolFlags, useOnlyExternalAliasing: boolean, visitedSymbolTablesMap: Map<SymbolTable[]> = createMap()): Symbol[] | undefined {
if (!(symbol && !isPropertyOrMethodDeclarationSymbol(symbol))) {
return undefined;
}
const id = "" + getSymbolId(symbol);
let visitedSymbolTables = visitedSymbolTablesMap.get(id);
if (!visitedSymbolTables) {
visitedSymbolTablesMap.set(id, visitedSymbolTables = []);
}
return forEachSymbolTableInScope(enclosingDeclaration, getAccessibleSymbolChainFromSymbolTable);
/**
* @param {ignoreQualification} boolean Set when a symbol is being looked for through the exports of another symbol (meaning we have a route to qualify it already)
*/
function getAccessibleSymbolChainFromSymbolTable(symbols: SymbolTable, ignoreQualification?: boolean): Symbol[] | undefined {
if (!pushIfUnique(visitedSymbolTables!, symbols)) {
return undefined;
}
const result = trySymbolTable(symbols, ignoreQualification);
visitedSymbolTables!.pop();
return result;
}
function canQualifySymbol(symbolFromSymbolTable: Symbol, meaning: SymbolFlags) {
// If the symbol is equivalent and doesn't need further qualification, this symbol is accessible
return !needsQualification(symbolFromSymbolTable, enclosingDeclaration, meaning) ||
// If symbol needs qualification, make sure that parent is accessible, if it is then this symbol is accessible too
!!getAccessibleSymbolChain(symbolFromSymbolTable.parent, enclosingDeclaration, getQualifiedLeftMeaning(meaning), useOnlyExternalAliasing, visitedSymbolTablesMap);
}
function isAccessible(symbolFromSymbolTable: Symbol, resolvedAliasSymbol?: Symbol, ignoreQualification?: boolean) {
return symbol === (resolvedAliasSymbol || symbolFromSymbolTable) &&
// if the symbolFromSymbolTable is not external module (it could be if it was determined as ambient external module and would be in globals table)
// and if symbolFromSymbolTable or alias resolution matches the symbol,
// check the symbol can be qualified, it is only then this symbol is accessible
!some(symbolFromSymbolTable.declarations, hasNonGlobalAugmentationExternalModuleSymbol) &&
(ignoreQualification || canQualifySymbol(symbolFromSymbolTable, meaning));
}
function trySymbolTable(symbols: SymbolTable, ignoreQualification: boolean | undefined): Symbol[] | undefined {
// If symbol is directly available by its name in the symbol table
if (isAccessible(symbols.get(symbol!.escapedName)!, /*resolvedAliasSymbol*/ undefined, ignoreQualification)) {
return [symbol!];
}
// Check if symbol is any of the alias
return forEachEntry(symbols, symbolFromSymbolTable => {
if (symbolFromSymbolTable.flags & SymbolFlags.Alias
&& symbolFromSymbolTable.escapedName !== InternalSymbolName.ExportEquals
&& symbolFromSymbolTable.escapedName !== InternalSymbolName.Default
&& !(isUMDExportSymbol(symbolFromSymbolTable) && enclosingDeclaration && isExternalModule(getSourceFileOfNode(enclosingDeclaration)))
// If `!useOnlyExternalAliasing`, we can use any type of alias to get the name
&& (!useOnlyExternalAliasing || some(symbolFromSymbolTable.declarations, isExternalModuleImportEqualsDeclaration))
// While exports are generally considered to be in scope, export-specifier declared symbols are _not_
// See similar comment in `resolveName` for details
&& (ignoreQualification || !getDeclarationOfKind(symbolFromSymbolTable, SyntaxKind.ExportSpecifier))
) {
const resolvedImportedSymbol = resolveAlias(symbolFromSymbolTable);
if (isAccessible(symbolFromSymbolTable, resolvedImportedSymbol, ignoreQualification)) {
return [symbolFromSymbolTable];
}
// Look in the exported members, if we can find accessibleSymbolChain, symbol is accessible using this chain
// but only if the symbolFromSymbolTable can be qualified
const candidateTable = getExportsOfSymbol(resolvedImportedSymbol);
const accessibleSymbolsFromExports = candidateTable && getAccessibleSymbolChainFromSymbolTable(candidateTable, /*ignoreQualification*/ true);
if (accessibleSymbolsFromExports && canQualifySymbol(symbolFromSymbolTable, getQualifiedLeftMeaning(meaning))) {
return [symbolFromSymbolTable].concat(accessibleSymbolsFromExports);
}
}
if (symbolFromSymbolTable.escapedName === symbol!.escapedName && symbolFromSymbolTable.exportSymbol) {
if (isAccessible(getMergedSymbol(symbolFromSymbolTable.exportSymbol), /*aliasSymbol*/ undefined, ignoreQualification)) {
return [symbol!];
}
}
});
}
}
function needsQualification(symbol: Symbol, enclosingDeclaration: Node | undefined, meaning: SymbolFlags) {
let qualify = false;
forEachSymbolTableInScope(enclosingDeclaration, symbolTable => {
// If symbol of this name is not available in the symbol table we are ok
let symbolFromSymbolTable = getMergedSymbol(symbolTable.get(symbol.escapedName));
if (!symbolFromSymbolTable) {
// Continue to the next symbol table
return false;
}
// If the symbol with this name is present it should refer to the symbol
if (symbolFromSymbolTable === symbol) {
// No need to qualify
return true;
}
// Qualify if the symbol from symbol table has same meaning as expected
symbolFromSymbolTable = (symbolFromSymbolTable.flags & SymbolFlags.Alias && !getDeclarationOfKind(symbolFromSymbolTable, SyntaxKind.ExportSpecifier)) ? resolveAlias(symbolFromSymbolTable) : symbolFromSymbolTable;
if (symbolFromSymbolTable.flags & meaning) {
qualify = true;
return true;
}
// Continue to the next symbol table
return false;
});
return qualify;
}
function isPropertyOrMethodDeclarationSymbol(symbol: Symbol) {
if (symbol.declarations && symbol.declarations.length) {
for (const declaration of symbol.declarations) {
switch (declaration.kind) {
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
continue;
default:
return false;
}
}
return true;
}
return false;
}
function isTypeSymbolAccessible(typeSymbol: Symbol, enclosingDeclaration: Node | undefined): boolean {
const access = isSymbolAccessible(typeSymbol, enclosingDeclaration, SymbolFlags.Type, /*shouldComputeAliasesToMakeVisible*/ false);
return access.accessibility === SymbolAccessibility.Accessible;
}
function isValueSymbolAccessible(typeSymbol: Symbol, enclosingDeclaration: Node): boolean {
const access = isSymbolAccessible(typeSymbol, enclosingDeclaration, SymbolFlags.Value, /*shouldComputeAliasesToMakeVisible*/ false);
return access.accessibility === SymbolAccessibility.Accessible;
}
function isAnySymbolAccessible(symbols: Symbol[] | undefined, enclosingDeclaration: Node, initialSymbol: Symbol, meaning: SymbolFlags, shouldComputeAliasesToMakeVisible: boolean): SymbolAccessibilityResult | undefined {
if (!length(symbols)) return;
let hadAccessibleChain: Symbol | undefined;
for (const symbol of symbols!) {
// Symbol is accessible if it by itself is accessible
const accessibleSymbolChain = getAccessibleSymbolChain(symbol, enclosingDeclaration, meaning, /*useOnlyExternalAliasing*/ false);
if (accessibleSymbolChain) {
hadAccessibleChain = symbol;
const hasAccessibleDeclarations = hasVisibleDeclarations(accessibleSymbolChain[0], shouldComputeAliasesToMakeVisible);
if (hasAccessibleDeclarations) {
return hasAccessibleDeclarations;
}
}
else {
if (some(symbol.declarations, hasNonGlobalAugmentationExternalModuleSymbol)) {
// Any meaning of a module symbol is always accessible via an `import` type
return {
accessibility: SymbolAccessibility.Accessible
};
}
}
// If we haven't got the accessible symbol, it doesn't mean the symbol is actually inaccessible.
// It could be a qualified symbol and hence verify the path
// e.g.:
// module m {
// export class c {
// }
// }
// const x: typeof m.c
// In the above example when we start with checking if typeof m.c symbol is accessible,
// we are going to see if c can be accessed in scope directly.
// But it can't, hence the accessible is going to be undefined, but that doesn't mean m.c is inaccessible
// It is accessible if the parent m is accessible because then m.c can be accessed through qualification
let containers = getContainersOfSymbol(symbol, enclosingDeclaration);
// If we're trying to reference some object literal in, eg `var a = { x: 1 }`, the symbol for the literal, `__object`, is distinct
// from the symbol of the declaration it is being assigned to. Since we can use the declaration to refer to the literal, however,
// we'd like to make that connection here - potentially causing us to paint the declararation's visibiility, and therefore the literal.
const firstDecl: Node = first(symbol.declarations);
if (!length(containers) && meaning & SymbolFlags.Value && firstDecl && isObjectLiteralExpression(firstDecl)) {
if (firstDecl.parent && isVariableDeclaration(firstDecl.parent) && firstDecl === firstDecl.parent.initializer) {
containers = [getSymbolOfNode(firstDecl.parent)];
}
}
const parentResult = isAnySymbolAccessible(containers, enclosingDeclaration, initialSymbol, initialSymbol === symbol ? getQualifiedLeftMeaning(meaning) : meaning, shouldComputeAliasesToMakeVisible);
if (parentResult) {
return parentResult;
}
}
if (hadAccessibleChain) {
return {
accessibility: SymbolAccessibility.NotAccessible,
errorSymbolName: symbolToString(initialSymbol, enclosingDeclaration, meaning),
errorModuleName: hadAccessibleChain !== initialSymbol ? symbolToString(hadAccessibleChain, enclosingDeclaration, SymbolFlags.Namespace) : undefined,
};
}
}
/**
* Check if the given symbol in given enclosing declaration is accessible and mark all associated alias to be visible if requested
*
* @param symbol a Symbol to check if accessible
* @param enclosingDeclaration a Node containing reference to the symbol
* @param meaning a SymbolFlags to check if such meaning of the symbol is accessible
* @param shouldComputeAliasToMakeVisible a boolean value to indicate whether to return aliases to be mark visible in case the symbol is accessible
*/
function isSymbolAccessible(symbol: Symbol | undefined, enclosingDeclaration: Node | undefined, meaning: SymbolFlags, shouldComputeAliasesToMakeVisible: boolean): SymbolAccessibilityResult {
if (symbol && enclosingDeclaration) {
const result = isAnySymbolAccessible([symbol], enclosingDeclaration, symbol, meaning, shouldComputeAliasesToMakeVisible);
if (result) {
return result;
}
// This could be a symbol that is not exported in the external module
// or it could be a symbol from different external module that is not aliased and hence cannot be named
const symbolExternalModule = forEach(symbol.declarations, getExternalModuleContainer);
if (symbolExternalModule) {
const enclosingExternalModule = getExternalModuleContainer(enclosingDeclaration);
if (symbolExternalModule !== enclosingExternalModule) {
// name from different external module that is not visible
return {
accessibility: SymbolAccessibility.CannotBeNamed,
errorSymbolName: symbolToString(symbol, enclosingDeclaration, meaning),
errorModuleName: symbolToString(symbolExternalModule)
};
}
}
// Just a local name that is not accessible
return {
accessibility: SymbolAccessibility.NotAccessible,
errorSymbolName: symbolToString(symbol, enclosingDeclaration, meaning),
};
}
return { accessibility: SymbolAccessibility.Accessible };
}
function getExternalModuleContainer(declaration: Node) {
const node = findAncestor(declaration, hasExternalModuleSymbol);
return node && getSymbolOfNode(node);
}
function hasExternalModuleSymbol(declaration: Node) {
return isAmbientModule(declaration) || (declaration.kind === SyntaxKind.SourceFile && isExternalOrCommonJsModule(<SourceFile>declaration));
}
function hasNonGlobalAugmentationExternalModuleSymbol(declaration: Node) {
return isModuleWithStringLiteralName(declaration) || (declaration.kind === SyntaxKind.SourceFile && isExternalOrCommonJsModule(<SourceFile>declaration));
}
function hasVisibleDeclarations(symbol: Symbol, shouldComputeAliasToMakeVisible: boolean): SymbolVisibilityResult | undefined {
let aliasesToMakeVisible: LateVisibilityPaintedStatement[] | undefined;
if (!every(symbol.declarations, getIsDeclarationVisible)) {
return undefined;
}
return { accessibility: SymbolAccessibility.Accessible, aliasesToMakeVisible };
function getIsDeclarationVisible(declaration: Declaration) {
if (!isDeclarationVisible(declaration)) {
// Mark the unexported alias as visible if its parent is visible
// because these kind of aliases can be used to name types in declaration file
const anyImportSyntax = getAnyImportSyntax(declaration);
if (anyImportSyntax &&
!hasModifier(anyImportSyntax, ModifierFlags.Export) && // import clause without export
isDeclarationVisible(anyImportSyntax.parent)) {
return addVisibleAlias(declaration, anyImportSyntax);
}
else if (isVariableDeclaration(declaration) && isVariableStatement(declaration.parent.parent) &&
!hasModifier(declaration.parent.parent, ModifierFlags.Export) && // unexported variable statement
isDeclarationVisible(declaration.parent.parent.parent)) {
return addVisibleAlias(declaration, declaration.parent.parent);
}
else if (isLateVisibilityPaintedStatement(declaration) // unexported top-level statement
&& !hasModifier(declaration, ModifierFlags.Export)
&& isDeclarationVisible(declaration.parent)) {
return addVisibleAlias(declaration, declaration);
}
// Declaration is not visible
return false;
}
return true;
}
function addVisibleAlias(declaration: Declaration, aliasingStatement: LateVisibilityPaintedStatement) {
// In function "buildTypeDisplay" where we decide whether to write type-alias or serialize types,
// we want to just check if type- alias is accessible or not but we don't care about emitting those alias at that time
// since we will do the emitting later in trackSymbol.
if (shouldComputeAliasToMakeVisible) {
getNodeLinks(declaration).isVisible = true;
aliasesToMakeVisible = appendIfUnique(aliasesToMakeVisible, aliasingStatement);
}
return true;
}
}
function isEntityNameVisible(entityName: EntityNameOrEntityNameExpression, enclosingDeclaration: Node): SymbolVisibilityResult {
// get symbol of the first identifier of the entityName
let meaning: SymbolFlags;
if (entityName.parent.kind === SyntaxKind.TypeQuery ||
isExpressionWithTypeArgumentsInClassExtendsClause(entityName.parent) ||
entityName.parent.kind === SyntaxKind.ComputedPropertyName) {
// Typeof value
meaning = SymbolFlags.Value | SymbolFlags.ExportValue;
}
else if (entityName.kind === SyntaxKind.QualifiedName || entityName.kind === SyntaxKind.PropertyAccessExpression ||
entityName.parent.kind === SyntaxKind.ImportEqualsDeclaration) {
// Left identifier from type reference or TypeAlias
// Entity name of the import declaration
meaning = SymbolFlags.Namespace;
}
else {
// Type Reference or TypeAlias entity = Identifier
meaning = SymbolFlags.Type;
}
const firstIdentifier = getFirstIdentifier(entityName);
const symbol = resolveName(enclosingDeclaration, firstIdentifier.escapedText, meaning, /*nodeNotFoundErrorMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ false);
// Verify if the symbol is accessible
return (symbol && hasVisibleDeclarations(symbol, /*shouldComputeAliasToMakeVisible*/ true)) || {
accessibility: SymbolAccessibility.NotAccessible,
errorSymbolName: getTextOfNode(firstIdentifier),
errorNode: firstIdentifier
};
}
function symbolToString(symbol: Symbol, enclosingDeclaration?: Node, meaning?: SymbolFlags, flags: SymbolFormatFlags = SymbolFormatFlags.AllowAnyNodeKind, writer?: EmitTextWriter): string {
let nodeFlags = NodeBuilderFlags.IgnoreErrors;
if (flags & SymbolFormatFlags.UseOnlyExternalAliasing) {
nodeFlags |= NodeBuilderFlags.UseOnlyExternalAliasing;
}
if (flags & SymbolFormatFlags.WriteTypeParametersOrArguments) {
nodeFlags |= NodeBuilderFlags.WriteTypeParametersInQualifiedName;
}
if (flags & SymbolFormatFlags.UseAliasDefinedOutsideCurrentScope) {
nodeFlags |= NodeBuilderFlags.UseAliasDefinedOutsideCurrentScope;
}
if (flags & SymbolFormatFlags.DoNotIncludeSymbolChain) {
nodeFlags |= NodeBuilderFlags.DoNotIncludeSymbolChain;
}
const builder = flags & SymbolFormatFlags.AllowAnyNodeKind ? nodeBuilder.symbolToExpression : nodeBuilder.symbolToEntityName;
return writer ? symbolToStringWorker(writer).getText() : usingSingleLineStringWriter(symbolToStringWorker);
function symbolToStringWorker(writer: EmitTextWriter) {
const entity = builder(symbol, meaning!, enclosingDeclaration, nodeFlags)!; // TODO: GH#18217
const printer = createPrinter({ removeComments: true });
const sourceFile = enclosingDeclaration && getSourceFileOfNode(enclosingDeclaration);
printer.writeNode(EmitHint.Unspecified, entity, /*sourceFile*/ sourceFile, writer);
return writer;
}
}
function signatureToString(signature: Signature, enclosingDeclaration?: Node, flags = TypeFormatFlags.None, kind?: SignatureKind, writer?: EmitTextWriter): string {
return writer ? signatureToStringWorker(writer).getText() : usingSingleLineStringWriter(signatureToStringWorker);
function signatureToStringWorker(writer: EmitTextWriter) {
let sigOutput: SyntaxKind;
if (flags & TypeFormatFlags.WriteArrowStyleSignature) {
sigOutput = kind === SignatureKind.Construct ? SyntaxKind.ConstructorType : SyntaxKind.FunctionType;
}
else {
sigOutput = kind === SignatureKind.Construct ? SyntaxKind.ConstructSignature : SyntaxKind.CallSignature;
}
const sig = nodeBuilder.signatureToSignatureDeclaration(signature, sigOutput, enclosingDeclaration, toNodeBuilderFlags(flags) | NodeBuilderFlags.IgnoreErrors | NodeBuilderFlags.WriteTypeParametersInQualifiedName);
const printer = createPrinter({ removeComments: true, omitTrailingSemicolon: true });
const sourceFile = enclosingDeclaration && getSourceFileOfNode(enclosingDeclaration);
printer.writeNode(EmitHint.Unspecified, sig!, /*sourceFile*/ sourceFile, getTrailingSemicolonOmittingWriter(writer)); // TODO: GH#18217
return writer;
}
}
function typeToString(type: Type, enclosingDeclaration?: Node, flags: TypeFormatFlags = TypeFormatFlags.AllowUniqueESSymbolType | TypeFormatFlags.UseAliasDefinedOutsideCurrentScope, writer: EmitTextWriter = createTextWriter("")): string {
const noTruncation = compilerOptions.noErrorTruncation || flags & TypeFormatFlags.NoTruncation;
const typeNode = nodeBuilder.typeToTypeNode(type, enclosingDeclaration, toNodeBuilderFlags(flags) | NodeBuilderFlags.IgnoreErrors | (noTruncation ? NodeBuilderFlags.NoTruncation : 0), writer);
if (typeNode === undefined) return Debug.fail("should always get typenode");
const options = { removeComments: true };
const printer = createPrinter(options);
const sourceFile = enclosingDeclaration && getSourceFileOfNode(enclosingDeclaration);
printer.writeNode(EmitHint.Unspecified, typeNode, /*sourceFile*/ sourceFile, writer);
const result = writer.getText();
const maxLength = noTruncation ? undefined : defaultMaximumTruncationLength * 2;
if (maxLength && result && result.length >= maxLength) {
return result.substr(0, maxLength - "...".length) + "...";
}
return result;
}
function toNodeBuilderFlags(flags = TypeFormatFlags.None): NodeBuilderFlags {
return flags & TypeFormatFlags.NodeBuilderFlagsMask;
}
function createNodeBuilder() {
return {
typeToTypeNode: (type: Type, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker) =>
withContext(enclosingDeclaration, flags, tracker, context => typeToTypeNodeHelper(type, context)),
indexInfoToIndexSignatureDeclaration: (indexInfo: IndexInfo, kind: IndexKind, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker) =>
withContext(enclosingDeclaration, flags, tracker, context => indexInfoToIndexSignatureDeclarationHelper(indexInfo, kind, context))!, // TODO: GH#18217
signatureToSignatureDeclaration: (signature: Signature, kind: SyntaxKind, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker) =>
withContext(enclosingDeclaration, flags, tracker, context => signatureToSignatureDeclarationHelper(signature, kind, context)),
symbolToEntityName: (symbol: Symbol, meaning: SymbolFlags, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker) =>
withContext(enclosingDeclaration, flags, tracker, context => symbolToName(symbol, context, meaning, /*expectsIdentifier*/ false)),
symbolToExpression: (symbol: Symbol, meaning: SymbolFlags, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker) =>
withContext(enclosingDeclaration, flags, tracker, context => symbolToExpression(symbol, context, meaning)),
symbolToTypeParameterDeclarations: (symbol: Symbol, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker) =>
withContext(enclosingDeclaration, flags, tracker, context => typeParametersToTypeParameterDeclarations(symbol, context)),
symbolToParameterDeclaration: (symbol: Symbol, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker) =>
withContext(enclosingDeclaration, flags, tracker, context => symbolToParameterDeclaration(symbol, context)),
typeParameterToDeclaration: (parameter: TypeParameter, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker) =>
withContext(enclosingDeclaration, flags, tracker, context => typeParameterToDeclaration(parameter, context)),
};
function withContext<T>(enclosingDeclaration: Node | undefined, flags: NodeBuilderFlags | undefined, tracker: SymbolTracker | undefined, cb: (context: NodeBuilderContext) => T): T | undefined {
Debug.assert(enclosingDeclaration === undefined || (enclosingDeclaration.flags & NodeFlags.Synthesized) === 0);
const context: NodeBuilderContext = {
enclosingDeclaration,
flags: flags || NodeBuilderFlags.None,
// If no full tracker is provided, fake up a dummy one with a basic limited-functionality moduleResolverHost
tracker: tracker && tracker.trackSymbol ? tracker : { trackSymbol: noop, moduleResolverHost: flags! & NodeBuilderFlags.DoNotIncludeSymbolChain ? {
getCommonSourceDirectory: (host as Program).getCommonSourceDirectory ? () => (host as Program).getCommonSourceDirectory() : () => "",
getSourceFiles: () => host.getSourceFiles(),
getCurrentDirectory: host.getCurrentDirectory && (() => host.getCurrentDirectory!())
} : undefined },
encounteredError: false,
visitedTypes: undefined,
symbolDepth: undefined,
inferTypeParameters: undefined,
approximateLength: 0
};
const resultingNode = cb(context);
return context.encounteredError ? undefined : resultingNode;
}
function checkTruncationLength(context: NodeBuilderContext): boolean {
if (context.truncating) return context.truncating;
return context.truncating = !(context.flags & NodeBuilderFlags.NoTruncation) && context.approximateLength > defaultMaximumTruncationLength;
}
function typeToTypeNodeHelper(type: Type, context: NodeBuilderContext): TypeNode {
if (cancellationToken && cancellationToken.throwIfCancellationRequested) {
cancellationToken.throwIfCancellationRequested();
}
const inTypeAlias = context.flags & NodeBuilderFlags.InTypeAlias;
context.flags &= ~NodeBuilderFlags.InTypeAlias;
if (!type) {
context.encounteredError = true;
return undefined!; // TODO: GH#18217
}
if (type.flags & TypeFlags.Any) {
context.approximateLength += 3;
return createKeywordTypeNode(SyntaxKind.AnyKeyword);
}
if (type.flags & TypeFlags.Unknown) {
return createKeywordTypeNode(SyntaxKind.UnknownKeyword);
}
if (type.flags & TypeFlags.String) {
context.approximateLength += 6;
return createKeywordTypeNode(SyntaxKind.StringKeyword);
}
if (type.flags & TypeFlags.Number) {
context.approximateLength += 6;
return createKeywordTypeNode(SyntaxKind.NumberKeyword);
}
if (type.flags & TypeFlags.BigInt) {
context.approximateLength += 6;
return createKeywordTypeNode(SyntaxKind.BigIntKeyword);
}
if (type.flags & TypeFlags.Boolean) {
context.approximateLength += 7;
return createKeywordTypeNode(SyntaxKind.BooleanKeyword);
}
if (type.flags & TypeFlags.EnumLiteral && !(type.flags & TypeFlags.Union)) {
const parentSymbol = getParentOfSymbol(type.symbol)!;
const parentName = symbolToTypeNode(parentSymbol, context, SymbolFlags.Type);
const enumLiteralName = getDeclaredTypeOfSymbol(parentSymbol) === type
? parentName
: appendReferenceToType(
parentName as TypeReferenceNode | ImportTypeNode,
createTypeReferenceNode(symbolName(type.symbol), /*typeArguments*/ undefined)
);
return enumLiteralName;
}
if (type.flags & TypeFlags.EnumLike) {
return symbolToTypeNode(type.symbol, context, SymbolFlags.Type);
}
if (type.flags & TypeFlags.StringLiteral) {
context.approximateLength += ((<StringLiteralType>type).value.length + 2);
return createLiteralTypeNode(setEmitFlags(createLiteral((<StringLiteralType>type).value), EmitFlags.NoAsciiEscaping));
}
if (type.flags & TypeFlags.NumberLiteral) {
context.approximateLength += (("" + (<NumberLiteralType>type).value).length);
return createLiteralTypeNode((createLiteral((<NumberLiteralType>type).value)));
}
if (type.flags & TypeFlags.BigIntLiteral) {
context.approximateLength += (pseudoBigIntToString((<BigIntLiteralType>type).value).length) + 1;
return createLiteralTypeNode((createLiteral((<BigIntLiteralType>type).value)));
}
if (type.flags & TypeFlags.BooleanLiteral) {
context.approximateLength += (<IntrinsicType>type).intrinsicName.length;
return (<IntrinsicType>type).intrinsicName === "true" ? createTrue() : createFalse();
}
if (type.flags & TypeFlags.UniqueESSymbol) {
if (!(context.flags & NodeBuilderFlags.AllowUniqueESSymbolType)) {
if (isValueSymbolAccessible(type.symbol, context.enclosingDeclaration!)) {
context.approximateLength += 6;
return symbolToTypeNode(type.symbol, context, SymbolFlags.Value);
}
if (context.tracker.reportInaccessibleUniqueSymbolError) {
context.tracker.reportInaccessibleUniqueSymbolError();
}
}
context.approximateLength += 13;
return createTypeOperatorNode(SyntaxKind.UniqueKeyword, createKeywordTypeNode(SyntaxKind.SymbolKeyword));
}
if (type.flags & TypeFlags.Void) {
context.approximateLength += 4;
return createKeywordTypeNode(SyntaxKind.VoidKeyword);
}
if (type.flags & TypeFlags.Undefined) {
context.approximateLength += 9;
return createKeywordTypeNode(SyntaxKind.UndefinedKeyword);
}
if (type.flags & TypeFlags.Null) {
context.approximateLength += 4;
return createKeywordTypeNode(SyntaxKind.NullKeyword);
}
if (type.flags & TypeFlags.Never) {
context.approximateLength += 5;
return createKeywordTypeNode(SyntaxKind.NeverKeyword);
}
if (type.flags & TypeFlags.ESSymbol) {
context.approximateLength += 6;
return createKeywordTypeNode(SyntaxKind.SymbolKeyword);
}
if (type.flags & TypeFlags.NonPrimitive) {
context.approximateLength += 6;
return createKeywordTypeNode(SyntaxKind.ObjectKeyword);
}
if (type.flags & TypeFlags.TypeParameter && (type as TypeParameter).isThisType) {
if (context.flags & NodeBuilderFlags.InObjectTypeLiteral) {
if (!context.encounteredError && !(context.flags & NodeBuilderFlags.AllowThisInObjectLiteral)) {
context.encounteredError = true;
}
if (context.tracker.reportInaccessibleThisError) {
context.tracker.reportInaccessibleThisError();
}
}
context.approximateLength += 4;
return createThis();
}
const objectFlags = getObjectFlags(type);
if (objectFlags & ObjectFlags.Reference) {
Debug.assert(!!(type.flags & TypeFlags.Object));
return typeReferenceToTypeNode(<TypeReference>type);
}
if (type.flags & TypeFlags.TypeParameter || objectFlags & ObjectFlags.ClassOrInterface) {
if (type.flags & TypeFlags.TypeParameter && contains(context.inferTypeParameters, type)) {
context.approximateLength += (symbolName(type.symbol).length + 6);
return createInferTypeNode(typeParameterToDeclarationWithConstraint(type as TypeParameter, context, /*constraintNode*/ undefined));
}
if (context.flags & NodeBuilderFlags.GenerateNamesForShadowedTypeParams &&
type.flags & TypeFlags.TypeParameter &&
length(type.symbol.declarations) &&
isTypeParameterDeclaration(type.symbol.declarations[0]) &&
typeParameterShadowsNameInScope(type, context) &&
!isTypeSymbolAccessible(type.symbol, context.enclosingDeclaration)) {
const name = (type.symbol.declarations[0] as TypeParameterDeclaration).name;
context.approximateLength += idText(name).length;
return createTypeReferenceNode(getGeneratedNameForNode(name, GeneratedIdentifierFlags.Optimistic | GeneratedIdentifierFlags.ReservedInNestedScopes), /*typeArguments*/ undefined);
}
// Ignore constraint/default when creating a usage (as opposed to declaration) of a type parameter.
return type.symbol
? symbolToTypeNode(type.symbol, context, SymbolFlags.Type)
: createTypeReferenceNode(createIdentifier("?"), /*typeArguments*/ undefined);
}
if (!inTypeAlias && type.aliasSymbol && (context.flags & NodeBuilderFlags.UseAliasDefinedOutsideCurrentScope || isTypeSymbolAccessible(type.aliasSymbol, context.enclosingDeclaration))) {
const typeArgumentNodes = mapToTypeNodes(type.aliasTypeArguments, context);
if (isReservedMemberName(type.aliasSymbol.escapedName) && !(type.aliasSymbol.flags & SymbolFlags.Class)) return createTypeReferenceNode(createIdentifier(""), typeArgumentNodes);
return symbolToTypeNode(type.aliasSymbol, context, SymbolFlags.Type, typeArgumentNodes);
}
if (type.flags & (TypeFlags.Union | TypeFlags.Intersection)) {
const types = type.flags & TypeFlags.Union ? formatUnionTypes((<UnionType>type).types) : (<IntersectionType>type).types;
if (length(types) === 1) {
return typeToTypeNodeHelper(types[0], context);
}
const typeNodes = mapToTypeNodes(types, context, /*isBareList*/ true);
if (typeNodes && typeNodes.length > 0) {
const unionOrIntersectionTypeNode = createUnionOrIntersectionTypeNode(type.flags & TypeFlags.Union ? SyntaxKind.UnionType : SyntaxKind.IntersectionType, typeNodes);
return unionOrIntersectionTypeNode;
}
else {
if (!context.encounteredError && !(context.flags & NodeBuilderFlags.AllowEmptyUnionOrIntersection)) {
context.encounteredError = true;
}
return undefined!; // TODO: GH#18217
}
}
if (objectFlags & (ObjectFlags.Anonymous | ObjectFlags.Mapped)) {
Debug.assert(!!(type.flags & TypeFlags.Object));
// The type is an object literal type.
return createAnonymousTypeNode(<ObjectType>type);
}
if (type.flags & TypeFlags.Index) {
const indexedType = (<IndexType>type).type;
context.approximateLength += 6;
const indexTypeNode = typeToTypeNodeHelper(indexedType, context);
return createTypeOperatorNode(indexTypeNode);
}
if (type.flags & TypeFlags.IndexedAccess) {
const objectTypeNode = typeToTypeNodeHelper((<IndexedAccessType>type).objectType, context);
const indexTypeNode = typeToTypeNodeHelper((<IndexedAccessType>type).indexType, context);
context.approximateLength += 2;
return createIndexedAccessTypeNode(objectTypeNode, indexTypeNode);
}
if (type.flags & TypeFlags.Conditional) {
const checkTypeNode = typeToTypeNodeHelper((<ConditionalType>type).checkType, context);
const saveInferTypeParameters = context.inferTypeParameters;
context.inferTypeParameters = (<ConditionalType>type).root.inferTypeParameters;
const extendsTypeNode = typeToTypeNodeHelper((<ConditionalType>type).extendsType, context);
context.inferTypeParameters = saveInferTypeParameters;
const trueTypeNode = typeToTypeNodeHelper(getTrueTypeFromConditionalType(<ConditionalType>type), context);
const falseTypeNode = typeToTypeNodeHelper(getFalseTypeFromConditionalType(<ConditionalType>type), context);
context.approximateLength += 15;
return createConditionalTypeNode(checkTypeNode, extendsTypeNode, trueTypeNode, falseTypeNode);
}
if (type.flags & TypeFlags.Substitution) {
return typeToTypeNodeHelper((<SubstitutionType>type).typeVariable, context);
}
return Debug.fail("Should be unreachable.");
function createMappedTypeNodeFromType(type: MappedType) {
Debug.assert(!!(type.flags & TypeFlags.Object));
const readonlyToken = type.declaration.readonlyToken ? <ReadonlyToken | PlusToken | MinusToken>createToken(type.declaration.readonlyToken.kind) : undefined;
const questionToken = type.declaration.questionToken ? <QuestionToken | PlusToken | MinusToken>createToken(type.declaration.questionToken.kind) : undefined;
let appropriateConstraintTypeNode: TypeNode;
if (isMappedTypeWithKeyofConstraintDeclaration(type)) {
// We have a { [P in keyof T]: X }
// We do this to ensure we retain the toplevel keyof-ness of the type which may be lost due to keyof distribution during `getConstraintTypeFromMappedType`
appropriateConstraintTypeNode = createTypeOperatorNode(typeToTypeNodeHelper(getModifiersTypeFromMappedType(type), context));
}
else {
appropriateConstraintTypeNode = typeToTypeNodeHelper(getConstraintTypeFromMappedType(type), context);
}
const typeParameterNode = typeParameterToDeclarationWithConstraint(getTypeParameterFromMappedType(type), context, appropriateConstraintTypeNode);
const templateTypeNode = typeToTypeNodeHelper(getTemplateTypeFromMappedType(type), context);
const mappedTypeNode = createMappedTypeNode(readonlyToken, typeParameterNode, questionToken, templateTypeNode);
context.approximateLength += 10;
return setEmitFlags(mappedTypeNode, EmitFlags.SingleLine);
}
function createAnonymousTypeNode(type: ObjectType): TypeNode {
const typeId = "" + type.id;
const symbol = type.symbol;
let id: string;
if (symbol) {
const isConstructorObject = getObjectFlags(type) & ObjectFlags.Anonymous && type.symbol && type.symbol.flags & SymbolFlags.Class;
id = (isConstructorObject ? "+" : "") + getSymbolId(symbol);
if (isJSConstructor(symbol.valueDeclaration)) {
// Instance and static types share the same symbol; only add 'typeof' for the static side.
const isInstanceType = type === getInferredClassType(symbol) ? SymbolFlags.Type : SymbolFlags.Value;
return symbolToTypeNode(symbol, context, isInstanceType);
}
// Always use 'typeof T' for type of class, enum, and module objects
else if (symbol.flags & SymbolFlags.Class && !getBaseTypeVariableOfClass(symbol) && !(symbol.valueDeclaration.kind === SyntaxKind.ClassExpression && context.flags & NodeBuilderFlags.WriteClassExpressionAsTypeLiteral) ||
symbol.flags & (SymbolFlags.Enum | SymbolFlags.ValueModule) ||
shouldWriteTypeOfFunctionSymbol()) {
return symbolToTypeNode(symbol, context, SymbolFlags.Value);
}
else if (context.visitedTypes && context.visitedTypes.has(typeId)) {
// If type is an anonymous type literal in a type alias declaration, use type alias name
const typeAlias = getTypeAliasForTypeLiteral(type);
if (typeAlias) {
// The specified symbol flags need to be reinterpreted as type flags
return symbolToTypeNode(typeAlias, context, SymbolFlags.Type);
}
else {
return createElidedInformationPlaceholder(context);
}
}
else {
// Since instantiations of the same anonymous type have the same symbol, tracking symbols instead
// of types allows us to catch circular references to instantiations of the same anonymous type
if (!context.visitedTypes) {
context.visitedTypes = createMap<true>();
}
if (!context.symbolDepth) {
context.symbolDepth = createMap<number>();
}
const depth = context.symbolDepth.get(id) || 0;
if (depth > 10) {
return createElidedInformationPlaceholder(context);
}
context.symbolDepth.set(id, depth + 1);
context.visitedTypes.set(typeId, true);
const result = createTypeNodeFromObjectType(type);
context.visitedTypes.delete(typeId);
context.symbolDepth.set(id, depth);
return result;
}
}
else {
// Anonymous types without a symbol are never circular.
return createTypeNodeFromObjectType(type);
}
function shouldWriteTypeOfFunctionSymbol() {
const isStaticMethodSymbol = !!(symbol.flags & SymbolFlags.Method) && // typeof static method
some(symbol.declarations, declaration => hasModifier(declaration, ModifierFlags.Static));
const isNonLocalFunctionSymbol = !!(symbol.flags & SymbolFlags.Function) &&
(symbol.parent || // is exported function symbol
forEach(symbol.declarations, declaration =>
declaration.parent.kind === SyntaxKind.SourceFile || declaration.parent.kind === SyntaxKind.ModuleBlock));
if (isStaticMethodSymbol || isNonLocalFunctionSymbol) {
// typeof is allowed only for static/non local functions
return (!!(context.flags & NodeBuilderFlags.UseTypeOfFunction) || (context.visitedTypes && context.visitedTypes.has(typeId))) && // it is type of the symbol uses itself recursively
(!(context.flags & NodeBuilderFlags.UseStructuralFallback) || isValueSymbolAccessible(symbol, context.enclosingDeclaration!)); // TODO: GH#18217 // And the build is going to succeed without visibility error or there is no structural fallback allowed
}
}
}
function createTypeNodeFromObjectType(type: ObjectType): TypeNode {
if (isGenericMappedType(type)) {
return createMappedTypeNodeFromType(type);
}
const resolved = resolveStructuredTypeMembers(type);
if (!resolved.properties.length && !resolved.stringIndexInfo && !resolved.numberIndexInfo) {
if (!resolved.callSignatures.length && !resolved.constructSignatures.length) {
context.approximateLength += 2;
return setEmitFlags(createTypeLiteralNode(/*members*/ undefined), EmitFlags.SingleLine);
}
if (resolved.callSignatures.length === 1 && !resolved.constructSignatures.length) {
const signature = resolved.callSignatures[0];
const signatureNode = <FunctionTypeNode>signatureToSignatureDeclarationHelper(signature, SyntaxKind.FunctionType, context);
return signatureNode;
}
if (resolved.constructSignatures.length === 1 && !resolved.callSignatures.length) {
const signature = resolved.constructSignatures[0];
const signatureNode = <ConstructorTypeNode>signatureToSignatureDeclarationHelper(signature, SyntaxKind.ConstructorType, context);
return signatureNode;
}
}
const savedFlags = context.flags;
context.flags |= NodeBuilderFlags.InObjectTypeLiteral;
const members = createTypeNodesFromResolvedType(resolved);
context.flags = savedFlags;
const typeLiteralNode = createTypeLiteralNode(members);
context.approximateLength += 2;
return setEmitFlags(typeLiteralNode, (context.flags & NodeBuilderFlags.MultilineObjectLiterals) ? 0 : EmitFlags.SingleLine);
}
function typeReferenceToTypeNode(type: TypeReference) {
const typeArguments: ReadonlyArray<Type> = type.typeArguments || emptyArray;
if (type.target === globalArrayType || type.target === globalReadonlyArrayType) {
if (context.flags & NodeBuilderFlags.WriteArrayAsGenericType) {
const typeArgumentNode = typeToTypeNodeHelper(typeArguments[0], context);
return createTypeReferenceNode(type.target === globalArrayType ? "Array" : "ReadonlyArray", [typeArgumentNode]);
}
const elementType = typeToTypeNodeHelper(typeArguments[0], context);
const arrayType = createArrayTypeNode(elementType);
return type.target === globalArrayType ? arrayType : createTypeOperatorNode(SyntaxKind.ReadonlyKeyword, arrayType);
}
else if (type.target.objectFlags & ObjectFlags.Tuple) {
if (typeArguments.length > 0) {
const arity = getTypeReferenceArity(type);
const tupleConstituentNodes = mapToTypeNodes(typeArguments.slice(0, arity), context);
const hasRestElement = (<TupleType>type.target).hasRestElement;
if (tupleConstituentNodes) {
for (let i = (<TupleType>type.target).minLength; i < Math.min(arity, tupleConstituentNodes.length); i++) {
tupleConstituentNodes[i] = hasRestElement && i === arity - 1 ?
createRestTypeNode(createArrayTypeNode(tupleConstituentNodes[i])) :
createOptionalTypeNode(tupleConstituentNodes[i]);
}
const tupleTypeNode = createTupleTypeNode(tupleConstituentNodes);
return (<TupleType>type.target).readonly ? createTypeOperatorNode(SyntaxKind.ReadonlyKeyword, tupleTypeNode) : tupleTypeNode;
}
}
if (context.encounteredError || (context.flags & NodeBuilderFlags.AllowEmptyTuple)) {
const tupleTypeNode = createTupleTypeNode([]);
return (<TupleType>type.target).readonly ? createTypeOperatorNode(SyntaxKind.ReadonlyKeyword, tupleTypeNode) : tupleTypeNode;
}
context.encounteredError = true;
return undefined!; // TODO: GH#18217
}
else if (context.flags & NodeBuilderFlags.WriteClassExpressionAsTypeLiteral &&
type.symbol.valueDeclaration &&
isClassLike(type.symbol.valueDeclaration) &&
!isValueSymbolAccessible(type.symbol, context.enclosingDeclaration!)
) {
return createAnonymousTypeNode(type);
}
else {
const outerTypeParameters = type.target.outerTypeParameters;
let i = 0;
let resultType: TypeReferenceNode | ImportTypeNode | undefined;
if (outerTypeParameters) {
const length = outerTypeParameters.length;
while (i < length) {
// Find group of type arguments for type parameters with the same declaring container.
const start = i;
const parent = getParentSymbolOfTypeParameter(outerTypeParameters[i])!;
do {
i++;
} while (i < length && getParentSymbolOfTypeParameter(outerTypeParameters[i]) === parent);
// When type parameters are their own type arguments for the whole group (i.e. we have
// the default outer type arguments), we don't show the group.
if (!rangeEquals(outerTypeParameters, typeArguments, start, i)) {
const typeArgumentSlice = mapToTypeNodes(typeArguments.slice(start, i), context);
const flags = context.flags;
context.flags |= NodeBuilderFlags.ForbidIndexedAccessSymbolReferences;
const ref = symbolToTypeNode(parent, context, SymbolFlags.Type, typeArgumentSlice) as TypeReferenceNode | ImportTypeNode;
context.flags = flags;
resultType = !resultType ? ref : appendReferenceToType(resultType, ref as TypeReferenceNode);
}
}
}
let typeArgumentNodes: ReadonlyArray<TypeNode> | undefined;
if (typeArguments.length > 0) {
const typeParameterCount = (type.target.typeParameters || emptyArray).length;
typeArgumentNodes = mapToTypeNodes(typeArguments.slice(i, typeParameterCount), context);
}
const flags = context.flags;
context.flags |= NodeBuilderFlags.ForbidIndexedAccessSymbolReferences;
const finalRef = symbolToTypeNode(type.symbol, context, SymbolFlags.Type, typeArgumentNodes);
context.flags = flags;
return !resultType ? finalRef : appendReferenceToType(resultType, finalRef as TypeReferenceNode);
}
}
function appendReferenceToType(root: TypeReferenceNode | ImportTypeNode, ref: TypeReferenceNode): TypeReferenceNode | ImportTypeNode {
if (isImportTypeNode(root)) {
// first shift type arguments
const innerParams = root.typeArguments;
if (root.qualifier) {
(isIdentifier(root.qualifier) ? root.qualifier : root.qualifier.right).typeArguments = innerParams;
}
root.typeArguments = ref.typeArguments;
// then move qualifiers
const ids = getAccessStack(ref);
for (const id of ids) {
root.qualifier = root.qualifier ? createQualifiedName(root.qualifier, id) : id;
}
return root;
}
else {
// first shift type arguments
const innerParams = root.typeArguments;
(isIdentifier(root.typeName) ? root.typeName : root.typeName.right).typeArguments = innerParams;
root.typeArguments = ref.typeArguments;
// then move qualifiers
const ids = getAccessStack(ref);
for (const id of ids) {
root.typeName = createQualifiedName(root.typeName, id);
}
return root;
}
}
function getAccessStack(ref: TypeReferenceNode): Identifier[] {
let state = ref.typeName;
const ids = [];
while (!isIdentifier(state)) {
ids.unshift(state.right);
state = state.left;
}
ids.unshift(state);
return ids;
}
function createTypeNodesFromResolvedType(resolvedType: ResolvedType): TypeElement[] | undefined {
if (checkTruncationLength(context)) {
return [createPropertySignature(/*modifiers*/ undefined, "...", /*questionToken*/ undefined, /*type*/ undefined, /*initializer*/ undefined)];
}
const typeElements: TypeElement[] = [];
for (const signature of resolvedType.callSignatures) {
typeElements.push(<CallSignatureDeclaration>signatureToSignatureDeclarationHelper(signature, SyntaxKind.CallSignature, context));
}
for (const signature of resolvedType.constructSignatures) {
typeElements.push(<ConstructSignatureDeclaration>signatureToSignatureDeclarationHelper(signature, SyntaxKind.ConstructSignature, context));
}
if (resolvedType.stringIndexInfo) {
let indexSignature: IndexSignatureDeclaration;
if (resolvedType.objectFlags & ObjectFlags.ReverseMapped) {
indexSignature = indexInfoToIndexSignatureDeclarationHelper(createIndexInfo(anyType, resolvedType.stringIndexInfo.isReadonly, resolvedType.stringIndexInfo.declaration), IndexKind.String, context);
indexSignature.type = createElidedInformationPlaceholder(context);
}
else {
indexSignature = indexInfoToIndexSignatureDeclarationHelper(resolvedType.stringIndexInfo, IndexKind.String, context);
}
typeElements.push(indexSignature);
}
if (resolvedType.numberIndexInfo) {
typeElements.push(indexInfoToIndexSignatureDeclarationHelper(resolvedType.numberIndexInfo, IndexKind.Number, context));
}
const properties = resolvedType.properties;
if (!properties) {
return typeElements;
}
let i = 0;
for (const propertySymbol of properties) {
i++;
if (context.flags & NodeBuilderFlags.WriteClassExpressionAsTypeLiteral) {
if (propertySymbol.flags & SymbolFlags.Prototype) {
continue;
}
if (getDeclarationModifierFlagsFromSymbol(propertySymbol) & (ModifierFlags.Private | ModifierFlags.Protected) && context.tracker.reportPrivateInBaseOfClassExpression) {
context.tracker.reportPrivateInBaseOfClassExpression(unescapeLeadingUnderscores(propertySymbol.escapedName));
}
}
if (checkTruncationLength(context) && (i + 2 < properties.length - 1)) {
typeElements.push(createPropertySignature(/*modifiers*/ undefined, `... ${properties.length - i} more ...`, /*questionToken*/ undefined, /*type*/ undefined, /*initializer*/ undefined));
addPropertyToElementList(properties[properties.length - 1], context, typeElements);
break;
}
addPropertyToElementList(propertySymbol, context, typeElements);
}
return typeElements.length ? typeElements : undefined;
}
}
function createElidedInformationPlaceholder(context: NodeBuilderContext) {
context.approximateLength += 3;
if (!(context.flags & NodeBuilderFlags.NoTruncation)) {
return createTypeReferenceNode(createIdentifier("..."), /*typeArguments*/ undefined);
}
return createKeywordTypeNode(SyntaxKind.AnyKeyword);
}
function addPropertyToElementList(propertySymbol: Symbol, context: NodeBuilderContext, typeElements: TypeElement[]) {
const propertyIsReverseMapped = !!(getCheckFlags(propertySymbol) & CheckFlags.ReverseMapped);
const propertyType = propertyIsReverseMapped && context.flags & NodeBuilderFlags.InReverseMappedType ?
anyType : getTypeOfSymbol(propertySymbol);
const saveEnclosingDeclaration = context.enclosingDeclaration;
context.enclosingDeclaration = undefined;
if (context.tracker.trackSymbol && getCheckFlags(propertySymbol) & CheckFlags.Late) {
const decl = first(propertySymbol.declarations);
if (hasLateBindableName(decl)) {
trackComputedName(decl.name, saveEnclosingDeclaration, context);
}
}
const propertyName = symbolToName(propertySymbol, context, SymbolFlags.Value, /*expectsIdentifier*/ true);
context.approximateLength += (symbolName(propertySymbol).length + 1);
context.enclosingDeclaration = saveEnclosingDeclaration;
const optionalToken = propertySymbol.flags & SymbolFlags.Optional ? createToken(SyntaxKind.QuestionToken) : undefined;
if (propertySymbol.flags & (SymbolFlags.Function | SymbolFlags.Method) && !getPropertiesOfObjectType(propertyType).length && !isReadonlySymbol(propertySymbol)) {
const signatures = getSignaturesOfType(propertyType, SignatureKind.Call);
for (const signature of signatures) {
const methodDeclaration = <MethodSignature>signatureToSignatureDeclarationHelper(signature, SyntaxKind.MethodSignature, context);
methodDeclaration.name = propertyName;
methodDeclaration.questionToken = optionalToken;
if (propertySymbol.valueDeclaration) {
// Copy comments to node for declaration emit
setCommentRange(methodDeclaration, propertySymbol.valueDeclaration);
}
typeElements.push(methodDeclaration);
}
}
else {
const savedFlags = context.flags;
context.flags |= propertyIsReverseMapped ? NodeBuilderFlags.InReverseMappedType : 0;
let propertyTypeNode: TypeNode;
if (propertyIsReverseMapped && !!(savedFlags & NodeBuilderFlags.InReverseMappedType)) {
propertyTypeNode = createElidedInformationPlaceholder(context);
}
else {
propertyTypeNode = propertyType ? typeToTypeNodeHelper(propertyType, context) : createKeywordTypeNode(SyntaxKind.AnyKeyword);
}
context.flags = savedFlags;
const modifiers = isReadonlySymbol(propertySymbol) ? [createToken(SyntaxKind.ReadonlyKeyword)] : undefined;
if (modifiers) {
context.approximateLength += 9;
}
const propertySignature = createPropertySignature(
modifiers,
propertyName,
optionalToken,
propertyTypeNode,
/*initializer*/ undefined);
if (propertySymbol.valueDeclaration) {
// Copy comments to node for declaration emit
setCommentRange(propertySignature, propertySymbol.valueDeclaration);
}
typeElements.push(propertySignature);
}
}
function mapToTypeNodes(types: ReadonlyArray<Type> | undefined, context: NodeBuilderContext, isBareList?: boolean): TypeNode[] | undefined {
if (some(types)) {
if (checkTruncationLength(context)) {
if (!isBareList) {
return [createTypeReferenceNode("...", /*typeArguments*/ undefined)];
}
else if (types.length > 2) {
return [
typeToTypeNodeHelper(types[0], context),
createTypeReferenceNode(`... ${types.length - 2} more ...`, /*typeArguments*/ undefined),
typeToTypeNodeHelper(types[types.length - 1], context)
];
}
}
const result = [];
let i = 0;
for (const type of types) {
i++;
if (checkTruncationLength(context) && (i + 2 < types.length - 1)) {
result.push(createTypeReferenceNode(`... ${types.length - i} more ...`, /*typeArguments*/ undefined));
const typeNode = typeToTypeNodeHelper(types[types.length - 1], context);
if (typeNode) {
result.push(typeNode);
}
break;
}
context.approximateLength += 2; // Account for whitespace + separator
const typeNode = typeToTypeNodeHelper(type, context);
if (typeNode) {
result.push(typeNode);
}
}
return result;
}
}
function indexInfoToIndexSignatureDeclarationHelper(indexInfo: IndexInfo, kind: IndexKind, context: NodeBuilderContext): IndexSignatureDeclaration {
const name = getNameFromIndexInfo(indexInfo) || "x";
const indexerTypeNode = createKeywordTypeNode(kind === IndexKind.String ? SyntaxKind.StringKeyword : SyntaxKind.NumberKeyword);
const indexingParameter = createParameter(
/*decorators*/ undefined,
/*modifiers*/ undefined,
/*dotDotDotToken*/ undefined,
name,
/*questionToken*/ undefined,
indexerTypeNode,
/*initializer*/ undefined);
const typeNode = typeToTypeNodeHelper(indexInfo.type || anyType, context);
if (!indexInfo.type && !(context.flags & NodeBuilderFlags.AllowEmptyIndexInfoType)) {
context.encounteredError = true;
}
context.approximateLength += (name.length + 4);
return createIndexSignature(
/*decorators*/ undefined,
indexInfo.isReadonly ? [createToken(SyntaxKind.ReadonlyKeyword)] : undefined,
[indexingParameter],
typeNode);
}
function signatureToSignatureDeclarationHelper(signature: Signature, kind: SyntaxKind, context: NodeBuilderContext): SignatureDeclaration {
let typeParameters: TypeParameterDeclaration[] | undefined;
let typeArguments: TypeNode[] | undefined;
if (context.flags & NodeBuilderFlags.WriteTypeArgumentsOfSignature && signature.target && signature.mapper && signature.target.typeParameters) {
typeArguments = signature.target.typeParameters.map(parameter => typeToTypeNodeHelper(instantiateType(parameter, signature.mapper!), context));
}
else {
typeParameters = signature.typeParameters && signature.typeParameters.map(parameter => typeParameterToDeclaration(parameter, context));
}
const parameters = getExpandedParameters(signature).map(parameter => symbolToParameterDeclaration(parameter, context, kind === SyntaxKind.Constructor));
if (signature.thisParameter) {
const thisParameter = symbolToParameterDeclaration(signature.thisParameter, context);
parameters.unshift(thisParameter);
}
let returnTypeNode: TypeNode | undefined;
const typePredicate = getTypePredicateOfSignature(signature);
if (typePredicate) {
const parameterName = typePredicate.kind === TypePredicateKind.Identifier ?
setEmitFlags(createIdentifier(typePredicate.parameterName), EmitFlags.NoAsciiEscaping) :
createThisTypeNode();
const typeNode = typeToTypeNodeHelper(typePredicate.type, context);
returnTypeNode = createTypePredicateNode(parameterName, typeNode);
}
else {
const returnType = getReturnTypeOfSignature(signature);
returnTypeNode = returnType && typeToTypeNodeHelper(returnType, context);
}
if (context.flags & NodeBuilderFlags.SuppressAnyReturnType) {
if (returnTypeNode && returnTypeNode.kind === SyntaxKind.AnyKeyword) {
returnTypeNode = undefined;
}
}
else if (!returnTypeNode) {
returnTypeNode = createKeywordTypeNode(SyntaxKind.AnyKeyword);
}
context.approximateLength += 3; // Usually a signature contributes a few more characters than this, but 3 is the minimum
return createSignatureDeclaration(kind, typeParameters, parameters, returnTypeNode, typeArguments);
}
function typeParameterShadowsNameInScope(type: TypeParameter, context: NodeBuilderContext) {
return !!resolveName(context.enclosingDeclaration, type.symbol.escapedName, SymbolFlags.Type, /*nameNotFoundArg*/ undefined, type.symbol.escapedName, /*isUse*/ false);
}
function typeParameterToDeclarationWithConstraint(type: TypeParameter, context: NodeBuilderContext, constraintNode: TypeNode | undefined): TypeParameterDeclaration {
const savedContextFlags = context.flags;
context.flags &= ~NodeBuilderFlags.WriteTypeParametersInQualifiedName; // Avoids potential infinite loop when building for a claimspace with a generic
const shouldUseGeneratedName =
context.flags & NodeBuilderFlags.GenerateNamesForShadowedTypeParams &&
type.symbol.declarations && type.symbol.declarations[0] &&
isTypeParameterDeclaration(type.symbol.declarations[0]) &&
typeParameterShadowsNameInScope(type, context);
const name = shouldUseGeneratedName
? getGeneratedNameForNode((type.symbol.declarations[0] as TypeParameterDeclaration).name, GeneratedIdentifierFlags.Optimistic | GeneratedIdentifierFlags.ReservedInNestedScopes)
: symbolToName(type.symbol, context, SymbolFlags.Type, /*expectsIdentifier*/ true);
const defaultParameter = getDefaultFromTypeParameter(type);
const defaultParameterNode = defaultParameter && typeToTypeNodeHelper(defaultParameter, context);
context.flags = savedContextFlags;
return createTypeParameterDeclaration(name, constraintNode, defaultParameterNode);
}
function typeParameterToDeclaration(type: TypeParameter, context: NodeBuilderContext, constraint = getConstraintOfTypeParameter(type)): TypeParameterDeclaration {
const constraintNode = constraint && typeToTypeNodeHelper(constraint, context);
return typeParameterToDeclarationWithConstraint(type, context, constraintNode);
}
function symbolToParameterDeclaration(parameterSymbol: Symbol, context: NodeBuilderContext, preserveModifierFlags?: boolean): ParameterDeclaration {
let parameterDeclaration: ParameterDeclaration | JSDocParameterTag | undefined = getDeclarationOfKind<ParameterDeclaration>(parameterSymbol, SyntaxKind.Parameter);
if (!parameterDeclaration && !isTransientSymbol(parameterSymbol)) {
parameterDeclaration = getDeclarationOfKind<JSDocParameterTag>(parameterSymbol, SyntaxKind.JSDocParameterTag);
}
let parameterType = getTypeOfSymbol(parameterSymbol);
if (parameterDeclaration && isRequiredInitializedParameter(parameterDeclaration)) {
parameterType = getOptionalType(parameterType);
}
const parameterTypeNode = typeToTypeNodeHelper(parameterType, context);
const modifiers = !(context.flags & NodeBuilderFlags.OmitParameterModifiers) && preserveModifierFlags && parameterDeclaration && parameterDeclaration.modifiers ? parameterDeclaration.modifiers.map(getSynthesizedClone) : undefined;
const isRest = parameterDeclaration && isRestParameter(parameterDeclaration) || getCheckFlags(parameterSymbol) & CheckFlags.RestParameter;
const dotDotDotToken = isRest ? createToken(SyntaxKind.DotDotDotToken) : undefined;
const name = parameterDeclaration
? parameterDeclaration.name ?
parameterDeclaration.name.kind === SyntaxKind.Identifier ? setEmitFlags(getSynthesizedClone(parameterDeclaration.name), EmitFlags.NoAsciiEscaping) :
parameterDeclaration.name.kind === SyntaxKind.QualifiedName ? setEmitFlags(getSynthesizedClone(parameterDeclaration.name.right), EmitFlags.NoAsciiEscaping) :
cloneBindingName(parameterDeclaration.name) :
symbolName(parameterSymbol)
: symbolName(parameterSymbol);
const isOptional = parameterDeclaration && isOptionalParameter(parameterDeclaration) || getCheckFlags(parameterSymbol) & CheckFlags.OptionalParameter;
const questionToken = isOptional ? createToken(SyntaxKind.QuestionToken) : undefined;
const parameterNode = createParameter(
/*decorators*/ undefined,
modifiers,
dotDotDotToken,
name,
questionToken,
parameterTypeNode,
/*initializer*/ undefined);
context.approximateLength += symbolName(parameterSymbol).length + 3;
return parameterNode;
function cloneBindingName(node: BindingName): BindingName {
return <BindingName>elideInitializerAndSetEmitFlags(node);
function elideInitializerAndSetEmitFlags(node: Node): Node {
if (context.tracker.trackSymbol && isComputedPropertyName(node) && isLateBindableName(node)) {
trackComputedName(node, context.enclosingDeclaration, context);
}
const visited = visitEachChild(node, elideInitializerAndSetEmitFlags, nullTransformationContext, /*nodesVisitor*/ undefined, elideInitializerAndSetEmitFlags)!;
const clone = nodeIsSynthesized(visited) ? visited : getSynthesizedClone(visited);
if (clone.kind === SyntaxKind.BindingElement) {
(<BindingElement>clone).initializer = undefined;
}
return setEmitFlags(clone, EmitFlags.SingleLine | EmitFlags.NoAsciiEscaping);
}
}
}
function trackComputedName(node: LateBoundName, enclosingDeclaration: Node | undefined, context: NodeBuilderContext) {
if (!context.tracker.trackSymbol) return;
// get symbol of the first identifier of the entityName
const firstIdentifier = getFirstIdentifier(node.expression);
const name = resolveName(firstIdentifier, firstIdentifier.escapedText, SymbolFlags.Value | SymbolFlags.ExportValue, /*nodeNotFoundErrorMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ true);
if (name) {
context.tracker.trackSymbol(name, enclosingDeclaration, SymbolFlags.Value);
}
}
function lookupSymbolChain(symbol: Symbol, context: NodeBuilderContext, meaning: SymbolFlags, yieldModuleSymbol?: boolean) {
context.tracker.trackSymbol!(symbol, context.enclosingDeclaration, meaning); // TODO: GH#18217
// Try to get qualified name if the symbol is not a type parameter and there is an enclosing declaration.
let chain: Symbol[];
const isTypeParameter = symbol.flags & SymbolFlags.TypeParameter;
if (!isTypeParameter && (context.enclosingDeclaration || context.flags & NodeBuilderFlags.UseFullyQualifiedType) && !(context.flags & NodeBuilderFlags.DoNotIncludeSymbolChain)) {
chain = Debug.assertDefined(getSymbolChain(symbol, meaning, /*endOfChain*/ true));
Debug.assert(chain && chain.length > 0);
}
else {
chain = [symbol];
}
return chain;
/** @param endOfChain Set to false for recursive calls; non-recursive calls should always output something. */
function getSymbolChain(symbol: Symbol, meaning: SymbolFlags, endOfChain: boolean): Symbol[] | undefined {
let accessibleSymbolChain = getAccessibleSymbolChain(symbol, context.enclosingDeclaration, meaning, !!(context.flags & NodeBuilderFlags.UseOnlyExternalAliasing));
let parentSpecifiers: (string | undefined)[];
if (!accessibleSymbolChain ||
needsQualification(accessibleSymbolChain[0], context.enclosingDeclaration, accessibleSymbolChain.length === 1 ? meaning : getQualifiedLeftMeaning(meaning))) {
// Go up and add our parent.
const parents = getContainersOfSymbol(accessibleSymbolChain ? accessibleSymbolChain[0] : symbol, context.enclosingDeclaration);
if (length(parents)) {
parentSpecifiers = parents!.map(symbol =>
some(symbol.declarations, hasNonGlobalAugmentationExternalModuleSymbol)
? getSpecifierForModuleSymbol(symbol, context)
: undefined);
const indices = parents!.map((_, i) => i);
indices.sort(sortByBestName);
const sortedParents = indices.map(i => parents![i]);
for (const parent of sortedParents) {
const parentChain = getSymbolChain(parent, getQualifiedLeftMeaning(meaning), /*endOfChain*/ false);
if (parentChain) {
accessibleSymbolChain = parentChain.concat(accessibleSymbolChain || [getAliasForSymbolInContainer(parent, symbol) || symbol]);
break;
}
}
}
}
if (accessibleSymbolChain) {
return accessibleSymbolChain;
}
if (
// If this is the last part of outputting the symbol, always output. The cases apply only to parent symbols.
endOfChain ||
// If a parent symbol is an anonymous type, don't write it.
!(symbol.flags & (SymbolFlags.TypeLiteral | SymbolFlags.ObjectLiteral))) {
// If a parent symbol is an external module, don't write it. (We prefer just `x` vs `"foo/bar".x`.)
if (!endOfChain && !yieldModuleSymbol && !!forEach(symbol.declarations, hasNonGlobalAugmentationExternalModuleSymbol)) {
return;
}
return [symbol];
}
function sortByBestName(a: number, b: number) {
const specifierA = parentSpecifiers[a];
const specifierB = parentSpecifiers[b];
if (specifierA && specifierB) {
const isBRelative = pathIsRelative(specifierB);
if (pathIsRelative(specifierA) === isBRelative) {
// Both relative or both non-relative, sort by number of parts
return moduleSpecifiers.countPathComponents(specifierA) - moduleSpecifiers.countPathComponents(specifierB);
}
if (isBRelative) {
// A is non-relative, B is relative: prefer A
return -1;
}
// A is relative, B is non-relative: prefer B
return 1;
}
return 0;
}
}
}
function typeParametersToTypeParameterDeclarations(symbol: Symbol, context: NodeBuilderContext) {
let typeParameterNodes: NodeArray<TypeParameterDeclaration> | undefined;
const targetSymbol = getTargetSymbol(symbol);
if (targetSymbol.flags & (SymbolFlags.Class | SymbolFlags.Interface | SymbolFlags.TypeAlias)) {
typeParameterNodes = createNodeArray(map(getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(symbol), tp => typeParameterToDeclaration(tp, context)));
}
return typeParameterNodes;
}
function lookupTypeParameterNodes(chain: Symbol[], index: number, context: NodeBuilderContext) {
Debug.assert(chain && 0 <= index && index < chain.length);
const symbol = chain[index];
let typeParameterNodes: ReadonlyArray<TypeNode> | ReadonlyArray<TypeParameterDeclaration> | undefined;
if (context.flags & NodeBuilderFlags.WriteTypeParametersInQualifiedName && index < (chain.length - 1)) {
const parentSymbol = symbol;
const nextSymbol = chain[index + 1];
if (getCheckFlags(nextSymbol) & CheckFlags.Instantiated) {
const params = getTypeParametersOfClassOrInterface(
parentSymbol.flags & SymbolFlags.Alias ? resolveAlias(parentSymbol) : parentSymbol
);
typeParameterNodes = mapToTypeNodes(map(params, (nextSymbol as TransientSymbol).mapper!), context);
}
else {
typeParameterNodes = typeParametersToTypeParameterDeclarations(symbol, context);
}
}
return typeParameterNodes;
}
/**
* Given A[B][C][D], finds A[B]
*/
function getTopmostIndexedAccessType(top: IndexedAccessTypeNode): IndexedAccessTypeNode {
if (isIndexedAccessTypeNode(top.objectType)) {
return getTopmostIndexedAccessType(top.objectType);
}
return top;
}
function getSpecifierForModuleSymbol(symbol: Symbol, context: NodeBuilderContext) {
const file = getDeclarationOfKind<SourceFile>(symbol, SyntaxKind.SourceFile);
if (file && file.moduleName !== undefined) {
// Use the amd name if it is available
return file.moduleName;
}
if (!file) {
if (context.tracker.trackReferencedAmbientModule) {
const ambientDecls = filter(symbol.declarations, isAmbientModule);
if (length(ambientDecls)) {
for (const decl of ambientDecls) {
context.tracker.trackReferencedAmbientModule(decl, symbol);
}
}
}
if (ambientModuleSymbolRegex.test(symbol.escapedName as string)) {
return (symbol.escapedName as string).substring(1, (symbol.escapedName as string).length - 1);
}
}
if (!context.enclosingDeclaration || !context.tracker.moduleResolverHost) {
// If there's no context declaration, we can't lookup a non-ambient specifier, so we just use the symbol name
if (ambientModuleSymbolRegex.test(symbol.escapedName as string)) {
return (symbol.escapedName as string).substring(1, (symbol.escapedName as string).length - 1);
}
return getSourceFileOfNode(getNonAugmentationDeclaration(symbol)!).fileName; // A resolver may not be provided for baselines and errors - in those cases we use the fileName in full
}
const contextFile = getSourceFileOfNode(getOriginalNode(context.enclosingDeclaration));
const links = getSymbolLinks(symbol);
let specifier = links.specifierCache && links.specifierCache.get(contextFile.path);
if (!specifier) {
const isBundle = (compilerOptions.out || compilerOptions.outFile);
// For declaration bundles, we need to generate absolute paths relative to the common source dir for imports,
// just like how the declaration emitter does for the ambient module declarations - we can easily accomplish this
// using the `baseUrl` compiler option (which we would otherwise never use in declaration emit) and a non-relative
// specifier preference
const { moduleResolverHost } = context.tracker;
const specifierCompilerOptions = isBundle ? { ...compilerOptions, baseUrl: moduleResolverHost.getCommonSourceDirectory() } : compilerOptions;
specifier = first(moduleSpecifiers.getModuleSpecifiers(
symbol,
specifierCompilerOptions,
contextFile,
moduleResolverHost,
host.getSourceFiles(),
{ importModuleSpecifierPreference: isBundle ? "non-relative" : "relative" },
host.redirectTargetsMap,
));
links.specifierCache = links.specifierCache || createMap();
links.specifierCache.set(contextFile.path, specifier);
}
return specifier;
}
function symbolToTypeNode(symbol: Symbol, context: NodeBuilderContext, meaning: SymbolFlags, overrideTypeArguments?: ReadonlyArray<TypeNode>): TypeNode {
const chain = lookupSymbolChain(symbol, context, meaning, !(context.flags & NodeBuilderFlags.UseAliasDefinedOutsideCurrentScope)); // If we're using aliases outside the current scope, dont bother with the module
const isTypeOf = meaning === SymbolFlags.Value;
if (some(chain[0].declarations, hasNonGlobalAugmentationExternalModuleSymbol)) {
// module is root, must use `ImportTypeNode`
const nonRootParts = chain.length > 1 ? createAccessFromSymbolChain(chain, chain.length - 1, 1) : undefined;
const typeParameterNodes = overrideTypeArguments || lookupTypeParameterNodes(chain, 0, context);
const specifier = getSpecifierForModuleSymbol(chain[0], context);
if (!(context.flags & NodeBuilderFlags.AllowNodeModulesRelativePaths) && getEmitModuleResolutionKind(compilerOptions) === ModuleResolutionKind.NodeJs && specifier.indexOf("/node_modules/") >= 0) {
// If ultimately we can only name the symbol with a reference that dives into a `node_modules` folder, we should error
// since declaration files with these kinds of references are liable to fail when published :(
context.encounteredError = true;
if (context.tracker.reportLikelyUnsafeImportRequiredError) {
context.tracker.reportLikelyUnsafeImportRequiredError(specifier);
}
}
const lit = createLiteralTypeNode(createLiteral(specifier));
if (context.tracker.trackExternalModuleSymbolOfImportTypeNode) context.tracker.trackExternalModuleSymbolOfImportTypeNode(chain[0]);
context.approximateLength += specifier.length + 10; // specifier + import("")
if (!nonRootParts || isEntityName(nonRootParts)) {
if (nonRootParts) {
const lastId = isIdentifier(nonRootParts) ? nonRootParts : nonRootParts.right;
lastId.typeArguments = undefined;
}
return createImportTypeNode(lit, nonRootParts as EntityName, typeParameterNodes as ReadonlyArray<TypeNode>, isTypeOf);
}
else {
const splitNode = getTopmostIndexedAccessType(nonRootParts);
const qualifier = (splitNode.objectType as TypeReferenceNode).typeName;
return createIndexedAccessTypeNode(createImportTypeNode(lit, qualifier, typeParameterNodes as ReadonlyArray<TypeNode>, isTypeOf), splitNode.indexType);
}
}
const entityName = createAccessFromSymbolChain(chain, chain.length - 1, 0);
if (isIndexedAccessTypeNode(entityName)) {
return entityName; // Indexed accesses can never be `typeof`
}
if (isTypeOf) {
return createTypeQueryNode(entityName);
}
else {
const lastId = isIdentifier(entityName) ? entityName : entityName.right;
const lastTypeArgs = lastId.typeArguments;
lastId.typeArguments = undefined;
return createTypeReferenceNode(entityName, lastTypeArgs as NodeArray<TypeNode>);
}
function createAccessFromSymbolChain(chain: Symbol[], index: number, stopper: number): EntityName | IndexedAccessTypeNode {
const typeParameterNodes = index === (chain.length - 1) ? overrideTypeArguments : lookupTypeParameterNodes(chain, index, context);
const symbol = chain[index];
if (index === 0) {
context.flags |= NodeBuilderFlags.InInitialEntityName;
}
const symbolName = getNameOfSymbolAsWritten(symbol, context);
context.approximateLength += symbolName.length + 1;
if (index === 0) {
context.flags ^= NodeBuilderFlags.InInitialEntityName;
}
const parent = chain[index - 1];
if (!(context.flags & NodeBuilderFlags.ForbidIndexedAccessSymbolReferences) && parent && getMembersOfSymbol(parent) && getMembersOfSymbol(parent).get(symbol.escapedName) === symbol) {
// Should use an indexed access
const LHS = createAccessFromSymbolChain(chain, index - 1, stopper);
if (isIndexedAccessTypeNode(LHS)) {
return createIndexedAccessTypeNode(LHS, createLiteralTypeNode(createLiteral(symbolName)));
}
else {
return createIndexedAccessTypeNode(createTypeReferenceNode(LHS, typeParameterNodes as ReadonlyArray<TypeNode>), createLiteralTypeNode(createLiteral(symbolName)));
}
}
const identifier = setEmitFlags(createIdentifier(symbolName, typeParameterNodes), EmitFlags.NoAsciiEscaping);
identifier.symbol = symbol;
if (index > stopper) {
const LHS = createAccessFromSymbolChain(chain, index - 1, stopper);
if (!isEntityName(LHS)) {
return Debug.fail("Impossible construct - an export of an indexed access cannot be reachable");
}
return createQualifiedName(LHS, identifier);
}
return identifier;
}
}
function symbolToName(symbol: Symbol, context: NodeBuilderContext, meaning: SymbolFlags, expectsIdentifier: true): Identifier;
function symbolToName(symbol: Symbol, context: NodeBuilderContext, meaning: SymbolFlags, expectsIdentifier: false): EntityName;
function symbolToName(symbol: Symbol, context: NodeBuilderContext, meaning: SymbolFlags, expectsIdentifier: boolean): EntityName {
const chain = lookupSymbolChain(symbol, context, meaning);
if (expectsIdentifier && chain.length !== 1
&& !context.encounteredError
&& !(context.flags & NodeBuilderFlags.AllowQualifedNameInPlaceOfIdentifier)) {
context.encounteredError = true;
}
return createEntityNameFromSymbolChain(chain, chain.length - 1);
function createEntityNameFromSymbolChain(chain: Symbol[], index: number): EntityName {
const typeParameterNodes = lookupTypeParameterNodes(chain, index, context);
const symbol = chain[index];
if (index === 0) {
context.flags |= NodeBuilderFlags.InInitialEntityName;
}
const symbolName = getNameOfSymbolAsWritten(symbol, context);
if (index === 0) {
context.flags ^= NodeBuilderFlags.InInitialEntityName;
}
const identifier = setEmitFlags(createIdentifier(symbolName, typeParameterNodes), EmitFlags.NoAsciiEscaping);
identifier.symbol = symbol;
return index > 0 ? createQualifiedName(createEntityNameFromSymbolChain(chain, index - 1), identifier) : identifier;
}
}
function symbolToExpression(symbol: Symbol, context: NodeBuilderContext, meaning: SymbolFlags) {
const chain = lookupSymbolChain(symbol, context, meaning);
return createExpressionFromSymbolChain(chain, chain.length - 1);
function createExpressionFromSymbolChain(chain: Symbol[], index: number): Expression {
const typeParameterNodes = lookupTypeParameterNodes(chain, index, context);
const symbol = chain[index];
if (some(symbol.declarations, hasNonGlobalAugmentationExternalModuleSymbol)) {
return createLiteral(getSpecifierForModuleSymbol(symbol, context));
}
if (index === 0) {
context.flags |= NodeBuilderFlags.InInitialEntityName;
}
let symbolName = getNameOfSymbolAsWritten(symbol, context);
if (index === 0) {
context.flags ^= NodeBuilderFlags.InInitialEntityName;
}
let firstChar = symbolName.charCodeAt(0);
const canUsePropertyAccess = isIdentifierStart(firstChar, languageVersion);
if (index === 0 || canUsePropertyAccess) {
const identifier = setEmitFlags(createIdentifier(symbolName, typeParameterNodes), EmitFlags.NoAsciiEscaping);
identifier.symbol = symbol;
return index > 0 ? createPropertyAccess(createExpressionFromSymbolChain(chain, index - 1), identifier) : identifier;
}
else {
if (firstChar === CharacterCodes.openBracket) {
symbolName = symbolName.substring(1, symbolName.length - 1);
firstChar = symbolName.charCodeAt(0);
}
let expression: Expression | undefined;
if (isSingleOrDoubleQuote(firstChar)) {
expression = createLiteral(symbolName.substring(1, symbolName.length - 1).replace(/\\./g, s => s.substring(1)));
(expression as StringLiteral).singleQuote = firstChar === CharacterCodes.singleQuote;
}
else if (("" + +symbolName) === symbolName) {
expression = createLiteral(+symbolName);
}
if (!expression) {
expression = setEmitFlags(createIdentifier(symbolName, typeParameterNodes), EmitFlags.NoAsciiEscaping);
expression.symbol = symbol;
}
return createElementAccess(createExpressionFromSymbolChain(chain, index - 1), expression);
}
}
}
}
function typePredicateToString(typePredicate: TypePredicate, enclosingDeclaration?: Node, flags: TypeFormatFlags = TypeFormatFlags.UseAliasDefinedOutsideCurrentScope, writer?: EmitTextWriter): string {
return writer ? typePredicateToStringWorker(writer).getText() : usingSingleLineStringWriter(typePredicateToStringWorker);
function typePredicateToStringWorker(writer: EmitTextWriter) {
const predicate = createTypePredicateNode(
typePredicate.kind === TypePredicateKind.Identifier ? createIdentifier(typePredicate.parameterName) : createThisTypeNode(),
nodeBuilder.typeToTypeNode(typePredicate.type, enclosingDeclaration, toNodeBuilderFlags(flags) | NodeBuilderFlags.IgnoreErrors | NodeBuilderFlags.WriteTypeParametersInQualifiedName)!, // TODO: GH#18217
);
const printer = createPrinter({ removeComments: true });
const sourceFile = enclosingDeclaration && getSourceFileOfNode(enclosingDeclaration);
printer.writeNode(EmitHint.Unspecified, predicate, /*sourceFile*/ sourceFile, writer);
return writer;
}
}
function formatUnionTypes(types: ReadonlyArray<Type>): Type[] {
const result: Type[] = [];
let flags: TypeFlags = 0;
for (let i = 0; i < types.length; i++) {
const t = types[i];
flags |= t.flags;
if (!(t.flags & TypeFlags.Nullable)) {
if (t.flags & (TypeFlags.BooleanLiteral | TypeFlags.EnumLiteral)) {
const baseType = t.flags & TypeFlags.BooleanLiteral ? booleanType : getBaseTypeOfEnumLiteralType(<LiteralType>t);
if (baseType.flags & TypeFlags.Union) {
const count = (<UnionType>baseType).types.length;
if (i + count <= types.length && getRegularTypeOfLiteralType(types[i + count - 1]) === getRegularTypeOfLiteralType((<UnionType>baseType).types[count - 1])) {
result.push(baseType);
i += count - 1;
continue;
}
}
}
result.push(t);
}
}
if (flags & TypeFlags.Null) result.push(nullType);
if (flags & TypeFlags.Undefined) result.push(undefinedType);
return result || types;
}
function visibilityToString(flags: ModifierFlags): string | undefined {
if (flags === ModifierFlags.Private) {
return "private";
}
if (flags === ModifierFlags.Protected) {
return "protected";
}
return "public";
}
function getTypeAliasForTypeLiteral(type: Type): Symbol | undefined {
if (type.symbol && type.symbol.flags & SymbolFlags.TypeLiteral) {
const node = findAncestor(type.symbol.declarations[0].parent, n => n.kind !== SyntaxKind.ParenthesizedType)!;
if (node.kind === SyntaxKind.TypeAliasDeclaration) {
return getSymbolOfNode(node);
}
}
return undefined;
}
function isTopLevelInExternalModuleAugmentation(node: Node): boolean {
return node && node.parent &&
node.parent.kind === SyntaxKind.ModuleBlock &&
isExternalModuleAugmentation(node.parent.parent);
}
interface NodeBuilderContext {
enclosingDeclaration: Node | undefined;
flags: NodeBuilderFlags;
tracker: SymbolTracker;
// State
encounteredError: boolean;
visitedTypes: Map<true> | undefined;
symbolDepth: Map<number> | undefined;
inferTypeParameters: TypeParameter[] | undefined;
approximateLength: number;
truncating?: boolean;
}
function isDefaultBindingContext(location: Node) {
return location.kind === SyntaxKind.SourceFile || isAmbientModule(location);
}
function getNameOfSymbolFromNameType(symbol: Symbol, context?: NodeBuilderContext) {
const nameType = symbol.nameType;
if (nameType) {
if (nameType.flags & TypeFlags.StringOrNumberLiteral) {
const name = "" + (<StringLiteralType | NumberLiteralType>nameType).value;
if (!isIdentifierText(name, compilerOptions.target) && !isNumericLiteralName(name)) {
return `"${escapeString(name, CharacterCodes.doubleQuote)}"`;
}
return name;
}
if (nameType.flags & TypeFlags.UniqueESSymbol) {
return `[${getNameOfSymbolAsWritten((<UniqueESSymbolType>nameType).symbol, context)}]`;
}
}
}
/**
* Gets a human-readable name for a symbol.
* Should *not* be used for the right-hand side of a `.` -- use `symbolName(symbol)` for that instead.
*
* Unlike `symbolName(symbol)`, this will include quotes if the name is from a string literal.
* It will also use a representation of a number as written instead of a decimal form, e.g. `0o11` instead of `9`.
*/
function getNameOfSymbolAsWritten(symbol: Symbol, context?: NodeBuilderContext): string {
if (context && symbol.escapedName === InternalSymbolName.Default && !(context.flags & NodeBuilderFlags.UseAliasDefinedOutsideCurrentScope) &&
// If it's not the first part of an entity name, it must print as `default`
(!(context.flags & NodeBuilderFlags.InInitialEntityName) ||
// if the symbol is synthesized, it will only be referenced externally it must print as `default`
!symbol.declarations ||
// if not in the same binding context (source file, module declaration), it must print as `default`
(context.enclosingDeclaration && findAncestor(symbol.declarations[0], isDefaultBindingContext) !== findAncestor(context.enclosingDeclaration, isDefaultBindingContext)))) {
return "default";
}
if (symbol.declarations && symbol.declarations.length) {
const declaration = symbol.declarations[0];
const name = getNameOfDeclaration(declaration);
if (name) {
if (isCallExpression(declaration) && isBindableObjectDefinePropertyCall(declaration)) {
return symbolName(symbol);
}
if (isComputedPropertyName(name) && !(getCheckFlags(symbol) & CheckFlags.Late) && symbol.nameType && symbol.nameType.flags & TypeFlags.StringOrNumberLiteral) {
// Computed property name isn't late bound, but has a well-known name type - use name type to generate a symbol name
const result = getNameOfSymbolFromNameType(symbol, context);
if (result !== undefined) {
return result;
}
}
return declarationNameToString(name);
}
if (declaration.parent && declaration.parent.kind === SyntaxKind.VariableDeclaration) {
return declarationNameToString((<VariableDeclaration>declaration.parent).name);
}
switch (declaration.kind) {
case SyntaxKind.ClassExpression:
case SyntaxKind.FunctionExpression:
case SyntaxKind.ArrowFunction:
if (context && !context.encounteredError && !(context.flags & NodeBuilderFlags.AllowAnonymousIdentifier)) {
context.encounteredError = true;
}
return declaration.kind === SyntaxKind.ClassExpression ? "(Anonymous class)" : "(Anonymous function)";
}
}
const name = getNameOfSymbolFromNameType(symbol, context);
return name !== undefined ? name : symbolName(symbol);
}
function isDeclarationVisible(node: Node): boolean {
if (node) {
const links = getNodeLinks(node);
if (links.isVisible === undefined) {
links.isVisible = !!determineIfDeclarationIsVisible();
}
return links.isVisible;
}
return false;
function determineIfDeclarationIsVisible() {
switch (node.kind) {
case SyntaxKind.JSDocCallbackTag:
case SyntaxKind.JSDocTypedefTag:
// Top-level jsdoc type aliases are considered exported
// First parent is comment node, second is hosting declaration or token; we only care about those tokens or declarations whose parent is a source file
return !!(node.parent && node.parent.parent && node.parent.parent.parent && isSourceFile(node.parent.parent.parent));
case SyntaxKind.BindingElement:
return isDeclarationVisible(node.parent.parent);
case SyntaxKind.VariableDeclaration:
if (isBindingPattern((node as VariableDeclaration).name) &&
!((node as VariableDeclaration).name as BindingPattern).elements.length) {
// If the binding pattern is empty, this variable declaration is not visible
return false;
}
// falls through
case SyntaxKind.ModuleDeclaration:
case SyntaxKind.ClassDeclaration:
case SyntaxKind.InterfaceDeclaration:
case SyntaxKind.TypeAliasDeclaration:
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.EnumDeclaration:
case SyntaxKind.ImportEqualsDeclaration:
// external module augmentation is always visible
if (isExternalModuleAugmentation(node)) {
return true;
}
const parent = getDeclarationContainer(node);
// If the node is not exported or it is not ambient module element (except import declaration)
if (!(getCombinedModifierFlags(node as Declaration) & ModifierFlags.Export) &&
!(node.kind !== SyntaxKind.ImportEqualsDeclaration && parent.kind !== SyntaxKind.SourceFile && parent.flags & NodeFlags.Ambient)) {
return isGlobalSourceFile(parent);
}
// Exported members/ambient module elements (exception import declaration) are visible if parent is visible
return isDeclarationVisible(parent);
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.PropertySignature:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.MethodSignature:
if (hasModifier(node, ModifierFlags.Private | ModifierFlags.Protected)) {
// Private/protected properties/methods are not visible
return false;
}
// Public properties/methods are visible if its parents are visible, so:
// falls through
case SyntaxKind.Constructor:
case SyntaxKind.ConstructSignature:
case SyntaxKind.CallSignature:
case SyntaxKind.IndexSignature:
case SyntaxKind.Parameter:
case SyntaxKind.ModuleBlock:
case SyntaxKind.FunctionType:
case SyntaxKind.ConstructorType:
case SyntaxKind.TypeLiteral:
case SyntaxKind.TypeReference:
case SyntaxKind.ArrayType:
case SyntaxKind.TupleType:
case SyntaxKind.UnionType:
case SyntaxKind.IntersectionType:
case SyntaxKind.ParenthesizedType:
return isDeclarationVisible(node.parent);
// Default binding, import specifier and namespace import is visible
// only on demand so by default it is not visible
case SyntaxKind.ImportClause:
case SyntaxKind.NamespaceImport:
case SyntaxKind.ImportSpecifier:
return false;
// Type parameters are always visible
case SyntaxKind.TypeParameter:
// Source file and namespace export are always visible
case SyntaxKind.SourceFile:
case SyntaxKind.NamespaceExportDeclaration:
return true;
// Export assignments do not create name bindings outside the module
case SyntaxKind.ExportAssignment:
return false;
default:
return false;
}
}
}
function collectLinkedAliases(node: Identifier, setVisibility?: boolean): Node[] | undefined {
let exportSymbol: Symbol | undefined;
if (node.parent && node.parent.kind === SyntaxKind.ExportAssignment) {
exportSymbol = resolveName(node, node.escapedText, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace | SymbolFlags.Alias, /*nameNotFoundMessage*/ undefined, node, /*isUse*/ false);
}
else if (node.parent.kind === SyntaxKind.ExportSpecifier) {
exportSymbol = getTargetOfExportSpecifier(<ExportSpecifier>node.parent, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace | SymbolFlags.Alias);
}
let result: Node[] | undefined;
if (exportSymbol) {
buildVisibleNodeList(exportSymbol.declarations);
}
return result;
function buildVisibleNodeList(declarations: Declaration[]) {
forEach(declarations, declaration => {
const resultNode = getAnyImportSyntax(declaration) || declaration;
if (setVisibility) {
getNodeLinks(declaration).isVisible = true;
}
else {
result = result || [];
pushIfUnique(result, resultNode);
}
if (isInternalModuleImportEqualsDeclaration(declaration)) {
// Add the referenced top container visible
const internalModuleReference = <Identifier | QualifiedName>declaration.moduleReference;
const firstIdentifier = getFirstIdentifier(internalModuleReference);
const importSymbol = resolveName(declaration, firstIdentifier.escapedText, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace,
undefined, undefined, /*isUse*/ false);
if (importSymbol) {
buildVisibleNodeList(importSymbol.declarations);
}
}
});
}
}
/**
* Push an entry on the type resolution stack. If an entry with the given target and the given property name
* is already on the stack, and no entries in between already have a type, then a circularity has occurred.
* In this case, the result values of the existing entry and all entries pushed after it are changed to false,
* and the value false is returned. Otherwise, the new entry is just pushed onto the stack, and true is returned.
* In order to see if the same query has already been done before, the target object and the propertyName both
* must match the one passed in.
*
* @param target The symbol, type, or signature whose type is being queried
* @param propertyName The property name that should be used to query the target for its type
*/
function pushTypeResolution(target: TypeSystemEntity, propertyName: TypeSystemPropertyName): boolean {
const resolutionCycleStartIndex = findResolutionCycleStartIndex(target, propertyName);
if (resolutionCycleStartIndex >= 0) {
// A cycle was found
const { length } = resolutionTargets;
for (let i = resolutionCycleStartIndex; i < length; i++) {
resolutionResults[i] = false;
}
return false;
}
resolutionTargets.push(target);
resolutionResults.push(/*items*/ true);
resolutionPropertyNames.push(propertyName);
return true;
}
function findResolutionCycleStartIndex(target: TypeSystemEntity, propertyName: TypeSystemPropertyName): number {
for (let i = resolutionTargets.length - 1; i >= 0; i--) {
if (hasType(resolutionTargets[i], resolutionPropertyNames[i])) {
return -1;
}
if (resolutionTargets[i] === target && resolutionPropertyNames[i] === propertyName) {
return i;
}
}
return -1;
}
function hasType(target: TypeSystemEntity, propertyName: TypeSystemPropertyName): boolean {
switch (propertyName) {
case TypeSystemPropertyName.Type:
return !!getSymbolLinks(<Symbol>target).type;
case TypeSystemPropertyName.EnumTagType:
return !!(getNodeLinks(target as JSDocEnumTag).resolvedEnumType);
case TypeSystemPropertyName.DeclaredType:
return !!getSymbolLinks(<Symbol>target).declaredType;
case TypeSystemPropertyName.ResolvedBaseConstructorType:
return !!(<InterfaceType>target).resolvedBaseConstructorType;
case TypeSystemPropertyName.ResolvedReturnType:
return !!(<Signature>target).resolvedReturnType;
case TypeSystemPropertyName.ImmediateBaseConstraint:
return !!(<Type>target).immediateBaseConstraint;
case TypeSystemPropertyName.JSDocTypeReference:
return !!getSymbolLinks(target as Symbol).resolvedJSDocType;
}
return Debug.assertNever(propertyName);
}
// Pop an entry from the type resolution stack and return its associated result value. The result value will
// be true if no circularities were detected, or false if a circularity was found.
function popTypeResolution(): boolean {
resolutionTargets.pop();
resolutionPropertyNames.pop();
return resolutionResults.pop()!;
}
function getDeclarationContainer(node: Node): Node {
return findAncestor(getRootDeclaration(node), node => {
switch (node.kind) {
case SyntaxKind.VariableDeclaration:
case SyntaxKind.VariableDeclarationList:
case SyntaxKind.ImportSpecifier:
case SyntaxKind.NamedImports:
case SyntaxKind.NamespaceImport:
case SyntaxKind.ImportClause:
return false;
default:
return true;
}
})!.parent;
}
function getTypeOfPrototypeProperty(prototype: Symbol): Type {
// TypeScript 1.0 spec (April 2014): 8.4
// Every class automatically contains a static property member named 'prototype',
// the type of which is an instantiation of the class type with type Any supplied as a type argument for each type parameter.
// It is an error to explicitly declare a static property member with the name 'prototype'.
const classType = <InterfaceType>getDeclaredTypeOfSymbol(getParentOfSymbol(prototype)!);
return classType.typeParameters ? createTypeReference(<GenericType>classType, map(classType.typeParameters, _ => anyType)) : classType;
}
// Return the type of the given property in the given type, or undefined if no such property exists
function getTypeOfPropertyOfType(type: Type, name: __String): Type | undefined {
const prop = getPropertyOfType(type, name);
return prop ? getTypeOfSymbol(prop) : undefined;
}
function getTypeOfPropertyOrIndexSignature(type: Type, name: __String): Type {
return getTypeOfPropertyOfType(type, name) || isNumericLiteralName(name) && getIndexTypeOfType(type, IndexKind.Number) || getIndexTypeOfType(type, IndexKind.String) || unknownType;
}
function isTypeAny(type: Type | undefined) {
return type && (type.flags & TypeFlags.Any) !== 0;
}
// Return the type of a binding element parent. We check SymbolLinks first to see if a type has been
// assigned by contextual typing.
function getTypeForBindingElementParent(node: BindingElementGrandparent) {
const symbol = getSymbolOfNode(node);
return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node, /*includeOptionality*/ false);
}
function isComputedNonLiteralName(name: PropertyName): boolean {
return name.kind === SyntaxKind.ComputedPropertyName && !isStringOrNumericLiteralLike(name.expression);
}
function getRestType(source: Type, properties: PropertyName[], symbol: Symbol | undefined): Type {
source = filterType(source, t => !(t.flags & TypeFlags.Nullable));
if (source.flags & TypeFlags.Never) {
return emptyObjectType;
}
if (source.flags & TypeFlags.Union) {
return mapType(source, t => getRestType(t, properties, symbol));
}
const omitKeyType = getUnionType(map(properties, getLiteralTypeFromPropertyName));
if (isGenericObjectType(source) || isGenericIndexType(omitKeyType)) {
if (omitKeyType.flags & TypeFlags.Never) {
return source;
}
const pickTypeAlias = getGlobalPickSymbol();
const excludeTypeAlias = getGlobalExcludeSymbol();
if (!pickTypeAlias || !excludeTypeAlias) {
return errorType;
}
const pickKeys = getTypeAliasInstantiation(excludeTypeAlias, [getIndexType(source), omitKeyType]);
return getTypeAliasInstantiation(pickTypeAlias, [source, pickKeys]);
}
const members = createSymbolTable();
for (const prop of getPropertiesOfType(source)) {
if (!isTypeAssignableTo(getLiteralTypeFromProperty(prop, TypeFlags.StringOrNumberLiteralOrUnique), omitKeyType)
&& !(getDeclarationModifierFlagsFromSymbol(prop) & (ModifierFlags.Private | ModifierFlags.Protected))
&& isSpreadableProperty(prop)) {
members.set(prop.escapedName, getSpreadSymbol(prop, /*readonly*/ false));
}
}
const stringIndexInfo = getIndexInfoOfType(source, IndexKind.String);
const numberIndexInfo = getIndexInfoOfType(source, IndexKind.Number);
return createAnonymousType(symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
}
// Determine the control flow type associated with a destructuring declaration or assignment. The following
// forms of destructuring are possible:
// let { x } = obj; // BindingElement
// let [ x ] = obj; // BindingElement
// { x } = obj; // ShorthandPropertyAssignment
// { x: v } = obj; // PropertyAssignment
// [ x ] = obj; // Expression
// We construct a synthetic element access expression corresponding to 'obj.x' such that the control
// flow analyzer doesn't have to handle all the different syntactic forms.
function getFlowTypeOfDestructuring(node: BindingElement | PropertyAssignment | ShorthandPropertyAssignment | Expression, declaredType: Type) {
const reference = getSyntheticElementAccess(node);
return reference ? getFlowTypeOfReference(reference, declaredType) : declaredType;
}
function getSyntheticElementAccess(node: BindingElement | PropertyAssignment | ShorthandPropertyAssignment | Expression): ElementAccessExpression | undefined {
const parentAccess = getParentElementAccess(node);
if (parentAccess && parentAccess.flowNode) {
const propName = getDestructuringPropertyName(node);
if (propName) {
const result = <ElementAccessExpression>createNode(SyntaxKind.ElementAccessExpression, node.pos, node.end);
result.parent = node;
result.expression = <LeftHandSideExpression>parentAccess;
const literal = <StringLiteral>createNode(SyntaxKind.StringLiteral, node.pos, node.end);
literal.parent = result;
literal.text = propName;
result.argumentExpression = literal;
result.flowNode = parentAccess.flowNode;
return result;
}
}
}
function getParentElementAccess(node: BindingElement | PropertyAssignment | ShorthandPropertyAssignment | Expression) {
const ancestor = node.parent.parent;
switch (ancestor.kind) {
case SyntaxKind.BindingElement:
case SyntaxKind.PropertyAssignment:
return getSyntheticElementAccess(<BindingElement | PropertyAssignment>ancestor);
case SyntaxKind.ArrayLiteralExpression:
return getSyntheticElementAccess(<Expression>node.parent);
case SyntaxKind.VariableDeclaration:
return (<VariableDeclaration>ancestor).initializer;
case SyntaxKind.BinaryExpression:
return (<BinaryExpression>ancestor).right;
}
}
function getDestructuringPropertyName(node: BindingElement | PropertyAssignment | ShorthandPropertyAssignment | Expression) {
const parent = node.parent;
if (node.kind === SyntaxKind.BindingElement && parent.kind === SyntaxKind.ObjectBindingPattern) {
return getLiteralPropertyNameText((<BindingElement>node).propertyName || <Identifier>(<BindingElement>node).name);
}
if (node.kind === SyntaxKind.PropertyAssignment || node.kind === SyntaxKind.ShorthandPropertyAssignment) {
return getLiteralPropertyNameText((<PropertyAssignment | ShorthandPropertyAssignment>node).name);
}
return "" + (<NodeArray<Node>>(<BindingPattern | ArrayLiteralExpression>parent).elements).indexOf(node);
}
function getLiteralPropertyNameText(name: PropertyName) {
const type = getLiteralTypeFromPropertyName(name);
return type.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral) ? "" + (<StringLiteralType | NumberLiteralType>type).value : undefined;
}
/** Return the inferred type for a binding element */
function getTypeForBindingElement(declaration: BindingElement): Type | undefined {
const pattern = declaration.parent;
let parentType = getTypeForBindingElementParent(pattern.parent);
// If no type or an any type was inferred for parent, infer that for the binding element
if (!parentType || isTypeAny(parentType)) {
return parentType;
}
// Relax null check on ambient destructuring parameters, since the parameters have no implementation and are just documentation
if (strictNullChecks && declaration.flags & NodeFlags.Ambient && isParameterDeclaration(declaration)) {
parentType = getNonNullableType(parentType);
}
let type: Type | undefined;
if (pattern.kind === SyntaxKind.ObjectBindingPattern) {
if (declaration.dotDotDotToken) {
if (parentType.flags & TypeFlags.Unknown || !isValidSpreadType(parentType)) {
error(declaration, Diagnostics.Rest_types_may_only_be_created_from_object_types);
return errorType;
}
const literalMembers: PropertyName[] = [];
for (const element of pattern.elements) {
if (!element.dotDotDotToken) {
literalMembers.push(element.propertyName || element.name as Identifier);
}
}
type = getRestType(parentType, literalMembers, declaration.symbol);
}
else {
// Use explicitly specified property name ({ p: xxx } form), or otherwise the implied name ({ p } form)
const name = declaration.propertyName || <Identifier>declaration.name;
const indexType = getLiteralTypeFromPropertyName(name);
const declaredType = getConstraintForLocation(getIndexedAccessType(parentType, indexType, name), declaration.name);
type = getFlowTypeOfDestructuring(declaration, declaredType);
}
}
else {
// This elementType will be used if the specific property corresponding to this index is not
// present (aka the tuple element property). This call also checks that the parentType is in
// fact an iterable or array (depending on target language).
const elementType = checkIteratedTypeOrElementType(parentType, pattern, /*allowStringInput*/ false, /*allowAsyncIterables*/ false);
const index = pattern.elements.indexOf(declaration);
if (declaration.dotDotDotToken) {
// If the parent is a tuple type, the rest element has a tuple type of the
// remaining tuple element types. Otherwise, the rest element has an array type with same
// element type as the parent type.
type = everyType(parentType, isTupleType) ?
mapType(parentType, t => sliceTupleType(<TupleTypeReference>t, index)) :
createArrayType(elementType);
}
else if (isArrayLikeType(parentType)) {
const indexType = getLiteralType(index);
const declaredType = getConstraintForLocation(getIndexedAccessType(parentType, indexType, declaration.name), declaration.name);
type = getFlowTypeOfDestructuring(declaration, declaredType);
}
else {
type = elementType;
}
}
// In strict null checking mode, if a default value of a non-undefined type is specified, remove
// undefined from the final type.
if (strictNullChecks && declaration.initializer && !(getFalsyFlags(checkDeclarationInitializer(declaration)) & TypeFlags.Undefined)) {
type = getTypeWithFacts(type, TypeFacts.NEUndefined);
}
return declaration.initializer && !getEffectiveTypeAnnotationNode(walkUpBindingElementsAndPatterns(declaration)) ?
getUnionType([type, checkDeclarationInitializer(declaration)], UnionReduction.Subtype) :
type;
}
function getTypeForDeclarationFromJSDocComment(declaration: Node) {
const jsdocType = getJSDocType(declaration);
if (jsdocType) {
return getTypeFromTypeNode(jsdocType);
}
return undefined;
}
function isNullOrUndefined(node: Expression) {
const expr = skipParentheses(node);
return expr.kind === SyntaxKind.NullKeyword || expr.kind === SyntaxKind.Identifier && getResolvedSymbol(<Identifier>expr) === undefinedSymbol;
}
function isEmptyArrayLiteral(node: Expression) {
const expr = skipParentheses(node);
return expr.kind === SyntaxKind.ArrayLiteralExpression && (<ArrayLiteralExpression>expr).elements.length === 0;
}
function addOptionality(type: Type, optional = true): Type {
return strictNullChecks && optional ? getOptionalType(type) : type;
}
function isParameterOfContextuallyTypedFunction(node: Declaration) {
return node.kind === SyntaxKind.Parameter &&
(node.parent.kind === SyntaxKind.FunctionExpression || node.parent.kind === SyntaxKind.ArrowFunction) &&
!!getContextualType(<Expression>node.parent);
}
// Return the inferred type for a variable, parameter, or property declaration
function getTypeForVariableLikeDeclaration(declaration: ParameterDeclaration | PropertyDeclaration | PropertySignature | VariableDeclaration | BindingElement, includeOptionality: boolean): Type | undefined {
// A variable declared in a for..in statement is of type string, or of type keyof T when the
// right hand expression is of a type parameter type.
if (isVariableDeclaration(declaration) && declaration.parent.parent.kind === SyntaxKind.ForInStatement) {
const indexType = getIndexType(getNonNullableTypeIfNeeded(checkExpression(declaration.parent.parent.expression)));
return indexType.flags & (TypeFlags.TypeParameter | TypeFlags.Index) ? getExtractStringType(indexType) : stringType;
}
if (isVariableDeclaration(declaration) && declaration.parent.parent.kind === SyntaxKind.ForOfStatement) {
// checkRightHandSideOfForOf will return undefined if the for-of expression type was
// missing properties/signatures required to get its iteratedType (like
// [Symbol.iterator] or next). This may be because we accessed properties from anyType,
// or it may have led to an error inside getElementTypeOfIterable.
const forOfStatement = declaration.parent.parent;
return checkRightHandSideOfForOf(forOfStatement.expression, forOfStatement.awaitModifier) || anyType;
}
if (isBindingPattern(declaration.parent)) {
return getTypeForBindingElement(<BindingElement>declaration);
}
const isOptional = includeOptionality && (
isParameter(declaration) && isJSDocOptionalParameter(declaration)
|| !isBindingElement(declaration) && !isVariableDeclaration(declaration) && !!declaration.questionToken);
// Use type from type annotation if one is present
const declaredType = tryGetTypeFromEffectiveTypeNode(declaration);
if (declaredType) {
return addOptionality(declaredType, isOptional);
}
if ((noImplicitAny || isInJSFile(declaration)) &&
declaration.kind === SyntaxKind.VariableDeclaration && !isBindingPattern(declaration.name) &&
!(getCombinedModifierFlags(declaration) & ModifierFlags.Export) && !(declaration.flags & NodeFlags.Ambient)) {
// If --noImplicitAny is on or the declaration is in a Javascript file,
// use control flow tracked 'any' type for non-ambient, non-exported var or let variables with no
// initializer or a 'null' or 'undefined' initializer.
if (!(getCombinedNodeFlags(declaration) & NodeFlags.Const) && (!declaration.initializer || isNullOrUndefined(declaration.initializer))) {
return autoType;
}
// Use control flow tracked 'any[]' type for non-ambient, non-exported variables with an empty array
// literal initializer.
if (declaration.initializer && isEmptyArrayLiteral(declaration.initializer)) {
return autoArrayType;
}
}
if (declaration.kind === SyntaxKind.Parameter) {
const func = <FunctionLikeDeclaration>declaration.parent;
// For a parameter of a set accessor, use the type of the get accessor if one is present
if (func.kind === SyntaxKind.SetAccessor && !hasNonBindableDynamicName(func)) {
const getter = getDeclarationOfKind<AccessorDeclaration>(getSymbolOfNode(declaration.parent), SyntaxKind.GetAccessor);
if (getter) {
const getterSignature = getSignatureFromDeclaration(getter);
const thisParameter = getAccessorThisParameter(func as AccessorDeclaration);
if (thisParameter && declaration === thisParameter) {
// Use the type from the *getter*
Debug.assert(!thisParameter.type);
return getTypeOfSymbol(getterSignature.thisParameter!);
}
return getReturnTypeOfSignature(getterSignature);
}
}
if (isInJSFile(declaration)) {
const typeTag = getJSDocType(func);
if (typeTag && isFunctionTypeNode(typeTag)) {
return getTypeAtPosition(getSignatureFromDeclaration(typeTag), func.parameters.indexOf(declaration));
}
}
// Use contextual parameter type if one is available
const type = declaration.symbol.escapedName === InternalSymbolName.This ? getContextualThisParameterType(func) : getContextuallyTypedParameterType(declaration);
if (type) {
return addOptionality(type, isOptional);
}
}
else if (isInJSFile(declaration)) {
const containerObjectType = getJSContainerObjectType(declaration, getSymbolOfNode(declaration), getDeclaredExpandoInitializer(declaration));
if (containerObjectType) {
return containerObjectType;
}
}
// Use the type of the initializer expression if one is present and the declaration is
// not a parameter of a contextually typed function
if (declaration.initializer && !isParameterOfContextuallyTypedFunction(declaration)) {
const type = checkDeclarationInitializer(declaration);
return addOptionality(type, isOptional);
}
if (isJsxAttribute(declaration)) {
// if JSX attribute doesn't have initializer, by default the attribute will have boolean value of true.
// I.e <Elem attr /> is sugar for <Elem attr={true} />
return trueType;
}
// If the declaration specifies a binding pattern and is not a parameter of a contextually
// typed function, use the type implied by the binding pattern
if (isBindingPattern(declaration.name) && !isParameterOfContextuallyTypedFunction(declaration)) {
return getTypeFromBindingPattern(declaration.name, /*includePatternInType*/ false, /*reportErrors*/ true);
}
// No type specified and nothing can be inferred
return undefined;
}
function getWidenedTypeFromAssignmentDeclaration(symbol: Symbol, resolvedSymbol?: Symbol) {
// function/class/{} initializers are themselves containers, so they won't merge in the same way as other initializers
const container = getAssignedExpandoInitializer(symbol.valueDeclaration);
if (container) {
const tag = getJSDocTypeTag(container);
if (tag && tag.typeExpression) {
return getTypeFromTypeNode(tag.typeExpression);
}
const containerObjectType = getJSContainerObjectType(symbol.valueDeclaration, symbol, container);
return containerObjectType || getWidenedLiteralType(checkExpressionCached(container));
}
let definedInConstructor = false;
let definedInMethod = false;
let jsdocType: Type | undefined;
let types: Type[] | undefined;
for (const declaration of symbol.declarations) {
const expression = (isBinaryExpression(declaration) || isCallExpression(declaration)) ? declaration :
isPropertyAccessExpression(declaration) ? isBinaryExpression(declaration.parent) ? declaration.parent : declaration :
undefined;
if (!expression) {
return errorType;
}
const kind = isPropertyAccessExpression(expression) ? getAssignmentDeclarationPropertyAccessKind(expression) : getAssignmentDeclarationKind(expression);
if (kind === AssignmentDeclarationKind.ThisProperty) {
if (isDeclarationInConstructor(expression)) {
definedInConstructor = true;
}
else {
definedInMethod = true;
}
}
if (!isCallExpression(expression)) {
jsdocType = getJSDocTypeFromAssignmentDeclaration(jsdocType, expression, symbol, declaration);
}
if (!jsdocType) {
(types || (types = [])).push((isBinaryExpression(expression) || isCallExpression(expression)) ? getInitializerTypeFromAssignmentDeclaration(symbol, resolvedSymbol, expression, kind) : neverType);
}
}
let type = jsdocType;
if (!type) {
let constructorTypes = definedInConstructor ? getConstructorDefinedThisAssignmentTypes(types!, symbol.declarations) : undefined;
// use only the constructor types unless they were only assigned null | undefined (including widening variants)
if (definedInMethod) {
const propType = getTypeOfAssignmentDeclarationPropertyOfBaseType(symbol);
if (propType) {
(constructorTypes || (constructorTypes = [])).push(propType);
definedInConstructor = true;
}
}
const sourceTypes = some(constructorTypes, t => !!(t.flags & ~TypeFlags.Nullable)) ? constructorTypes : types; // TODO: GH#18217
type = getUnionType(sourceTypes!, UnionReduction.Subtype);
}
const widened = getWidenedType(addOptionality(type, definedInMethod && !definedInConstructor));
if (filterType(widened, t => !!(t.flags & ~TypeFlags.Nullable)) === neverType) {
reportImplicitAny(symbol.valueDeclaration, anyType);
return anyType;
}
return widened;
}
function getJSContainerObjectType(decl: Node, symbol: Symbol, init: Expression | undefined): Type | undefined {
if (!isInJSFile(decl) || !init || !isObjectLiteralExpression(init) || init.properties.length) {
return undefined;
}
const exports = createSymbolTable();
while (isBinaryExpression(decl) || isPropertyAccessExpression(decl)) {
const s = getSymbolOfNode(decl);
if (s && hasEntries(s.exports)) {
mergeSymbolTable(exports, s.exports);
}
decl = isBinaryExpression(decl) ? decl.parent : decl.parent.parent;
}
const s = getSymbolOfNode(decl);
if (s && hasEntries(s.exports)) {
mergeSymbolTable(exports, s.exports);
}
const type = createAnonymousType(symbol, exports, emptyArray, emptyArray, undefined, undefined);
type.objectFlags |= ObjectFlags.JSLiteral;
return type;
}
function getJSDocTypeFromAssignmentDeclaration(declaredType: Type | undefined, expression: Expression, _symbol: Symbol, declaration: Declaration) {
const typeNode = getJSDocType(expression.parent);
if (typeNode) {
const type = getWidenedType(getTypeFromTypeNode(typeNode));
if (!declaredType) {
return type;
}
else if (declaredType !== errorType && type !== errorType && !isTypeIdenticalTo(declaredType, type)) {
errorNextVariableOrPropertyDeclarationMustHaveSameType(declaredType, declaration, type);
}
}
return declaredType;
}
/** If we don't have an explicit JSDoc type, get the type from the initializer. */
function getInitializerTypeFromAssignmentDeclaration(symbol: Symbol, resolvedSymbol: Symbol | undefined, expression: BinaryExpression | CallExpression, kind: AssignmentDeclarationKind) {
if (isCallExpression(expression)) {
if (resolvedSymbol) {
return getTypeOfSymbol(resolvedSymbol); // This shouldn't happen except under some hopefully forbidden merges of export assignments and object define assignments
}
const objectLitType = checkExpressionCached((expression as BindableObjectDefinePropertyCall).arguments[2]);
const valueType = getTypeOfPropertyOfType(objectLitType, "value" as __String);
if (valueType) {
return valueType;
}
const getFunc = getTypeOfPropertyOfType(objectLitType, "get" as __String);
if (getFunc) {
const getSig = getSingleCallSignature(getFunc);
if (getSig) {
return getReturnTypeOfSignature(getSig);
}
}
const setFunc = getTypeOfPropertyOfType(objectLitType, "set" as __String);
if (setFunc) {
const setSig = getSingleCallSignature(setFunc);
if (setSig) {
return getTypeOfFirstParameterOfSignature(setSig);
}
}
return anyType;
}
const type = resolvedSymbol ? getTypeOfSymbol(resolvedSymbol) : getWidenedLiteralType(checkExpressionCached(expression.right));
if (type.flags & TypeFlags.Object &&
kind === AssignmentDeclarationKind.ModuleExports &&
symbol.escapedName === InternalSymbolName.ExportEquals) {
const exportedType = resolveStructuredTypeMembers(type as ObjectType);
const members = createSymbolTable();
copyEntries(exportedType.members, members);
if (resolvedSymbol && !resolvedSymbol.exports) {
resolvedSymbol.exports = createSymbolTable();
}
(resolvedSymbol || symbol).exports!.forEach((s, name) => {
if (members.has(name)) {
const exportedMember = exportedType.members.get(name)!;
const union = createSymbol(s.flags | exportedMember.flags, name);
union.type = getUnionType([getTypeOfSymbol(s), getTypeOfSymbol(exportedMember)]);
members.set(name, union);
}
else {
members.set(name, s);
}
});
const result = createAnonymousType(
exportedType.symbol,
members,
exportedType.callSignatures,
exportedType.constructSignatures,
exportedType.stringIndexInfo,
exportedType.numberIndexInfo);
result.objectFlags |= (getObjectFlags(type) & ObjectFlags.JSLiteral); // Propagate JSLiteral flag
return result;
}
if (isEmptyArrayLiteralType(type)) {
reportImplicitAny(expression, anyArrayType);
return anyArrayType;
}
return type;
}
function isDeclarationInConstructor(expression: Expression) {
const thisContainer = getThisContainer(expression, /*includeArrowFunctions*/ false);
// Properties defined in a constructor (or base constructor, or javascript constructor function) don't get undefined added.
// Function expressions that are assigned to the prototype count as methods.
return thisContainer.kind === SyntaxKind.Constructor ||
thisContainer.kind === SyntaxKind.FunctionDeclaration ||
(thisContainer.kind === SyntaxKind.FunctionExpression && !isPrototypePropertyAssignment(thisContainer.parent));
}
function getConstructorDefinedThisAssignmentTypes(types: Type[], declarations: Declaration[]): Type[] | undefined {
Debug.assert(types.length === declarations.length);
return types.filter((_, i) => {
const declaration = declarations[i];
const expression = isBinaryExpression(declaration) ? declaration :
isBinaryExpression(declaration.parent) ? declaration.parent : undefined;
return expression && isDeclarationInConstructor(expression);
});
}
/** check for definition in base class if any declaration is in a class */
function getTypeOfAssignmentDeclarationPropertyOfBaseType(property: Symbol) {
const parentDeclaration = forEach(property.declarations, d => {
const parent = getThisContainer(d, /*includeArrowFunctions*/ false).parent;
return isClassLike(parent) && parent;
});
if (parentDeclaration) {
const classType = getDeclaredTypeOfSymbol(getSymbolOfNode(parentDeclaration)) as InterfaceType;
const baseClassType = classType && getBaseTypes(classType)[0];
if (baseClassType) {
return getTypeOfPropertyOfType(baseClassType, property.escapedName);
}
}
}
// Return the type implied by a binding pattern element. This is the type of the initializer of the element if
// one is present. Otherwise, if the element is itself a binding pattern, it is the type implied by the binding
// pattern. Otherwise, it is the type any.
function getTypeFromBindingElement(element: BindingElement, includePatternInType?: boolean, reportErrors?: boolean): Type {
if (element.initializer) {
return addOptionality(checkDeclarationInitializer(element));
}
if (isBindingPattern(element.name)) {
return getTypeFromBindingPattern(element.name, includePatternInType, reportErrors);
}
if (reportErrors && !declarationBelongsToPrivateAmbientMember(element)) {
reportImplicitAny(element, anyType);
}
return anyType;
}
// Return the type implied by an object binding pattern
function getTypeFromObjectBindingPattern(pattern: ObjectBindingPattern, includePatternInType: boolean, reportErrors: boolean): Type {
const members = createSymbolTable();
let stringIndexInfo: IndexInfo | undefined;
let objectFlags = ObjectFlags.ObjectLiteral | ObjectFlags.ContainsObjectLiteral;
forEach(pattern.elements, e => {
const name = e.propertyName || <Identifier>e.name;
if (e.dotDotDotToken) {
stringIndexInfo = createIndexInfo(anyType, /*isReadonly*/ false);
return;
}
const exprType = getLiteralTypeFromPropertyName(name);
if (!isTypeUsableAsPropertyName(exprType)) {
// do not include computed properties in the implied type
objectFlags |= ObjectFlags.ObjectLiteralPatternWithComputedProperties;
return;
}
const text = getPropertyNameFromType(exprType);
const flags = SymbolFlags.Property | (e.initializer ? SymbolFlags.Optional : 0);
const symbol = createSymbol(flags, text);
symbol.type = getTypeFromBindingElement(e, includePatternInType, reportErrors);
symbol.bindingElement = e;
members.set(symbol.escapedName, symbol);
});
const result = createAnonymousType(undefined, members, emptyArray, emptyArray, stringIndexInfo, undefined);
result.objectFlags |= objectFlags;
if (includePatternInType) {
result.pattern = pattern;
}
return result;
}
// Return the type implied by an array binding pattern
function getTypeFromArrayBindingPattern(pattern: BindingPattern, includePatternInType: boolean, reportErrors: boolean): Type {
const elements = pattern.elements;
const lastElement = lastOrUndefined(elements);
const hasRestElement = !!(lastElement && lastElement.kind === SyntaxKind.BindingElement && lastElement.dotDotDotToken);
if (elements.length === 0 || elements.length === 1 && hasRestElement) {
return languageVersion >= ScriptTarget.ES2015 ? createIterableType(anyType) : anyArrayType;
}
const elementTypes = map(elements, e => isOmittedExpression(e) ? anyType : getTypeFromBindingElement(e, includePatternInType, reportErrors));
const minLength = findLastIndex(elements, e => !isOmittedExpression(e) && !hasDefaultValue(e), elements.length - (hasRestElement ? 2 : 1)) + 1;
let result = <TypeReference>createTupleType(elementTypes, minLength, hasRestElement);
if (includePatternInType) {
result = cloneTypeReference(result);
result.pattern = pattern;
}
return result;
}
// Return the type implied by a binding pattern. This is the type implied purely by the binding pattern itself
// and without regard to its context (i.e. without regard any type annotation or initializer associated with the
// declaration in which the binding pattern is contained). For example, the implied type of [x, y] is [any, any]
// and the implied type of { x, y: z = 1 } is { x: any; y: number; }. The type implied by a binding pattern is
// used as the contextual type of an initializer associated with the binding pattern. Also, for a destructuring
// parameter with no type annotation or initializer, the type implied by the binding pattern becomes the type of
// the parameter.
function getTypeFromBindingPattern(pattern: BindingPattern, includePatternInType = false, reportErrors = false): Type {
return pattern.kind === SyntaxKind.ObjectBindingPattern
? getTypeFromObjectBindingPattern(pattern, includePatternInType, reportErrors)
: getTypeFromArrayBindingPattern(pattern, includePatternInType, reportErrors);
}
// Return the type associated with a variable, parameter, or property declaration. In the simple case this is the type
// specified in a type annotation or inferred from an initializer. However, in the case of a destructuring declaration it
// is a bit more involved. For example:
//
// var [x, s = ""] = [1, "one"];
//
// Here, the array literal [1, "one"] is contextually typed by the type [any, string], which is the implied type of the
// binding pattern [x, s = ""]. Because the contextual type is a tuple type, the resulting type of [1, "one"] is the
// tuple type [number, string]. Thus, the type inferred for 'x' is number and the type inferred for 's' is string.
function getWidenedTypeForVariableLikeDeclaration(declaration: ParameterDeclaration | PropertyDeclaration | PropertySignature | VariableDeclaration | BindingElement, reportErrors?: boolean): Type {
return widenTypeForVariableLikeDeclaration(getTypeForVariableLikeDeclaration(declaration, /*includeOptionality*/ true), declaration, reportErrors);
}
function widenTypeForVariableLikeDeclaration(type: Type | undefined, declaration: any, reportErrors?: boolean) {
if (type) {
if (reportErrors) {
reportErrorsFromWidening(declaration, type);
}
// always widen a 'unique symbol' type if the type was created for a different declaration.
if (type.flags & TypeFlags.UniqueESSymbol && (isBindingElement(declaration) || !declaration.type) && type.symbol !== getSymbolOfNode(declaration)) {
type = esSymbolType;
}
return getWidenedType(type);
}
// Rest parameters default to type any[], other parameters default to type any
type = isParameter(declaration) && declaration.dotDotDotToken ? anyArrayType : anyType;
// Report implicit any errors unless this is a private property within an ambient declaration
if (reportErrors) {
if (!declarationBelongsToPrivateAmbientMember(declaration)) {
reportImplicitAny(declaration, type);
}
}
return type;
}
function declarationBelongsToPrivateAmbientMember(declaration: VariableLikeDeclaration) {
const root = getRootDeclaration(declaration);
const memberDeclaration = root.kind === SyntaxKind.Parameter ? root.parent : root;
return isPrivateWithinAmbient(memberDeclaration);
}
function tryGetTypeFromEffectiveTypeNode(declaration: Declaration) {
const typeNode = getEffectiveTypeAnnotationNode(declaration);
if (typeNode) {
return getTypeFromTypeNode(typeNode);
}
}
function getTypeOfVariableOrParameterOrProperty(symbol: Symbol): Type {
const links = getSymbolLinks(symbol);
if (!links.type) {
const type = getTypeOfVariableOrParameterOrPropertyWorker(symbol);
// For a contextually typed parameter it is possible that a type has already
// been assigned (in assignTypeToParameterAndFixTypeParameters), and we want
// to preserve this type.
if (!links.type) {
links.type = type;
}
}
return links.type;
}
function getTypeOfVariableOrParameterOrPropertyWorker(symbol: Symbol) {
// Handle prototype property
if (symbol.flags & SymbolFlags.Prototype) {
return getTypeOfPrototypeProperty(symbol);
}
// CommonsJS require and module both have type any.
if (symbol === requireSymbol) {
return anyType;
}
if (symbol.flags & SymbolFlags.ModuleExports) {
const fileSymbol = getSymbolOfNode(getSourceFileOfNode(symbol.valueDeclaration));
const members = createSymbolTable();
members.set("exports" as __String, fileSymbol);
return createAnonymousType(symbol, members, emptyArray, emptyArray, undefined, undefined);
}
// Handle catch clause variables
const declaration = symbol.valueDeclaration;
if (isCatchClauseVariableDeclarationOrBindingElement(declaration)) {
return anyType;
}
// Handle export default expressions
if (isSourceFile(declaration) && isJsonSourceFile(declaration)) {
if (!declaration.statements.length) {
return emptyObjectType;
}
const type = getWidenedLiteralType(checkExpression(declaration.statements[0].expression));
if (type.flags & TypeFlags.Object) {
return getRegularTypeOfObjectLiteral(type);
}
return type;
}
if (declaration.kind === SyntaxKind.ExportAssignment) {
return widenTypeForVariableLikeDeclaration(checkExpressionCached((<ExportAssignment>declaration).expression), declaration);
}
// Handle variable, parameter or property
if (!pushTypeResolution(symbol, TypeSystemPropertyName.Type)) {
// Symbol is property of some kind that is merged with something - should use `getTypeOfFuncClassEnumModule` and not `getTypeOfVariableOrParameterOrProperty`
if (symbol.flags & SymbolFlags.ValueModule) {
return getTypeOfFuncClassEnumModule(symbol);
}
return reportCircularityError(symbol);
}
let type: Type | undefined;
if (isInJSFile(declaration) &&
(isCallExpression(declaration) || isBinaryExpression(declaration) || isPropertyAccessExpression(declaration) && isBinaryExpression(declaration.parent))) {
type = getWidenedTypeFromAssignmentDeclaration(symbol);
}
else if (isJSDocPropertyLikeTag(declaration)
|| isPropertyAccessExpression(declaration)
|| isIdentifier(declaration)
|| isClassDeclaration(declaration)
|| isFunctionDeclaration(declaration)
|| (isMethodDeclaration(declaration) && !isObjectLiteralMethod(declaration))
|| isMethodSignature(declaration)
|| isSourceFile(declaration)) {
// Symbol is property of some kind that is merged with something - should use `getTypeOfFuncClassEnumModule` and not `getTypeOfVariableOrParameterOrProperty`
if (symbol.flags & (SymbolFlags.Function | SymbolFlags.Method | SymbolFlags.Class | SymbolFlags.Enum | SymbolFlags.ValueModule)) {
return getTypeOfFuncClassEnumModule(symbol);
}
type = isBinaryExpression(declaration.parent) ?
getWidenedTypeFromAssignmentDeclaration(symbol) :
tryGetTypeFromEffectiveTypeNode(declaration) || anyType;
}
else if (isPropertyAssignment(declaration)) {
type = tryGetTypeFromEffectiveTypeNode(declaration) || checkPropertyAssignment(declaration);
}
else if (isJsxAttribute(declaration)) {
type = tryGetTypeFromEffectiveTypeNode(declaration) || checkJsxAttribute(declaration);
}
else if (isShorthandPropertyAssignment(declaration)) {
type = tryGetTypeFromEffectiveTypeNode(declaration) || checkExpressionForMutableLocation(declaration.name, CheckMode.Normal);
}
else if (isObjectLiteralMethod(declaration)) {
type = tryGetTypeFromEffectiveTypeNode(declaration) || checkObjectLiteralMethod(declaration, CheckMode.Normal);
}
else if (isParameter(declaration)
|| isPropertyDeclaration(declaration)
|| isPropertySignature(declaration)
|| isVariableDeclaration(declaration)
|| isBindingElement(declaration)) {
type = getWidenedTypeForVariableLikeDeclaration(declaration, /*includeOptionality*/ true);
}
// getTypeOfSymbol dispatches some JS merges incorrectly because their symbol flags are not mutually exclusive.
// Re-dispatch based on valueDeclaration.kind instead.
else if (isEnumDeclaration(declaration)) {
type = getTypeOfFuncClassEnumModule(symbol);
}
else if (isEnumMember(declaration)) {
type = getTypeOfEnumMember(symbol);
}
else {
return Debug.fail("Unhandled declaration kind! " + Debug.showSyntaxKind(declaration) + " for " + Debug.showSymbol(symbol));
}
if (!popTypeResolution()) {
// Symbol is property of some kind that is merged with something - should use `getTypeOfFuncClassEnumModule` and not `getTypeOfVariableOrParameterOrProperty`
if (symbol.flags & SymbolFlags.ValueModule) {
return getTypeOfFuncClassEnumModule(symbol);
}
return reportCircularityError(symbol);
}
return type;
}
function getAnnotatedAccessorTypeNode(accessor: AccessorDeclaration | undefined): TypeNode | undefined {
if (accessor) {
if (accessor.kind === SyntaxKind.GetAccessor) {
const getterTypeAnnotation = getEffectiveReturnTypeNode(accessor);
return getterTypeAnnotation;
}
else {
const setterTypeAnnotation = getEffectiveSetAccessorTypeAnnotationNode(accessor);
return setterTypeAnnotation;
}
}
return undefined;
}
function getAnnotatedAccessorType(accessor: AccessorDeclaration | undefined): Type | undefined {
const node = getAnnotatedAccessorTypeNode(accessor);
return node && getTypeFromTypeNode(node);
}
function getAnnotatedAccessorThisParameter(accessor: AccessorDeclaration): Symbol | undefined {
const parameter = getAccessorThisParameter(accessor);
return parameter && parameter.symbol;
}
function getThisTypeOfDeclaration(declaration: SignatureDeclaration): Type | undefined {
return getThisTypeOfSignature(getSignatureFromDeclaration(declaration));
}
function getTypeOfAccessors(symbol: Symbol): Type {
const links = getSymbolLinks(symbol);
return links.type || (links.type = getTypeOfAccessorsWorker(symbol));
}
function getTypeOfAccessorsWorker(symbol: Symbol): Type {
const getter = getDeclarationOfKind<AccessorDeclaration>(symbol, SyntaxKind.GetAccessor);
const setter = getDeclarationOfKind<AccessorDeclaration>(symbol, SyntaxKind.SetAccessor);
if (getter && isInJSFile(getter)) {
const jsDocType = getTypeForDeclarationFromJSDocComment(getter);
if (jsDocType) {
return jsDocType;
}
}
if (!pushTypeResolution(symbol, TypeSystemPropertyName.Type)) {
return errorType;
}
let type: Type;
// First try to see if the user specified a return type on the get-accessor.
const getterReturnType = getAnnotatedAccessorType(getter);
if (getterReturnType) {
type = getterReturnType;
}
else {
// If the user didn't specify a return type, try to use the set-accessor's parameter type.
const setterParameterType = getAnnotatedAccessorType(setter);
if (setterParameterType) {
type = setterParameterType;
}
else {
// If there are no specified types, try to infer it from the body of the get accessor if it exists.
if (getter && getter.body) {
type = getReturnTypeFromBody(getter);
}
// Otherwise, fall back to 'any'.
else {
if (setter) {
errorOrSuggestion(noImplicitAny, setter, Diagnostics.Property_0_implicitly_has_type_any_because_its_set_accessor_lacks_a_parameter_type_annotation, symbolToString(symbol));
}
else {
Debug.assert(!!getter, "there must existed getter as we are current checking either setter or getter in this function");
errorOrSuggestion(noImplicitAny, getter!, Diagnostics.Property_0_implicitly_has_type_any_because_its_get_accessor_lacks_a_return_type_annotation, symbolToString(symbol));
}
type = anyType;
}
}
}
if (!popTypeResolution()) {
type = anyType;
if (noImplicitAny) {
const getter = getDeclarationOfKind<AccessorDeclaration>(symbol, SyntaxKind.GetAccessor);
error(getter, Diagnostics._0_implicitly_has_return_type_any_because_it_does_not_have_a_return_type_annotation_and_is_referenced_directly_or_indirectly_in_one_of_its_return_expressions, symbolToString(symbol));
}
}
return type;
}
function getBaseTypeVariableOfClass(symbol: Symbol) {
const baseConstructorType = getBaseConstructorTypeOfClass(getDeclaredTypeOfClassOrInterface(symbol));
return baseConstructorType.flags & TypeFlags.TypeVariable ? baseConstructorType : undefined;
}
function getTypeOfFuncClassEnumModule(symbol: Symbol): Type {
let links = getSymbolLinks(symbol);
const originalLinks = links;
if (!links.type) {
const jsDeclaration = getDeclarationOfExpando(symbol.valueDeclaration);
if (jsDeclaration) {
const jsSymbol = getSymbolOfNode(jsDeclaration);
if (jsSymbol && (hasEntries(jsSymbol.exports) || hasEntries(jsSymbol.members))) {
symbol = cloneSymbol(symbol);
// note:we overwrite links because we just cloned the symbol
links = symbol as TransientSymbol;
if (hasEntries(jsSymbol.exports)) {
symbol.exports = symbol.exports || createSymbolTable();
mergeSymbolTable(symbol.exports, jsSymbol.exports);
}
if (hasEntries(jsSymbol.members)) {
symbol.members = symbol.members || createSymbolTable();
mergeSymbolTable(symbol.members, jsSymbol.members);
}
}
}
originalLinks.type = links.type = getTypeOfFuncClassEnumModuleWorker(symbol);
}
return links.type;
}
function getTypeOfFuncClassEnumModuleWorker(symbol: Symbol): Type {
const declaration = symbol.valueDeclaration;
if (symbol.flags & SymbolFlags.Module && isShorthandAmbientModuleSymbol(symbol)) {
return anyType;
}
else if (declaration.kind === SyntaxKind.BinaryExpression ||
declaration.kind === SyntaxKind.PropertyAccessExpression && declaration.parent.kind === SyntaxKind.BinaryExpression) {
return getWidenedTypeFromAssignmentDeclaration(symbol);
}
else if (symbol.flags & SymbolFlags.ValueModule && declaration && isSourceFile(declaration) && declaration.commonJsModuleIndicator) {
const resolvedModule = resolveExternalModuleSymbol(symbol);
if (resolvedModule !== symbol) {
if (!pushTypeResolution(symbol, TypeSystemPropertyName.Type)) {
return errorType;
}
const exportEquals = getMergedSymbol(symbol.exports!.get(InternalSymbolName.ExportEquals)!);
const type = getWidenedTypeFromAssignmentDeclaration(exportEquals, exportEquals === resolvedModule ? undefined : resolvedModule);
if (!popTypeResolution()) {
return reportCircularityError(symbol);
}
return type;
}
}
const type = createObjectType(ObjectFlags.Anonymous, symbol);
if (symbol.flags & SymbolFlags.Class) {
const baseTypeVariable = getBaseTypeVariableOfClass(symbol);
return baseTypeVariable ? getIntersectionType([type, baseTypeVariable]) : type;
}
else {
return strictNullChecks && symbol.flags & SymbolFlags.Optional ? getOptionalType(type) : type;
}
}
function getTypeOfEnumMember(symbol: Symbol): Type {
const links = getSymbolLinks(symbol);
return links.type || (links.type = getDeclaredTypeOfEnumMember(symbol));
}
function getTypeOfAlias(symbol: Symbol): Type {
const links = getSymbolLinks(symbol);
if (!links.type) {
const targetSymbol = resolveAlias(symbol);
// It only makes sense to get the type of a value symbol. If the result of resolving
// the alias is not a value, then it has no type. To get the type associated with a
// type symbol, call getDeclaredTypeOfSymbol.
// This check is important because without it, a call to getTypeOfSymbol could end
// up recursively calling getTypeOfAlias, causing a stack overflow.
links.type = targetSymbol.flags & SymbolFlags.Value
? getTypeOfSymbol(targetSymbol)
: errorType;
}
return links.type;
}
function getTypeOfInstantiatedSymbol(symbol: Symbol): Type {
const links = getSymbolLinks(symbol);
if (!links.type) {
if (!pushTypeResolution(symbol, TypeSystemPropertyName.Type)) {
return links.type = errorType;
}
let type = instantiateType(getTypeOfSymbol(links.target!), links.mapper!);
if (!popTypeResolution()) {
type = reportCircularityError(symbol);
}
links.type = type;
}
return links.type;
}
function reportCircularityError(symbol: Symbol) {
const declaration = <VariableLikeDeclaration>symbol.valueDeclaration;
// Check if variable has type annotation that circularly references the variable itself
if (getEffectiveTypeAnnotationNode(declaration)) {
error(symbol.valueDeclaration, Diagnostics._0_is_referenced_directly_or_indirectly_in_its_own_type_annotation,
symbolToString(symbol));
return errorType;
}
// Check if variable has initializer that circularly references the variable itself
if (noImplicitAny && (declaration.kind !== SyntaxKind.Parameter || (<HasInitializer>declaration).initializer)) {
error(symbol.valueDeclaration, Diagnostics._0_implicitly_has_type_any_because_it_does_not_have_a_type_annotation_and_is_referenced_directly_or_indirectly_in_its_own_initializer,
symbolToString(symbol));
}
// Circularities could also result from parameters in function expressions that end up
// having themselves as contextual types following type argument inference. In those cases
// we have already reported an implicit any error so we don't report anything here.
return anyType;
}
function getTypeOfSymbol(symbol: Symbol): Type {
if (getCheckFlags(symbol) & CheckFlags.Instantiated) {
return getTypeOfInstantiatedSymbol(symbol);
}
if (getCheckFlags(symbol) & CheckFlags.ReverseMapped) {
return getTypeOfReverseMappedSymbol(symbol as ReverseMappedSymbol);
}
if (symbol.flags & (SymbolFlags.Variable | SymbolFlags.Property)) {
return getTypeOfVariableOrParameterOrProperty(symbol);
}
if (symbol.flags & (SymbolFlags.Function | SymbolFlags.Method | SymbolFlags.Class | SymbolFlags.Enum | SymbolFlags.ValueModule)) {
return getTypeOfFuncClassEnumModule(symbol);
}
if (symbol.flags & SymbolFlags.EnumMember) {
return getTypeOfEnumMember(symbol);
}
if (symbol.flags & SymbolFlags.Accessor) {
return getTypeOfAccessors(symbol);
}
if (symbol.flags & SymbolFlags.Alias) {
return getTypeOfAlias(symbol);
}
return errorType;
}
function isReferenceToType(type: Type, target: Type) {
return type !== undefined
&& target !== undefined
&& (getObjectFlags(type) & ObjectFlags.Reference) !== 0
&& (<TypeReference>type).target === target;
}
function getTargetType(type: Type): Type {
return getObjectFlags(type) & ObjectFlags.Reference ? (<TypeReference>type).target : type;
}
// TODO: GH#18217 If `checkBase` is undefined, we should not call this because this will always return false.
function hasBaseType(type: Type, checkBase: Type | undefined) {
return check(type);
function check(type: Type): boolean {
if (getObjectFlags(type) & (ObjectFlags.ClassOrInterface | ObjectFlags.Reference)) {
const target = <InterfaceType>getTargetType(type);
return target === checkBase || some(getBaseTypes(target), check);
}
else if (type.flags & TypeFlags.Intersection) {
return some((<IntersectionType>type).types, check);
}
return false;
}
}
// Appends the type parameters given by a list of declarations to a set of type parameters and returns the resulting set.
// The function allocates a new array if the input type parameter set is undefined, but otherwise it modifies the set
// in-place and returns the same array.
function appendTypeParameters(typeParameters: TypeParameter[] | undefined, declarations: ReadonlyArray<TypeParameterDeclaration>): TypeParameter[] | undefined {
for (const declaration of declarations) {
typeParameters = appendIfUnique(typeParameters, getDeclaredTypeOfTypeParameter(getSymbolOfNode(declaration)));
}
return typeParameters;
}
// Return the outer type parameters of a node or undefined if the node has no outer type parameters.
function getOuterTypeParameters(node: Node, includeThisTypes?: boolean): TypeParameter[] | undefined {
while (true) {
node = node.parent; // TODO: GH#18217 Use SourceFile kind check instead
if (!node) {
return undefined;
}
switch (node.kind) {
case SyntaxKind.ClassDeclaration:
case SyntaxKind.ClassExpression:
case SyntaxKind.InterfaceDeclaration:
case SyntaxKind.CallSignature:
case SyntaxKind.ConstructSignature:
case SyntaxKind.MethodSignature:
case SyntaxKind.FunctionType:
case SyntaxKind.ConstructorType:
case SyntaxKind.JSDocFunctionType:
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.FunctionExpression:
case SyntaxKind.ArrowFunction:
case SyntaxKind.TypeAliasDeclaration:
case SyntaxKind.JSDocTemplateTag:
case SyntaxKind.JSDocTypedefTag:
case SyntaxKind.JSDocCallbackTag:
case SyntaxKind.MappedType:
case SyntaxKind.ConditionalType:
const outerTypeParameters = getOuterTypeParameters(node, includeThisTypes);
if (node.kind === SyntaxKind.MappedType) {
return append(outerTypeParameters, getDeclaredTypeOfTypeParameter(getSymbolOfNode((<MappedTypeNode>node).typeParameter)));
}
else if (node.kind === SyntaxKind.ConditionalType) {
return concatenate(outerTypeParameters, getInferTypeParameters(<ConditionalTypeNode>node));
}
const outerAndOwnTypeParameters = appendTypeParameters(outerTypeParameters, getEffectiveTypeParameterDeclarations(<DeclarationWithTypeParameters>node));
const thisType = includeThisTypes &&
(node.kind === SyntaxKind.ClassDeclaration || node.kind === SyntaxKind.ClassExpression || node.kind === SyntaxKind.InterfaceDeclaration) &&
getDeclaredTypeOfClassOrInterface(getSymbolOfNode(node as ClassLikeDeclaration | InterfaceDeclaration)).thisType;
return thisType ? append(outerAndOwnTypeParameters, thisType) : outerAndOwnTypeParameters;
}
}
}
// The outer type parameters are those defined by enclosing generic classes, methods, or functions.
function getOuterTypeParametersOfClassOrInterface(symbol: Symbol): TypeParameter[] | undefined {
const declaration = symbol.flags & SymbolFlags.Class ? symbol.valueDeclaration : getDeclarationOfKind(symbol, SyntaxKind.InterfaceDeclaration)!;
return getOuterTypeParameters(declaration);
}
// The local type parameters are the combined set of type parameters from all declarations of the class,
// interface, or type alias.
function getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(symbol: Symbol): TypeParameter[] | undefined {
let result: TypeParameter[] | undefined;
for (const node of symbol.declarations) {
if (node.kind === SyntaxKind.InterfaceDeclaration ||
node.kind === SyntaxKind.ClassDeclaration ||
node.kind === SyntaxKind.ClassExpression ||
isTypeAlias(node)) {
const declaration = <InterfaceDeclaration | TypeAliasDeclaration | JSDocTypedefTag | JSDocCallbackTag>node;
result = appendTypeParameters(result, getEffectiveTypeParameterDeclarations(declaration));
}
}
return result;
}
// The full set of type parameters for a generic class or interface type consists of its outer type parameters plus
// its locally declared type parameters.
function getTypeParametersOfClassOrInterface(symbol: Symbol): TypeParameter[] | undefined {
return concatenate(getOuterTypeParametersOfClassOrInterface(symbol), getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(symbol));
}
// A type is a mixin constructor if it has a single construct signature taking no type parameters and a single
// rest parameter of type any[].
function isMixinConstructorType(type: Type) {
const signatures = getSignaturesOfType(type, SignatureKind.Construct);
if (signatures.length === 1) {
const s = signatures[0];
return !s.typeParameters && s.parameters.length === 1 && s.hasRestParameter && getTypeOfParameter(s.parameters[0]) === anyArrayType;
}
return false;
}
function isConstructorType(type: Type): boolean {
if (isValidBaseType(type) && getSignaturesOfType(type, SignatureKind.Construct).length > 0) {
return true;
}
if (type.flags & TypeFlags.TypeVariable) {
const constraint = getBaseConstraintOfType(type);
return !!constraint && isValidBaseType(constraint) && isMixinConstructorType(constraint);
}
return isJSConstructorType(type);
}
function getBaseTypeNodeOfClass(type: InterfaceType): ExpressionWithTypeArguments | undefined {
return getEffectiveBaseTypeNode(type.symbol.valueDeclaration as ClassLikeDeclaration);
}
function getConstructorsForTypeArguments(type: Type, typeArgumentNodes: ReadonlyArray<TypeNode> | undefined, location: Node): ReadonlyArray<Signature> {
const typeArgCount = length(typeArgumentNodes);
const isJavascript = isInJSFile(location);
return filter(getSignaturesOfType(type, SignatureKind.Construct),
sig => (isJavascript || typeArgCount >= getMinTypeArgumentCount(sig.typeParameters)) && typeArgCount <= length(sig.typeParameters));
}
function getInstantiatedConstructorsForTypeArguments(type: Type, typeArgumentNodes: ReadonlyArray<TypeNode> | undefined, location: Node): ReadonlyArray<Signature> {
const signatures = getConstructorsForTypeArguments(type, typeArgumentNodes, location);
const typeArguments = map(typeArgumentNodes, getTypeFromTypeNode);
return sameMap<Signature>(signatures, sig => some(sig.typeParameters) ? getSignatureInstantiation(sig, typeArguments, isInJSFile(location)) : sig);
}
/**
* The base constructor of a class can resolve to
* * undefinedType if the class has no extends clause,
* * unknownType if an error occurred during resolution of the extends expression,
* * nullType if the extends expression is the null value,
* * anyType if the extends expression has type any, or
* * an object type with at least one construct signature.
*/
function getBaseConstructorTypeOfClass(type: InterfaceType): Type {
if (!type.resolvedBaseConstructorType) {
const decl = <ClassLikeDeclaration>type.symbol.valueDeclaration;
const extended = getEffectiveBaseTypeNode(decl);
const baseTypeNode = getBaseTypeNodeOfClass(type);
if (!baseTypeNode) {
return type.resolvedBaseConstructorType = undefinedType;
}
if (!pushTypeResolution(type, TypeSystemPropertyName.ResolvedBaseConstructorType)) {
return errorType;
}
const baseConstructorType = checkExpression(baseTypeNode.expression);
if (extended && baseTypeNode !== extended) {
Debug.assert(!extended.typeArguments); // Because this is in a JS file, and baseTypeNode is in an @extends tag
checkExpression(extended.expression);
}
if (baseConstructorType.flags & (TypeFlags.Object | TypeFlags.Intersection)) {
// Resolving the members of a class requires us to resolve the base class of that class.
// We force resolution here such that we catch circularities now.
resolveStructuredTypeMembers(<ObjectType>baseConstructorType);
}
if (!popTypeResolution()) {
error(type.symbol.valueDeclaration, Diagnostics._0_is_referenced_directly_or_indirectly_in_its_own_base_expression, symbolToString(type.symbol));
return type.resolvedBaseConstructorType = errorType;
}
if (!(baseConstructorType.flags & TypeFlags.Any) && baseConstructorType !== nullWideningType && !isConstructorType(baseConstructorType)) {
const err = error(baseTypeNode.expression, Diagnostics.Type_0_is_not_a_constructor_function_type, typeToString(baseConstructorType));
if (baseConstructorType.flags & TypeFlags.TypeParameter) {
const constraint = getConstraintFromTypeParameter(baseConstructorType);
let ctorReturn: Type = unknownType;
if (constraint) {
const ctorSig = getSignaturesOfType(constraint, SignatureKind.Construct);
if (ctorSig[0]) {
ctorReturn = getReturnTypeOfSignature(ctorSig[0]);
}
}
addRelatedInfo(err, createDiagnosticForNode(baseConstructorType.symbol.declarations[0], Diagnostics.Did_you_mean_for_0_to_be_constrained_to_type_new_args_Colon_any_1, symbolToString(baseConstructorType.symbol), typeToString(ctorReturn)));
}
return type.resolvedBaseConstructorType = errorType;
}
type.resolvedBaseConstructorType = baseConstructorType;
}
return type.resolvedBaseConstructorType;
}
function getBaseTypes(type: InterfaceType): BaseType[] {
if (!type.resolvedBaseTypes) {
if (type.objectFlags & ObjectFlags.Tuple) {
type.resolvedBaseTypes = [createArrayType(getUnionType(type.typeParameters || emptyArray), (<TupleType>type).readonly)];
}
else if (type.symbol.flags & (SymbolFlags.Class | SymbolFlags.Interface)) {
if (type.symbol.flags & SymbolFlags.Class) {
resolveBaseTypesOfClass(type);
}
if (type.symbol.flags & SymbolFlags.Interface) {
resolveBaseTypesOfInterface(type);
}
}
else {
Debug.fail("type must be class or interface");
}
}
return type.resolvedBaseTypes;
}
function resolveBaseTypesOfClass(type: InterfaceType) {
type.resolvedBaseTypes = resolvingEmptyArray;
const baseConstructorType = getApparentType(getBaseConstructorTypeOfClass(type));
if (!(baseConstructorType.flags & (TypeFlags.Object | TypeFlags.Intersection | TypeFlags.Any))) {
return type.resolvedBaseTypes = emptyArray;
}
const baseTypeNode = getBaseTypeNodeOfClass(type)!;
const typeArgs = typeArgumentsFromTypeReferenceNode(baseTypeNode);
let baseType: Type;
const originalBaseType = isJSConstructorType(baseConstructorType) ? baseConstructorType :
baseConstructorType.symbol ? getDeclaredTypeOfSymbol(baseConstructorType.symbol) :
undefined;
if (baseConstructorType.symbol && baseConstructorType.symbol.flags & SymbolFlags.Class &&
areAllOuterTypeParametersApplied(originalBaseType!)) {
// When base constructor type is a class with no captured type arguments we know that the constructors all have the same type parameters as the
// class and all return the instance type of the class. There is no need for further checks and we can apply the
// type arguments in the same manner as a type reference to get the same error reporting experience.
baseType = getTypeFromClassOrInterfaceReference(baseTypeNode, baseConstructorType.symbol, typeArgs);
}
else if (baseConstructorType.flags & TypeFlags.Any) {
baseType = baseConstructorType;
}
else if (isJSConstructorType(baseConstructorType)) {
baseType = !baseTypeNode.typeArguments && getJSClassType(baseConstructorType.symbol) || anyType;
}
else {
// The class derives from a "class-like" constructor function, check that we have at least one construct signature
// with a matching number of type parameters and use the return type of the first instantiated signature. Elsewhere
// we check that all instantiated signatures return the same type.
const constructors = getInstantiatedConstructorsForTypeArguments(baseConstructorType, baseTypeNode.typeArguments, baseTypeNode);
if (!constructors.length) {
error(baseTypeNode.expression, Diagnostics.No_base_constructor_has_the_specified_number_of_type_arguments);
return type.resolvedBaseTypes = emptyArray;
}
baseType = getReturnTypeOfSignature(constructors[0]);
}
if (baseType === errorType) {
return type.resolvedBaseTypes = emptyArray;
}
if (!isValidBaseType(baseType)) {
error(baseTypeNode.expression, Diagnostics.Base_constructor_return_type_0_is_not_an_object_type_or_intersection_of_object_types_with_statically_known_members, typeToString(baseType));
return type.resolvedBaseTypes = emptyArray;
}
if (type === baseType || hasBaseType(baseType, type)) {
error(type.symbol.valueDeclaration, Diagnostics.Type_0_recursively_references_itself_as_a_base_type,
typeToString(type, /*enclosingDeclaration*/ undefined, TypeFormatFlags.WriteArrayAsGenericType));
return type.resolvedBaseTypes = emptyArray;
}
if (type.resolvedBaseTypes === resolvingEmptyArray) {
// Circular reference, likely through instantiation of default parameters
// (otherwise there'd be an error from hasBaseType) - this is fine, but `.members` should be reset
// as `getIndexedAccessType` via `instantiateType` via `getTypeFromClassOrInterfaceReference` forces a
// partial instantiation of the members without the base types fully resolved
type.members = undefined;
}
return type.resolvedBaseTypes = [baseType];
}
function areAllOuterTypeParametersApplied(type: Type): boolean { // TODO: GH#18217 Shouldn't this take an InterfaceType?
// An unapplied type parameter has its symbol still the same as the matching argument symbol.
// Since parameters are applied outer-to-inner, only the last outer parameter needs to be checked.
const outerTypeParameters = (<InterfaceType>type).outerTypeParameters;
if (outerTypeParameters) {
const last = outerTypeParameters.length - 1;
const typeArguments = (<TypeReference>type).typeArguments!;
return outerTypeParameters[last].symbol !== typeArguments[last].symbol;
}
return true;
}
// A valid base type is `any`, any non-generic object type or intersection of non-generic
// object types.
function isValidBaseType(type: Type): type is BaseType {
return !!(type.flags & (TypeFlags.Object | TypeFlags.NonPrimitive | TypeFlags.Any)) && !isGenericMappedType(type) ||
!!(type.flags & TypeFlags.Intersection) && every((<IntersectionType>type).types, isValidBaseType);
}
function resolveBaseTypesOfInterface(type: InterfaceType): void {
type.resolvedBaseTypes = type.resolvedBaseTypes || emptyArray;
for (const declaration of type.symbol.declarations) {
if (declaration.kind === SyntaxKind.InterfaceDeclaration && getInterfaceBaseTypeNodes(<InterfaceDeclaration>declaration)) {
for (const node of getInterfaceBaseTypeNodes(<InterfaceDeclaration>declaration)!) {
const baseType = getTypeFromTypeNode(node);
if (baseType !== errorType) {
if (isValidBaseType(baseType)) {
if (type !== baseType && !hasBaseType(baseType, type)) {
if (type.resolvedBaseTypes === emptyArray) {
type.resolvedBaseTypes = [<ObjectType>baseType];
}
else {
type.resolvedBaseTypes.push(baseType);
}
}
else {
error(declaration, Diagnostics.Type_0_recursively_references_itself_as_a_base_type, typeToString(type, /*enclosingDeclaration*/ undefined, TypeFormatFlags.WriteArrayAsGenericType));
}
}
else {
error(node, Diagnostics.An_interface_can_only_extend_an_object_type_or_intersection_of_object_types_with_statically_known_members);
}
}
}
}
}
}
/**
* Returns true if the interface given by the symbol is free of "this" references.
*
* Specifically, the result is true if the interface itself contains no references
* to "this" in its body, if all base types are interfaces,
* and if none of the base interfaces have a "this" type.
*/
function isThislessInterface(symbol: Symbol): boolean {
for (const declaration of symbol.declarations) {
if (declaration.kind === SyntaxKind.InterfaceDeclaration) {
if (declaration.flags & NodeFlags.ContainsThis) {
return false;
}
const baseTypeNodes = getInterfaceBaseTypeNodes(<InterfaceDeclaration>declaration);
if (baseTypeNodes) {
for (const node of baseTypeNodes) {
if (isEntityNameExpression(node.expression)) {
const baseSymbol = resolveEntityName(node.expression, SymbolFlags.Type, /*ignoreErrors*/ true);
if (!baseSymbol || !(baseSymbol.flags & SymbolFlags.Interface) || getDeclaredTypeOfClassOrInterface(baseSymbol).thisType) {
return false;
}
}
}
}
}
}
return true;
}
function getDeclaredTypeOfClassOrInterface(symbol: Symbol): InterfaceType {
const links = getSymbolLinks(symbol);
if (!links.declaredType) {
const kind = symbol.flags & SymbolFlags.Class ? ObjectFlags.Class : ObjectFlags.Interface;
const type = links.declaredType = <InterfaceType>createObjectType(kind, symbol);
const outerTypeParameters = getOuterTypeParametersOfClassOrInterface(symbol);
const localTypeParameters = getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(symbol);
// A class or interface is generic if it has type parameters or a "this" type. We always give classes a "this" type
// because it is not feasible to analyze all members to determine if the "this" type escapes the class (in particular,
// property types inferred from initializers and method return types inferred from return statements are very hard
// to exhaustively analyze). We give interfaces a "this" type if we can't definitely determine that they are free of
// "this" references.
if (outerTypeParameters || localTypeParameters || kind === ObjectFlags.Class || !isThislessInterface(symbol)) {
type.objectFlags |= ObjectFlags.Reference;
type.typeParameters = concatenate(outerTypeParameters, localTypeParameters);
type.outerTypeParameters = outerTypeParameters;
type.localTypeParameters = localTypeParameters;
(<GenericType>type).instantiations = createMap<TypeReference>();
(<GenericType>type).instantiations.set(getTypeListId(type.typeParameters), <GenericType>type);
(<GenericType>type).target = <GenericType>type;
(<GenericType>type).typeArguments = type.typeParameters;
type.thisType = createTypeParameter(symbol);
type.thisType.isThisType = true;
type.thisType.constraint = type;
}
}
return <InterfaceType>links.declaredType;
}
function getDeclaredTypeOfTypeAlias(symbol: Symbol): Type {
const links = getSymbolLinks(symbol);
if (!links.declaredType) {
// Note that we use the links object as the target here because the symbol object is used as the unique
// identity for resolution of the 'type' property in SymbolLinks.
if (!pushTypeResolution(symbol, TypeSystemPropertyName.DeclaredType)) {
return errorType;
}
const declaration = <JSDocTypedefTag | JSDocCallbackTag | TypeAliasDeclaration>find(symbol.declarations, d =>
isJSDocTypeAlias(d) || d.kind === SyntaxKind.TypeAliasDeclaration);
const typeNode = isJSDocTypeAlias(declaration) ? declaration.typeExpression : declaration.type;
// If typeNode is missing, we will error in checkJSDocTypedefTag.
let type = typeNode ? getTypeFromTypeNode(typeNode) : errorType;
if (popTypeResolution()) {
const typeParameters = getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(symbol);
if (typeParameters) {
// Initialize the instantiation cache for generic type aliases. The declared type corresponds to
// an instantiation of the type alias with the type parameters supplied as type arguments.
links.typeParameters = typeParameters;
links.instantiations = createMap<Type>();
links.instantiations.set(getTypeListId(typeParameters), type);
}
}
else {
type = errorType;
error(declaration.name, Diagnostics.Type_alias_0_circularly_references_itself, symbolToString(symbol));
}
links.declaredType = type;
}
return links.declaredType;
}
function isStringConcatExpression(expr: Node): boolean {
if (expr.kind === SyntaxKind.StringLiteral) {
return true;
}
else if (expr.kind === SyntaxKind.BinaryExpression) {
return isStringConcatExpression((<BinaryExpression>expr).left) && isStringConcatExpression((<BinaryExpression>expr).right);
}
return false;
}
function isLiteralEnumMember(member: EnumMember) {
const expr = member.initializer;
if (!expr) {
return !(member.flags & NodeFlags.Ambient);
}
switch (expr.kind) {
case SyntaxKind.StringLiteral:
case SyntaxKind.NumericLiteral:
return true;
case SyntaxKind.PrefixUnaryExpression:
return (<PrefixUnaryExpression>expr).operator === SyntaxKind.MinusToken &&
(<PrefixUnaryExpression>expr).operand.kind === SyntaxKind.NumericLiteral;
case SyntaxKind.Identifier:
return nodeIsMissing(expr) || !!getSymbolOfNode(member.parent).exports!.get((<Identifier>expr).escapedText);
case SyntaxKind.BinaryExpression:
return isStringConcatExpression(expr);
default:
return false;
}
}
function getEnumKind(symbol: Symbol): EnumKind {
const links = getSymbolLinks(symbol);
if (links.enumKind !== undefined) {
return links.enumKind;
}
let hasNonLiteralMember = false;
for (const declaration of symbol.declarations) {
if (declaration.kind === SyntaxKind.EnumDeclaration) {
for (const member of (<EnumDeclaration>declaration).members) {
if (member.initializer && member.initializer.kind === SyntaxKind.StringLiteral) {
return links.enumKind = EnumKind.Literal;
}
if (!isLiteralEnumMember(member)) {
hasNonLiteralMember = true;
}
}
}
}
return links.enumKind = hasNonLiteralMember ? EnumKind.Numeric : EnumKind.Literal;
}
function getBaseTypeOfEnumLiteralType(type: Type) {
return type.flags & TypeFlags.EnumLiteral && !(type.flags & TypeFlags.Union) ? getDeclaredTypeOfSymbol(getParentOfSymbol(type.symbol)!) : type;
}
function getDeclaredTypeOfEnum(symbol: Symbol): Type {
const links = getSymbolLinks(symbol);
if (links.declaredType) {
return links.declaredType;
}
if (getEnumKind(symbol) === EnumKind.Literal) {
enumCount++;
const memberTypeList: Type[] = [];
for (const declaration of symbol.declarations) {
if (declaration.kind === SyntaxKind.EnumDeclaration) {
for (const member of (<EnumDeclaration>declaration).members) {
const memberType = getFreshTypeOfLiteralType(getLiteralType(getEnumMemberValue(member)!, enumCount, getSymbolOfNode(member))); // TODO: GH#18217
getSymbolLinks(getSymbolOfNode(member)).declaredType = memberType;
memberTypeList.push(getRegularTypeOfLiteralType(memberType));
}
}
}
if (memberTypeList.length) {
const enumType = getUnionType(memberTypeList, UnionReduction.Literal, symbol, /*aliasTypeArguments*/ undefined);
if (enumType.flags & TypeFlags.Union) {
enumType.flags |= TypeFlags.EnumLiteral;
enumType.symbol = symbol;
}
return links.declaredType = enumType;
}
}
const enumType = createType(TypeFlags.Enum);
enumType.symbol = symbol;
return links.declaredType = enumType;
}
function getDeclaredTypeOfEnumMember(symbol: Symbol): Type {
const links = getSymbolLinks(symbol);
if (!links.declaredType) {
const enumType = getDeclaredTypeOfEnum(getParentOfSymbol(symbol)!);
if (!links.declaredType) {
links.declaredType = enumType;
}
}
return links.declaredType;
}
function getDeclaredTypeOfTypeParameter(symbol: Symbol): TypeParameter {
const links = getSymbolLinks(symbol);
return links.declaredType || (links.declaredType = createTypeParameter(symbol));
}
function getDeclaredTypeOfAlias(symbol: Symbol): Type {
const links = getSymbolLinks(symbol);
return links.declaredType || (links.declaredType = getDeclaredTypeOfSymbol(resolveAlias(symbol)));
}
function getDeclaredTypeOfSymbol(symbol: Symbol): Type {
return tryGetDeclaredTypeOfSymbol(symbol) || errorType;
}
function tryGetDeclaredTypeOfSymbol(symbol: Symbol): Type | undefined {
if (symbol.flags & (SymbolFlags.Class | SymbolFlags.Interface)) {
return getDeclaredTypeOfClassOrInterface(symbol);
}
if (symbol.flags & SymbolFlags.TypeAlias) {
return getDeclaredTypeOfTypeAlias(symbol);
}
if (symbol.flags & SymbolFlags.TypeParameter) {
return getDeclaredTypeOfTypeParameter(symbol);
}
if (symbol.flags & SymbolFlags.Enum) {
return getDeclaredTypeOfEnum(symbol);
}
if (symbol.flags & SymbolFlags.EnumMember) {
return getDeclaredTypeOfEnumMember(symbol);
}
if (symbol.flags & SymbolFlags.Alias) {
return getDeclaredTypeOfAlias(symbol);
}
return undefined;
}
/**
* A type is free of this references if it's the any, string, number, boolean, symbol, or void keyword, a string
* literal type, an array with an element type that is free of this references, or a type reference that is
* free of this references.
*/
function isThislessType(node: TypeNode): boolean {
switch (node.kind) {
case SyntaxKind.AnyKeyword:
case SyntaxKind.UnknownKeyword:
case SyntaxKind.StringKeyword:
case SyntaxKind.NumberKeyword:
case SyntaxKind.BigIntKeyword:
case SyntaxKind.BooleanKeyword:
case SyntaxKind.SymbolKeyword:
case SyntaxKind.ObjectKeyword:
case SyntaxKind.VoidKeyword:
case SyntaxKind.UndefinedKeyword:
case SyntaxKind.NullKeyword:
case SyntaxKind.NeverKeyword:
case SyntaxKind.LiteralType:
return true;
case SyntaxKind.ArrayType:
return isThislessType((<ArrayTypeNode>node).elementType);
case SyntaxKind.TypeReference:
return !(node as TypeReferenceNode).typeArguments || (node as TypeReferenceNode).typeArguments!.every(isThislessType);
}
return false;
}
/** A type parameter is thisless if its constraint is thisless, or if it has no constraint. */
function isThislessTypeParameter(node: TypeParameterDeclaration) {
const constraint = getEffectiveConstraintOfTypeParameter(node);
return !constraint || isThislessType(constraint);
}
/**
* A variable-like declaration is free of this references if it has a type annotation
* that is thisless, or if it has no type annotation and no initializer (and is thus of type any).
*/
function isThislessVariableLikeDeclaration(node: VariableLikeDeclaration): boolean {
const typeNode = getEffectiveTypeAnnotationNode(node);
return typeNode ? isThislessType(typeNode) : !hasInitializer(node);
}
/**
* A function-like declaration is considered free of `this` references if it has a return type
* annotation that is free of this references and if each parameter is thisless and if
* each type parameter (if present) is thisless.
*/
function isThislessFunctionLikeDeclaration(node: FunctionLikeDeclaration): boolean {
const returnType = getEffectiveReturnTypeNode(node);
const typeParameters = getEffectiveTypeParameterDeclarations(node);
return (node.kind === SyntaxKind.Constructor || (!!returnType && isThislessType(returnType))) &&
node.parameters.every(isThislessVariableLikeDeclaration) &&
typeParameters.every(isThislessTypeParameter);
}
/**
* Returns true if the class or interface member given by the symbol is free of "this" references. The
* function may return false for symbols that are actually free of "this" references because it is not
* feasible to perform a complete analysis in all cases. In particular, property members with types
* inferred from their initializers and function members with inferred return types are conservatively
* assumed not to be free of "this" references.
*/
function isThisless(symbol: Symbol): boolean {
if (symbol.declarations && symbol.declarations.length === 1) {
const declaration = symbol.declarations[0];
if (declaration) {
switch (declaration.kind) {
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.PropertySignature:
return isThislessVariableLikeDeclaration(<VariableLikeDeclaration>declaration);
case SyntaxKind.MethodDeclaration:
case SyntaxKind.MethodSignature:
case SyntaxKind.Constructor:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
return isThislessFunctionLikeDeclaration(<FunctionLikeDeclaration | AccessorDeclaration>declaration);
}
}
}
return false;
}
// The mappingThisOnly flag indicates that the only type parameter being mapped is "this". When the flag is true,
// we check symbols to see if we can quickly conclude they are free of "this" references, thus needing no instantiation.
function createInstantiatedSymbolTable(symbols: Symbol[], mapper: TypeMapper, mappingThisOnly: boolean): SymbolTable {
const result = createSymbolTable();
for (const symbol of symbols) {
result.set(symbol.escapedName, mappingThisOnly && isThisless(symbol) ? symbol : instantiateSymbol(symbol, mapper));
}
return result;
}
function addInheritedMembers(symbols: SymbolTable, baseSymbols: Symbol[]) {
for (const s of baseSymbols) {
if (!symbols.has(s.escapedName)) {
symbols.set(s.escapedName, s);
}
}
}
function resolveDeclaredMembers(type: InterfaceType): InterfaceTypeWithDeclaredMembers {
if (!(<InterfaceTypeWithDeclaredMembers>type).declaredProperties) {
const symbol = type.symbol;
const members = getMembersOfSymbol(symbol);
(<InterfaceTypeWithDeclaredMembers>type).declaredProperties = getNamedMembers(members);
// Start with signatures at empty array in case of recursive types
(<InterfaceTypeWithDeclaredMembers>type).declaredCallSignatures = emptyArray;
(<InterfaceTypeWithDeclaredMembers>type).declaredConstructSignatures = emptyArray;
(<InterfaceTypeWithDeclaredMembers>type).declaredCallSignatures = getSignaturesOfSymbol(members.get(InternalSymbolName.Call));
(<InterfaceTypeWithDeclaredMembers>type).declaredConstructSignatures = getSignaturesOfSymbol(members.get(InternalSymbolName.New));
(<InterfaceTypeWithDeclaredMembers>type).declaredStringIndexInfo = getIndexInfoOfSymbol(symbol, IndexKind.String);
(<InterfaceTypeWithDeclaredMembers>type).declaredNumberIndexInfo = getIndexInfoOfSymbol(symbol, IndexKind.Number);
}
return <InterfaceTypeWithDeclaredMembers>type;
}
/**
* Indicates whether a type can be used as a property name.
*/
function isTypeUsableAsPropertyName(type: Type): type is StringLiteralType | NumberLiteralType | UniqueESSymbolType {
return !!(type.flags & TypeFlags.StringOrNumberLiteralOrUnique);
}
/**
* Indicates whether a declaration name is definitely late-bindable.
* A declaration name is only late-bindable if:
* - It is a `ComputedPropertyName`.
* - Its expression is an `Identifier` or either a `PropertyAccessExpression` an
* `ElementAccessExpression` consisting only of these same three types of nodes.
* - The type of its expression is a string or numeric literal type, or is a `unique symbol` type.
*/
function isLateBindableName(node: DeclarationName): node is LateBoundName {
return isComputedPropertyName(node)
&& isEntityNameExpression(node.expression)
&& isTypeUsableAsPropertyName(checkComputedPropertyName(node));
}
function isLateBoundName(name: __String): boolean {
return (name as string).charCodeAt(0) === CharacterCodes._ &&
(name as string).charCodeAt(1) === CharacterCodes._ &&
(name as string).charCodeAt(2) === CharacterCodes.at;
}
/**
* Indicates whether a declaration has a late-bindable dynamic name.
*/
function hasLateBindableName(node: Declaration): node is LateBoundDeclaration {
const name = getNameOfDeclaration(node);
return !!name && isLateBindableName(name);
}
/**
* Indicates whether a declaration has a dynamic name that cannot be late-bound.
*/
function hasNonBindableDynamicName(node: Declaration) {
return hasDynamicName(node) && !hasLateBindableName(node);
}
/**
* Indicates whether a declaration name is a dynamic name that cannot be late-bound.
*/
function isNonBindableDynamicName(node: DeclarationName) {
return isDynamicName(node) && !isLateBindableName(node);
}
/**
* Gets the symbolic name for a member from its type.
*/
function getPropertyNameFromType(type: StringLiteralType | NumberLiteralType | UniqueESSymbolType): __String {
if (type.flags & TypeFlags.UniqueESSymbol) {
return (<UniqueESSymbolType>type).escapedName;
}
if (type.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral)) {
return escapeLeadingUnderscores("" + (<StringLiteralType | NumberLiteralType>type).value);
}
return Debug.fail();
}
/**
* Adds a declaration to a late-bound dynamic member. This performs the same function for
* late-bound members that `addDeclarationToSymbol` in binder.ts performs for early-bound
* members.
*/
function addDeclarationToLateBoundSymbol(symbol: Symbol, member: LateBoundDeclaration, symbolFlags: SymbolFlags) {
Debug.assert(!!(getCheckFlags(symbol) & CheckFlags.Late), "Expected a late-bound symbol.");
symbol.flags |= symbolFlags;
getSymbolLinks(member.symbol).lateSymbol = symbol;
if (!symbol.declarations) {
symbol.declarations = [member];
}
else {
symbol.declarations.push(member);
}
if (symbolFlags & SymbolFlags.Value) {
if (!symbol.valueDeclaration || symbol.valueDeclaration.kind !== member.kind) {
symbol.valueDeclaration = member;
}
}
}
/**
* Performs late-binding of a dynamic member. This performs the same function for
* late-bound members that `declareSymbol` in binder.ts performs for early-bound
* members.
*
* If a symbol is a dynamic name from a computed property, we perform an additional "late"
* binding phase to attempt to resolve the name for the symbol from the type of the computed
* property's expression. If the type of the expression is a string-literal, numeric-literal,
* or unique symbol type, we can use that type as the name of the symbol.
*
* For example, given:
*
* const x = Symbol();
*
* interface I {
* [x]: number;
* }
*
* The binder gives the property `[x]: number` a special symbol with the name "__computed".
* In the late-binding phase we can type-check the expression `x` and see that it has a
* unique symbol type which we can then use as the name of the member. This allows users
* to define custom symbols that can be used in the members of an object type.
*
* @param parent The containing symbol for the member.
* @param earlySymbols The early-bound symbols of the parent.
* @param lateSymbols The late-bound symbols of the parent.
* @param decl The member to bind.
*/
function lateBindMember(parent: Symbol, earlySymbols: SymbolTable | undefined, lateSymbols: SymbolTable, decl: LateBoundDeclaration) {
Debug.assert(!!decl.symbol, "The member is expected to have a symbol.");
const links = getNodeLinks(decl);
if (!links.resolvedSymbol) {
// In the event we attempt to resolve the late-bound name of this member recursively,
// fall back to the early-bound name of this member.
links.resolvedSymbol = decl.symbol;
const type = checkComputedPropertyName(decl.name);
if (isTypeUsableAsPropertyName(type)) {
const memberName = getPropertyNameFromType(type);
const symbolFlags = decl.symbol.flags;
// Get or add a late-bound symbol for the member. This allows us to merge late-bound accessor declarations.
let lateSymbol = lateSymbols.get(memberName);
if (!lateSymbol) lateSymbols.set(memberName, lateSymbol = createSymbol(SymbolFlags.None, memberName, CheckFlags.Late));
// Report an error if a late-bound member has the same name as an early-bound member,
// or if we have another early-bound symbol declaration with the same name and
// conflicting flags.
const earlySymbol = earlySymbols && earlySymbols.get(memberName);
if (lateSymbol.flags & getExcludedSymbolFlags(symbolFlags) || earlySymbol) {
// If we have an existing early-bound member, combine its declarations so that we can
// report an error at each declaration.
const declarations = earlySymbol ? concatenate(earlySymbol.declarations, lateSymbol.declarations) : lateSymbol.declarations;
const name = !(type.flags & TypeFlags.UniqueESSymbol) && unescapeLeadingUnderscores(memberName) || declarationNameToString(decl.name);
forEach(declarations, declaration => error(getNameOfDeclaration(declaration) || declaration, Diagnostics.Property_0_was_also_declared_here, name));
error(decl.name || decl, Diagnostics.Duplicate_property_0, name);
lateSymbol = createSymbol(SymbolFlags.None, memberName, CheckFlags.Late);
}
lateSymbol.nameType = type;
addDeclarationToLateBoundSymbol(lateSymbol, decl, symbolFlags);
if (lateSymbol.parent) {
Debug.assert(lateSymbol.parent === parent, "Existing symbol parent should match new one");
}
else {
lateSymbol.parent = parent;
}
return links.resolvedSymbol = lateSymbol;
}
}
return links.resolvedSymbol;
}
function getResolvedMembersOrExportsOfSymbol(symbol: Symbol, resolutionKind: MembersOrExportsResolutionKind): UnderscoreEscapedMap<Symbol> {
const links = getSymbolLinks(symbol);
if (!links[resolutionKind]) {
const isStatic = resolutionKind === MembersOrExportsResolutionKind.resolvedExports;
const earlySymbols = !isStatic ? symbol.members :
symbol.flags & SymbolFlags.Module ? getExportsOfModuleWorker(symbol) :
symbol.exports;
// In the event we recursively resolve the members/exports of the symbol, we
// set the initial value of resolvedMembers/resolvedExports to the early-bound
// members/exports of the symbol.
links[resolutionKind] = earlySymbols || emptySymbols;
// fill in any as-yet-unresolved late-bound members.
const lateSymbols = createSymbolTable();
for (const decl of symbol.declarations) {
const members = getMembersOfDeclaration(decl);
if (members) {
for (const member of members) {
if (isStatic === hasStaticModifier(member) && hasLateBindableName(member)) {
lateBindMember(symbol, earlySymbols, lateSymbols, member);
}
}
}
}
links[resolutionKind] = combineSymbolTables(earlySymbols, lateSymbols) || emptySymbols;
}
return links[resolutionKind]!;
}
/**
* Gets a SymbolTable containing both the early- and late-bound members of a symbol.
*
* For a description of late-binding, see `lateBindMember`.
*/
function getMembersOfSymbol(symbol: Symbol) {
return symbol.flags & SymbolFlags.LateBindingContainer
? getResolvedMembersOrExportsOfSymbol(symbol, MembersOrExportsResolutionKind.resolvedMembers)
: symbol.members || emptySymbols;
}
/**
* If a symbol is the dynamic name of the member of an object type, get the late-bound
* symbol of the member.
*
* For a description of late-binding, see `lateBindMember`.
*/
function getLateBoundSymbol(symbol: Symbol): Symbol {
if (symbol.flags & SymbolFlags.ClassMember && symbol.escapedName === InternalSymbolName.Computed) {
const links = getSymbolLinks(symbol);
if (!links.lateSymbol && some(symbol.declarations, hasLateBindableName)) {
// force late binding of members/exports. This will set the late-bound symbol
if (some(symbol.declarations, hasStaticModifier)) {
getExportsOfSymbol(symbol.parent!);
}
else {
getMembersOfSymbol(symbol.parent!);
}
}
return links.lateSymbol || (links.lateSymbol = symbol);
}
return symbol;
}
function getTypeWithThisArgument(type: Type, thisArgument?: Type, needApparentType?: boolean): Type {
if (getObjectFlags(type) & ObjectFlags.Reference) {
const target = (<TypeReference>type).target;
const typeArguments = (<TypeReference>type).typeArguments;
if (length(target.typeParameters) === length(typeArguments)) {
const ref = createTypeReference(target, concatenate(typeArguments, [thisArgument || target.thisType!]));
return needApparentType ? getApparentType(ref) : ref;
}
}
else if (type.flags & TypeFlags.Intersection) {
return getIntersectionType(map((<IntersectionType>type).types, t => getTypeWithThisArgument(t, thisArgument, needApparentType)));
}
return needApparentType ? getApparentType(type) : type;
}
function resolveObjectTypeMembers(type: ObjectType, source: InterfaceTypeWithDeclaredMembers, typeParameters: ReadonlyArray<TypeParameter>, typeArguments: ReadonlyArray<Type>) {
let mapper: TypeMapper;
let members: SymbolTable;
let callSignatures: ReadonlyArray<Signature>;
let constructSignatures: ReadonlyArray<Signature> | undefined;
let stringIndexInfo: IndexInfo | undefined;
let numberIndexInfo: IndexInfo | undefined;
if (rangeEquals(typeParameters, typeArguments, 0, typeParameters.length)) {
mapper = identityMapper;
members = source.symbol ? getMembersOfSymbol(source.symbol) : createSymbolTable(source.declaredProperties);
callSignatures = source.declaredCallSignatures;
constructSignatures = source.declaredConstructSignatures;
stringIndexInfo = source.declaredStringIndexInfo;
numberIndexInfo = source.declaredNumberIndexInfo;
}
else {
mapper = createTypeMapper(typeParameters, typeArguments);
members = createInstantiatedSymbolTable(source.declaredProperties, mapper, /*mappingThisOnly*/ typeParameters.length === 1);
callSignatures = instantiateSignatures(source.declaredCallSignatures, mapper);
constructSignatures = instantiateSignatures(source.declaredConstructSignatures, mapper);
stringIndexInfo = instantiateIndexInfo(source.declaredStringIndexInfo, mapper);
numberIndexInfo = instantiateIndexInfo(source.declaredNumberIndexInfo, mapper);
}
const baseTypes = getBaseTypes(source);
if (baseTypes.length) {
if (source.symbol && members === getMembersOfSymbol(source.symbol)) {
members = createSymbolTable(source.declaredProperties);
}
setStructuredTypeMembers(type, members, callSignatures, constructSignatures, stringIndexInfo, numberIndexInfo);
const thisArgument = lastOrUndefined(typeArguments);
for (const baseType of baseTypes) {
const instantiatedBaseType = thisArgument ? getTypeWithThisArgument(instantiateType(baseType, mapper), thisArgument) : baseType;
addInheritedMembers(members, getPropertiesOfType(instantiatedBaseType));
callSignatures = concatenate(callSignatures, getSignaturesOfType(instantiatedBaseType, SignatureKind.Call));
constructSignatures = concatenate(constructSignatures, getSignaturesOfType(instantiatedBaseType, SignatureKind.Construct));
if (!stringIndexInfo) {
stringIndexInfo = instantiatedBaseType === anyType ?
createIndexInfo(anyType, /*isReadonly*/ false) :
getIndexInfoOfType(instantiatedBaseType, IndexKind.String);
}
numberIndexInfo = numberIndexInfo || getIndexInfoOfType(instantiatedBaseType, IndexKind.Number);
}
}
setStructuredTypeMembers(type, members, callSignatures, constructSignatures, stringIndexInfo, numberIndexInfo);
}
function resolveClassOrInterfaceMembers(type: InterfaceType): void {
resolveObjectTypeMembers(type, resolveDeclaredMembers(type), emptyArray, emptyArray);
}
function resolveTypeReferenceMembers(type: TypeReference): void {
const source = resolveDeclaredMembers(type.target);
const typeParameters = concatenate(source.typeParameters!, [source.thisType!]);
const typeArguments = type.typeArguments && type.typeArguments.length === typeParameters.length ?
type.typeArguments : concatenate(type.typeArguments, [type]);
resolveObjectTypeMembers(type, source, typeParameters, typeArguments);
}
function createSignature(
declaration: SignatureDeclaration | JSDocSignature | undefined,
typeParameters: ReadonlyArray<TypeParameter> | undefined,
thisParameter: Symbol | undefined,
parameters: ReadonlyArray<Symbol>,
resolvedReturnType: Type | undefined,
resolvedTypePredicate: TypePredicate | undefined,
minArgumentCount: number,
hasRestParameter: boolean,
hasLiteralTypes: boolean,
): Signature {
const sig = new Signature(checker);
sig.declaration = declaration;
sig.typeParameters = typeParameters;
sig.parameters = parameters;
sig.thisParameter = thisParameter;
sig.resolvedReturnType = resolvedReturnType;
sig.resolvedTypePredicate = resolvedTypePredicate;
sig.minArgumentCount = minArgumentCount;
sig.hasRestParameter = hasRestParameter;
sig.hasLiteralTypes = hasLiteralTypes;
sig.target = undefined;
sig.mapper = undefined;
return sig;
}
function cloneSignature(sig: Signature): Signature {
return createSignature(sig.declaration, sig.typeParameters, sig.thisParameter, sig.parameters, /*resolvedReturnType*/ undefined,
/*resolvedTypePredicate*/ undefined, sig.minArgumentCount, sig.hasRestParameter, sig.hasLiteralTypes);
}
function getExpandedParameters(sig: Signature): ReadonlyArray<Symbol> {
if (sig.hasRestParameter) {
const restIndex = sig.parameters.length - 1;
const restParameter = sig.parameters[restIndex];
const restType = getTypeOfSymbol(restParameter);
if (isTupleType(restType)) {
const elementTypes = restType.typeArguments || emptyArray;
const minLength = restType.target.minLength;
const tupleRestIndex = restType.target.hasRestElement ? elementTypes.length - 1 : -1;
const restParams = map(elementTypes, (t, i) => {
const name = getParameterNameAtPosition(sig, restIndex + i);
const checkFlags = i === tupleRestIndex ? CheckFlags.RestParameter :
i >= minLength ? CheckFlags.OptionalParameter : 0;
const symbol = createSymbol(SymbolFlags.FunctionScopedVariable, name, checkFlags);
symbol.type = i === tupleRestIndex ? createArrayType(t) : t;
return symbol;
});
return concatenate(sig.parameters.slice(0, restIndex), restParams);
}
}
return sig.parameters;
}
function getDefaultConstructSignatures(classType: InterfaceType): Signature[] {
const baseConstructorType = getBaseConstructorTypeOfClass(classType);
const baseSignatures = getSignaturesOfType(baseConstructorType, SignatureKind.Construct);
if (baseSignatures.length === 0) {
return [createSignature(undefined, classType.localTypeParameters, undefined, emptyArray, classType, /*resolvedTypePredicate*/ undefined, 0, /*hasRestParameter*/ false, /*hasLiteralTypes*/ false)]; // TODO: GH#18217
}
const baseTypeNode = getBaseTypeNodeOfClass(classType)!;
const isJavaScript = isInJSFile(baseTypeNode);
const typeArguments = typeArgumentsFromTypeReferenceNode(baseTypeNode);
const typeArgCount = length(typeArguments);
const result: Signature[] = [];
for (const baseSig of baseSignatures) {
const minTypeArgumentCount = getMinTypeArgumentCount(baseSig.typeParameters);
const typeParamCount = length(baseSig.typeParameters);
if (isJavaScript || typeArgCount >= minTypeArgumentCount && typeArgCount <= typeParamCount) {
const sig = typeParamCount ? createSignatureInstantiation(baseSig, fillMissingTypeArguments(typeArguments, baseSig.typeParameters, minTypeArgumentCount, isJavaScript)!) : cloneSignature(baseSig);
sig.typeParameters = classType.localTypeParameters;
sig.resolvedReturnType = classType;
result.push(sig);
}
}
return result;
}
function findMatchingSignature(signatureList: ReadonlyArray<Signature>, signature: Signature, partialMatch: boolean, ignoreThisTypes: boolean, ignoreReturnTypes: boolean): Signature | undefined {
for (const s of signatureList) {
if (compareSignaturesIdentical(s, signature, partialMatch, ignoreThisTypes, ignoreReturnTypes, partialMatch ? compareTypesSubtypeOf : compareTypesIdentical)) {
return s;
}
}
}
function findMatchingSignatures(signatureLists: ReadonlyArray<ReadonlyArray<Signature>>, signature: Signature, listIndex: number): Signature[] | undefined {
if (signature.typeParameters) {
// We require an exact match for generic signatures, so we only return signatures from the first
// signature list and only if they have exact matches in the other signature lists.
if (listIndex > 0) {
return undefined;
}
for (let i = 1; i < signatureLists.length; i++) {
if (!findMatchingSignature(signatureLists[i], signature, /*partialMatch*/ false, /*ignoreThisTypes*/ false, /*ignoreReturnTypes*/ false)) {
return undefined;
}
}
return [signature];
}
let result: Signature[] | undefined;
for (let i = 0; i < signatureLists.length; i++) {
// Allow matching non-generic signatures to have excess parameters and different return types
const match = i === listIndex ? signature : findMatchingSignature(signatureLists[i], signature, /*partialMatch*/ true, /*ignoreThisTypes*/ true, /*ignoreReturnTypes*/ true);
if (!match) {
return undefined;
}
result = appendIfUnique(result, match);
}
return result;
}
// The signatures of a union type are those signatures that are present in each of the constituent types.
// Generic signatures must match exactly, but non-generic signatures are allowed to have extra optional
// parameters and may differ in return types. When signatures differ in return types, the resulting return
// type is the union of the constituent return types.
function getUnionSignatures(signatureLists: ReadonlyArray<ReadonlyArray<Signature>>): Signature[] {
let result: Signature[] | undefined;
let indexWithLengthOverOne: number | undefined;
for (let i = 0; i < signatureLists.length; i++) {
if (signatureLists[i].length === 0) return emptyArray;
if (signatureLists[i].length > 1) {
indexWithLengthOverOne = indexWithLengthOverOne === undefined ? i : -1; // -1 is a signal there are multiple overload sets
}
for (const signature of signatureLists[i]) {
// Only process signatures with parameter lists that aren't already in the result list
if (!result || !findMatchingSignature(result, signature, /*partialMatch*/ false, /*ignoreThisTypes*/ true, /*ignoreReturnTypes*/ true)) {
const unionSignatures = findMatchingSignatures(signatureLists, signature, i);
if (unionSignatures) {
let s = signature;
// Union the result types when more than one signature matches
if (unionSignatures.length > 1) {
let thisParameter = signature.thisParameter;
if (forEach(unionSignatures, sig => sig.thisParameter)) {
// TODO: GH#18217 We tested that *some* has thisParameter and now act as if *all* do
const thisType = getUnionType(map(unionSignatures, sig => sig.thisParameter ? getTypeOfSymbol(sig.thisParameter) : anyType), UnionReduction.Subtype);
thisParameter = createSymbolWithType(signature.thisParameter!, thisType);
}
s = cloneSignature(signature);
s.thisParameter = thisParameter;
s.unionSignatures = unionSignatures;
}
(result || (result = [])).push(s);
}
}
}
}
if (!length(result) && indexWithLengthOverOne !== -1) {
// No sufficiently similar signature existed to subsume all the other signatures in the union - time to see if we can make a single
// signature that handles all over them. We only do this when there are overloads in only one constituent.
// (Overloads are conditional in nature and having overloads in multiple constituents would necessitate making a power set of
// signatures from the type, whose ordering would be non-obvious)
const masterList = signatureLists[indexWithLengthOverOne !== undefined ? indexWithLengthOverOne : 0];
let results: Signature[] | undefined = masterList.slice();
for (const signatures of signatureLists) {
if (signatures !== masterList) {
const signature = signatures[0];
Debug.assert(!!signature, "getUnionSignatures bails early on empty signature lists and should not have empty lists on second pass");
results = signature.typeParameters && some(results, s => !!s.typeParameters) ? undefined : map(results, sig => combineSignaturesOfUnionMembers(sig, signature));
if (!results) {
break;
}
}
}
result = results;
}
return result || emptyArray;
}
function combineUnionThisParam(left: Symbol | undefined, right: Symbol | undefined): Symbol | undefined {
if (!left || !right) {
return left || right;
}
// A signature `this` type might be a read or a write position... It's very possible that it should be invariant
// and we should refuse to merge signatures if there are `this` types and they do not match. However, so as to be
// permissive when calling, for now, we'll union the `this` types just like the overlapping-union-signature check does
const thisType = getUnionType([getTypeOfSymbol(left), getTypeOfSymbol(right)], UnionReduction.Subtype);
return createSymbolWithType(left, thisType);
}
function combineUnionParameters(left: Signature, right: Signature) {
const longest = getParameterCount(left) >= getParameterCount(right) ? left : right;
const shorter = longest === left ? right : left;
const longestCount = getParameterCount(longest);
const eitherHasEffectiveRest = (hasEffectiveRestParameter(left) || hasEffectiveRestParameter(right));
const needsExtraRestElement = eitherHasEffectiveRest && !hasEffectiveRestParameter(longest);
const params = new Array<Symbol>(longestCount + (needsExtraRestElement ? 1 : 0));
for (let i = 0; i < longestCount; i++) {
const longestParamType = tryGetTypeAtPosition(longest, i)!;
const shorterParamType = tryGetTypeAtPosition(shorter, i) || unknownType;
const unionParamType = getIntersectionType([longestParamType, shorterParamType]);
const isRestParam = eitherHasEffectiveRest && !needsExtraRestElement && i === (longestCount - 1);
const isOptional = i >= getMinArgumentCount(longest) && i >= getMinArgumentCount(shorter);
const leftName = getParameterNameAtPosition(left, i);
const rightName = getParameterNameAtPosition(right, i);
const paramSymbol = createSymbol(
SymbolFlags.FunctionScopedVariable | (isOptional && !isRestParam ? SymbolFlags.Optional : 0),
leftName === rightName ? leftName : `arg${i}` as __String
);
paramSymbol.type = isRestParam ? createArrayType(unionParamType) : unionParamType;
params[i] = paramSymbol;
}
if (needsExtraRestElement) {
const restParamSymbol = createSymbol(SymbolFlags.FunctionScopedVariable, "args" as __String);
restParamSymbol.type = createArrayType(getTypeAtPosition(shorter, longestCount));
params[longestCount] = restParamSymbol;
}
return params;
}
function combineSignaturesOfUnionMembers(left: Signature, right: Signature): Signature {
const declaration = left.declaration;
const params = combineUnionParameters(left, right);
const thisParam = combineUnionThisParam(left.thisParameter, right.thisParameter);
const minArgCount = Math.max(left.minArgumentCount, right.minArgumentCount);
const hasRestParam = left.hasRestParameter || right.hasRestParameter;
const hasLiteralTypes = left.hasLiteralTypes || right.hasLiteralTypes;
const result = createSignature(
declaration,
left.typeParameters || right.typeParameters,
thisParam,
params,
/*resolvedReturnType*/ undefined,
/*resolvedTypePredicate*/ undefined,
minArgCount,
hasRestParam,
hasLiteralTypes
);
result.unionSignatures = concatenate(left.unionSignatures || [left], [right]);
return result;
}
function getUnionIndexInfo(types: ReadonlyArray<Type>, kind: IndexKind): IndexInfo | undefined {
const indexTypes: Type[] = [];
let isAnyReadonly = false;
for (const type of types) {
const indexInfo = getIndexInfoOfType(type, kind);
if (!indexInfo) {
return undefined;
}
indexTypes.push(indexInfo.type);
isAnyReadonly = isAnyReadonly || indexInfo.isReadonly;
}
return createIndexInfo(getUnionType(indexTypes, UnionReduction.Subtype), isAnyReadonly);
}
function resolveUnionTypeMembers(type: UnionType) {
// The members and properties collections are empty for union types. To get all properties of a union
// type use getPropertiesOfType (only the language service uses this).
const callSignatures = getUnionSignatures(map(type.types, t => t === globalFunctionType ? [unknownSignature] : getSignaturesOfType(t, SignatureKind.Call)));
const constructSignatures = getUnionSignatures(map(type.types, t => getSignaturesOfType(t, SignatureKind.Construct)));
const stringIndexInfo = getUnionIndexInfo(type.types, IndexKind.String);
const numberIndexInfo = getUnionIndexInfo(type.types, IndexKind.Number);
setStructuredTypeMembers(type, emptySymbols, callSignatures, constructSignatures, stringIndexInfo, numberIndexInfo);
}
function intersectTypes(type1: Type, type2: Type): Type;
function intersectTypes(type1: Type | undefined, type2: Type | undefined): Type | undefined;
function intersectTypes(type1: Type | undefined, type2: Type | undefined): Type | undefined {
return !type1 ? type2 : !type2 ? type1 : getIntersectionType([type1, type2]);
}
function intersectIndexInfos(info1: IndexInfo | undefined, info2: IndexInfo | undefined): IndexInfo | undefined {
return !info1 ? info2 : !info2 ? info1 : createIndexInfo(
getIntersectionType([info1.type, info2.type]), info1.isReadonly && info2.isReadonly);
}
function unionSpreadIndexInfos(info1: IndexInfo | undefined, info2: IndexInfo | undefined): IndexInfo | undefined {
return info1 && info2 && createIndexInfo(
getUnionType([info1.type, info2.type]), info1.isReadonly || info2.isReadonly);
}
function includeMixinType(type: Type, types: ReadonlyArray<Type>, index: number): Type {
const mixedTypes: Type[] = [];
for (let i = 0; i < types.length; i++) {
if (i === index) {
mixedTypes.push(type);
}
else if (isMixinConstructorType(types[i])) {
mixedTypes.push(getReturnTypeOfSignature(getSignaturesOfType(types[i], SignatureKind.Construct)[0]));
}
}
return getIntersectionType(mixedTypes);
}
function resolveIntersectionTypeMembers(type: IntersectionType) {
// The members and properties collections are empty for intersection types. To get all properties of an
// intersection type use getPropertiesOfType (only the language service uses this).
let callSignatures: ReadonlyArray<Signature> = emptyArray;
let constructSignatures: ReadonlyArray<Signature> = emptyArray;
let stringIndexInfo: IndexInfo | undefined;
let numberIndexInfo: IndexInfo | undefined;
const types = type.types;
const mixinCount = countWhere(types, isMixinConstructorType);
for (let i = 0; i < types.length; i++) {
const t = type.types[i];
// When an intersection type contains mixin constructor types, the construct signatures from
// those types are discarded and their return types are mixed into the return types of all
// other construct signatures in the intersection type. For example, the intersection type
// '{ new(...args: any[]) => A } & { new(s: string) => B }' has a single construct signature
// 'new(s: string) => A & B'.
if (mixinCount === 0 || mixinCount === types.length && i === 0 || !isMixinConstructorType(t)) {
let signatures = getSignaturesOfType(t, SignatureKind.Construct);
if (signatures.length && mixinCount > 0) {
signatures = map(signatures, s => {
const clone = cloneSignature(s);
clone.resolvedReturnType = includeMixinType(getReturnTypeOfSignature(s), types, i);
return clone;
});
}
constructSignatures = concatenate(constructSignatures, signatures);
}
callSignatures = concatenate(callSignatures, getSignaturesOfType(t, SignatureKind.Call));
stringIndexInfo = intersectIndexInfos(stringIndexInfo, getIndexInfoOfType(t, IndexKind.String));
numberIndexInfo = intersectIndexInfos(numberIndexInfo, getIndexInfoOfType(t, IndexKind.Number));
}
setStructuredTypeMembers(type, emptySymbols, callSignatures, constructSignatures, stringIndexInfo, numberIndexInfo);
}
/**
* Converts an AnonymousType to a ResolvedType.
*/
function resolveAnonymousTypeMembers(type: AnonymousType) {
const symbol = type.symbol;
if (type.target) {
setStructuredTypeMembers(type, emptySymbols, emptyArray, emptyArray, undefined, undefined);
const members = createInstantiatedSymbolTable(getPropertiesOfObjectType(type.target), type.mapper!, /*mappingThisOnly*/ false);
const callSignatures = instantiateSignatures(getSignaturesOfType(type.target, SignatureKind.Call), type.mapper!);
const constructSignatures = instantiateSignatures(getSignaturesOfType(type.target, SignatureKind.Construct), type.mapper!);
const stringIndexInfo = instantiateIndexInfo(getIndexInfoOfType(type.target, IndexKind.String), type.mapper!);
const numberIndexInfo = instantiateIndexInfo(getIndexInfoOfType(type.target, IndexKind.Number), type.mapper!);
setStructuredTypeMembers(type, members, callSignatures, constructSignatures, stringIndexInfo, numberIndexInfo);
}
else if (symbol.flags & SymbolFlags.TypeLiteral) {
setStructuredTypeMembers(type, emptySymbols, emptyArray, emptyArray, undefined, undefined);
const members = getMembersOfSymbol(symbol);
const callSignatures = getSignaturesOfSymbol(members.get(InternalSymbolName.Call));
const constructSignatures = getSignaturesOfSymbol(members.get(InternalSymbolName.New));
const stringIndexInfo = getIndexInfoOfSymbol(symbol, IndexKind.String);
const numberIndexInfo = getIndexInfoOfSymbol(symbol, IndexKind.Number);
setStructuredTypeMembers(type, members, callSignatures, constructSignatures, stringIndexInfo, numberIndexInfo);
}
else {
// Combinations of function, class, enum and module
let members = emptySymbols;
let stringIndexInfo: IndexInfo | undefined;
if (symbol.exports) {
members = getExportsOfSymbol(symbol);
}
setStructuredTypeMembers(type, members, emptyArray, emptyArray, undefined, undefined);
if (symbol.flags & SymbolFlags.Class) {
const classType = getDeclaredTypeOfClassOrInterface(symbol);
const baseConstructorType = getBaseConstructorTypeOfClass(classType);
if (baseConstructorType.flags & (TypeFlags.Object | TypeFlags.Intersection | TypeFlags.TypeVariable)) {
members = createSymbolTable(getNamedMembers(members));
addInheritedMembers(members, getPropertiesOfType(baseConstructorType));
}
else if (baseConstructorType === anyType) {
stringIndexInfo = createIndexInfo(anyType, /*isReadonly*/ false);
}
}
const numberIndexInfo = symbol.flags & SymbolFlags.Enum ? enumNumberIndexInfo : undefined;
setStructuredTypeMembers(type, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
// We resolve the members before computing the signatures because a signature may use
// typeof with a qualified name expression that circularly references the type we are
// in the process of resolving (see issue #6072). The temporarily empty signature list
// will never be observed because a qualified name can't reference signatures.
if (symbol.flags & (SymbolFlags.Function | SymbolFlags.Method)) {
type.callSignatures = getSignaturesOfSymbol(symbol);
type.constructSignatures = filter(type.callSignatures, sig => isJSConstructor(sig.declaration));
}
// And likewise for construct signatures for classes
if (symbol.flags & SymbolFlags.Class) {
const classType = getDeclaredTypeOfClassOrInterface(symbol);
let constructSignatures = getSignaturesOfSymbol(symbol.members!.get(InternalSymbolName.Constructor));
if (!constructSignatures.length) {
constructSignatures = getDefaultConstructSignatures(classType);
}
type.constructSignatures = constructSignatures;
}
}
}
function resolveReverseMappedTypeMembers(type: ReverseMappedType) {
const indexInfo = getIndexInfoOfType(type.source, IndexKind.String);
const modifiers = getMappedTypeModifiers(type.mappedType);
const readonlyMask = modifiers & MappedTypeModifiers.IncludeReadonly ? false : true;
const optionalMask = modifiers & MappedTypeModifiers.IncludeOptional ? 0 : SymbolFlags.Optional;
const stringIndexInfo = indexInfo && createIndexInfo(inferReverseMappedType(indexInfo.type, type.mappedType, type.constraintType), readonlyMask && indexInfo.isReadonly);
const members = createSymbolTable();
for (const prop of getPropertiesOfType(type.source)) {
const checkFlags = CheckFlags.ReverseMapped | (readonlyMask && isReadonlySymbol(prop) ? CheckFlags.Readonly : 0);
const inferredProp = createSymbol(SymbolFlags.Property | prop.flags & optionalMask, prop.escapedName, checkFlags) as ReverseMappedSymbol;
inferredProp.declarations = prop.declarations;
inferredProp.nameType = prop.nameType;
inferredProp.propertyType = getTypeOfSymbol(prop);
inferredProp.mappedType = type.mappedType;
inferredProp.constraintType = type.constraintType;
members.set(prop.escapedName, inferredProp);
}
setStructuredTypeMembers(type, members, emptyArray, emptyArray, stringIndexInfo, undefined);
}
// Return the lower bound of the key type in a mapped type. Intuitively, the lower
// bound includes those keys that are known to always be present, for example because
// because of constraints on type parameters (e.g. 'keyof T' for a constrained T).
function getLowerBoundOfKeyType(type: Type): Type {
if (type.flags & (TypeFlags.Any | TypeFlags.Primitive)) {
return type;
}
if (type.flags & TypeFlags.Index) {
return getIndexType(getApparentType((<IndexType>type).type));
}
if (type.flags & TypeFlags.Conditional) {
return getLowerBoundOfConditionalType(<ConditionalType>type);
}
if (type.flags & TypeFlags.Union) {
return getUnionType(sameMap((<UnionType>type).types, getLowerBoundOfKeyType));
}
if (type.flags & TypeFlags.Intersection) {
return getIntersectionType(sameMap((<UnionType>type).types, getLowerBoundOfKeyType));
}
return neverType;
}
function getLowerBoundOfConditionalType(type: ConditionalType) {
if (type.root.isDistributive) {
const constraint = getLowerBoundOfKeyType(type.checkType);
if (constraint !== type.checkType) {
const mapper = makeUnaryTypeMapper(type.root.checkType, constraint);
return getConditionalTypeInstantiation(type, combineTypeMappers(mapper, type.mapper));
}
}
return type;
}
/** Resolve the members of a mapped type { [P in K]: T } */
function resolveMappedTypeMembers(type: MappedType) {
const members: SymbolTable = createSymbolTable();
let stringIndexInfo: IndexInfo | undefined;
let numberIndexInfo: IndexInfo | undefined;
// Resolve upfront such that recursive references see an empty object type.
setStructuredTypeMembers(type, emptySymbols, emptyArray, emptyArray, undefined, undefined);
// In { [P in K]: T }, we refer to P as the type parameter type, K as the constraint type,
// and T as the template type.
const typeParameter = getTypeParameterFromMappedType(type);
const constraintType = getConstraintTypeFromMappedType(type);
const templateType = getTemplateTypeFromMappedType(<MappedType>type.target || type);
const modifiersType = getApparentType(getModifiersTypeFromMappedType(type)); // The 'T' in 'keyof T'
const templateModifiers = getMappedTypeModifiers(type);
const include = keyofStringsOnly ? TypeFlags.StringLiteral : TypeFlags.StringOrNumberLiteralOrUnique;
if (isMappedTypeWithKeyofConstraintDeclaration(type)) {
// We have a { [P in keyof T]: X }
for (const prop of getPropertiesOfType(modifiersType)) {
addMemberForKeyType(getLiteralTypeFromProperty(prop, include));
}
if (modifiersType.flags & TypeFlags.Any || getIndexInfoOfType(modifiersType, IndexKind.String)) {
addMemberForKeyType(stringType);
}
if (!keyofStringsOnly && getIndexInfoOfType(modifiersType, IndexKind.Number)) {
addMemberForKeyType(numberType);
}
}
else {
forEachType(getLowerBoundOfKeyType(constraintType), addMemberForKeyType);
}
setStructuredTypeMembers(type, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
function addMemberForKeyType(t: Type) {
// Create a mapper from T to the current iteration type constituent. Then, if the
// mapped type is itself an instantiated type, combine the iteration mapper with the
// instantiation mapper.
const templateMapper = combineTypeMappers(type.mapper, createTypeMapper([typeParameter], [t]));
const propType = instantiateType(templateType, templateMapper);
// If the current iteration type constituent is a string literal type, create a property.
// Otherwise, for type string create a string index signature.
if (isTypeUsableAsPropertyName(t)) {
const propName = getPropertyNameFromType(t);
const modifiersProp = getPropertyOfType(modifiersType, propName);
const isOptional = !!(templateModifiers & MappedTypeModifiers.IncludeOptional ||
!(templateModifiers & MappedTypeModifiers.ExcludeOptional) && modifiersProp && modifiersProp.flags & SymbolFlags.Optional);
const isReadonly = !!(templateModifiers & MappedTypeModifiers.IncludeReadonly ||
!(templateModifiers & MappedTypeModifiers.ExcludeReadonly) && modifiersProp && isReadonlySymbol(modifiersProp));
const prop = createSymbol(SymbolFlags.Property | (isOptional ? SymbolFlags.Optional : 0), propName, isReadonly ? CheckFlags.Readonly : 0);
// When creating an optional property in strictNullChecks mode, if 'undefined' isn't assignable to the
// type, we include 'undefined' in the type. Similarly, when creating a non-optional property in strictNullChecks
// mode, if the underlying property is optional we remove 'undefined' from the type.
prop.type = strictNullChecks && isOptional && !isTypeAssignableTo(undefinedType, propType) ? getOptionalType(propType) :
strictNullChecks && !isOptional && modifiersProp && modifiersProp.flags & SymbolFlags.Optional ? getTypeWithFacts(propType, TypeFacts.NEUndefined) :
propType;
if (modifiersProp) {
prop.syntheticOrigin = modifiersProp;
prop.declarations = modifiersProp.declarations;
}
prop.nameType = t;
members.set(propName, prop);
}
else if (t.flags & (TypeFlags.Any | TypeFlags.String)) {
stringIndexInfo = createIndexInfo(propType, !!(templateModifiers & MappedTypeModifiers.IncludeReadonly));
}
else if (t.flags & TypeFlags.Number) {
numberIndexInfo = createIndexInfo(propType, !!(templateModifiers & MappedTypeModifiers.IncludeReadonly));
}
}
}
function getTypeParameterFromMappedType(type: MappedType) {
return type.typeParameter ||
(type.typeParameter = getDeclaredTypeOfTypeParameter(getSymbolOfNode(type.declaration.typeParameter)));
}
function getConstraintTypeFromMappedType(type: MappedType) {
return type.constraintType ||
(type.constraintType = getConstraintOfTypeParameter(getTypeParameterFromMappedType(type)) || errorType);
}
function getTemplateTypeFromMappedType(type: MappedType) {
return type.templateType ||
(type.templateType = type.declaration.type ?
instantiateType(addOptionality(getTypeFromTypeNode(type.declaration.type), !!(getMappedTypeModifiers(type) & MappedTypeModifiers.IncludeOptional)), type.mapper || identityMapper) :
errorType);
}
function getConstraintDeclarationForMappedType(type: MappedType) {
return getEffectiveConstraintOfTypeParameter(type.declaration.typeParameter);
}
function isMappedTypeWithKeyofConstraintDeclaration(type: MappedType) {
const constraintDeclaration = getConstraintDeclarationForMappedType(type)!; // TODO: GH#18217
return constraintDeclaration.kind === SyntaxKind.TypeOperator &&
(<TypeOperatorNode>constraintDeclaration).operator === SyntaxKind.KeyOfKeyword;
}
function getModifiersTypeFromMappedType(type: MappedType) {
if (!type.modifiersType) {
if (isMappedTypeWithKeyofConstraintDeclaration(type)) {
// If the constraint declaration is a 'keyof T' node, the modifiers type is T. We check
// AST nodes here because, when T is a non-generic type, the logic below eagerly resolves
// 'keyof T' to a literal union type and we can't recover T from that type.
type.modifiersType = instantiateType(getTypeFromTypeNode((<TypeOperatorNode>getConstraintDeclarationForMappedType(type)).type), type.mapper || identityMapper);
}
else {
// Otherwise, get the declared constraint type, and if the constraint type is a type parameter,
// get the constraint of that type parameter. If the resulting type is an indexed type 'keyof T',
// the modifiers type is T. Otherwise, the modifiers type is {}.
const declaredType = <MappedType>getTypeFromMappedTypeNode(type.declaration);
const constraint = getConstraintTypeFromMappedType(declaredType);
const extendedConstraint = constraint && constraint.flags & TypeFlags.TypeParameter ? getConstraintOfTypeParameter(<TypeParameter>constraint) : constraint;
type.modifiersType = extendedConstraint && extendedConstraint.flags & TypeFlags.Index ? instantiateType((<IndexType>extendedConstraint).type, type.mapper || identityMapper) : emptyObjectType;
}
}
return type.modifiersType;
}
function getMappedTypeModifiers(type: MappedType): MappedTypeModifiers {
const declaration = type.declaration;
return (declaration.readonlyToken ? declaration.readonlyToken.kind === SyntaxKind.MinusToken ? MappedTypeModifiers.ExcludeReadonly : MappedTypeModifiers.IncludeReadonly : 0) |
(declaration.questionToken ? declaration.questionToken.kind === SyntaxKind.MinusToken ? MappedTypeModifiers.ExcludeOptional : MappedTypeModifiers.IncludeOptional : 0);
}
function getMappedTypeOptionality(type: MappedType): number {
const modifiers = getMappedTypeModifiers(type);
return modifiers & MappedTypeModifiers.ExcludeOptional ? -1 : modifiers & MappedTypeModifiers.IncludeOptional ? 1 : 0;
}
function getCombinedMappedTypeOptionality(type: MappedType): number {
const optionality = getMappedTypeOptionality(type);
const modifiersType = getModifiersTypeFromMappedType(type);
return optionality || (isGenericMappedType(modifiersType) ? getMappedTypeOptionality(modifiersType) : 0);
}
function isPartialMappedType(type: Type) {
return !!(getObjectFlags(type) & ObjectFlags.Mapped && getMappedTypeModifiers(<MappedType>type) & MappedTypeModifiers.IncludeOptional);
}
function isGenericMappedType(type: Type): type is MappedType {
return !!(getObjectFlags(type) & ObjectFlags.Mapped) && isGenericIndexType(getConstraintTypeFromMappedType(<MappedType>type));
}
function resolveStructuredTypeMembers(type: StructuredType): ResolvedType {
if (!(<ResolvedType>type).members) {
if (type.flags & TypeFlags.Object) {
if ((<ObjectType>type).objectFlags & ObjectFlags.Reference) {
resolveTypeReferenceMembers(<TypeReference>type);
}
else if ((<ObjectType>type).objectFlags & ObjectFlags.ClassOrInterface) {
resolveClassOrInterfaceMembers(<InterfaceType>type);
}
else if ((<ReverseMappedType>type).objectFlags & ObjectFlags.ReverseMapped) {
resolveReverseMappedTypeMembers(type as ReverseMappedType);
}
else if ((<ObjectType>type).objectFlags & ObjectFlags.Anonymous) {
resolveAnonymousTypeMembers(<AnonymousType>type);
}
else if ((<MappedType>type).objectFlags & ObjectFlags.Mapped) {
resolveMappedTypeMembers(<MappedType>type);
}
}
else if (type.flags & TypeFlags.Union) {
resolveUnionTypeMembers(<UnionType>type);
}
else if (type.flags & TypeFlags.Intersection) {
resolveIntersectionTypeMembers(<IntersectionType>type);
}
}
return <ResolvedType>type;
}
/** Return properties of an object type or an empty array for other types */
function getPropertiesOfObjectType(type: Type): Symbol[] {
if (type.flags & TypeFlags.Object) {
return resolveStructuredTypeMembers(<ObjectType>type).properties;
}
return emptyArray;
}
/** If the given type is an object type and that type has a property by the given name,
* return the symbol for that property. Otherwise return undefined.
*/
function getPropertyOfObjectType(type: Type, name: __String): Symbol | undefined {
if (type.flags & TypeFlags.Object) {
const resolved = resolveStructuredTypeMembers(<ObjectType>type);
const symbol = resolved.members.get(name);
if (symbol && symbolIsValue(symbol)) {
return symbol;
}
}
}
function getPropertiesOfUnionOrIntersectionType(type: UnionOrIntersectionType): Symbol[] {
if (!type.resolvedProperties) {
const members = createSymbolTable();
for (const current of type.types) {
for (const prop of getPropertiesOfType(current)) {
if (!members.has(prop.escapedName)) {
const combinedProp = getPropertyOfUnionOrIntersectionType(type, prop.escapedName);
if (combinedProp) {
members.set(prop.escapedName, combinedProp);
}
}
}
// The properties of a union type are those that are present in all constituent types, so
// we only need to check the properties of the first type
if (type.flags & TypeFlags.Union) {
break;
}
}
type.resolvedProperties = getNamedMembers(members);
}
return type.resolvedProperties;
}
function getPropertiesOfType(type: Type): Symbol[] {
type = getApparentType(type);
return type.flags & TypeFlags.UnionOrIntersection ?
getPropertiesOfUnionOrIntersectionType(<UnionType>type) :
getPropertiesOfObjectType(type);
}
function isTypeInvalidDueToUnionDiscriminant(contextualType: Type, obj: ObjectLiteralExpression | JsxAttributes): boolean {
const list = obj.properties as NodeArray<ObjectLiteralElementLike | JsxAttributeLike>;
return list.some(property => {
const nameType = property.name && getLiteralTypeFromPropertyName(property.name);
const name = nameType && isTypeUsableAsPropertyName(nameType) ? getPropertyNameFromType(nameType) : undefined;
const expected = name === undefined ? undefined : getTypeOfPropertyOfType(contextualType, name);
return !!expected && isLiteralType(expected) && !isTypeAssignableTo(getTypeOfNode(property), expected);
});
}
function getAllPossiblePropertiesOfTypes(types: ReadonlyArray<Type>): Symbol[] {
const unionType = getUnionType(types);
if (!(unionType.flags & TypeFlags.Union)) {
return getAugmentedPropertiesOfType(unionType);
}
const props = createSymbolTable();
for (const memberType of types) {
for (const { escapedName } of getAugmentedPropertiesOfType(memberType)) {
if (!props.has(escapedName)) {
const prop = createUnionOrIntersectionProperty(unionType as UnionType, escapedName);
// May be undefined if the property is private
if (prop) props.set(escapedName, prop);
}
}
}
return arrayFrom(props.values());
}
function getConstraintOfType(type: InstantiableType | UnionOrIntersectionType): Type | undefined {
return type.flags & TypeFlags.TypeParameter ? getConstraintOfTypeParameter(<TypeParameter>type) :
type.flags & TypeFlags.IndexedAccess ? getConstraintOfIndexedAccess(<IndexedAccessType>type) :
type.flags & TypeFlags.Conditional ? getConstraintOfConditionalType(<ConditionalType>type) :
getBaseConstraintOfType(type);
}
function getConstraintOfTypeParameter(typeParameter: TypeParameter): Type | undefined {
return hasNonCircularBaseConstraint(typeParameter) ? getConstraintFromTypeParameter(typeParameter) : undefined;
}
function getConstraintOfIndexedAccess(type: IndexedAccessType) {
const objectType = getConstraintOfType(type.objectType) || type.objectType;
if (objectType !== type.objectType) {
const constraint = getIndexedAccessType(objectType, type.indexType, /*accessNode*/ undefined, errorType);
if (constraint && constraint !== errorType) {
return constraint;
}
}
const baseConstraint = getBaseConstraintOfType(type);
return baseConstraint && baseConstraint !== type ? baseConstraint : undefined;
}
function getDefaultConstraintOfConditionalType(type: ConditionalType) {
if (!type.resolvedDefaultConstraint) {
const rootTrueType = type.root.trueType;
const rootTrueConstraint = !(rootTrueType.flags & TypeFlags.Substitution)
? rootTrueType
: ((<SubstitutionType>rootTrueType).substitute).flags & TypeFlags.AnyOrUnknown
? (<SubstitutionType>rootTrueType).typeVariable
: getIntersectionType([(<SubstitutionType>rootTrueType).substitute, (<SubstitutionType>rootTrueType).typeVariable]);
type.resolvedDefaultConstraint = getUnionType([instantiateType(rootTrueConstraint, type.combinedMapper || type.mapper), getFalseTypeFromConditionalType(type)]);
}
return type.resolvedDefaultConstraint;
}
function getConstraintOfDistributiveConditionalType(type: ConditionalType): Type | undefined {
// Check if we have a conditional type of the form 'T extends U ? X : Y', where T is a constrained
// type parameter. If so, create an instantiation of the conditional type where T is replaced
// with its constraint. We do this because if the constraint is a union type it will be distributed
// over the conditional type and possibly reduced. For example, 'T extends undefined ? never : T'
// removes 'undefined' from T.
if (type.root.isDistributive) {
const simplified = getSimplifiedType(type.checkType);
const constraint = simplified === type.checkType ? getConstraintOfType(simplified) : simplified;
if (constraint && constraint !== type.checkType) {
const mapper = makeUnaryTypeMapper(type.root.checkType, constraint);
const instantiated = getConditionalTypeInstantiation(type, combineTypeMappers(mapper, type.mapper));
if (!(instantiated.flags & TypeFlags.Never)) {
return instantiated;
}
}
}
return undefined;
}
function getConstraintOfConditionalType(type: ConditionalType) {
return getConstraintOfDistributiveConditionalType(type) || getDefaultConstraintOfConditionalType(type);
}
function getUnionConstraintOfIntersection(type: IntersectionType, targetIsUnion: boolean) {
let constraints: Type[] | undefined;
let hasDisjointDomainType = false;
for (const t of type.types) {
if (t.flags & TypeFlags.Instantiable) {
// We keep following constraints as long as we have an instantiable type that is known
// not to be circular or infinite (hence we stop on index access types).
let constraint = getConstraintOfType(t);
while (constraint && constraint.flags & (TypeFlags.TypeParameter | TypeFlags.Index | TypeFlags.Conditional)) {
constraint = getConstraintOfType(constraint);
}
if (constraint) {
// A constraint that isn't a union type implies that the final type would be a non-union
// type as well. Since non-union constraints are of no interest, we can exit here.
if (!(constraint.flags & TypeFlags.Union)) {
return undefined;
}
constraints = append(constraints, constraint);
}
}
else if (t.flags & TypeFlags.DisjointDomains) {
hasDisjointDomainType = true;
}
}
// If the target is a union type or if we are intersecting with types belonging to one of the
// disjoint domans, we may end up producing a constraint that hasn't been examined before.
if (constraints && (targetIsUnion || hasDisjointDomainType)) {
if (hasDisjointDomainType) {
// We add any types belong to one of the disjoint domans because they might cause the final
// intersection operation to reduce the union constraints.
for (const t of type.types) {
if (t.flags & TypeFlags.DisjointDomains) {
constraints = append(constraints, t);
}
}
}
return getIntersectionType(constraints);
}
return undefined;
}
function getBaseConstraintOfType(type: Type): Type | undefined {
if (type.flags & (TypeFlags.InstantiableNonPrimitive | TypeFlags.UnionOrIntersection)) {
const constraint = getResolvedBaseConstraint(<InstantiableType | UnionOrIntersectionType>type);
return constraint !== noConstraintType && constraint !== circularConstraintType ? constraint : undefined;
}
return type.flags & TypeFlags.Index ? keyofConstraintType : undefined;
}
/**
* This is similar to `getBaseConstraintOfType` except it returns the input type if there's no base constraint, instead of `undefined`
* It also doesn't map indexes to `string`, as where this is used this would be unneeded (and likely undesirable)
*/
function getBaseConstraintOrType(type: Type) {
return getBaseConstraintOfType(type) || type;
}
function hasNonCircularBaseConstraint(type: InstantiableType): boolean {
return getResolvedBaseConstraint(type) !== circularConstraintType;
}
/**
* Return the resolved base constraint of a type variable. The noConstraintType singleton is returned if the
* type variable has no constraint, and the circularConstraintType singleton is returned if the constraint
* circularly references the type variable.
*/
function getResolvedBaseConstraint(type: InstantiableType | UnionOrIntersectionType): Type {
let nonTerminating = false;
return type.resolvedBaseConstraint ||
(type.resolvedBaseConstraint = getTypeWithThisArgument(getImmediateBaseConstraint(type), type));
function getImmediateBaseConstraint(t: Type): Type {
if (!t.immediateBaseConstraint) {
if (!pushTypeResolution(t, TypeSystemPropertyName.ImmediateBaseConstraint)) {
return circularConstraintType;
}
if (constraintDepth === 50) {
// We have reached 50 recursive invocations of getImmediateBaseConstraint and there is a
// very high likelyhood we're dealing with an infinite generic type that perpetually generates
// new type identities as we descend into it. We stop the recursion here and mark this type
// and the outer types as having circular constraints.
error(currentNode, Diagnostics.Type_instantiation_is_excessively_deep_and_possibly_infinite);
nonTerminating = true;
return t.immediateBaseConstraint = noConstraintType;
}
constraintDepth++;
let result = computeBaseConstraint(getSimplifiedType(t));
constraintDepth--;
if (!popTypeResolution()) {
if (t.flags & TypeFlags.TypeParameter) {
const errorNode = getConstraintDeclaration(<TypeParameter>t);
if (errorNode) {
const diagnostic = error(errorNode, Diagnostics.Type_parameter_0_has_a_circular_constraint, typeToString(t));
if (currentNode && !isNodeDescendantOf(errorNode, currentNode) && !isNodeDescendantOf(currentNode, errorNode)) {
addRelatedInfo(diagnostic, createDiagnosticForNode(currentNode, Diagnostics.Circularity_originates_in_type_at_this_location));
}
}
}
result = circularConstraintType;
}
if (nonTerminating) {
result = circularConstraintType;
}
t.immediateBaseConstraint = result || noConstraintType;
}
return t.immediateBaseConstraint;
}
function getBaseConstraint(t: Type): Type | undefined {
const c = getImmediateBaseConstraint(t);
return c !== noConstraintType && c !== circularConstraintType ? c : undefined;
}
function computeBaseConstraint(t: Type): Type | undefined {
if (t.flags & TypeFlags.TypeParameter) {
const constraint = getConstraintFromTypeParameter(<TypeParameter>t);
return (t as TypeParameter).isThisType || !constraint ?
constraint :
getBaseConstraint(constraint);
}
if (t.flags & TypeFlags.UnionOrIntersection) {
const types = (<UnionOrIntersectionType>t).types;
const baseTypes: Type[] = [];
for (const type of types) {
const baseType = getBaseConstraint(type);
if (baseType) {
baseTypes.push(baseType);
}
}
return t.flags & TypeFlags.Union && baseTypes.length === types.length ? getUnionType(baseTypes) :
t.flags & TypeFlags.Intersection && baseTypes.length ? getIntersectionType(baseTypes) :
undefined;
}
if (t.flags & TypeFlags.Index) {
return keyofConstraintType;
}
if (t.flags & TypeFlags.IndexedAccess) {
const baseObjectType = getBaseConstraint((<IndexedAccessType>t).objectType);
const baseIndexType = getBaseConstraint((<IndexedAccessType>t).indexType);
const baseIndexedAccess = baseObjectType && baseIndexType ? getIndexedAccessType(baseObjectType, baseIndexType, /*accessNode*/ undefined, errorType) : undefined;
return baseIndexedAccess && baseIndexedAccess !== errorType ? getBaseConstraint(baseIndexedAccess) : undefined;
}
if (t.flags & TypeFlags.Conditional) {
const constraint = getConstraintOfConditionalType(<ConditionalType>t);
return constraint && getBaseConstraint(constraint);
}
if (t.flags & TypeFlags.Substitution) {
return getBaseConstraint((<SubstitutionType>t).substitute);
}
return t;
}
}
function getApparentTypeOfIntersectionType(type: IntersectionType) {
return type.resolvedApparentType || (type.resolvedApparentType = getTypeWithThisArgument(type, type, /*apparentType*/ true));
}
function getResolvedTypeParameterDefault(typeParameter: TypeParameter): Type | undefined {
if (!typeParameter.default) {
if (typeParameter.target) {
const targetDefault = getResolvedTypeParameterDefault(typeParameter.target);
typeParameter.default = targetDefault ? instantiateType(targetDefault, typeParameter.mapper!) : noConstraintType;
}
else {
// To block recursion, set the initial value to the resolvingDefaultType.
typeParameter.default = resolvingDefaultType;
const defaultDeclaration = typeParameter.symbol && forEach(typeParameter.symbol.declarations, decl => isTypeParameterDeclaration(decl) && decl.default);
const defaultType = defaultDeclaration ? getTypeFromTypeNode(defaultDeclaration) : noConstraintType;
if (typeParameter.default === resolvingDefaultType) {
// If we have not been called recursively, set the correct default type.
typeParameter.default = defaultType;
}
}
}
else if (typeParameter.default === resolvingDefaultType) {
// If we are called recursively for this type parameter, mark the default as circular.
typeParameter.default = circularConstraintType;
}
return typeParameter.default;
}
/**
* Gets the default type for a type parameter.
*
* If the type parameter is the result of an instantiation, this gets the instantiated
* default type of its target. If the type parameter has no default type or the default is
* circular, `undefined` is returned.
*/
function getDefaultFromTypeParameter(typeParameter: TypeParameter): Type | undefined {
const defaultType = getResolvedTypeParameterDefault(typeParameter);
return defaultType !== noConstraintType && defaultType !== circularConstraintType ? defaultType : undefined;
}
function hasNonCircularTypeParameterDefault(typeParameter: TypeParameter) {
return getResolvedTypeParameterDefault(typeParameter) !== circularConstraintType;
}
/**
* Indicates whether the declaration of a typeParameter has a default type.
*/
function hasTypeParameterDefault(typeParameter: TypeParameter): boolean {
return !!(typeParameter.symbol && forEach(typeParameter.symbol.declarations, decl => isTypeParameterDeclaration(decl) && decl.default));
}
function getApparentTypeOfMappedType(type: MappedType) {
return type.resolvedApparentType || (type.resolvedApparentType = getResolvedApparentTypeOfMappedType(type));
}
function getResolvedApparentTypeOfMappedType(type: MappedType) {
const typeVariable = getHomomorphicTypeVariable(type);
if (typeVariable) {
const constraint = getConstraintOfTypeParameter(typeVariable);
if (constraint && (isArrayType(constraint) || isTupleType(constraint))) {
const mapper = makeUnaryTypeMapper(typeVariable, constraint);
return instantiateType(type, combineTypeMappers(mapper, type.mapper));
}
}
return type;
}
/**
* For a type parameter, return the base constraint of the type parameter. For the string, number,
* boolean, and symbol primitive types, return the corresponding object types. Otherwise return the
* type itself. Note that the apparent type of a union type is the union type itself.
*/
function getApparentType(type: Type): Type {
const t = type.flags & TypeFlags.Instantiable ? getBaseConstraintOfType(type) || emptyObjectType : type;
return getObjectFlags(t) & ObjectFlags.Mapped ? getApparentTypeOfMappedType(<MappedType>t) :
t.flags & TypeFlags.Intersection ? getApparentTypeOfIntersectionType(<IntersectionType>t) :
t.flags & TypeFlags.StringLike ? globalStringType :
t.flags & TypeFlags.NumberLike ? globalNumberType :
t.flags & TypeFlags.BigIntLike ? getGlobalBigIntType(/*reportErrors*/ languageVersion >= ScriptTarget.ESNext) :
t.flags & TypeFlags.BooleanLike ? globalBooleanType :
t.flags & TypeFlags.ESSymbolLike ? getGlobalESSymbolType(/*reportErrors*/ languageVersion >= ScriptTarget.ES2015) :
t.flags & TypeFlags.NonPrimitive ? emptyObjectType :
t.flags & TypeFlags.Index ? keyofConstraintType :
t;
}
function createUnionOrIntersectionProperty(containingType: UnionOrIntersectionType, name: __String): Symbol | undefined {
let props: Symbol[] | undefined;
let indexTypes: Type[] | undefined;
const isUnion = containingType.flags & TypeFlags.Union;
const excludeModifiers = isUnion ? ModifierFlags.NonPublicAccessibilityModifier : 0;
// Flags we want to propagate to the result if they exist in all source symbols
let commonFlags = isUnion ? SymbolFlags.None : SymbolFlags.Optional;
let syntheticFlag = CheckFlags.SyntheticMethod;
let checkFlags = 0;
for (const current of containingType.types) {
const type = getApparentType(current);
if (type !== errorType) {
const prop = getPropertyOfType(type, name);
const modifiers = prop ? getDeclarationModifierFlagsFromSymbol(prop) : 0;
if (prop && !(modifiers & excludeModifiers)) {
commonFlags &= prop.flags;
props = appendIfUnique(props, prop);
checkFlags |= (isReadonlySymbol(prop) ? CheckFlags.Readonly : 0) |
(!(modifiers & ModifierFlags.NonPublicAccessibilityModifier) ? CheckFlags.ContainsPublic : 0) |
(modifiers & ModifierFlags.Protected ? CheckFlags.ContainsProtected : 0) |
(modifiers & ModifierFlags.Private ? CheckFlags.ContainsPrivate : 0) |
(modifiers & ModifierFlags.Static ? CheckFlags.ContainsStatic : 0);
if (!isPrototypeProperty(prop)) {
syntheticFlag = CheckFlags.SyntheticProperty;
}
}
else if (isUnion) {
const indexInfo = !isLateBoundName(name) && (isNumericLiteralName(name) && getIndexInfoOfType(type, IndexKind.Number) || getIndexInfoOfType(type, IndexKind.String));
if (indexInfo) {
checkFlags |= indexInfo.isReadonly ? CheckFlags.Readonly : 0;
indexTypes = append(indexTypes, isTupleType(type) ? getRestTypeOfTupleType(type) || undefinedType : indexInfo.type);
}
else {
checkFlags |= CheckFlags.Partial;
}
}
}
}
if (!props) {
return undefined;
}
if (props.length === 1 && !(checkFlags & CheckFlags.Partial) && !indexTypes) {
return props[0];
}
let declarations: Declaration[] | undefined;
let firstType: Type | undefined;
let nameType: Type | undefined;
const propTypes: Type[] = [];
let firstValueDeclaration: Declaration | undefined;
let hasNonUniformValueDeclaration = false;
for (const prop of props) {
if (!firstValueDeclaration) {
firstValueDeclaration = prop.valueDeclaration;
}
else if (prop.valueDeclaration !== firstValueDeclaration) {
hasNonUniformValueDeclaration = true;
}
declarations = addRange(declarations, prop.declarations);
const type = getTypeOfSymbol(prop);
if (!firstType) {
firstType = type;
nameType = prop.nameType;
}
else if (type !== firstType) {
checkFlags |= CheckFlags.HasNonUniformType;
}
if (isLiteralType(type)) {
checkFlags |= CheckFlags.HasLiteralType;
}
propTypes.push(type);
}
addRange(propTypes, indexTypes);
const result = createSymbol(SymbolFlags.Property | commonFlags, name, syntheticFlag | checkFlags);
result.containingType = containingType;
if (!hasNonUniformValueDeclaration && firstValueDeclaration) {
result.valueDeclaration = firstValueDeclaration;
// Inherit information about parent type.
if (firstValueDeclaration.symbol.parent) {
result.parent = firstValueDeclaration.symbol.parent;
}
}
result.declarations = declarations!;
result.nameType = nameType;
result.type = isUnion ? getUnionType(propTypes) : getIntersectionType(propTypes);
return result;
}
// Return the symbol for a given property in a union or intersection type, or undefined if the property
// does not exist in any constituent type. Note that the returned property may only be present in some
// constituents, in which case the isPartial flag is set when the containing type is union type. We need
// these partial properties when identifying discriminant properties, but otherwise they are filtered out
// and do not appear to be present in the union type.
function getUnionOrIntersectionProperty(type: UnionOrIntersectionType, name: __String): Symbol | undefined {
const properties = type.propertyCache || (type.propertyCache = createSymbolTable());
let property = properties.get(name);
if (!property) {
property = createUnionOrIntersectionProperty(type, name);
if (property) {
properties.set(name, property);
}
}
return property;
}
function getPropertyOfUnionOrIntersectionType(type: UnionOrIntersectionType, name: __String): Symbol | undefined {
const property = getUnionOrIntersectionProperty(type, name);
// We need to filter out partial properties in union types
return property && !(getCheckFlags(property) & CheckFlags.Partial) ? property : undefined;
}
/**
* Return the symbol for the property with the given name in the given type. Creates synthetic union properties when
* necessary, maps primitive types and type parameters are to their apparent types, and augments with properties from
* Object and Function as appropriate.
*
* @param type a type to look up property from
* @param name a name of property to look up in a given type
*/
function getPropertyOfType(type: Type, name: __String): Symbol | undefined {
type = getApparentType(type);
if (type.flags & TypeFlags.Object) {
const resolved = resolveStructuredTypeMembers(<ObjectType>type);
const symbol = resolved.members.get(name);
if (symbol && symbolIsValue(symbol)) {
return symbol;
}
const functionType = resolved === anyFunctionType ? globalFunctionType :
resolved.callSignatures.length ? globalCallableFunctionType :
resolved.constructSignatures.length ? globalNewableFunctionType :
undefined;
if (functionType) {
const symbol = getPropertyOfObjectType(functionType, name);
if (symbol) {
return symbol;
}
}
return getPropertyOfObjectType(globalObjectType, name);
}
if (type.flags & TypeFlags.UnionOrIntersection) {
return getPropertyOfUnionOrIntersectionType(<UnionOrIntersectionType>type, name);
}
return undefined;
}
function getSignaturesOfStructuredType(type: Type, kind: SignatureKind): ReadonlyArray<Signature> {
if (type.flags & TypeFlags.StructuredType) {
const resolved = resolveStructuredTypeMembers(<ObjectType>type);
return kind === SignatureKind.Call ? resolved.callSignatures : resolved.constructSignatures;
}
return emptyArray;
}
/**
* Return the signatures of the given kind in the given type. Creates synthetic union signatures when necessary and
* maps primitive types and type parameters are to their apparent types.
*/
function getSignaturesOfType(type: Type, kind: SignatureKind): ReadonlyArray<Signature> {
return getSignaturesOfStructuredType(getApparentType(type), kind);
}
function getIndexInfoOfStructuredType(type: Type, kind: IndexKind): IndexInfo | undefined {
if (type.flags & TypeFlags.StructuredType) {
const resolved = resolveStructuredTypeMembers(<ObjectType>type);
return kind === IndexKind.String ? resolved.stringIndexInfo : resolved.numberIndexInfo;
}
}
function getIndexTypeOfStructuredType(type: Type, kind: IndexKind): Type | undefined {
const info = getIndexInfoOfStructuredType(type, kind);
return info && info.type;
}
// Return the indexing info of the given kind in the given type. Creates synthetic union index types when necessary and
// maps primitive types and type parameters are to their apparent types.
function getIndexInfoOfType(type: Type, kind: IndexKind): IndexInfo | undefined {
return getIndexInfoOfStructuredType(getApparentType(type), kind);
}
// Return the index type of the given kind in the given type. Creates synthetic union index types when necessary and
// maps primitive types and type parameters are to their apparent types.
function getIndexTypeOfType(type: Type, kind: IndexKind): Type | undefined {
return getIndexTypeOfStructuredType(getApparentType(type), kind);
}
function getImplicitIndexTypeOfType(type: Type, kind: IndexKind): Type | undefined {
if (isObjectTypeWithInferableIndex(type)) {
const propTypes: Type[] = [];
for (const prop of getPropertiesOfType(type)) {
if (kind === IndexKind.String || isNumericLiteralName(prop.escapedName)) {
propTypes.push(getTypeOfSymbol(prop));
}
}
if (propTypes.length) {
return getUnionType(propTypes, UnionReduction.Subtype);
}
}
return undefined;
}
// Return list of type parameters with duplicates removed (duplicate identifier errors are generated in the actual
// type checking functions).
function getTypeParametersFromDeclaration(declaration: DeclarationWithTypeParameters): TypeParameter[] | undefined {
let result: TypeParameter[] | undefined;
for (const node of getEffectiveTypeParameterDeclarations(declaration)) {
result = appendIfUnique(result, getDeclaredTypeOfTypeParameter(node.symbol));
}
return result;
}
function symbolsToArray(symbols: SymbolTable): Symbol[] {
const result: Symbol[] = [];
symbols.forEach((symbol, id) => {
if (!isReservedMemberName(id)) {
result.push(symbol);
}
});
return result;
}
function isJSDocOptionalParameter(node: ParameterDeclaration) {
return isInJSFile(node) && (
// node.type should only be a JSDocOptionalType when node is a parameter of a JSDocFunctionType
node.type && node.type.kind === SyntaxKind.JSDocOptionalType
|| getJSDocParameterTags(node).some(({ isBracketed, typeExpression }) =>
isBracketed || !!typeExpression && typeExpression.type.kind === SyntaxKind.JSDocOptionalType));
}
function tryFindAmbientModule(moduleName: string, withAugmentations: boolean) {
if (isExternalModuleNameRelative(moduleName)) {
return undefined;
}
const symbol = getSymbol(globals, '"' + moduleName + '"' as __String, SymbolFlags.ValueModule);
// merged symbol is module declaration symbol combined with all augmentations
return symbol && withAugmentations ? getMergedSymbol(symbol) : symbol;
}
function isOptionalParameter(node: ParameterDeclaration | JSDocParameterTag) {
if (hasQuestionToken(node) || isOptionalJSDocParameterTag(node) || isJSDocOptionalParameter(node)) {
return true;
}
if (node.initializer) {
const signature = getSignatureFromDeclaration(node.parent);
const parameterIndex = node.parent.parameters.indexOf(node);
Debug.assert(parameterIndex >= 0);
return parameterIndex >= getMinArgumentCount(signature);
}
const iife = getImmediatelyInvokedFunctionExpression(node.parent);
if (iife) {
return !node.type &&
!node.dotDotDotToken &&
node.parent.parameters.indexOf(node) >= iife.arguments.length;
}
return false;
}
function isOptionalJSDocParameterTag(node: Node): node is JSDocParameterTag {
if (!isJSDocParameterTag(node)) {
return false;
}
const { isBracketed, typeExpression } = node;
return isBracketed || !!typeExpression && typeExpression.type.kind === SyntaxKind.JSDocOptionalType;
}
function createIdentifierTypePredicate(parameterName: string, parameterIndex: number, type: Type): IdentifierTypePredicate {
return { kind: TypePredicateKind.Identifier, parameterName, parameterIndex, type };
}
function createThisTypePredicate(type: Type): ThisTypePredicate {
return { kind: TypePredicateKind.This, type };
}
/**
* Gets the minimum number of type arguments needed to satisfy all non-optional type
* parameters.
*/
function getMinTypeArgumentCount(typeParameters: ReadonlyArray<TypeParameter> | undefined): number {
let minTypeArgumentCount = 0;
if (typeParameters) {
for (let i = 0; i < typeParameters.length; i++) {
if (!hasTypeParameterDefault(typeParameters[i])) {
minTypeArgumentCount = i + 1;
}
}
}
return minTypeArgumentCount;
}
/**
* Fill in default types for unsupplied type arguments. If `typeArguments` is undefined
* when a default type is supplied, a new array will be created and returned.
*
* @param typeArguments The supplied type arguments.
* @param typeParameters The requested type parameters.
* @param minTypeArgumentCount The minimum number of required type arguments.
*/
function fillMissingTypeArguments(typeArguments: ReadonlyArray<Type>, typeParameters: ReadonlyArray<TypeParameter> | undefined, minTypeArgumentCount: number, isJavaScriptImplicitAny: boolean): Type[];
function fillMissingTypeArguments(typeArguments: ReadonlyArray<Type> | undefined, typeParameters: ReadonlyArray<TypeParameter> | undefined, minTypeArgumentCount: number, isJavaScriptImplicitAny: boolean): Type[] | undefined;
function fillMissingTypeArguments(typeArguments: ReadonlyArray<Type> | undefined, typeParameters: ReadonlyArray<TypeParameter> | undefined, minTypeArgumentCount: number, isJavaScriptImplicitAny: boolean) {
const numTypeParameters = length(typeParameters);
if (!numTypeParameters) {
return [];
}
const numTypeArguments = length(typeArguments);
if (isJavaScriptImplicitAny || (numTypeArguments >= minTypeArgumentCount && numTypeArguments <= numTypeParameters)) {
const result = typeArguments ? typeArguments.slice() : [];
// Map invalid forward references in default types to the error type
for (let i = numTypeArguments; i < numTypeParameters; i++) {
result[i] = errorType;
}
const baseDefaultType = getDefaultTypeArgumentType(isJavaScriptImplicitAny);
for (let i = numTypeArguments; i < numTypeParameters; i++) {
let defaultType = getDefaultFromTypeParameter(typeParameters![i]);
if (isJavaScriptImplicitAny && defaultType && isTypeIdenticalTo(defaultType, emptyObjectType)) {
defaultType = anyType;
}
result[i] = defaultType ? instantiateType(defaultType, createTypeMapper(typeParameters!, result)) : baseDefaultType;
}
result.length = typeParameters!.length;
return result;
}
return typeArguments && typeArguments.slice();
}
function getSignatureFromDeclaration(declaration: SignatureDeclaration | JSDocSignature): Signature {
const links = getNodeLinks(declaration);
if (!links.resolvedSignature) {
const parameters: Symbol[] = [];
let hasLiteralTypes = false;
let minArgumentCount = 0;
let thisParameter: Symbol | undefined;
let hasThisParameter = false;
const iife = getImmediatelyInvokedFunctionExpression(declaration);
const isJSConstructSignature = isJSDocConstructSignature(declaration);
const isUntypedSignatureInJSFile = !iife &&
isInJSFile(declaration) &&
isValueSignatureDeclaration(declaration) &&
!hasJSDocParameterTags(declaration) &&
!getJSDocType(declaration);
// If this is a JSDoc construct signature, then skip the first parameter in the
// parameter list. The first parameter represents the return type of the construct
// signature.
for (let i = isJSConstructSignature ? 1 : 0; i < declaration.parameters.length; i++) {
const param = declaration.parameters[i];
let paramSymbol = param.symbol;
const type = isJSDocParameterTag(param) ? (param.typeExpression && param.typeExpression.type) : param.type;
// Include parameter symbol instead of property symbol in the signature
if (paramSymbol && !!(paramSymbol.flags & SymbolFlags.Property) && !isBindingPattern(param.name)) {
const resolvedSymbol = resolveName(param, paramSymbol.escapedName, SymbolFlags.Value, undefined, undefined, /*isUse*/ false);
paramSymbol = resolvedSymbol!;
}
if (i === 0 && paramSymbol.escapedName === InternalSymbolName.This) {
hasThisParameter = true;
thisParameter = param.symbol;
}
else {
parameters.push(paramSymbol);
}
if (type && type.kind === SyntaxKind.LiteralType) {
hasLiteralTypes = true;
}
// Record a new minimum argument count if this is not an optional parameter
const isOptionalParameter = isOptionalJSDocParameterTag(param) ||
param.initializer || param.questionToken || param.dotDotDotToken ||
iife && parameters.length > iife.arguments.length && !type ||
isUntypedSignatureInJSFile ||
isJSDocOptionalParameter(param);
if (!isOptionalParameter) {
minArgumentCount = parameters.length;
}
}
// If only one accessor includes a this-type annotation, the other behaves as if it had the same type annotation
if ((declaration.kind === SyntaxKind.GetAccessor || declaration.kind === SyntaxKind.SetAccessor) &&
!hasNonBindableDynamicName(declaration) &&
(!hasThisParameter || !thisParameter)) {
const otherKind = declaration.kind === SyntaxKind.GetAccessor ? SyntaxKind.SetAccessor : SyntaxKind.GetAccessor;
const other = getDeclarationOfKind<AccessorDeclaration>(getSymbolOfNode(declaration), otherKind);
if (other) {
thisParameter = getAnnotatedAccessorThisParameter(other);
}
}
const classType = declaration.kind === SyntaxKind.Constructor ?
getDeclaredTypeOfClassOrInterface(getMergedSymbol((<ClassDeclaration>declaration.parent).symbol))
: undefined;
const typeParameters = classType ? classType.localTypeParameters : getTypeParametersFromDeclaration(declaration);
const hasRestLikeParameter = hasRestParameter(declaration) || isInJSFile(declaration) && maybeAddJsSyntheticRestParameter(declaration, parameters);
links.resolvedSignature = createSignature(declaration, typeParameters, thisParameter, parameters,
/*resolvedReturnType*/ undefined, /*resolvedTypePredicate*/ undefined,
minArgumentCount, hasRestLikeParameter, hasLiteralTypes);
}
return links.resolvedSignature;
}
/**
* A JS function gets a synthetic rest parameter if it references `arguments` AND:
* 1. It has no parameters but at least one `@param` with a type that starts with `...`
* OR
* 2. It has at least one parameter, and the last parameter has a matching `@param` with a type that starts with `...`
*/
function maybeAddJsSyntheticRestParameter(declaration: SignatureDeclaration | JSDocSignature, parameters: Symbol[]): boolean {
if (isJSDocSignature(declaration) || !containsArgumentsReference(declaration)) {
return false;
}
const lastParam = lastOrUndefined(declaration.parameters);
const lastParamTags = lastParam ? getJSDocParameterTags(lastParam) : getJSDocTags(declaration).filter(isJSDocParameterTag);
const lastParamVariadicType = firstDefined(lastParamTags, p =>
p.typeExpression && isJSDocVariadicType(p.typeExpression.type) ? p.typeExpression.type : undefined);
const syntheticArgsSymbol = createSymbol(SymbolFlags.Variable, "args" as __String, CheckFlags.RestParameter);
syntheticArgsSymbol.type = lastParamVariadicType ? createArrayType(getTypeFromTypeNode(lastParamVariadicType.type)) : anyArrayType;
if (lastParamVariadicType) {
// Replace the last parameter with a rest parameter.
parameters.pop();
}
parameters.push(syntheticArgsSymbol);
return true;
}
function getSignatureOfTypeTag(node: SignatureDeclaration | JSDocSignature) {
const typeTag = isInJSFile(node) ? getJSDocTypeTag(node) : undefined;
const signature = typeTag && typeTag.typeExpression && getSingleCallSignature(getTypeFromTypeNode(typeTag.typeExpression));
return signature && getErasedSignature(signature);
}
function getReturnTypeOfTypeTag(node: SignatureDeclaration | JSDocSignature) {
const signature = getSignatureOfTypeTag(node);
return signature && getReturnTypeOfSignature(signature);
}
function containsArgumentsReference(declaration: SignatureDeclaration): boolean {
const links = getNodeLinks(declaration);
if (links.containsArgumentsReference === undefined) {
if (links.flags & NodeCheckFlags.CaptureArguments) {
links.containsArgumentsReference = true;
}
else {
links.containsArgumentsReference = traverse((declaration as FunctionLikeDeclaration).body!);
}
}
return links.containsArgumentsReference;
function traverse(node: Node): boolean {
if (!node) return false;
switch (node.kind) {
case SyntaxKind.Identifier:
return (<Identifier>node).escapedText === "arguments" && isExpressionNode(node);
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
return (<NamedDeclaration>node).name!.kind === SyntaxKind.ComputedPropertyName
&& traverse((<NamedDeclaration>node).name!);
default:
return !nodeStartsNewLexicalEnvironment(node) && !isPartOfTypeNode(node) && !!forEachChild(node, traverse);
}
}
}
function getSignaturesOfSymbol(symbol: Symbol | undefined): Signature[] {
if (!symbol) return emptyArray;
const result: Signature[] = [];
for (let i = 0; i < symbol.declarations.length; i++) {
const decl = symbol.declarations[i];
if (!isFunctionLike(decl)) continue;
// Don't include signature if node is the implementation of an overloaded function. A node is considered
// an implementation node if it has a body and the previous node is of the same kind and immediately
// precedes the implementation node (i.e. has the same parent and ends where the implementation starts).
if (i > 0 && (decl as FunctionLikeDeclaration).body) {
const previous = symbol.declarations[i - 1];
if (decl.parent === previous.parent && decl.kind === previous.kind && decl.pos === previous.end) {
continue;
}
}
result.push(getSignatureFromDeclaration(decl));
}
return result;
}
function resolveExternalModuleTypeByLiteral(name: StringLiteral) {
const moduleSym = resolveExternalModuleName(name, name);
if (moduleSym) {
const resolvedModuleSymbol = resolveExternalModuleSymbol(moduleSym);
if (resolvedModuleSymbol) {
return getTypeOfSymbol(resolvedModuleSymbol);
}
}
return anyType;
}
function getThisTypeOfSignature(signature: Signature): Type | undefined {
if (signature.thisParameter) {
return getTypeOfSymbol(signature.thisParameter);
}
}
function signatureHasTypePredicate(signature: Signature): boolean {
return getTypePredicateOfSignature(signature) !== undefined;
}
function getTypePredicateOfSignature(signature: Signature): TypePredicate | undefined {
if (!signature.resolvedTypePredicate) {
if (signature.target) {
const targetTypePredicate = getTypePredicateOfSignature(signature.target);
signature.resolvedTypePredicate = targetTypePredicate ? instantiateTypePredicate(targetTypePredicate, signature.mapper!) : noTypePredicate;
}
else if (signature.unionSignatures) {
signature.resolvedTypePredicate = getUnionTypePredicate(signature.unionSignatures) || noTypePredicate;
}
else {
const type = signature.declaration && getEffectiveReturnTypeNode(signature.declaration);
let jsdocPredicate: TypePredicate | undefined;
if (!type && isInJSFile(signature.declaration)) {
const jsdocSignature = getSignatureOfTypeTag(signature.declaration!);
if (jsdocSignature && signature !== jsdocSignature) {
jsdocPredicate = getTypePredicateOfSignature(jsdocSignature);
}
}
signature.resolvedTypePredicate = type && isTypePredicateNode(type) ?
createTypePredicateFromTypePredicateNode(type, signature.declaration!) :
jsdocPredicate || noTypePredicate;
}
Debug.assert(!!signature.resolvedTypePredicate);
}
return signature.resolvedTypePredicate === noTypePredicate ? undefined : signature.resolvedTypePredicate;
}
function createTypePredicateFromTypePredicateNode(node: TypePredicateNode, func: SignatureDeclaration | JSDocSignature): IdentifierTypePredicate | ThisTypePredicate {
const { parameterName } = node;
const type = getTypeFromTypeNode(node.type);
if (parameterName.kind === SyntaxKind.Identifier) {
return createIdentifierTypePredicate(
parameterName.escapedText as string,
getTypePredicateParameterIndex(func.parameters, parameterName),
type);
}
else {
return createThisTypePredicate(type);
}
}
function getTypePredicateParameterIndex(parameterList: ReadonlyArray<ParameterDeclaration | JSDocParameterTag>, parameter: Identifier): number {
for (let i = 0; i < parameterList.length; i++) {
const param = parameterList[i];
if (param.name.kind === SyntaxKind.Identifier && param.name.escapedText === parameter.escapedText) {
return i;
}
}
return -1;
}
function getReturnTypeOfSignature(signature: Signature): Type {
if (!signature.resolvedReturnType) {
if (!pushTypeResolution(signature, TypeSystemPropertyName.ResolvedReturnType)) {
return errorType;
}
let type = signature.target ? instantiateType(getReturnTypeOfSignature(signature.target), signature.mapper!) :
signature.unionSignatures ? getUnionType(map(signature.unionSignatures, getReturnTypeOfSignature), UnionReduction.Subtype) :
getReturnTypeFromAnnotation(signature.declaration!) ||
isJSConstructor(signature.declaration) && getJSClassType(getSymbolOfNode(signature.declaration!)) ||
(nodeIsMissing((<FunctionLikeDeclaration>signature.declaration).body) ? anyType : getReturnTypeFromBody(<FunctionLikeDeclaration>signature.declaration));
if (!popTypeResolution()) {
if (signature.declaration) {
const typeNode = getEffectiveReturnTypeNode(signature.declaration);
if (typeNode) {
error(typeNode, Diagnostics.Return_type_annotation_circularly_references_itself);
}
else if (noImplicitAny) {
const declaration = <Declaration>signature.declaration;
const name = getNameOfDeclaration(declaration);
if (name) {
error(name, Diagnostics._0_implicitly_has_return_type_any_because_it_does_not_have_a_return_type_annotation_and_is_referenced_directly_or_indirectly_in_one_of_its_return_expressions, declarationNameToString(name));
}
else {
error(declaration, Diagnostics.Function_implicitly_has_return_type_any_because_it_does_not_have_a_return_type_annotation_and_is_referenced_directly_or_indirectly_in_one_of_its_return_expressions);
}
}
}
type = anyType;
}
signature.resolvedReturnType = type;
}
return signature.resolvedReturnType;
}
function getReturnTypeFromAnnotation(declaration: SignatureDeclaration | JSDocSignature) {
if (declaration.kind === SyntaxKind.Constructor) {
return getDeclaredTypeOfClassOrInterface(getMergedSymbol((<ClassDeclaration>declaration.parent).symbol));
}
if (isJSDocConstructSignature(declaration)) {
return getTypeFromTypeNode((declaration.parameters[0] as ParameterDeclaration).type!); // TODO: GH#18217
}
const typeNode = getEffectiveReturnTypeNode(declaration);
if (typeNode) {
return getTypeFromTypeNode(typeNode);
}
if (declaration.kind === SyntaxKind.GetAccessor && !hasNonBindableDynamicName(declaration)) {
const jsDocType = isInJSFile(declaration) && getTypeForDeclarationFromJSDocComment(declaration);
if (jsDocType) {
return jsDocType;
}
const setter = getDeclarationOfKind<AccessorDeclaration>(getSymbolOfNode(declaration), SyntaxKind.SetAccessor);
const setterType = getAnnotatedAccessorType(setter);
if (setterType) {
return setterType;
}
}
return getReturnTypeOfTypeTag(declaration);
}
function isResolvingReturnTypeOfSignature(signature: Signature) {
return !signature.resolvedReturnType && findResolutionCycleStartIndex(signature, TypeSystemPropertyName.ResolvedReturnType) >= 0;
}
function getRestTypeOfSignature(signature: Signature): Type {
return tryGetRestTypeOfSignature(signature) || anyType;
}
function tryGetRestTypeOfSignature(signature: Signature): Type | undefined {
if (signature.hasRestParameter) {
const sigRestType = getTypeOfSymbol(signature.parameters[signature.parameters.length - 1]);
const restType = isTupleType(sigRestType) ? getRestTypeOfTupleType(sigRestType) : sigRestType;
return restType && getIndexTypeOfType(restType, IndexKind.Number);
}
return undefined;
}
function getSignatureInstantiation(signature: Signature, typeArguments: Type[] | undefined, isJavascript: boolean, inferredTypeParameters?: ReadonlyArray<TypeParameter>): Signature {
const instantiatedSignature = getSignatureInstantiationWithoutFillingInTypeArguments(signature, fillMissingTypeArguments(typeArguments, signature.typeParameters, getMinTypeArgumentCount(signature.typeParameters), isJavascript));
if (inferredTypeParameters) {
const returnSignature = getSingleCallSignature(getReturnTypeOfSignature(instantiatedSignature));
if (returnSignature) {
const newReturnSignature = cloneSignature(returnSignature);
newReturnSignature.typeParameters = inferredTypeParameters;
newReturnSignature.target = returnSignature.target;
newReturnSignature.mapper = returnSignature.mapper;
const newInstantiatedSignature = cloneSignature(instantiatedSignature);
newInstantiatedSignature.resolvedReturnType = getOrCreateTypeFromSignature(newReturnSignature);
return newInstantiatedSignature;
}
}
return instantiatedSignature;
}
function getSignatureInstantiationWithoutFillingInTypeArguments(signature: Signature, typeArguments: ReadonlyArray<Type> | undefined): Signature {
const instantiations = signature.instantiations || (signature.instantiations = createMap<Signature>());
const id = getTypeListId(typeArguments);
let instantiation = instantiations.get(id);
if (!instantiation) {
instantiations.set(id, instantiation = createSignatureInstantiation(signature, typeArguments));
}
return instantiation;
}
function createSignatureInstantiation(signature: Signature, typeArguments: ReadonlyArray<Type> | undefined): Signature {
return instantiateSignature(signature, createSignatureTypeMapper(signature, typeArguments), /*eraseTypeParameters*/ true);
}
function createSignatureTypeMapper(signature: Signature, typeArguments: ReadonlyArray<Type> | undefined): TypeMapper {
return createTypeMapper(signature.typeParameters!, typeArguments);
}
function getErasedSignature(signature: Signature): Signature {
return signature.typeParameters ?
signature.erasedSignatureCache || (signature.erasedSignatureCache = createErasedSignature(signature)) :
signature;
}
function createErasedSignature(signature: Signature) {
// Create an instantiation of the signature where all type arguments are the any type.
return instantiateSignature(signature, createTypeEraser(signature.typeParameters!), /*eraseTypeParameters*/ true);
}
function getCanonicalSignature(signature: Signature): Signature {
return signature.typeParameters ?
signature.canonicalSignatureCache || (signature.canonicalSignatureCache = createCanonicalSignature(signature)) :
signature;
}
function createCanonicalSignature(signature: Signature) {
// Create an instantiation of the signature where each unconstrained type parameter is replaced with
// its original. When a generic class or interface is instantiated, each generic method in the class or
// interface is instantiated with a fresh set of cloned type parameters (which we need to handle scenarios
// where different generations of the same type parameter are in scope). This leads to a lot of new type
// identities, and potentially a lot of work comparing those identities, so here we create an instantiation
// that uses the original type identities for all unconstrained type parameters.
return getSignatureInstantiation(
signature,
map(signature.typeParameters, tp => tp.target && !getConstraintOfTypeParameter(tp.target) ? tp.target : tp),
isInJSFile(signature.declaration));
}
function getBaseSignature(signature: Signature) {
const typeParameters = signature.typeParameters;
if (typeParameters) {
const typeEraser = createTypeEraser(typeParameters);
const baseConstraints = map(typeParameters, tp => instantiateType(getBaseConstraintOfType(tp), typeEraser) || emptyObjectType);
return instantiateSignature(signature, createTypeMapper(typeParameters, baseConstraints), /*eraseTypeParameters*/ true);
}
return signature;
}
function getOrCreateTypeFromSignature(signature: Signature): ObjectType {
// There are two ways to declare a construct signature, one is by declaring a class constructor
// using the constructor keyword, and the other is declaring a bare construct signature in an
// object type literal or interface (using the new keyword). Each way of declaring a constructor
// will result in a different declaration kind.
if (!signature.isolatedSignatureType) {
const isConstructor = signature.declaration!.kind === SyntaxKind.Constructor || signature.declaration!.kind === SyntaxKind.ConstructSignature; // TODO: GH#18217
const type = createObjectType(ObjectFlags.Anonymous);
type.members = emptySymbols;
type.properties = emptyArray;
type.callSignatures = !isConstructor ? [signature] : emptyArray;
type.constructSignatures = isConstructor ? [signature] : emptyArray;
signature.isolatedSignatureType = type;
}
return signature.isolatedSignatureType;
}
function getIndexSymbol(symbol: Symbol): Symbol | undefined {
return symbol.members!.get(InternalSymbolName.Index);
}
function getIndexDeclarationOfSymbol(symbol: Symbol, kind: IndexKind): IndexSignatureDeclaration | undefined {
const syntaxKind = kind === IndexKind.Number ? SyntaxKind.NumberKeyword : SyntaxKind.StringKeyword;
const indexSymbol = getIndexSymbol(symbol);
if (indexSymbol) {
for (const decl of indexSymbol.declarations) {
const node = cast(decl, isIndexSignatureDeclaration);
if (node.parameters.length === 1) {
const parameter = node.parameters[0];
if (parameter.type && parameter.type.kind === syntaxKind) {
return node;
}
}
}
}
return undefined;
}
function createIndexInfo(type: Type, isReadonly: boolean, declaration?: IndexSignatureDeclaration): IndexInfo {
return { type, isReadonly, declaration };
}
function getIndexInfoOfSymbol(symbol: Symbol, kind: IndexKind): IndexInfo | undefined {
const declaration = getIndexDeclarationOfSymbol(symbol, kind);
if (declaration) {
return createIndexInfo(declaration.type ? getTypeFromTypeNode(declaration.type) : anyType,
hasModifier(declaration, ModifierFlags.Readonly), declaration);
}
return undefined;
}
function getConstraintDeclaration(type: TypeParameter) {
const decl = type.symbol && getDeclarationOfKind<TypeParameterDeclaration>(type.symbol, SyntaxKind.TypeParameter);
return decl && getEffectiveConstraintOfTypeParameter(decl);
}
function getInferredTypeParameterConstraint(typeParameter: TypeParameter) {
let inferences: Type[] | undefined;
if (typeParameter.symbol) {
for (const declaration of typeParameter.symbol.declarations) {
if (declaration.parent.kind === SyntaxKind.InferType) {
// When an 'infer T' declaration is immediately contained in a type reference node
// (such as 'Foo<infer T>'), T's constraint is inferred from the constraint of the
// corresponding type parameter in 'Foo'. When multiple 'infer T' declarations are
// present, we form an intersection of the inferred constraint types.
const grandParent = declaration.parent.parent;
if (grandParent.kind === SyntaxKind.TypeReference) {
const typeReference = <TypeReferenceNode>grandParent;
const typeParameters = getTypeParametersForTypeReference(typeReference);
if (typeParameters) {
const index = typeReference.typeArguments!.indexOf(<TypeNode>declaration.parent);
if (index < typeParameters.length) {
const declaredConstraint = getConstraintOfTypeParameter(typeParameters[index]);
if (declaredConstraint) {
// Type parameter constraints can reference other type parameters so
// constraints need to be instantiated. If instantiation produces the
// type parameter itself, we discard that inference. For example, in
// type Foo<T extends string, U extends T> = [T, U];
// type Bar<T> = T extends Foo<infer X, infer X> ? Foo<X, X> : T;
// the instantiated constraint for U is X, so we discard that inference.
const mapper = createTypeMapper(typeParameters, getEffectiveTypeArguments(typeReference, typeParameters));
const constraint = instantiateType(declaredConstraint, mapper);
if (constraint !== typeParameter) {
inferences = append(inferences, constraint);
}
}
}
}
}
// When an 'infer T' declaration is immediately contained in a rest parameter
// declaration, we infer an 'unknown[]' constraint.
else if (grandParent.kind === SyntaxKind.Parameter && (<ParameterDeclaration>grandParent).dotDotDotToken) {
inferences = append(inferences, createArrayType(unknownType));
}
}
}
}
return inferences && getIntersectionType(inferences);
}
/** This is a worker function. Use getConstraintOfTypeParameter which guards against circular constraints. */
function getConstraintFromTypeParameter(typeParameter: TypeParameter): Type | undefined {
if (!typeParameter.constraint) {
if (typeParameter.target) {
const targetConstraint = getConstraintOfTypeParameter(typeParameter.target);
typeParameter.constraint = targetConstraint ? instantiateType(targetConstraint, typeParameter.mapper!) : noConstraintType;
}
else {
const constraintDeclaration = getConstraintDeclaration(typeParameter);
typeParameter.constraint = constraintDeclaration ? getTypeFromTypeNode(constraintDeclaration) :
getInferredTypeParameterConstraint(typeParameter) || noConstraintType;
}
}
return typeParameter.constraint === noConstraintType ? undefined : typeParameter.constraint;
}
function getParentSymbolOfTypeParameter(typeParameter: TypeParameter): Symbol | undefined {
const tp = getDeclarationOfKind<TypeParameterDeclaration>(typeParameter.symbol, SyntaxKind.TypeParameter)!;
const host = isJSDocTemplateTag(tp.parent) ? getHostSignatureFromJSDoc(tp.parent) : tp.parent;
return host && getSymbolOfNode(host);
}
function getTypeListId(types: ReadonlyArray<Type> | undefined) {
let result = "";
if (types) {
const length = types.length;
let i = 0;
while (i < length) {
const startId = types[i].id;
let count = 1;
while (i + count < length && types[i + count].id === startId + count) {
count++;
}
if (result.length) {
result += ",";
}
result += startId;
if (count > 1) {
result += ":" + count;
}
i += count;
}
}
return result;
}
// This function is used to propagate certain flags when creating new object type references and union types.
// It is only necessary to do so if a constituent type might be the undefined type, the null type, the type
// of an object literal or the anyFunctionType. This is because there are operations in the type checker
// that care about the presence of such types at arbitrary depth in a containing type.
function getPropagatingFlagsOfTypes(types: ReadonlyArray<Type>, excludeKinds: TypeFlags): ObjectFlags {
let result: ObjectFlags = 0;
for (const type of types) {
if (!(type.flags & excludeKinds)) {
result |= getObjectFlags(type);
}
}
return result & ObjectFlags.PropagatingFlags;
}
function createTypeReference(target: GenericType, typeArguments: ReadonlyArray<Type> | undefined): TypeReference {
const id = getTypeListId(typeArguments);
let type = target.instantiations.get(id);
if (!type) {
type = <TypeReference>createObjectType(ObjectFlags.Reference, target.symbol);
target.instantiations.set(id, type);
type.objectFlags |= typeArguments ? getPropagatingFlagsOfTypes(typeArguments, /*excludeKinds*/ 0) : 0;
type.target = target;
type.typeArguments = typeArguments;
}
return type;
}
function cloneTypeReference(source: TypeReference): TypeReference {
const type = <TypeReference>createType(source.flags);
type.symbol = source.symbol;
type.objectFlags = source.objectFlags;
type.target = source.target;
type.typeArguments = source.typeArguments;
return type;
}
function getTypeReferenceArity(type: TypeReference): number {
return length(type.target.typeParameters);
}
/**
* Get type from type-reference that reference to class or interface
*/
function getTypeFromClassOrInterfaceReference(node: NodeWithTypeArguments, symbol: Symbol, typeArgs: Type[] | undefined): Type {
const type = <InterfaceType>getDeclaredTypeOfSymbol(getMergedSymbol(symbol));
const typeParameters = type.localTypeParameters;
if (typeParameters) {
const numTypeArguments = length(node.typeArguments);
const minTypeArgumentCount = getMinTypeArgumentCount(typeParameters);
const isJs = isInJSFile(node);
const isJsImplicitAny = !noImplicitAny && isJs;
if (!isJsImplicitAny && (numTypeArguments < minTypeArgumentCount || numTypeArguments > typeParameters.length)) {
const missingAugmentsTag = isJs && isExpressionWithTypeArguments(node) && !isJSDocAugmentsTag(node.parent);
const diag = minTypeArgumentCount === typeParameters.length
? missingAugmentsTag
? Diagnostics.Expected_0_type_arguments_provide_these_with_an_extends_tag
: Diagnostics.Generic_type_0_requires_1_type_argument_s
: missingAugmentsTag
? Diagnostics.Expected_0_1_type_arguments_provide_these_with_an_extends_tag
: Diagnostics.Generic_type_0_requires_between_1_and_2_type_arguments;
const typeStr = typeToString(type, /*enclosingDeclaration*/ undefined, TypeFormatFlags.WriteArrayAsGenericType);
error(node, diag, typeStr, minTypeArgumentCount, typeParameters.length);
if (!isJs) {
// TODO: Adopt same permissive behavior in TS as in JS to reduce follow-on editing experience failures (requires editing fillMissingTypeArguments)
return errorType;
}
}
// In a type reference, the outer type parameters of the referenced class or interface are automatically
// supplied as type arguments and the type reference only specifies arguments for the local type parameters
// of the class or interface.
const typeArguments = concatenate(type.outerTypeParameters, fillMissingTypeArguments(typeArgs, typeParameters, minTypeArgumentCount, isJs));
return createTypeReference(<GenericType>type, typeArguments);
}
return checkNoTypeArguments(node, symbol) ? type : errorType;
}
function getTypeAliasInstantiation(symbol: Symbol, typeArguments: ReadonlyArray<Type> | undefined): Type {
const type = getDeclaredTypeOfSymbol(symbol);
const links = getSymbolLinks(symbol);
const typeParameters = links.typeParameters!;
const id = getTypeListId(typeArguments);
let instantiation = links.instantiations!.get(id);
if (!instantiation) {
links.instantiations!.set(id, instantiation = instantiateType(type, createTypeMapper(typeParameters, fillMissingTypeArguments(typeArguments, typeParameters, getMinTypeArgumentCount(typeParameters), isInJSFile(symbol.valueDeclaration)))));
}
return instantiation;
}
/**
* Get type from reference to type alias. When a type alias is generic, the declared type of the type alias may include
* references to the type parameters of the alias. We replace those with the actual type arguments by instantiating the
* declared type. Instantiations are cached using the type identities of the type arguments as the key.
*/
function getTypeFromTypeAliasReference(node: NodeWithTypeArguments, symbol: Symbol, typeArguments: Type[] | undefined): Type {
const type = getDeclaredTypeOfSymbol(symbol);
const typeParameters = getSymbolLinks(symbol).typeParameters;
if (typeParameters) {
const numTypeArguments = length(node.typeArguments);
const minTypeArgumentCount = getMinTypeArgumentCount(typeParameters);
if (numTypeArguments < minTypeArgumentCount || numTypeArguments > typeParameters.length) {
error(node,
minTypeArgumentCount === typeParameters.length
? Diagnostics.Generic_type_0_requires_1_type_argument_s
: Diagnostics.Generic_type_0_requires_between_1_and_2_type_arguments,
symbolToString(symbol),
minTypeArgumentCount,
typeParameters.length);
return errorType;
}
return getTypeAliasInstantiation(symbol, typeArguments);
}
return checkNoTypeArguments(node, symbol) ? type : errorType;
}
function getTypeReferenceName(node: TypeReferenceType): EntityNameOrEntityNameExpression | undefined {
switch (node.kind) {
case SyntaxKind.TypeReference:
return node.typeName;
case SyntaxKind.ExpressionWithTypeArguments:
// We only support expressions that are simple qualified names. For other
// expressions this produces undefined.
const expr = node.expression;
if (isEntityNameExpression(expr)) {
return expr;
}
// fall through;
}
return undefined;
}
function resolveTypeReferenceName(typeReferenceName: EntityNameExpression | EntityName | undefined, meaning: SymbolFlags) {
if (!typeReferenceName) {
return unknownSymbol;
}
return resolveEntityName(typeReferenceName, meaning) || unknownSymbol;
}
function getTypeReferenceType(node: NodeWithTypeArguments, symbol: Symbol): Type {
const typeArguments = typeArgumentsFromTypeReferenceNode(node); // Do unconditionally so we mark type arguments as referenced.
if (symbol === unknownSymbol) {
return errorType;
}
const type = getTypeReferenceTypeWorker(node, symbol, typeArguments);
if (type) {
return type;
}
// JS enums are 'string' or 'number', not an enum type.
const enumTag = isInJSFile(node) && symbol.valueDeclaration && getJSDocEnumTag(symbol.valueDeclaration);
if (enumTag) {
const links = getNodeLinks(enumTag);
if (!pushTypeResolution(enumTag, TypeSystemPropertyName.EnumTagType)) {
return errorType;
}
let type = enumTag.typeExpression ? getTypeFromTypeNode(enumTag.typeExpression) : errorType;
if (!popTypeResolution()) {
type = errorType;
error(node, Diagnostics.Enum_type_0_circularly_references_itself, symbolToString(symbol));
}
return (links.resolvedEnumType = type);
}
// Get type from reference to named type that cannot be generic (enum or type parameter)
const res = tryGetDeclaredTypeOfSymbol(symbol);
if (res) {
return checkNoTypeArguments(node, symbol) ?
res.flags & TypeFlags.TypeParameter ? getConstrainedTypeVariable(<TypeParameter>res, node) : getRegularTypeOfLiteralType(res) :
errorType;
}
if (!(symbol.flags & SymbolFlags.Value && isJSDocTypeReference(node))) {
return errorType;
}
const jsdocType = getJSDocTypeReference(node, symbol, typeArguments);
if (jsdocType) {
return jsdocType;
}
// Resolve the type reference as a Type for the purpose of reporting errors.
resolveTypeReferenceName(getTypeReferenceName(node), SymbolFlags.Type);
return getTypeOfSymbol(symbol);
}
/**
* A jsdoc TypeReference may have resolved to a value (as opposed to a type). If
* the symbol is a constructor function, return the inferred class type; otherwise,
* the type of this reference is just the type of the value we resolved to.
*/
function getJSDocTypeReference(node: NodeWithTypeArguments, symbol: Symbol, typeArguments: Type[] | undefined): Type | undefined {
// In the case of an assignment of a function expression (binary expressions, variable declarations, etc.), we will get the
// correct instance type for the symbol on the LHS by finding the type for RHS. For example if we want to get the type of the symbol `foo`:
// var foo = function() {}
// We will find the static type of the assigned anonymous function.
const staticType = getTypeOfSymbol(symbol);
const instanceType =
staticType.symbol &&
staticType.symbol !== symbol && // Make sure this is an assignment like expression by checking that symbol -> type -> symbol doesn't roundtrips.
getTypeReferenceTypeWorker(node, staticType.symbol, typeArguments); // Get the instance type of the RHS symbol.
if (instanceType) {
return getSymbolLinks(symbol).resolvedJSDocType = instanceType;
}
}
function getTypeReferenceTypeWorker(node: NodeWithTypeArguments, symbol: Symbol, typeArguments: Type[] | undefined): Type | undefined {
if (symbol.flags & (SymbolFlags.Class | SymbolFlags.Interface)) {
if (symbol.valueDeclaration && isBinaryExpression(symbol.valueDeclaration.parent)) {
const jsdocType = getJSDocTypeReference(node, symbol, typeArguments);
if (jsdocType) {
return jsdocType;
}
}
return getTypeFromClassOrInterfaceReference(node, symbol, typeArguments);
}
if (symbol.flags & SymbolFlags.TypeAlias) {
return getTypeFromTypeAliasReference(node, symbol, typeArguments);
}
if (symbol.flags & SymbolFlags.Function &&
isJSDocTypeReference(node) &&
isJSConstructor(symbol.valueDeclaration)) {
const resolved = resolveStructuredTypeMembers(<ObjectType>getTypeOfSymbol(symbol));
if (resolved.callSignatures.length === 1) {
return getReturnTypeOfSignature(resolved.callSignatures[0]);
}
}
}
function getSubstitutionType(typeVariable: TypeVariable, substitute: Type) {
const result = <SubstitutionType>createType(TypeFlags.Substitution);
result.typeVariable = typeVariable;
result.substitute = substitute;
return result;
}
function isUnaryTupleTypeNode(node: TypeNode) {
return node.kind === SyntaxKind.TupleType && (<TupleTypeNode>node).elementTypes.length === 1;
}
function getImpliedConstraint(typeVariable: TypeVariable, checkNode: TypeNode, extendsNode: TypeNode): Type | undefined {
return isUnaryTupleTypeNode(checkNode) && isUnaryTupleTypeNode(extendsNode) ? getImpliedConstraint(typeVariable, (<TupleTypeNode>checkNode).elementTypes[0], (<TupleTypeNode>extendsNode).elementTypes[0]) :
getActualTypeVariable(getTypeFromTypeNode(checkNode)) === typeVariable ? getTypeFromTypeNode(extendsNode) :
undefined;
}
function getConstrainedTypeVariable(typeVariable: TypeVariable, node: Node) {
let constraints: Type[] | undefined;
while (node && !isStatement(node) && node.kind !== SyntaxKind.JSDocComment) {
const parent = node.parent;
if (parent.kind === SyntaxKind.ConditionalType && node === (<ConditionalTypeNode>parent).trueType) {
const constraint = getImpliedConstraint(typeVariable, (<ConditionalTypeNode>parent).checkType, (<ConditionalTypeNode>parent).extendsType);
if (constraint) {
constraints = append(constraints, constraint);
}
}
node = parent;
}
return constraints ? getSubstitutionType(typeVariable, getIntersectionType(append(constraints, typeVariable))) : typeVariable;
}
function isJSDocTypeReference(node: Node): node is TypeReferenceNode {
return !!(node.flags & NodeFlags.JSDoc) && (node.kind === SyntaxKind.TypeReference || node.kind === SyntaxKind.ImportType);
}
function checkNoTypeArguments(node: NodeWithTypeArguments, symbol?: Symbol) {
if (node.typeArguments) {
error(node, Diagnostics.Type_0_is_not_generic, symbol ? symbolToString(symbol) : (<TypeReferenceNode>node).typeName ? declarationNameToString((<TypeReferenceNode>node).typeName) : "(anonymous)");
return false;
}
return true;
}
function getIntendedTypeFromJSDocTypeReference(node: TypeReferenceNode): Type | undefined {
if (isIdentifier(node.typeName)) {
const typeArgs = node.typeArguments;
switch (node.typeName.escapedText) {
case "String":
checkNoTypeArguments(node);
return stringType;
case "Number":
checkNoTypeArguments(node);
return numberType;
case "Boolean":
checkNoTypeArguments(node);
return booleanType;
case "Void":
checkNoTypeArguments(node);
return voidType;
case "Undefined":
checkNoTypeArguments(node);
return undefinedType;
case "Null":
checkNoTypeArguments(node);
return nullType;
case "Function":
case "function":
checkNoTypeArguments(node);
return globalFunctionType;
case "Array":
case "array":
return !typeArgs || !typeArgs.length ? anyArrayType : undefined;
case "Promise":
case "promise":
return !typeArgs || !typeArgs.length ? createPromiseType(anyType) : undefined;
case "Object":
if (typeArgs && typeArgs.length === 2) {
if (isJSDocIndexSignature(node)) {
const indexed = getTypeFromTypeNode(typeArgs[0]);
const target = getTypeFromTypeNode(typeArgs[1]);
const index = createIndexInfo(target, /*isReadonly*/ false);
return createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, indexed === stringType ? index : undefined, indexed === numberType ? index : undefined);
}
return anyType;
}
checkNoTypeArguments(node);
return anyType;
}
}
}
function getTypeFromJSDocNullableTypeNode(node: JSDocNullableType) {
const type = getTypeFromTypeNode(node.type);
return strictNullChecks ? getNullableType(type, TypeFlags.Null) : type;
}
function getTypeFromTypeReference(node: TypeReferenceType): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
let symbol: Symbol | undefined;
let type: Type | undefined;
let meaning = SymbolFlags.Type;
if (isJSDocTypeReference(node)) {
type = getIntendedTypeFromJSDocTypeReference(node);
meaning |= SymbolFlags.Value;
}
if (!type) {
symbol = resolveTypeReferenceName(getTypeReferenceName(node), meaning);
type = getTypeReferenceType(node, symbol);
}
// Cache both the resolved symbol and the resolved type. The resolved symbol is needed when we check the
// type reference in checkTypeReferenceNode.
links.resolvedSymbol = symbol;
links.resolvedType = type;
}
return links.resolvedType;
}
function typeArgumentsFromTypeReferenceNode(node: NodeWithTypeArguments): Type[] | undefined {
return map(node.typeArguments, getTypeFromTypeNode);
}
function getTypeFromTypeQueryNode(node: TypeQueryNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
// TypeScript 1.0 spec (April 2014): 3.6.3
// The expression is processed as an identifier expression (section 4.3)
// or property access expression(section 4.10),
// the widened type(section 3.9) of which becomes the result.
links.resolvedType = getRegularTypeOfLiteralType(getWidenedType(checkExpression(node.exprName)));
}
return links.resolvedType;
}
function getTypeOfGlobalSymbol(symbol: Symbol | undefined, arity: number): ObjectType {
function getTypeDeclaration(symbol: Symbol): Declaration | undefined {
const declarations = symbol.declarations;
for (const declaration of declarations) {
switch (declaration.kind) {
case SyntaxKind.ClassDeclaration:
case SyntaxKind.InterfaceDeclaration:
case SyntaxKind.EnumDeclaration:
return declaration;
}
}
}
if (!symbol) {
return arity ? emptyGenericType : emptyObjectType;
}
const type = getDeclaredTypeOfSymbol(symbol);
if (!(type.flags & TypeFlags.Object)) {
error(getTypeDeclaration(symbol), Diagnostics.Global_type_0_must_be_a_class_or_interface_type, symbolName(symbol));
return arity ? emptyGenericType : emptyObjectType;
}
if (length((<InterfaceType>type).typeParameters) !== arity) {
error(getTypeDeclaration(symbol), Diagnostics.Global_type_0_must_have_1_type_parameter_s, symbolName(symbol), arity);
return arity ? emptyGenericType : emptyObjectType;
}
return <ObjectType>type;
}
function getGlobalValueSymbol(name: __String, reportErrors: boolean): Symbol | undefined {
return getGlobalSymbol(name, SymbolFlags.Value, reportErrors ? Diagnostics.Cannot_find_global_value_0 : undefined);
}
function getGlobalTypeSymbol(name: __String, reportErrors: boolean): Symbol | undefined {
return getGlobalSymbol(name, SymbolFlags.Type, reportErrors ? Diagnostics.Cannot_find_global_type_0 : undefined);
}
function getGlobalSymbol(name: __String, meaning: SymbolFlags, diagnostic: DiagnosticMessage | undefined): Symbol | undefined {
// Don't track references for global symbols anyway, so value if `isReference` is arbitrary
return resolveName(undefined, name, meaning, diagnostic, name, /*isUse*/ false);
}
function getGlobalType(name: __String, arity: 0, reportErrors: boolean): ObjectType;
function getGlobalType(name: __String, arity: number, reportErrors: boolean): GenericType;
function getGlobalType(name: __String, arity: number, reportErrors: boolean): ObjectType | undefined {
const symbol = getGlobalTypeSymbol(name, reportErrors);
return symbol || reportErrors ? getTypeOfGlobalSymbol(symbol, arity) : undefined;
}
function getGlobalTypedPropertyDescriptorType() {
return deferredGlobalTypedPropertyDescriptorType || (deferredGlobalTypedPropertyDescriptorType = getGlobalType("TypedPropertyDescriptor" as __String, /*arity*/ 1, /*reportErrors*/ true)) || emptyGenericType;
}
function getGlobalTemplateStringsArrayType() {
return deferredGlobalTemplateStringsArrayType || (deferredGlobalTemplateStringsArrayType = getGlobalType("TemplateStringsArray" as __String, /*arity*/ 0, /*reportErrors*/ true)) || emptyObjectType;
}
function getGlobalImportMetaType() {
return deferredGlobalImportMetaType || (deferredGlobalImportMetaType = getGlobalType("ImportMeta" as __String, /*arity*/ 0, /*reportErrors*/ true)) || emptyObjectType;
}
function getGlobalESSymbolConstructorSymbol(reportErrors: boolean) {
return deferredGlobalESSymbolConstructorSymbol || (deferredGlobalESSymbolConstructorSymbol = getGlobalValueSymbol("Symbol" as __String, reportErrors));
}
function getGlobalESSymbolType(reportErrors: boolean) {
return deferredGlobalESSymbolType || (deferredGlobalESSymbolType = getGlobalType("Symbol" as __String, /*arity*/ 0, reportErrors)) || emptyObjectType;
}
function getGlobalPromiseType(reportErrors: boolean) {
return deferredGlobalPromiseType || (deferredGlobalPromiseType = getGlobalType("Promise" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType;
}
function getGlobalPromiseLikeType(reportErrors: boolean) {
return deferredGlobalPromiseLikeType || (deferredGlobalPromiseLikeType = getGlobalType("PromiseLike" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType;
}
function getGlobalPromiseConstructorSymbol(reportErrors: boolean): Symbol | undefined {
return deferredGlobalPromiseConstructorSymbol || (deferredGlobalPromiseConstructorSymbol = getGlobalValueSymbol("Promise" as __String, reportErrors));
}
function getGlobalPromiseConstructorLikeType(reportErrors: boolean) {
return deferredGlobalPromiseConstructorLikeType || (deferredGlobalPromiseConstructorLikeType = getGlobalType("PromiseConstructorLike" as __String, /*arity*/ 0, reportErrors)) || emptyObjectType;
}
function getGlobalAsyncIterableType(reportErrors: boolean) {
return deferredGlobalAsyncIterableType || (deferredGlobalAsyncIterableType = getGlobalType("AsyncIterable" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType;
}
function getGlobalAsyncIteratorType(reportErrors: boolean) {
return deferredGlobalAsyncIteratorType || (deferredGlobalAsyncIteratorType = getGlobalType("AsyncIterator" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType;
}
function getGlobalAsyncIterableIteratorType(reportErrors: boolean) {
return deferredGlobalAsyncIterableIteratorType || (deferredGlobalAsyncIterableIteratorType = getGlobalType("AsyncIterableIterator" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType;
}
function getGlobalIterableType(reportErrors: boolean) {
return deferredGlobalIterableType || (deferredGlobalIterableType = getGlobalType("Iterable" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType;
}
function getGlobalIteratorType(reportErrors: boolean) {
return deferredGlobalIteratorType || (deferredGlobalIteratorType = getGlobalType("Iterator" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType;
}
function getGlobalIterableIteratorType(reportErrors: boolean) {
return deferredGlobalIterableIteratorType || (deferredGlobalIterableIteratorType = getGlobalType("IterableIterator" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType;
}
function getGlobalTypeOrUndefined(name: __String, arity = 0): ObjectType | undefined {
const symbol = getGlobalSymbol(name, SymbolFlags.Type, /*diagnostic*/ undefined);
return symbol && <GenericType>getTypeOfGlobalSymbol(symbol, arity);
}
function getGlobalExtractSymbol(): Symbol {
return deferredGlobalExtractSymbol || (deferredGlobalExtractSymbol = getGlobalSymbol("Extract" as __String, SymbolFlags.TypeAlias, Diagnostics.Cannot_find_global_type_0)!); // TODO: GH#18217
}
function getGlobalExcludeSymbol(): Symbol {
return deferredGlobalExcludeSymbol || (deferredGlobalExcludeSymbol = getGlobalSymbol("Exclude" as __String, SymbolFlags.TypeAlias, Diagnostics.Cannot_find_global_type_0)!); // TODO: GH#18217
}
function getGlobalPickSymbol(): Symbol {
return deferredGlobalPickSymbol || (deferredGlobalPickSymbol = getGlobalSymbol("Pick" as __String, SymbolFlags.TypeAlias, Diagnostics.Cannot_find_global_type_0)!); // TODO: GH#18217
}
function getGlobalBigIntType(reportErrors: boolean) {
return deferredGlobalBigIntType || (deferredGlobalBigIntType = getGlobalType("BigInt" as __String, /*arity*/ 0, reportErrors)) || emptyObjectType;
}
/**
* Instantiates a global type that is generic with some element type, and returns that instantiation.
*/
function createTypeFromGenericGlobalType(genericGlobalType: GenericType, typeArguments: ReadonlyArray<Type>): ObjectType {
return genericGlobalType !== emptyGenericType ? createTypeReference(genericGlobalType, typeArguments) : emptyObjectType;
}
function createTypedPropertyDescriptorType(propertyType: Type): Type {
return createTypeFromGenericGlobalType(getGlobalTypedPropertyDescriptorType(), [propertyType]);
}
function createAsyncIterableType(iteratedType: Type): Type {
return createTypeFromGenericGlobalType(getGlobalAsyncIterableType(/*reportErrors*/ true), [iteratedType]);
}
function createAsyncIterableIteratorType(iteratedType: Type): Type {
return createTypeFromGenericGlobalType(getGlobalAsyncIterableIteratorType(/*reportErrors*/ true), [iteratedType]);
}
function createIterableType(iteratedType: Type): Type {
return createTypeFromGenericGlobalType(getGlobalIterableType(/*reportErrors*/ true), [iteratedType]);
}
function createIterableIteratorType(iteratedType: Type): Type {
return createTypeFromGenericGlobalType(getGlobalIterableIteratorType(/*reportErrors*/ true), [iteratedType]);
}
function createArrayType(elementType: Type, readonly?: boolean): ObjectType {
return createTypeFromGenericGlobalType(readonly ? globalReadonlyArrayType : globalArrayType, [elementType]);
}
function getTypeFromArrayTypeNode(node: ArrayTypeNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
links.resolvedType = createArrayType(getTypeFromTypeNode(node.elementType), isReadonlyTypeOperator(node.parent));
}
return links.resolvedType;
}
function isReadonlyTypeOperator(node: Node) {
return isTypeOperatorNode(node) && node.operator === SyntaxKind.ReadonlyKeyword;
}
// We represent tuple types as type references to synthesized generic interface types created by
// this function. The types are of the form:
//
// interface Tuple<T0, T1, T2, ...> extends Array<T0 | T1 | T2 | ...> { 0: T0, 1: T1, 2: T2, ... }
//
// Note that the generic type created by this function has no symbol associated with it. The same
// is true for each of the synthesized type parameters.
function createTupleTypeOfArity(arity: number, minLength: number, hasRestElement: boolean, readonly: boolean, associatedNames: __String[] | undefined): TupleType {
let typeParameters: TypeParameter[] | undefined;
const properties: Symbol[] = [];
const maxLength = hasRestElement ? arity - 1 : arity;
if (arity) {
typeParameters = new Array(arity);
for (let i = 0; i < arity; i++) {
const typeParameter = typeParameters[i] = createTypeParameter();
if (i < maxLength) {
const property = createSymbol(SymbolFlags.Property | (i >= minLength ? SymbolFlags.Optional : 0),
"" + i as __String, readonly ? CheckFlags.Readonly : 0);
property.type = typeParameter;
properties.push(property);
}
}
}
const literalTypes = [];
for (let i = minLength; i <= maxLength; i++) literalTypes.push(getLiteralType(i));
const lengthSymbol = createSymbol(SymbolFlags.Property, "length" as __String);
lengthSymbol.type = hasRestElement ? numberType : getUnionType(literalTypes);
properties.push(lengthSymbol);
const type = <TupleType & InterfaceTypeWithDeclaredMembers>createObjectType(ObjectFlags.Tuple | ObjectFlags.Reference);
type.typeParameters = typeParameters;
type.outerTypeParameters = undefined;
type.localTypeParameters = typeParameters;
type.instantiations = createMap<TypeReference>();
type.instantiations.set(getTypeListId(type.typeParameters), <GenericType>type);
type.target = <GenericType>type;
type.typeArguments = type.typeParameters;
type.thisType = createTypeParameter();
type.thisType.isThisType = true;
type.thisType.constraint = type;
type.declaredProperties = properties;
type.declaredCallSignatures = emptyArray;
type.declaredConstructSignatures = emptyArray;
type.declaredStringIndexInfo = undefined;
type.declaredNumberIndexInfo = undefined;
type.minLength = minLength;
type.hasRestElement = hasRestElement;
type.readonly = readonly;
type.associatedNames = associatedNames;
return type;
}
function getTupleTypeOfArity(arity: number, minLength: number, hasRestElement: boolean, readonly: boolean, associatedNames?: __String[]): GenericType {
const key = arity + (hasRestElement ? "+" : ",") + minLength + (readonly ? "R" : "") + (associatedNames && associatedNames.length ? "," + associatedNames.join(",") : "");
let type = tupleTypes.get(key);
if (!type) {
tupleTypes.set(key, type = createTupleTypeOfArity(arity, minLength, hasRestElement, readonly, associatedNames));
}
return type;
}
function createTupleType(elementTypes: ReadonlyArray<Type>, minLength = elementTypes.length, hasRestElement = false, readonly = false, associatedNames?: __String[]) {
const arity = elementTypes.length;
if (arity === 1 && hasRestElement) {
return createArrayType(elementTypes[0], readonly);
}
const tupleType = getTupleTypeOfArity(arity, minLength, arity > 0 && hasRestElement, readonly, associatedNames);
return elementTypes.length ? createTypeReference(tupleType, elementTypes) : tupleType;
}
function getTypeFromTupleTypeNode(node: TupleTypeNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
const lastElement = lastOrUndefined(node.elementTypes);
const restElement = lastElement && lastElement.kind === SyntaxKind.RestType ? lastElement : undefined;
const minLength = findLastIndex(node.elementTypes, n => n.kind !== SyntaxKind.OptionalType && n !== restElement) + 1;
const elementTypes = map(node.elementTypes, n => {
const type = getTypeFromTypeNode(n);
return n === restElement && getIndexTypeOfType(type, IndexKind.Number) || type;
});
links.resolvedType = createTupleType(elementTypes, minLength, !!restElement, isReadonlyTypeOperator(node.parent));
}
return links.resolvedType;
}
function sliceTupleType(type: TupleTypeReference, index: number) {
const tuple = type.target;
if (tuple.hasRestElement) {
// don't slice off rest element
index = Math.min(index, getTypeReferenceArity(type) - 1);
}
return createTupleType(
(type.typeArguments || emptyArray).slice(index),
Math.max(0, tuple.minLength - index),
tuple.hasRestElement,
tuple.readonly,
tuple.associatedNames && tuple.associatedNames.slice(index),
);
}
function getTypeFromOptionalTypeNode(node: OptionalTypeNode): Type {
const type = getTypeFromTypeNode(node.type);
return strictNullChecks ? getOptionalType(type) : type;
}
function getTypeId(type: Type) {
return type.id;
}
function containsType(types: ReadonlyArray<Type>, type: Type): boolean {
return binarySearch(types, type, getTypeId, compareValues) >= 0;
}
function insertType(types: Type[], type: Type): boolean {
const index = binarySearch(types, type, getTypeId, compareValues);
if (index < 0) {
types.splice(~index, 0, type);
return true;
}
return false;
}
// Return true if the given intersection type contains
// more than one unit type or,
// an object type and a nullable type (null or undefined), or
// a string-like type and a type known to be non-string-like, or
// a number-like type and a type known to be non-number-like, or
// a symbol-like type and a type known to be non-symbol-like, or
// a void-like type and a type known to be non-void-like, or
// a non-primitive type and a type known to be primitive.
function isEmptyIntersectionType(type: IntersectionType) {
let combined: TypeFlags = 0;
for (const t of type.types) {
if (t.flags & TypeFlags.Unit && combined & TypeFlags.Unit) {
return true;
}
combined |= t.flags;
if (combined & TypeFlags.Nullable && combined & (TypeFlags.Object | TypeFlags.NonPrimitive) ||
combined & TypeFlags.NonPrimitive && combined & (TypeFlags.DisjointDomains & ~TypeFlags.NonPrimitive) ||
combined & TypeFlags.StringLike && combined & (TypeFlags.DisjointDomains & ~TypeFlags.StringLike) ||
combined & TypeFlags.NumberLike && combined & (TypeFlags.DisjointDomains & ~TypeFlags.NumberLike) ||
combined & TypeFlags.BigIntLike && combined & (TypeFlags.DisjointDomains & ~TypeFlags.BigIntLike) ||
combined & TypeFlags.ESSymbolLike && combined & (TypeFlags.DisjointDomains & ~TypeFlags.ESSymbolLike) ||
combined & TypeFlags.VoidLike && combined & (TypeFlags.DisjointDomains & ~TypeFlags.VoidLike)) {
return true;
}
}
return false;
}
function addTypeToUnion(typeSet: Type[], includes: TypeFlags, type: Type) {
const flags = type.flags;
if (flags & TypeFlags.Union) {
return addTypesToUnion(typeSet, includes, (<UnionType>type).types);
}
// We ignore 'never' types in unions. Likewise, we ignore intersections of unit types as they are
// another form of 'never' (in that they have an empty value domain). We could in theory turn
// intersections of unit types into 'never' upon construction, but deferring the reduction makes it
// easier to reason about their origin.
if (!(flags & TypeFlags.Never || flags & TypeFlags.Intersection && isEmptyIntersectionType(<IntersectionType>type))) {
includes |= flags & TypeFlags.IncludesMask;
if (flags & TypeFlags.StructuredOrInstantiable) includes |= TypeFlags.IncludesStructuredOrInstantiable;
if (type === wildcardType) includes |= TypeFlags.IncludesWildcard;
if (!strictNullChecks && flags & TypeFlags.Nullable) {
if (!(getObjectFlags(type) & ObjectFlags.ContainsWideningType)) includes |= TypeFlags.IncludesNonWideningType;
}
else {
const len = typeSet.length;
const index = len && type.id > typeSet[len - 1].id ? ~len : binarySearch(typeSet, type, getTypeId, compareValues);
if (index < 0) {
typeSet.splice(~index, 0, type);
}
}
}
return includes;
}
// Add the given types to the given type set. Order is preserved, duplicates are removed,
// and nested types of the given kind are flattened into the set.
function addTypesToUnion(typeSet: Type[], includes: TypeFlags, types: ReadonlyArray<Type>): TypeFlags {
for (const type of types) {
includes = addTypeToUnion(typeSet, includes, type);
}
return includes;
}
function isSetOfLiteralsFromSameEnum(types: ReadonlyArray<Type>): boolean {
const first = types[0];
if (first.flags & TypeFlags.EnumLiteral) {
const firstEnum = getParentOfSymbol(first.symbol);
for (let i = 1; i < types.length; i++) {
const other = types[i];
if (!(other.flags & TypeFlags.EnumLiteral) || (firstEnum !== getParentOfSymbol(other.symbol))) {
return false;
}
}
return true;
}
return false;
}
function removeSubtypes(types: Type[], primitivesOnly: boolean): boolean {
const len = types.length;
if (len === 0 || isSetOfLiteralsFromSameEnum(types)) {
return true;
}
let i = len;
let count = 0;
while (i > 0) {
i--;
const source = types[i];
for (const target of types) {
if (source !== target) {
if (count === 100000) {
// After 100000 subtype checks we estimate the remaining amount of work by assuming the
// same ratio of checks per element. If the estimated number of remaining type checks is
// greater than an upper limit we deem the union type too complex to represent. The
// upper limit is 25M for unions of primitives only, and 1M otherwise. This for example
// caps union types at 5000 unique literal types and 1000 unique object types.
const estimatedCount = (count / (len - i)) * len;
if (estimatedCount > (primitivesOnly ? 25000000 : 1000000)) {
error(currentNode, Diagnostics.Expression_produces_a_union_type_that_is_too_complex_to_represent);
return false;
}
}
count++;
if (isTypeSubtypeOf(source, target) && (
!(getObjectFlags(getTargetType(source)) & ObjectFlags.Class) ||
!(getObjectFlags(getTargetType(target)) & ObjectFlags.Class) ||
isTypeDerivedFrom(source, target))) {
orderedRemoveItemAt(types, i);
break;
}
}
}
}
return true;
}
function removeRedundantLiteralTypes(types: Type[], includes: TypeFlags) {
let i = types.length;
while (i > 0) {
i--;
const t = types[i];
const remove =
t.flags & TypeFlags.StringLiteral && includes & TypeFlags.String ||
t.flags & TypeFlags.NumberLiteral && includes & TypeFlags.Number ||
t.flags & TypeFlags.BigIntLiteral && includes & TypeFlags.BigInt ||
t.flags & TypeFlags.UniqueESSymbol && includes & TypeFlags.ESSymbol ||
isFreshLiteralType(t) && containsType(types, (<LiteralType>t).regularType);
if (remove) {
orderedRemoveItemAt(types, i);
}
}
}
// We sort and deduplicate the constituent types based on object identity. If the subtypeReduction
// flag is specified we also reduce the constituent type set to only include types that aren't subtypes
// of other types. Subtype reduction is expensive for large union types and is possible only when union
// types are known not to circularly reference themselves (as is the case with union types created by
// expression constructs such as array literals and the || and ?: operators). Named types can
// circularly reference themselves and therefore cannot be subtype reduced during their declaration.
// For example, "type Item = string | (() => Item" is a named type that circularly references itself.
function getUnionType(types: ReadonlyArray<Type>, unionReduction: UnionReduction = UnionReduction.Literal, aliasSymbol?: Symbol, aliasTypeArguments?: ReadonlyArray<Type>): Type {
if (types.length === 0) {
return neverType;
}
if (types.length === 1) {
return types[0];
}
const typeSet: Type[] = [];
const includes = addTypesToUnion(typeSet, 0, types);
if (unionReduction !== UnionReduction.None) {
if (includes & TypeFlags.AnyOrUnknown) {
return includes & TypeFlags.Any ? includes & TypeFlags.IncludesWildcard ? wildcardType : anyType : unknownType;
}
switch (unionReduction) {
case UnionReduction.Literal:
if (includes & (TypeFlags.Literal | TypeFlags.UniqueESSymbol)) {
removeRedundantLiteralTypes(typeSet, includes);
}
break;
case UnionReduction.Subtype:
if (!removeSubtypes(typeSet, !(includes & TypeFlags.IncludesStructuredOrInstantiable))) {
return errorType;
}
break;
}
if (typeSet.length === 0) {
return includes & TypeFlags.Null ? includes & TypeFlags.IncludesNonWideningType ? nullType : nullWideningType :
includes & TypeFlags.Undefined ? includes & TypeFlags.IncludesNonWideningType ? undefinedType : undefinedWideningType :
neverType;
}
}
return getUnionTypeFromSortedList(typeSet, includes & TypeFlags.NotPrimitiveUnion ? 0 : ObjectFlags.PrimitiveUnion, aliasSymbol, aliasTypeArguments);
}
function getUnionTypePredicate(signatures: ReadonlyArray<Signature>): TypePredicate | undefined {
let first: TypePredicate | undefined;
const types: Type[] = [];
for (const sig of signatures) {
const pred = getTypePredicateOfSignature(sig);
if (!pred) {
continue;
}
if (first) {
if (!typePredicateKindsMatch(first, pred)) {
// No common type predicate.
return undefined;
}
}
else {
first = pred;
}
types.push(pred.type);
}
if (!first) {
// No union signatures had a type predicate.
return undefined;
}
const unionType = getUnionType(types);
return isIdentifierTypePredicate(first)
? createIdentifierTypePredicate(first.parameterName, first.parameterIndex, unionType)
: createThisTypePredicate(unionType);
}
function typePredicateKindsMatch(a: TypePredicate, b: TypePredicate): boolean {
return isIdentifierTypePredicate(a)
? isIdentifierTypePredicate(b) && a.parameterIndex === b.parameterIndex
: !isIdentifierTypePredicate(b);
}
// This function assumes the constituent type list is sorted and deduplicated.
function getUnionTypeFromSortedList(types: Type[], objectFlags: ObjectFlags, aliasSymbol?: Symbol, aliasTypeArguments?: ReadonlyArray<Type>): Type {
if (types.length === 0) {
return neverType;
}
if (types.length === 1) {
return types[0];
}
const id = getTypeListId(types);
let type = unionTypes.get(id);
if (!type) {
type = <UnionType>createType(TypeFlags.Union);
unionTypes.set(id, type);
type.objectFlags = objectFlags | getPropagatingFlagsOfTypes(types, /*excludeKinds*/ TypeFlags.Nullable);
type.types = types;
/*
Note: This is the alias symbol (or lack thereof) that we see when we first encounter this union type.
For aliases of identical unions, eg `type T = A | B; type U = A | B`, the symbol of the first alias encountered is the aliasSymbol.
(In the language service, the order may depend on the order in which a user takes actions, such as hovering over symbols.)
It's important that we create equivalent union types only once, so that's an unfortunate side effect.
*/
type.aliasSymbol = aliasSymbol;
type.aliasTypeArguments = aliasTypeArguments;
}
return type;
}
function getTypeFromUnionTypeNode(node: UnionTypeNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
const aliasSymbol = getAliasSymbolForTypeNode(node);
links.resolvedType = getUnionType(map(node.types, getTypeFromTypeNode), UnionReduction.Literal,
aliasSymbol, getTypeArgumentsForAliasSymbol(aliasSymbol));
}
return links.resolvedType;
}
function addTypeToIntersection(typeSet: Type[], includes: TypeFlags, type: Type) {
const flags = type.flags;
if (flags & TypeFlags.Intersection) {
return addTypesToIntersection(typeSet, includes, (<IntersectionType>type).types);
}
if (isEmptyAnonymousObjectType(type)) {
if (!(includes & TypeFlags.IncludesEmptyObject)) {
includes |= TypeFlags.IncludesEmptyObject;
typeSet.push(type);
}
}
else {
includes |= flags & TypeFlags.IncludesMask;
if (flags & TypeFlags.AnyOrUnknown) {
if (type === wildcardType) includes |= TypeFlags.IncludesWildcard;
}
else if ((strictNullChecks || !(flags & TypeFlags.Nullable)) && !contains(typeSet, type)) {
typeSet.push(type);
}
}
return includes;
}
// Add the given types to the given type set. Order is preserved, freshness is removed from literal
// types, duplicates are removed, and nested types of the given kind are flattened into the set.
function addTypesToIntersection(typeSet: Type[], includes: TypeFlags, types: ReadonlyArray<Type>) {
for (const type of types) {
includes = addTypeToIntersection(typeSet, includes, getRegularTypeOfLiteralType(type));
}
return includes;
}
function removeRedundantPrimitiveTypes(types: Type[], includes: TypeFlags) {
let i = types.length;
while (i > 0) {
i--;
const t = types[i];
const remove =
t.flags & TypeFlags.String && includes & TypeFlags.StringLiteral ||
t.flags & TypeFlags.Number && includes & TypeFlags.NumberLiteral ||
t.flags & TypeFlags.BigInt && includes & TypeFlags.BigIntLiteral ||
t.flags & TypeFlags.ESSymbol && includes & TypeFlags.UniqueESSymbol;
if (remove) {
orderedRemoveItemAt(types, i);
}
}
}
// Check that the given type has a match in every union. A given type is matched by
// an identical type, and a literal type is additionally matched by its corresponding
// primitive type.
function eachUnionContains(unionTypes: UnionType[], type: Type) {
for (const u of unionTypes) {
if (!containsType(u.types, type)) {
const primitive = type.flags & TypeFlags.StringLiteral ? stringType :
type.flags & TypeFlags.NumberLiteral ? numberType :
type.flags & TypeFlags.BigIntLiteral ? bigintType :
type.flags & TypeFlags.UniqueESSymbol ? esSymbolType :
undefined;
if (!primitive || !containsType(u.types, primitive)) {
return false;
}
}
}
return true;
}
// If the given list of types contains more than one union of primitive types, replace the
// first with a union containing an intersection of those primitive types, then remove the
// other unions and return true. Otherwise, do nothing and return false.
function intersectUnionsOfPrimitiveTypes(types: Type[]) {
let unionTypes: UnionType[] | undefined;
const index = findIndex(types, t => !!(getObjectFlags(t) & ObjectFlags.PrimitiveUnion));
if (index < 0) {
return false;
}
let i = index + 1;
// Remove all but the first union of primitive types and collect them in
// the unionTypes array.
while (i < types.length) {
const t = types[i];
if (getObjectFlags(t) & ObjectFlags.PrimitiveUnion) {
(unionTypes || (unionTypes = [<UnionType>types[index]])).push(<UnionType>t);
orderedRemoveItemAt(types, i);
}
else {
i++;
}
}
// Return false if there was only one union of primitive types
if (!unionTypes) {
return false;
}
// We have more than one union of primitive types, now intersect them. For each
// type in each union we check if the type is matched in every union and if so
// we include it in the result.
const checked: Type[] = [];
const result: Type[] = [];
for (const u of unionTypes) {
for (const t of u.types) {
if (insertType(checked, t)) {
if (eachUnionContains(unionTypes, t)) {
insertType(result, t);
}
}
}
}
// Finally replace the first union with the result
types[index] = getUnionTypeFromSortedList(result, ObjectFlags.PrimitiveUnion);
return true;
}
// We normalize combinations of intersection and union types based on the distributive property of the '&'
// operator. Specifically, because X & (A | B) is equivalent to X & A | X & B, we can transform intersection
// types with union type constituents into equivalent union types with intersection type constituents and
// effectively ensure that union types are always at the top level in type representations.
//
// We do not perform structural deduplication on intersection types. Intersection types are created only by the &
// type operator and we can't reduce those because we want to support recursive intersection types. For example,
// a type alias of the form "type List<T> = T & { next: List<T> }" cannot be reduced during its declaration.
// Also, unlike union types, the order of the constituent types is preserved in order that overload resolution
// for intersections of types with signatures can be deterministic.
function getIntersectionType(types: ReadonlyArray<Type>, aliasSymbol?: Symbol, aliasTypeArguments?: ReadonlyArray<Type>): Type {
const typeSet: Type[] = [];
const includes = addTypesToIntersection(typeSet, 0, types);
if (includes & TypeFlags.Never) {
return neverType;
}
if (includes & TypeFlags.Any) {
return includes & TypeFlags.IncludesWildcard ? wildcardType : anyType;
}
if (!strictNullChecks && includes & TypeFlags.Nullable) {
return includes & TypeFlags.Undefined ? undefinedType : nullType;
}
if (includes & TypeFlags.String && includes & TypeFlags.StringLiteral ||
includes & TypeFlags.Number && includes & TypeFlags.NumberLiteral ||
includes & TypeFlags.BigInt && includes & TypeFlags.BigIntLiteral ||
includes & TypeFlags.ESSymbol && includes & TypeFlags.UniqueESSymbol) {
removeRedundantPrimitiveTypes(typeSet, includes);
}
if (includes & TypeFlags.IncludesEmptyObject && includes & TypeFlags.Object) {
orderedRemoveItemAt(typeSet, findIndex(typeSet, isEmptyAnonymousObjectType));
}
if (typeSet.length === 0) {
return unknownType;
}
if (typeSet.length === 1) {
return typeSet[0];
}
if (includes & TypeFlags.Union) {
if (intersectUnionsOfPrimitiveTypes(typeSet)) {
// When the intersection creates a reduced set (which might mean that *all* union types have
// disappeared), we restart the operation to get a new set of combined flags. Once we have
// reduced we'll never reduce again, so this occurs at most once.
return getIntersectionType(typeSet, aliasSymbol, aliasTypeArguments);
}
// We are attempting to construct a type of the form X & (A | B) & Y. Transform this into a type of
// the form X & A & Y | X & B & Y and recursively reduce until no union type constituents remain.
const unionIndex = findIndex(typeSet, t => (t.flags & TypeFlags.Union) !== 0);
const unionType = <UnionType>typeSet[unionIndex];
return getUnionType(map(unionType.types, t => getIntersectionType(replaceElement(typeSet, unionIndex, t))),
UnionReduction.Literal, aliasSymbol, aliasTypeArguments);
}
const id = getTypeListId(typeSet);
let type = intersectionTypes.get(id);
if (!type) {
type = <IntersectionType>createType(TypeFlags.Intersection);
intersectionTypes.set(id, type);
type.objectFlags = getPropagatingFlagsOfTypes(typeSet, /*excludeKinds*/ TypeFlags.Nullable);
type.types = typeSet;
type.aliasSymbol = aliasSymbol; // See comment in `getUnionTypeFromSortedList`.
type.aliasTypeArguments = aliasTypeArguments;
}
return type;
}
function getTypeFromIntersectionTypeNode(node: IntersectionTypeNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
const aliasSymbol = getAliasSymbolForTypeNode(node);
links.resolvedType = getIntersectionType(map(node.types, getTypeFromTypeNode),
aliasSymbol, getTypeArgumentsForAliasSymbol(aliasSymbol));
}
return links.resolvedType;
}
function createIndexType(type: InstantiableType | UnionOrIntersectionType, stringsOnly: boolean) {
const result = <IndexType>createType(TypeFlags.Index);
result.type = type;
result.stringsOnly = stringsOnly;
return result;
}
function getIndexTypeForGenericType(type: InstantiableType | UnionOrIntersectionType, stringsOnly: boolean) {
return stringsOnly ?
type.resolvedStringIndexType || (type.resolvedStringIndexType = createIndexType(type, /*stringsOnly*/ true)) :
type.resolvedIndexType || (type.resolvedIndexType = createIndexType(type, /*stringsOnly*/ false));
}
function getLiteralTypeFromPropertyName(name: PropertyName) {
return isIdentifier(name) ? getLiteralType(unescapeLeadingUnderscores(name.escapedText)) :
getRegularTypeOfLiteralType(isComputedPropertyName(name) ? checkComputedPropertyName(name) : checkExpression(name));
}
function getBigIntLiteralType(node: BigIntLiteral): LiteralType {
return getLiteralType({
negative: false,
base10Value: parsePseudoBigInt(node.text)
});
}
function getLiteralTypeFromProperty(prop: Symbol, include: TypeFlags) {
if (!(getDeclarationModifierFlagsFromSymbol(prop) & ModifierFlags.NonPublicAccessibilityModifier)) {
let type = getLateBoundSymbol(prop).nameType;
if (!type && !isKnownSymbol(prop)) {
if (prop.escapedName === InternalSymbolName.Default) {
type = getLiteralType("default");
}
else {
const name = prop.valueDeclaration && getNameOfDeclaration(prop.valueDeclaration) as PropertyName;
type = name && getLiteralTypeFromPropertyName(name) || getLiteralType(symbolName(prop));
}
}
if (type && type.flags & include) {
return type;
}
}
return neverType;
}
function getLiteralTypeFromProperties(type: Type, include: TypeFlags) {
return getUnionType(map(getPropertiesOfType(type), p => getLiteralTypeFromProperty(p, include)));
}
function getNonEnumNumberIndexInfo(type: Type) {
const numberIndexInfo = getIndexInfoOfType(type, IndexKind.Number);
return numberIndexInfo !== enumNumberIndexInfo ? numberIndexInfo : undefined;
}
function getIndexType(type: Type, stringsOnly = keyofStringsOnly): Type {
return type.flags & TypeFlags.Union ? getIntersectionType(map((<IntersectionType>type).types, t => getIndexType(t, stringsOnly))) :
type.flags & TypeFlags.Intersection ? getUnionType(map((<IntersectionType>type).types, t => getIndexType(t, stringsOnly))) :
maybeTypeOfKind(type, TypeFlags.InstantiableNonPrimitive) ? getIndexTypeForGenericType(<InstantiableType | UnionOrIntersectionType>type, stringsOnly) :
getObjectFlags(type) & ObjectFlags.Mapped ? getConstraintTypeFromMappedType(<MappedType>type) :
type === wildcardType ? wildcardType :
type.flags & TypeFlags.Any ? keyofConstraintType :
stringsOnly ? getIndexInfoOfType(type, IndexKind.String) ? stringType : getLiteralTypeFromProperties(type, TypeFlags.StringLiteral) :
getIndexInfoOfType(type, IndexKind.String) ? getUnionType([stringType, numberType, getLiteralTypeFromProperties(type, TypeFlags.UniqueESSymbol)]) :
getNonEnumNumberIndexInfo(type) ? getUnionType([numberType, getLiteralTypeFromProperties(type, TypeFlags.StringLiteral | TypeFlags.UniqueESSymbol)]) :
getLiteralTypeFromProperties(type, TypeFlags.StringOrNumberLiteralOrUnique);
}
function getExtractStringType(type: Type) {
if (keyofStringsOnly) {
return type;
}
const extractTypeAlias = getGlobalExtractSymbol();
return extractTypeAlias ? getTypeAliasInstantiation(extractTypeAlias, [type, stringType]) : stringType;
}
function getIndexTypeOrString(type: Type): Type {
const indexType = getExtractStringType(getIndexType(type));
return indexType.flags & TypeFlags.Never ? stringType : indexType;
}
function getTypeFromTypeOperatorNode(node: TypeOperatorNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
switch (node.operator) {
case SyntaxKind.KeyOfKeyword:
links.resolvedType = getIndexType(getTypeFromTypeNode(node.type));
break;
case SyntaxKind.UniqueKeyword:
links.resolvedType = node.type.kind === SyntaxKind.SymbolKeyword
? getESSymbolLikeTypeForNode(walkUpParenthesizedTypes(node.parent))
: errorType;
break;
case SyntaxKind.ReadonlyKeyword:
links.resolvedType = getTypeFromTypeNode(node.type);
break;
}
}
return links.resolvedType!; // TODO: GH#18217
}
function createIndexedAccessType(objectType: Type, indexType: Type) {
const type = <IndexedAccessType>createType(TypeFlags.IndexedAccess);
type.objectType = objectType;
type.indexType = indexType;
return type;
}
/**
* Returns if a type is or consists of a JSLiteral object type
* In addition to objects which are directly literals,
* * unions where every element is a jsliteral
* * intersections where at least one element is a jsliteral
* * and instantiable types constrained to a jsliteral
* Should all count as literals and not print errors on access or assignment of possibly existing properties.
* This mirrors the behavior of the index signature propagation, to which this behaves similarly (but doesn't affect assignability or inference).
*/
function isJSLiteralType(type: Type): boolean {
if (noImplicitAny) {
return false; // Flag is meaningless under `noImplicitAny` mode
}
if (getObjectFlags(type) & ObjectFlags.JSLiteral) {
return true;
}
if (type.flags & TypeFlags.Union) {
return every((type as UnionType).types, isJSLiteralType);
}
if (type.flags & TypeFlags.Intersection) {
return some((type as IntersectionType).types, isJSLiteralType);
}
if (type.flags & TypeFlags.Instantiable) {
return isJSLiteralType(getResolvedBaseConstraint(type));
}
return false;
}
function getPropertyTypeForIndexType(objectType: Type, indexType: Type, accessNode: ElementAccessExpression | IndexedAccessTypeNode | PropertyName | BindingName | SyntheticExpression | undefined, cacheSymbol: boolean, missingType: Type) {
const accessExpression = accessNode && accessNode.kind === SyntaxKind.ElementAccessExpression ? accessNode : undefined;
const propName = isTypeUsableAsPropertyName(indexType) ?
getPropertyNameFromType(indexType) :
accessExpression && checkThatExpressionIsProperSymbolReference(accessExpression.argumentExpression, indexType, /*reportError*/ false) ?
getPropertyNameForKnownSymbolName(idText((<PropertyAccessExpression>accessExpression.argumentExpression).name)) :
accessNode && isPropertyName(accessNode) ?
// late bound names are handled in the first branch, so here we only need to handle normal names
getPropertyNameForPropertyNameNode(accessNode) :
undefined;
if (propName !== undefined) {
const prop = getPropertyOfType(objectType, propName);
if (prop) {
if (accessExpression) {
markPropertyAsReferenced(prop, accessExpression, /*isThisAccess*/ accessExpression.expression.kind === SyntaxKind.ThisKeyword);
if (isAssignmentTarget(accessExpression) && (isReferenceToReadonlyEntity(accessExpression, prop) || isReferenceThroughNamespaceImport(accessExpression))) {
error(accessExpression.argumentExpression, Diagnostics.Cannot_assign_to_0_because_it_is_a_read_only_property, symbolToString(prop));
return missingType;
}
if (cacheSymbol) {
getNodeLinks(accessNode!).resolvedSymbol = prop;
}
}
const propType = getTypeOfSymbol(prop);
return accessExpression && getAssignmentTargetKind(accessExpression) !== AssignmentKind.Definite ?
getFlowTypeOfReference(accessExpression, propType) :
propType;
}
if (everyType(objectType, isTupleType) && isNumericLiteralName(propName) && +propName >= 0) {
if (accessNode && everyType(objectType, t => !(<TupleTypeReference>t).target.hasRestElement)) {
const indexNode = getIndexNodeForAccessExpression(accessNode);
if (isTupleType(objectType)) {
error(indexNode, Diagnostics.Tuple_type_0_of_length_1_has_no_element_at_index_2,
typeToString(objectType), getTypeReferenceArity(objectType), unescapeLeadingUnderscores(propName));
}
else {
error(indexNode, Diagnostics.Property_0_does_not_exist_on_type_1, unescapeLeadingUnderscores(propName), typeToString(objectType));
}
}
return mapType(objectType, t => getRestTypeOfTupleType(<TupleTypeReference>t) || undefinedType);
}
}
if (!(indexType.flags & TypeFlags.Nullable) && isTypeAssignableToKind(indexType, TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.ESSymbolLike)) {
if (objectType.flags & (TypeFlags.Any | TypeFlags.Never)) {
return objectType;
}
const indexInfo = isTypeAssignableToKind(indexType, TypeFlags.NumberLike) && getIndexInfoOfType(objectType, IndexKind.Number) ||
getIndexInfoOfType(objectType, IndexKind.String) ||
undefined;
if (indexInfo) {
if (accessNode && !isTypeAssignableToKind(indexType, TypeFlags.String | TypeFlags.Number)) {
const indexNode = getIndexNodeForAccessExpression(accessNode);
error(indexNode, Diagnostics.Type_0_cannot_be_used_as_an_index_type, typeToString(indexType));
}
else if (accessExpression && indexInfo.isReadonly && (isAssignmentTarget(accessExpression) || isDeleteTarget(accessExpression))) {
error(accessExpression, Diagnostics.Index_signature_in_type_0_only_permits_reading, typeToString(objectType));
}
return indexInfo.type;
}
if (indexType.flags & TypeFlags.Never) {
return neverType;
}
if (isJSLiteralType(objectType)) {
return anyType;
}
if (accessExpression && !isConstEnumObjectType(objectType)) {
if (noImplicitAny && !compilerOptions.suppressImplicitAnyIndexErrors) {
if (propName !== undefined && typeHasStaticProperty(propName, objectType)) {
error(accessExpression, Diagnostics.Property_0_is_a_static_member_of_type_1, propName as string, typeToString(objectType));
}
else if (getIndexTypeOfType(objectType, IndexKind.Number)) {
error(accessExpression.argumentExpression, Diagnostics.Element_implicitly_has_an_any_type_because_index_expression_is_not_of_type_number);
}
else {
let suggestion: string | undefined;
if (propName !== undefined && (suggestion = getSuggestionForNonexistentProperty(propName as string, objectType))) {
if (suggestion !== undefined) {
error(accessExpression.argumentExpression, Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_mean_2, propName as string, typeToString(objectType), suggestion);
}
}
else {
error(accessExpression, Diagnostics.Element_implicitly_has_an_any_type_because_type_0_has_no_index_signature, typeToString(objectType));
}
}
}
return missingType;
}
}
if (isJSLiteralType(objectType)) {
return anyType;
}
if (accessNode) {
const indexNode = getIndexNodeForAccessExpression(accessNode);
if (indexType.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral)) {
error(indexNode, Diagnostics.Property_0_does_not_exist_on_type_1, "" + (<StringLiteralType | NumberLiteralType>indexType).value, typeToString(objectType));
}
else if (indexType.flags & (TypeFlags.String | TypeFlags.Number)) {
error(indexNode, Diagnostics.Type_0_has_no_matching_index_signature_for_type_1, typeToString(objectType), typeToString(indexType));
}
else {
error(indexNode, Diagnostics.Type_0_cannot_be_used_as_an_index_type, typeToString(indexType));
}
}
if (isTypeAny(indexType)) {
return indexType;
}
return missingType;
}
function getIndexNodeForAccessExpression(accessNode: ElementAccessExpression | IndexedAccessTypeNode | PropertyName | BindingName | SyntheticExpression) {
return accessNode.kind === SyntaxKind.ElementAccessExpression
? accessNode.argumentExpression
: accessNode.kind === SyntaxKind.IndexedAccessType
? accessNode.indexType
: accessNode.kind === SyntaxKind.ComputedPropertyName
? accessNode.expression
: accessNode;
}
function isGenericObjectType(type: Type): boolean {
return maybeTypeOfKind(type, TypeFlags.InstantiableNonPrimitive | TypeFlags.GenericMappedType);
}
function isGenericIndexType(type: Type): boolean {
return maybeTypeOfKind(type, TypeFlags.InstantiableNonPrimitive | TypeFlags.Index);
}
function getSimplifiedType(type: Type): Type {
return type.flags & TypeFlags.IndexedAccess ? getSimplifiedIndexedAccessType(<IndexedAccessType>type) : type;
}
function distributeIndexOverObjectType(objectType: Type, indexType: Type) {
// (T | U)[K] -> T[K] | U[K]
if (objectType.flags & TypeFlags.Union) {
return mapType(objectType, t => getSimplifiedType(getIndexedAccessType(t, indexType)));
}
// (T & U)[K] -> T[K] & U[K]
if (objectType.flags & TypeFlags.Intersection) {
return getIntersectionType(map((objectType as IntersectionType).types, t => getSimplifiedType(getIndexedAccessType(t, indexType))));
}
}
// Transform an indexed access to a simpler form, if possible. Return the simpler form, or return
// the type itself if no transformation is possible.
function getSimplifiedIndexedAccessType(type: IndexedAccessType): Type {
if (type.simplified) {
return type.simplified === circularConstraintType ? type : type.simplified;
}
type.simplified = circularConstraintType;
// We recursively simplify the object type as it may in turn be an indexed access type. For example, with
// '{ [P in T]: { [Q in U]: number } }[T][U]' we want to first simplify the inner indexed access type.
const objectType = getSimplifiedType(type.objectType);
const indexType = getSimplifiedType(type.indexType);
// T[A | B] -> T[A] | T[B]
if (indexType.flags & TypeFlags.Union) {
return type.simplified = mapType(indexType, t => getSimplifiedType(getIndexedAccessType(objectType, t)));
}
// Only do the inner distributions if the index can no longer be instantiated to cause index distribution again
if (!(indexType.flags & TypeFlags.Instantiable)) {
const simplified = distributeIndexOverObjectType(objectType, indexType);
if (simplified) {
return type.simplified = simplified;
}
}
// So ultimately:
// ((A & B) | C)[K1 | K2] -> ((A & B) | C)[K1] | ((A & B) | C)[K2] -> (A & B)[K1] | C[K1] | (A & B)[K2] | C[K2] -> (A[K1] & B[K1]) | C[K1] | (A[K2] & B[K2]) | C[K2]
// If the object type is a mapped type { [P in K]: E }, where K is generic, instantiate E using a mapper
// that substitutes the index type for P. For example, for an index access { [P in K]: Box<T[P]> }[X], we
// construct the type Box<T[X]>.
if (isGenericMappedType(objectType)) {
const mapper = createTypeMapper([getTypeParameterFromMappedType(objectType)], [type.indexType]);
const templateMapper = combineTypeMappers(objectType.mapper, mapper);
return type.simplified = mapType(instantiateType(getTemplateTypeFromMappedType(objectType), templateMapper), getSimplifiedType);
}
return type.simplified = type;
}
function getIndexedAccessType(objectType: Type, indexType: Type, accessNode?: ElementAccessExpression | IndexedAccessTypeNode | PropertyName | BindingName | SyntheticExpression, missingType = accessNode ? errorType : unknownType): Type {
if (objectType === wildcardType || indexType === wildcardType) {
return wildcardType;
}
// If the index type is generic, or if the object type is generic and doesn't originate in an expression,
// we are performing a higher-order index access where we cannot meaningfully access the properties of the
// object type. Note that for a generic T and a non-generic K, we eagerly resolve T[K] if it originates in
// an expression. This is to preserve backwards compatibility. For example, an element access 'this["foo"]'
// has always been resolved eagerly using the constraint type of 'this' at the given location.
if (isGenericIndexType(indexType) || !(accessNode && accessNode.kind !== SyntaxKind.IndexedAccessType) && isGenericObjectType(objectType)) {
if (objectType.flags & TypeFlags.AnyOrUnknown) {
return objectType;
}
// Defer the operation by creating an indexed access type.
const id = objectType.id + "," + indexType.id;
let type = indexedAccessTypes.get(id);
if (!type) {
indexedAccessTypes.set(id, type = createIndexedAccessType(objectType, indexType));
}
return type;
}
// In the following we resolve T[K] to the type of the property in T selected by K.
// We treat boolean as different from other unions to improve errors;
// skipping straight to getPropertyTypeForIndexType gives errors with 'boolean' instead of 'true'.
const apparentObjectType = getApparentType(objectType);
if (indexType.flags & TypeFlags.Union && !(indexType.flags & TypeFlags.Boolean)) {
const propTypes: Type[] = [];
let wasMissingProp = false;
for (const t of (<UnionType>indexType).types) {
const propType = getPropertyTypeForIndexType(apparentObjectType, t, accessNode, /*cacheSymbol*/ false, missingType);
if (propType === missingType) {
if (!accessNode) {
// If there's no error node, we can immeditely stop, since error reporting is off
return missingType;
}
else {
// Otherwise we set a flag and return at the end of the loop so we still mark all errors
wasMissingProp = true;
}
}
propTypes.push(propType);
}
if (wasMissingProp) {
return missingType;
}
return getUnionType(propTypes);
}
return getPropertyTypeForIndexType(apparentObjectType, indexType, accessNode, /*cacheSymbol*/ true, missingType);
}
function getTypeFromIndexedAccessTypeNode(node: IndexedAccessTypeNode) {
const links = getNodeLinks(node);
if (!links.resolvedType) {
const objectType = getTypeFromTypeNode(node.objectType);
const indexType = getTypeFromTypeNode(node.indexType);
const resolved = getIndexedAccessType(objectType, indexType, node);
links.resolvedType = resolved.flags & TypeFlags.IndexedAccess &&
(<IndexedAccessType>resolved).objectType === objectType &&
(<IndexedAccessType>resolved).indexType === indexType ?
getConstrainedTypeVariable(<IndexedAccessType>resolved, node) : resolved;
}
return links.resolvedType;
}
function getTypeFromMappedTypeNode(node: MappedTypeNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
const type = <MappedType>createObjectType(ObjectFlags.Mapped, node.symbol);
type.declaration = node;
type.aliasSymbol = getAliasSymbolForTypeNode(node);
type.aliasTypeArguments = getTypeArgumentsForAliasSymbol(type.aliasSymbol);
links.resolvedType = type;
// Eagerly resolve the constraint type which forces an error if the constraint type circularly
// references itself through one or more type aliases.
getConstraintTypeFromMappedType(type);
}
return links.resolvedType;
}
function getActualTypeVariable(type: Type) {
return type.flags & TypeFlags.Substitution ? (<SubstitutionType>type).typeVariable : type;
}
function getConditionalType(root: ConditionalRoot, mapper: TypeMapper | undefined): Type {
const checkType = instantiateType(root.checkType, mapper);
const extendsType = instantiateType(root.extendsType, mapper);
if (checkType === wildcardType || extendsType === wildcardType) {
return wildcardType;
}
const checkTypeInstantiable = maybeTypeOfKind(checkType, TypeFlags.Instantiable | TypeFlags.GenericMappedType);
let combinedMapper: TypeMapper | undefined;
if (root.inferTypeParameters) {
const context = createInferenceContext(root.inferTypeParameters, /*signature*/ undefined, InferenceFlags.None);
if (!checkTypeInstantiable) {
// We don't want inferences from constraints as they may cause us to eagerly resolve the
// conditional type instead of deferring resolution. Also, we always want strict function
// types rules (i.e. proper contravariance) for inferences.
inferTypes(context.inferences, checkType, extendsType, InferencePriority.NoConstraints | InferencePriority.AlwaysStrict);
}
combinedMapper = combineTypeMappers(mapper, context);
}
// Instantiate the extends type including inferences for 'infer T' type parameters
const inferredExtendsType = combinedMapper ? instantiateType(root.extendsType, combinedMapper) : extendsType;
// We attempt to resolve the conditional type only when the check and extends types are non-generic
if (!checkTypeInstantiable && !maybeTypeOfKind(inferredExtendsType, TypeFlags.Instantiable | TypeFlags.GenericMappedType)) {
if (inferredExtendsType.flags & TypeFlags.AnyOrUnknown) {
return instantiateType(root.trueType, mapper);
}
// Return union of trueType and falseType for 'any' since it matches anything
if (checkType.flags & TypeFlags.Any) {
return getUnionType([instantiateType(root.trueType, combinedMapper || mapper), instantiateType(root.falseType, mapper)]);
}
// Return falseType for a definitely false extends check. We check an instantiations of the two
// types with type parameters mapped to the wildcard type, the most permissive instantiations
// possible (the wildcard type is assignable to and from all types). If those are not related,
// then no instantiations will be and we can just return the false branch type.
if (!isTypeAssignableTo(getPermissiveInstantiation(checkType), getPermissiveInstantiation(inferredExtendsType))) {
return instantiateType(root.falseType, mapper);
}
// Return trueType for a definitely true extends check. We check instantiations of the two
// types with type parameters mapped to their restrictive form, i.e. a form of the type parameter
// that has no constraint. This ensures that, for example, the type
// type Foo<T extends { x: any }> = T extends { x: string } ? string : number
// doesn't immediately resolve to 'string' instead of being deferred.
if (isTypeAssignableTo(getRestrictiveInstantiation(checkType), getRestrictiveInstantiation(inferredExtendsType))) {
return instantiateType(root.trueType, combinedMapper || mapper);
}
}
// Return a deferred type for a check that is neither definitely true nor definitely false
const erasedCheckType = getActualTypeVariable(checkType);
const result = <ConditionalType>createType(TypeFlags.Conditional);
result.root = root;
result.checkType = erasedCheckType;
result.extendsType = extendsType;
result.mapper = mapper;
result.combinedMapper = combinedMapper;
result.aliasSymbol = root.aliasSymbol;
result.aliasTypeArguments = instantiateTypes(root.aliasTypeArguments, mapper!); // TODO: GH#18217
return result;
}
function getTrueTypeFromConditionalType(type: ConditionalType) {
return type.resolvedTrueType || (type.resolvedTrueType = instantiateType(type.root.trueType, type.mapper));
}
function getFalseTypeFromConditionalType(type: ConditionalType) {
return type.resolvedFalseType || (type.resolvedFalseType = instantiateType(type.root.falseType, type.mapper));
}
function getInferTypeParameters(node: ConditionalTypeNode): TypeParameter[] | undefined {
let result: TypeParameter[] | undefined;
if (node.locals) {
node.locals.forEach(symbol => {
if (symbol.flags & SymbolFlags.TypeParameter) {
result = append(result, getDeclaredTypeOfSymbol(symbol));
}
});
}
return result;
}
function isPossiblyReferencedInConditionalType(tp: TypeParameter, node: Node) {
if (isTypeParameterPossiblyReferenced(tp, node)) {
return true;
}
while (node) {
if (node.kind === SyntaxKind.ConditionalType) {
if (isTypeParameterPossiblyReferenced(tp, (<ConditionalTypeNode>node).extendsType)) {
return true;
}
}
node = node.parent;
}
return false;
}
function getTypeFromConditionalTypeNode(node: ConditionalTypeNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
const checkType = getTypeFromTypeNode(node.checkType);
const aliasSymbol = getAliasSymbolForTypeNode(node);
const aliasTypeArguments = getTypeArgumentsForAliasSymbol(aliasSymbol);
const allOuterTypeParameters = getOuterTypeParameters(node, /*includeThisTypes*/ true);
const outerTypeParameters = aliasTypeArguments ? allOuterTypeParameters : filter(allOuterTypeParameters, tp => isPossiblyReferencedInConditionalType(tp, node));
const root: ConditionalRoot = {
node,
checkType,
extendsType: getTypeFromTypeNode(node.extendsType),
trueType: getTypeFromTypeNode(node.trueType),
falseType: getTypeFromTypeNode(node.falseType),
isDistributive: !!(checkType.flags & TypeFlags.TypeParameter),
inferTypeParameters: getInferTypeParameters(node),
outerTypeParameters,
instantiations: undefined,
aliasSymbol,
aliasTypeArguments
};
links.resolvedType = getConditionalType(root, /*mapper*/ undefined);
if (outerTypeParameters) {
root.instantiations = createMap<Type>();
root.instantiations.set(getTypeListId(outerTypeParameters), links.resolvedType);
}
}
return links.resolvedType;
}
function getTypeFromInferTypeNode(node: InferTypeNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
links.resolvedType = getDeclaredTypeOfTypeParameter(getSymbolOfNode(node.typeParameter));
}
return links.resolvedType;
}
function getIdentifierChain(node: EntityName): Identifier[] {
if (isIdentifier(node)) {
return [node];
}
else {
return append(getIdentifierChain(node.left), node.right);
}
}
function getTypeFromImportTypeNode(node: ImportTypeNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
if (node.isTypeOf && node.typeArguments) { // Only the non-typeof form can make use of type arguments
error(node, Diagnostics.Type_arguments_cannot_be_used_here);
links.resolvedSymbol = unknownSymbol;
return links.resolvedType = errorType;
}
if (!isLiteralImportTypeNode(node)) {
error(node.argument, Diagnostics.String_literal_expected);
links.resolvedSymbol = unknownSymbol;
return links.resolvedType = errorType;
}
const targetMeaning = node.isTypeOf ? SymbolFlags.Value : node.flags & NodeFlags.JSDoc ? SymbolFlags.Value | SymbolFlags.Type : SymbolFlags.Type;
// TODO: Future work: support unions/generics/whatever via a deferred import-type
const innerModuleSymbol = resolveExternalModuleName(node, node.argument.literal);
if (!innerModuleSymbol) {
links.resolvedSymbol = unknownSymbol;
return links.resolvedType = errorType;
}
const moduleSymbol = resolveExternalModuleSymbol(innerModuleSymbol, /*dontResolveAlias*/ false);
if (!nodeIsMissing(node.qualifier)) {
const nameStack: Identifier[] = getIdentifierChain(node.qualifier!);
let currentNamespace = moduleSymbol;
let current: Identifier | undefined;
while (current = nameStack.shift()) {
const meaning = nameStack.length ? SymbolFlags.Namespace : targetMeaning;
const next = getSymbol(getExportsOfSymbol(getMergedSymbol(resolveSymbol(currentNamespace))), current.escapedText, meaning);
if (!next) {
error(current, Diagnostics.Namespace_0_has_no_exported_member_1, getFullyQualifiedName(currentNamespace), declarationNameToString(current));
return links.resolvedType = errorType;
}
getNodeLinks(current).resolvedSymbol = next;
getNodeLinks(current.parent).resolvedSymbol = next;
currentNamespace = next;
}
resolveImportSymbolType(node, links, currentNamespace, targetMeaning);
}
else {
if (moduleSymbol.flags & targetMeaning) {
resolveImportSymbolType(node, links, moduleSymbol, targetMeaning);
}
else {
const errorMessage = targetMeaning === SymbolFlags.Value
? Diagnostics.Module_0_does_not_refer_to_a_value_but_is_used_as_a_value_here
: Diagnostics.Module_0_does_not_refer_to_a_type_but_is_used_as_a_type_here_Did_you_mean_typeof_import_0;
error(node, errorMessage, node.argument.literal.text);
links.resolvedSymbol = unknownSymbol;
links.resolvedType = errorType;
}
}
}
return links.resolvedType!; // TODO: GH#18217
}
function resolveImportSymbolType(node: ImportTypeNode, links: NodeLinks, symbol: Symbol, meaning: SymbolFlags) {
const resolvedSymbol = resolveSymbol(symbol);
links.resolvedSymbol = resolvedSymbol;
if (meaning === SymbolFlags.Value) {
return links.resolvedType = getTypeOfSymbol(symbol); // intentionally doesn't use resolved symbol so type is cached as expected on the alias
}
else {
return links.resolvedType = getTypeReferenceType(node, resolvedSymbol); // getTypeReferenceType doesn't handle aliases - it must get the resolved symbol
}
}
function getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node: TypeNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
// Deferred resolution of members is handled by resolveObjectTypeMembers
const aliasSymbol = getAliasSymbolForTypeNode(node);
if (getMembersOfSymbol(node.symbol).size === 0 && !aliasSymbol) {
links.resolvedType = emptyTypeLiteralType;
}
else {
let type = createObjectType(ObjectFlags.Anonymous, node.symbol);
type.aliasSymbol = aliasSymbol;
type.aliasTypeArguments = getTypeArgumentsForAliasSymbol(aliasSymbol);
if (isJSDocTypeLiteral(node) && node.isArrayType) {
type = createArrayType(type);
}
links.resolvedType = type;
}
}
return links.resolvedType;
}
function getAliasSymbolForTypeNode(node: TypeNode) {
return isTypeAlias(node.parent) ? getSymbolOfNode(node.parent) : undefined;
}
function getTypeArgumentsForAliasSymbol(symbol: Symbol | undefined) {
return symbol ? getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(symbol) : undefined;
}
function isNonGenericObjectType(type: Type) {
return !!(type.flags & TypeFlags.Object) && !isGenericMappedType(type);
}
/**
* Since the source of spread types are object literals, which are not binary,
* this function should be called in a left folding style, with left = previous result of getSpreadType
* and right = the new element to be spread.
*/
function getSpreadType(left: Type, right: Type, symbol: Symbol | undefined, objectFlags: ObjectFlags, readonly: boolean): Type {
if (left.flags & TypeFlags.Any || right.flags & TypeFlags.Any) {
return anyType;
}
if (left.flags & TypeFlags.Unknown || right.flags & TypeFlags.Unknown) {
return unknownType;
}
if (left.flags & TypeFlags.Never) {
return right;
}
if (right.flags & TypeFlags.Never) {
return left;
}
if (left.flags & TypeFlags.Union) {
return mapType(left, t => getSpreadType(t, right, symbol, objectFlags, readonly));
}
if (right.flags & TypeFlags.Union) {
return mapType(right, t => getSpreadType(left, t, symbol, objectFlags, readonly));
}
if (right.flags & (TypeFlags.BooleanLike | TypeFlags.NumberLike | TypeFlags.BigIntLike | TypeFlags.StringLike | TypeFlags.EnumLike | TypeFlags.NonPrimitive | TypeFlags.Index)) {
return left;
}
if (isGenericObjectType(left) || isGenericObjectType(right)) {
if (isEmptyObjectType(left)) {
return right;
}
// When the left type is an intersection, we may need to merge the last constituent of the
// intersection with the right type. For example when the left type is 'T & { a: string }'
// and the right type is '{ b: string }' we produce 'T & { a: string, b: string }'.
if (left.flags & TypeFlags.Intersection) {
const types = (<IntersectionType>left).types;
const lastLeft = types[types.length - 1];
if (isNonGenericObjectType(lastLeft) && isNonGenericObjectType(right)) {
return getIntersectionType(concatenate(types.slice(0, types.length - 1), [getSpreadType(lastLeft, right, symbol, objectFlags, readonly)]));
}
}
return getIntersectionType([left, right]);
}
const members = createSymbolTable();
const skippedPrivateMembers = createUnderscoreEscapedMap<boolean>();
let stringIndexInfo: IndexInfo | undefined;
let numberIndexInfo: IndexInfo | undefined;
if (left === emptyObjectType) {
// for the first spread element, left === emptyObjectType, so take the right's string indexer
stringIndexInfo = getIndexInfoOfType(right, IndexKind.String);
numberIndexInfo = getIndexInfoOfType(right, IndexKind.Number);
}
else {
stringIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.String), getIndexInfoOfType(right, IndexKind.String));
numberIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.Number), getIndexInfoOfType(right, IndexKind.Number));
}
for (const rightProp of getPropertiesOfType(right)) {
if (getDeclarationModifierFlagsFromSymbol(rightProp) & (ModifierFlags.Private | ModifierFlags.Protected)) {
skippedPrivateMembers.set(rightProp.escapedName, true);
}
else if (isSpreadableProperty(rightProp)) {
members.set(rightProp.escapedName, getSpreadSymbol(rightProp, readonly));
}
}
for (const leftProp of getPropertiesOfType(left)) {
if (skippedPrivateMembers.has(leftProp.escapedName) || !isSpreadableProperty(leftProp)) {
continue;
}
if (members.has(leftProp.escapedName)) {
const rightProp = members.get(leftProp.escapedName)!;
const rightType = getTypeOfSymbol(rightProp);
if (rightProp.flags & SymbolFlags.Optional) {
const declarations = concatenate(leftProp.declarations, rightProp.declarations);
const flags = SymbolFlags.Property | (leftProp.flags & SymbolFlags.Optional);
const result = createSymbol(flags, leftProp.escapedName);
result.type = getUnionType([getTypeOfSymbol(leftProp), getTypeWithFacts(rightType, TypeFacts.NEUndefined)]);
result.leftSpread = leftProp;
result.rightSpread = rightProp;
result.declarations = declarations;
result.nameType = leftProp.nameType;
members.set(leftProp.escapedName, result);
}
}
else {
members.set(leftProp.escapedName, getSpreadSymbol(leftProp, readonly));
}
}
const spread = createAnonymousType(
symbol,
members,
emptyArray,
emptyArray,
getIndexInfoWithReadonly(stringIndexInfo, readonly),
getIndexInfoWithReadonly(numberIndexInfo, readonly));
spread.objectFlags |= ObjectFlags.ObjectLiteral | ObjectFlags.ContainsObjectLiteral | ObjectFlags.ContainsSpread | objectFlags;
return spread;
}
/** We approximate own properties as non-methods plus methods that are inside the object literal */
function isSpreadableProperty(prop: Symbol): boolean {
return !(prop.flags & (SymbolFlags.Method | SymbolFlags.GetAccessor | SymbolFlags.SetAccessor)) ||
!prop.declarations.some(decl => isClassLike(decl.parent));
}
function getSpreadSymbol(prop: Symbol, readonly: boolean) {
const isSetonlyAccessor = prop.flags & SymbolFlags.SetAccessor && !(prop.flags & SymbolFlags.GetAccessor);
if (!isSetonlyAccessor && readonly === isReadonlySymbol(prop)) {
return prop;
}
const flags = SymbolFlags.Property | (prop.flags & SymbolFlags.Optional);
const result = createSymbol(flags, prop.escapedName, readonly ? CheckFlags.Readonly : 0);
result.type = isSetonlyAccessor ? undefinedType : getTypeOfSymbol(prop);
result.declarations = prop.declarations;
result.nameType = prop.nameType;
result.syntheticOrigin = prop;
return result;
}
function getIndexInfoWithReadonly(info: IndexInfo | undefined, readonly: boolean) {
return info && info.isReadonly !== readonly ? createIndexInfo(info.type, readonly, info.declaration) : info;
}
function createLiteralType(flags: TypeFlags, value: string | number | PseudoBigInt, symbol: Symbol | undefined) {
const type = <LiteralType>createType(flags);
type.symbol = symbol!;
type.value = value;
return type;
}
function getFreshTypeOfLiteralType(type: Type): Type {
if (type.flags & TypeFlags.Literal) {
if (!(<LiteralType>type).freshType) {
const freshType = createLiteralType(type.flags, (<LiteralType>type).value, (<LiteralType>type).symbol);
freshType.regularType = <LiteralType>type;
freshType.freshType = freshType;
(<LiteralType>type).freshType = freshType;
}
return (<LiteralType>type).freshType;
}
return type;
}
function getRegularTypeOfLiteralType(type: Type): Type {
return type.flags & TypeFlags.Literal ? (<LiteralType>type).regularType :
type.flags & TypeFlags.Union ? getUnionType(sameMap((<UnionType>type).types, getRegularTypeOfLiteralType)) :
type;
}
function isFreshLiteralType(type: Type) {
return !!(type.flags & TypeFlags.Literal) && (<LiteralType>type).freshType === type;
}
function getLiteralType(value: string | number | PseudoBigInt, enumId?: number, symbol?: Symbol) {
// We store all literal types in a single map with keys of the form '#NNN' and '@SSS',
// where NNN is the text representation of a numeric literal and SSS are the characters
// of a string literal. For literal enum members we use 'EEE#NNN' and 'EEE@SSS', where
// EEE is a unique id for the containing enum type.
const qualifier = typeof value === "number" ? "#" : typeof value === "string" ? "@" : "n";
const key = (enumId ? enumId : "") + qualifier + (typeof value === "object" ? pseudoBigIntToString(value) : value);
let type = literalTypes.get(key);
if (!type) {
const flags = (typeof value === "number" ? TypeFlags.NumberLiteral :
typeof value === "string" ? TypeFlags.StringLiteral : TypeFlags.BigIntLiteral) |
(enumId ? TypeFlags.EnumLiteral : 0);
literalTypes.set(key, type = createLiteralType(flags, value, symbol));
type.regularType = type;
}
return type;
}
function getTypeFromLiteralTypeNode(node: LiteralTypeNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
links.resolvedType = getRegularTypeOfLiteralType(checkExpression(node.literal));
}
return links.resolvedType;
}
function createUniqueESSymbolType(symbol: Symbol) {
const type = <UniqueESSymbolType>createType(TypeFlags.UniqueESSymbol);
type.symbol = symbol;
type.escapedName = `__@${type.symbol.escapedName}@${getSymbolId(type.symbol)}` as __String;
return type;
}
function getESSymbolLikeTypeForNode(node: Node) {
if (isValidESSymbolDeclaration(node)) {
const symbol = getSymbolOfNode(node);
const links = getSymbolLinks(symbol);
return links.uniqueESSymbolType || (links.uniqueESSymbolType = createUniqueESSymbolType(symbol));
}
return esSymbolType;
}
function getThisType(node: Node): Type {
const container = getThisContainer(node, /*includeArrowFunctions*/ false);
const parent = container && container.parent;
if (parent && (isClassLike(parent) || parent.kind === SyntaxKind.InterfaceDeclaration)) {
if (!hasModifier(container, ModifierFlags.Static) &&
(container.kind !== SyntaxKind.Constructor || isNodeDescendantOf(node, (<ConstructorDeclaration>container).body!))) {
return getDeclaredTypeOfClassOrInterface(getSymbolOfNode(parent as ClassLikeDeclaration | InterfaceDeclaration)).thisType!;
}
}
error(node, Diagnostics.A_this_type_is_available_only_in_a_non_static_member_of_a_class_or_interface);
return errorType;
}
function getTypeFromThisTypeNode(node: ThisExpression | ThisTypeNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
links.resolvedType = getThisType(node);
}
return links.resolvedType;
}
function getTypeFromTypeNode(node: TypeNode): Type {
switch (node.kind) {
case SyntaxKind.AnyKeyword:
case SyntaxKind.JSDocAllType:
case SyntaxKind.JSDocUnknownType:
return anyType;
case SyntaxKind.UnknownKeyword:
return unknownType;
case SyntaxKind.StringKeyword:
return stringType;
case SyntaxKind.NumberKeyword:
return numberType;
case SyntaxKind.BigIntKeyword:
return bigintType;
case SyntaxKind.BooleanKeyword:
return booleanType;
case SyntaxKind.SymbolKeyword:
return esSymbolType;
case SyntaxKind.VoidKeyword:
return voidType;
case SyntaxKind.UndefinedKeyword:
return undefinedType;
case SyntaxKind.NullKeyword:
return nullType;
case SyntaxKind.NeverKeyword:
return neverType;
case SyntaxKind.ObjectKeyword:
return node.flags & NodeFlags.JavaScriptFile ? anyType : nonPrimitiveType;
case SyntaxKind.ThisType:
case SyntaxKind.ThisKeyword:
return getTypeFromThisTypeNode(node as ThisExpression | ThisTypeNode);
case SyntaxKind.LiteralType:
return getTypeFromLiteralTypeNode(<LiteralTypeNode>node);
case SyntaxKind.TypeReference:
return getTypeFromTypeReference(<TypeReferenceNode>node);
case SyntaxKind.TypePredicate:
return booleanType;
case SyntaxKind.ExpressionWithTypeArguments:
return getTypeFromTypeReference(<ExpressionWithTypeArguments>node);
case SyntaxKind.TypeQuery:
return getTypeFromTypeQueryNode(<TypeQueryNode>node);
case SyntaxKind.ArrayType:
return getTypeFromArrayTypeNode(<ArrayTypeNode>node);
case SyntaxKind.TupleType:
return getTypeFromTupleTypeNode(<TupleTypeNode>node);
case SyntaxKind.OptionalType:
return getTypeFromOptionalTypeNode(<OptionalTypeNode>node);
case SyntaxKind.UnionType:
return getTypeFromUnionTypeNode(<UnionTypeNode>node);
case SyntaxKind.IntersectionType:
return getTypeFromIntersectionTypeNode(<IntersectionTypeNode>node);
case SyntaxKind.JSDocNullableType:
return getTypeFromJSDocNullableTypeNode(<JSDocNullableType>node);
case SyntaxKind.JSDocOptionalType:
return addOptionality(getTypeFromTypeNode((node as JSDocOptionalType).type));
case SyntaxKind.ParenthesizedType:
case SyntaxKind.RestType:
case SyntaxKind.JSDocNonNullableType:
case SyntaxKind.JSDocTypeExpression:
return getTypeFromTypeNode((<ParenthesizedTypeNode | RestTypeNode | JSDocTypeReferencingNode | JSDocTypeExpression>node).type);
case SyntaxKind.JSDocVariadicType:
return getTypeFromJSDocVariadicType(node as JSDocVariadicType);
case SyntaxKind.FunctionType:
case SyntaxKind.ConstructorType:
case SyntaxKind.TypeLiteral:
case SyntaxKind.JSDocTypeLiteral:
case SyntaxKind.JSDocFunctionType:
case SyntaxKind.JSDocSignature:
return getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node);
case SyntaxKind.TypeOperator:
return getTypeFromTypeOperatorNode(<TypeOperatorNode>node);
case SyntaxKind.IndexedAccessType:
return getTypeFromIndexedAccessTypeNode(<IndexedAccessTypeNode>node);
case SyntaxKind.MappedType:
return getTypeFromMappedTypeNode(<MappedTypeNode>node);
case SyntaxKind.ConditionalType:
return getTypeFromConditionalTypeNode(<ConditionalTypeNode>node);
case SyntaxKind.InferType:
return getTypeFromInferTypeNode(<InferTypeNode>node);
case SyntaxKind.ImportType:
return getTypeFromImportTypeNode(<ImportTypeNode>node);
// This function assumes that an identifier or qualified name is a type expression
// Callers should first ensure this by calling isTypeNode
case SyntaxKind.Identifier:
case SyntaxKind.QualifiedName:
const symbol = getSymbolAtLocation(node);
return symbol ? getDeclaredTypeOfSymbol(symbol) : errorType;
default:
return errorType;
}
}
function instantiateList<T>(items: ReadonlyArray<T>, mapper: TypeMapper, instantiator: (item: T, mapper: TypeMapper) => T): ReadonlyArray<T>;
function instantiateList<T>(items: ReadonlyArray<T> | undefined, mapper: TypeMapper, instantiator: (item: T, mapper: TypeMapper) => T): ReadonlyArray<T> | undefined;
function instantiateList<T>(items: ReadonlyArray<T> | undefined, mapper: TypeMapper, instantiator: (item: T, mapper: TypeMapper) => T): ReadonlyArray<T> | undefined {
if (items && items.length) {
for (let i = 0; i < items.length; i++) {
const item = items[i];
const mapped = instantiator(item, mapper);
if (item !== mapped) {
const result = i === 0 ? [] : items.slice(0, i);
result.push(mapped);
for (i++; i < items.length; i++) {
result.push(instantiator(items[i], mapper));
}
return result;
}
}
}
return items;
}
function instantiateTypes(types: ReadonlyArray<Type>, mapper: TypeMapper): ReadonlyArray<Type>;
function instantiateTypes(types: ReadonlyArray<Type> | undefined, mapper: TypeMapper): ReadonlyArray<Type> | undefined;
function instantiateTypes(types: ReadonlyArray<Type> | undefined, mapper: TypeMapper): ReadonlyArray<Type> | undefined {
return instantiateList<Type>(types, mapper, instantiateType);
}
function instantiateSignatures(signatures: ReadonlyArray<Signature>, mapper: TypeMapper): ReadonlyArray<Signature> {
return instantiateList<Signature>(signatures, mapper, instantiateSignature);
}
function makeUnaryTypeMapper(source: Type, target: Type) {
return (t: Type) => t === source ? target : t;
}
function makeBinaryTypeMapper(source1: Type, target1: Type, source2: Type, target2: Type) {
return (t: Type) => t === source1 ? target1 : t === source2 ? target2 : t;
}
function makeArrayTypeMapper(sources: ReadonlyArray<Type>, targets: ReadonlyArray<Type> | undefined) {
return (t: Type) => {
for (let i = 0; i < sources.length; i++) {
if (t === sources[i]) {
return targets ? targets[i] : anyType;
}
}
return t;
};
}
function createTypeMapper(sources: ReadonlyArray<TypeParameter>, targets: ReadonlyArray<Type> | undefined): TypeMapper {
Debug.assert(targets === undefined || sources.length === targets.length);
return sources.length === 1 ? makeUnaryTypeMapper(sources[0], targets ? targets[0] : anyType) :
sources.length === 2 ? makeBinaryTypeMapper(sources[0], targets ? targets[0] : anyType, sources[1], targets ? targets[1] : anyType) :
makeArrayTypeMapper(sources, targets);
}
function createTypeEraser(sources: ReadonlyArray<TypeParameter>): TypeMapper {
return createTypeMapper(sources, /*targets*/ undefined);
}
/**
* Maps forward-references to later types parameters to the empty object type.
* This is used during inference when instantiating type parameter defaults.
*/
function createBackreferenceMapper(typeParameters: ReadonlyArray<TypeParameter>, index: number): TypeMapper {
return t => typeParameters.indexOf(t) >= index ? emptyObjectType : t;
}
function isInferenceContext(mapper: TypeMapper): mapper is InferenceContext {
return !!(<InferenceContext>mapper).typeParameters;
}
function cloneTypeMapper(mapper: TypeMapper, extraFlags: InferenceFlags = 0): TypeMapper {
return mapper && isInferenceContext(mapper) ?
createInferenceContext(mapper.typeParameters, mapper.signature, mapper.flags | extraFlags, mapper.compareTypes, mapper.inferences) :
mapper;
}
function cloneInferredPartOfContext(context: InferenceContext): InferenceContext | undefined {
// Filter context to only those parameters which actually have inference candidates
const params = [];
const inferences = [];
for (let i = 0; i < context.typeParameters.length; i++) {
const info = context.inferences[i];
if (info.candidates || info.contraCandidates) {
params.push(context.typeParameters[i]);
inferences.push(info);
}
}
if (!params.length) {
return undefined;
}
return createInferenceContext(params, context.signature, context.flags | InferenceFlags.NoDefault, context.compareTypes, inferences);
}
function combineTypeMappers(mapper1: TypeMapper | undefined, mapper2: TypeMapper): TypeMapper;
function combineTypeMappers(mapper1: TypeMapper, mapper2: TypeMapper | undefined): TypeMapper;
function combineTypeMappers(mapper1: TypeMapper, mapper2: TypeMapper): TypeMapper {
if (!mapper1) return mapper2;
if (!mapper2) return mapper1;
return t => instantiateType(mapper1(t), mapper2);
}
function createReplacementMapper(source: Type, target: Type, baseMapper: TypeMapper): TypeMapper {
return t => t === source ? target : baseMapper(t);
}
function permissiveMapper(type: Type) {
return type.flags & TypeFlags.TypeParameter ? wildcardType : type;
}
function getRestrictiveTypeParameter(tp: TypeParameter) {
return tp.constraint === unknownType ? tp : tp.restrictiveInstantiation || (
tp.restrictiveInstantiation = createTypeParameter(tp.symbol),
(tp.restrictiveInstantiation as TypeParameter).constraint = unknownType,
tp.restrictiveInstantiation
);
}
function restrictiveMapper(type: Type) {
return type.flags & TypeFlags.TypeParameter ? getRestrictiveTypeParameter(<TypeParameter>type) : type;
}
function cloneTypeParameter(typeParameter: TypeParameter): TypeParameter {
const result = createTypeParameter(typeParameter.symbol);
result.target = typeParameter;
return result;
}
function instantiateTypePredicate(predicate: TypePredicate, mapper: TypeMapper): ThisTypePredicate | IdentifierTypePredicate {
if (isIdentifierTypePredicate(predicate)) {
return {
kind: TypePredicateKind.Identifier,
parameterName: predicate.parameterName,
parameterIndex: predicate.parameterIndex,
type: instantiateType(predicate.type, mapper)
};
}
else {
return {
kind: TypePredicateKind.This,
type: instantiateType(predicate.type, mapper)
};
}
}
function instantiateSignature(signature: Signature, mapper: TypeMapper, eraseTypeParameters?: boolean): Signature {
let freshTypeParameters: TypeParameter[] | undefined;
if (signature.typeParameters && !eraseTypeParameters) {
// First create a fresh set of type parameters, then include a mapping from the old to the
// new type parameters in the mapper function. Finally store this mapper in the new type
// parameters such that we can use it when instantiating constraints.
freshTypeParameters = map(signature.typeParameters, cloneTypeParameter);
mapper = combineTypeMappers(createTypeMapper(signature.typeParameters, freshTypeParameters), mapper);
for (const tp of freshTypeParameters) {
tp.mapper = mapper;
}
}
// Don't compute resolvedReturnType and resolvedTypePredicate now,
// because using `mapper` now could trigger inferences to become fixed. (See `createInferenceContext`.)
// See GH#17600.
const result = createSignature(signature.declaration, freshTypeParameters,
signature.thisParameter && instantiateSymbol(signature.thisParameter, mapper),
instantiateList(signature.parameters, mapper, instantiateSymbol),
/*resolvedReturnType*/ undefined,
/*resolvedTypePredicate*/ undefined,
signature.minArgumentCount,
signature.hasRestParameter,
signature.hasLiteralTypes);
result.target = signature;
result.mapper = mapper;
return result;
}
function instantiateSymbol(symbol: Symbol, mapper: TypeMapper): Symbol {
const links = getSymbolLinks(symbol);
if (links.type && !maybeTypeOfKind(links.type, TypeFlags.Object | TypeFlags.Instantiable)) {
// If the type of the symbol is already resolved, and if that type could not possibly
// be affected by instantiation, simply return the symbol itself.
return symbol;
}
if (getCheckFlags(symbol) & CheckFlags.Instantiated) {
// If symbol being instantiated is itself a instantiation, fetch the original target and combine the
// type mappers. This ensures that original type identities are properly preserved and that aliases
// always reference a non-aliases.
symbol = links.target!;
mapper = combineTypeMappers(links.mapper!, mapper);
}
// Keep the flags from the symbol we're instantiating. Mark that is instantiated, and
// also transient so that we can just store data on it directly.
const result = createSymbol(symbol.flags, symbol.escapedName, CheckFlags.Instantiated | getCheckFlags(symbol) & (CheckFlags.Readonly | CheckFlags.Late | CheckFlags.OptionalParameter | CheckFlags.RestParameter));
result.declarations = symbol.declarations;
result.parent = symbol.parent;
result.target = symbol;
result.mapper = mapper;
if (symbol.valueDeclaration) {
result.valueDeclaration = symbol.valueDeclaration;
}
if (symbol.nameType) {
result.nameType = symbol.nameType;
}
return result;
}
function getAnonymousTypeInstantiation(type: AnonymousType, mapper: TypeMapper) {
const target = type.objectFlags & ObjectFlags.Instantiated ? type.target! : type;
const { symbol } = target;
const links = getSymbolLinks(symbol);
let typeParameters = links.outerTypeParameters;
if (!typeParameters) {
// The first time an anonymous type is instantiated we compute and store a list of the type
// parameters that are in scope (and therefore potentially referenced). For type literals that
// aren't the right hand side of a generic type alias declaration we optimize by reducing the
// set of type parameters to those that are possibly referenced in the literal.
let declaration = symbol.declarations[0];
if (isInJSFile(declaration)) {
const paramTag = findAncestor(declaration, isJSDocParameterTag);
if (paramTag) {
const paramSymbol = getParameterSymbolFromJSDoc(paramTag);
if (paramSymbol) {
declaration = paramSymbol.valueDeclaration;
}
}
}
let outerTypeParameters = getOuterTypeParameters(declaration, /*includeThisTypes*/ true);
if (isJSConstructor(declaration)) {
const templateTagParameters = getTypeParametersFromDeclaration(declaration as DeclarationWithTypeParameters);
outerTypeParameters = addRange(outerTypeParameters, templateTagParameters);
}
typeParameters = outerTypeParameters || emptyArray;
typeParameters = symbol.flags & SymbolFlags.TypeLiteral && !target.aliasTypeArguments ?
filter(typeParameters, tp => isTypeParameterPossiblyReferenced(tp, declaration)) :
typeParameters;
links.outerTypeParameters = typeParameters;
if (typeParameters.length) {
links.instantiations = createMap<Type>();
links.instantiations.set(getTypeListId(typeParameters), target);
}
}
if (typeParameters.length) {
// We are instantiating an anonymous type that has one or more type parameters in scope. Apply the
// mapper to the type parameters to produce the effective list of type arguments, and compute the
// instantiation cache key from the type IDs of the type arguments.
const combinedMapper = type.objectFlags & ObjectFlags.Instantiated ? combineTypeMappers(type.mapper!, mapper) : mapper;
const typeArguments: Type[] = map(typeParameters, combinedMapper);
const id = getTypeListId(typeArguments);
let result = links.instantiations!.get(id);
if (!result) {
const newMapper = createTypeMapper(typeParameters, typeArguments);
result = target.objectFlags & ObjectFlags.Mapped ? instantiateMappedType(<MappedType>target, newMapper) : instantiateAnonymousType(target, newMapper);
links.instantiations!.set(id, result);
}
return result;
}
return type;
}
function maybeTypeParameterReference(node: Node) {
return !(node.kind === SyntaxKind.QualifiedName ||
node.parent.kind === SyntaxKind.TypeReference && (<TypeReferenceNode>node.parent).typeArguments && node === (<TypeReferenceNode>node.parent).typeName);
}
function isTypeParameterPossiblyReferenced(tp: TypeParameter, node: Node) {
// If the type parameter doesn't have exactly one declaration, if there are invening statement blocks
// between the node and the type parameter declaration, if the node contains actual references to the
// type parameter, or if the node contains type queries, we consider the type parameter possibly referenced.
if (tp.symbol && tp.symbol.declarations && tp.symbol.declarations.length === 1) {
const container = tp.symbol.declarations[0].parent;
if (findAncestor(node, n => n.kind === SyntaxKind.Block ? "quit" : n === container)) {
return !!forEachChild(node, containsReference);
}
}
return true;
function containsReference(node: Node): boolean {
switch (node.kind) {
case SyntaxKind.ThisType:
return !!tp.isThisType;
case SyntaxKind.Identifier:
return !tp.isThisType && isPartOfTypeNode(node) && maybeTypeParameterReference(node) &&
getTypeFromTypeNode(<TypeNode>node) === tp;
case SyntaxKind.TypeQuery:
return true;
}
return !!forEachChild(node, containsReference);
}
}
function getHomomorphicTypeVariable(type: MappedType) {
const constraintType = getConstraintTypeFromMappedType(type);
if (constraintType.flags & TypeFlags.Index) {
const typeVariable = getActualTypeVariable((<IndexType>constraintType).type);
if (typeVariable.flags & TypeFlags.TypeParameter) {
return <TypeParameter>typeVariable;
}
}
return undefined;
}
function instantiateMappedType(type: MappedType, mapper: TypeMapper): Type {
// For a homomorphic mapped type { [P in keyof T]: X }, where T is some type variable, the mapping
// operation depends on T as follows:
// * If T is a primitive type no mapping is performed and the result is simply T.
// * If T is a union type we distribute the mapped type over the union.
// * If T is an array we map to an array where the element type has been transformed.
// * If T is a tuple we map to a tuple where the element types have been transformed.
// * Otherwise we map to an object type where the type of each property has been transformed.
// For example, when T is instantiated to a union type A | B, we produce { [P in keyof A]: X } |
// { [P in keyof B]: X }, and when when T is instantiated to a union type A | undefined, we produce
// { [P in keyof A]: X } | undefined.
const typeVariable = getHomomorphicTypeVariable(type);
if (typeVariable) {
const mappedTypeVariable = instantiateType(typeVariable, mapper);
if (typeVariable !== mappedTypeVariable) {
return mapType(mappedTypeVariable, t => {
if (t.flags & (TypeFlags.AnyOrUnknown | TypeFlags.InstantiableNonPrimitive | TypeFlags.Object | TypeFlags.Intersection) && t !== wildcardType && t !== errorType) {
const replacementMapper = createReplacementMapper(typeVariable, t, mapper);
return isArrayType(t) ? instantiateMappedArrayType(t, type, replacementMapper) :
isTupleType(t) ? instantiateMappedTupleType(t, type, replacementMapper) :
instantiateAnonymousType(type, replacementMapper);
}
return t;
});
}
}
return instantiateAnonymousType(type, mapper);
}
function getModifiedReadonlyState(state: boolean, modifiers: MappedTypeModifiers) {
return modifiers & MappedTypeModifiers.IncludeReadonly ? true : modifiers & MappedTypeModifiers.ExcludeReadonly ? false : state;
}
function instantiateMappedArrayType(arrayType: Type, mappedType: MappedType, mapper: TypeMapper) {
const elementType = instantiateMappedTypeTemplate(mappedType, numberType, /*isOptional*/ true, mapper);
return elementType === errorType ? errorType :
createArrayType(elementType, getModifiedReadonlyState(isReadonlyArrayType(arrayType), getMappedTypeModifiers(mappedType)));
}
function instantiateMappedTupleType(tupleType: TupleTypeReference, mappedType: MappedType, mapper: TypeMapper) {
const minLength = tupleType.target.minLength;
const elementTypes = map(tupleType.typeArguments || emptyArray, (_, i) =>
instantiateMappedTypeTemplate(mappedType, getLiteralType("" + i), i >= minLength, mapper));
const modifiers = getMappedTypeModifiers(mappedType);
const newMinLength = modifiers & MappedTypeModifiers.IncludeOptional ? 0 :
modifiers & MappedTypeModifiers.ExcludeOptional ? getTypeReferenceArity(tupleType) - (tupleType.target.hasRestElement ? 1 : 0) :
minLength;
const newReadonly = getModifiedReadonlyState(tupleType.target.readonly, modifiers);
return contains(elementTypes, errorType) ? errorType :
createTupleType(elementTypes, newMinLength, tupleType.target.hasRestElement, newReadonly, tupleType.target.associatedNames);
}
function instantiateMappedTypeTemplate(type: MappedType, key: Type, isOptional: boolean, mapper: TypeMapper) {
const templateMapper = combineTypeMappers(mapper, createTypeMapper([getTypeParameterFromMappedType(type)], [key]));
const propType = instantiateType(getTemplateTypeFromMappedType(<MappedType>type.target || type), templateMapper);
const modifiers = getMappedTypeModifiers(type);
return strictNullChecks && modifiers & MappedTypeModifiers.IncludeOptional && !isTypeAssignableTo(undefinedType, propType) ? getOptionalType(propType) :
strictNullChecks && modifiers & MappedTypeModifiers.ExcludeOptional && isOptional ? getTypeWithFacts(propType, TypeFacts.NEUndefined) :
propType;
}
function instantiateAnonymousType(type: AnonymousType, mapper: TypeMapper): AnonymousType {
const result = <AnonymousType>createObjectType(type.objectFlags | ObjectFlags.Instantiated, type.symbol);
if (type.objectFlags & ObjectFlags.Mapped) {
(<MappedType>result).declaration = (<MappedType>type).declaration;
// C.f. instantiateSignature
const origTypeParameter = getTypeParameterFromMappedType(<MappedType>type);
const freshTypeParameter = cloneTypeParameter(origTypeParameter);
(<MappedType>result).typeParameter = freshTypeParameter;
mapper = combineTypeMappers(makeUnaryTypeMapper(origTypeParameter, freshTypeParameter), mapper);
freshTypeParameter.mapper = mapper;
}
result.target = type;
result.mapper = mapper;
result.aliasSymbol = type.aliasSymbol;
result.aliasTypeArguments = instantiateTypes(type.aliasTypeArguments, mapper);
return result;
}
function getConditionalTypeInstantiation(type: ConditionalType, mapper: TypeMapper): Type {
const root = type.root;
if (root.outerTypeParameters) {
// We are instantiating a conditional type that has one or more type parameters in scope. Apply the
// mapper to the type parameters to produce the effective list of type arguments, and compute the
// instantiation cache key from the type IDs of the type arguments.
const typeArguments = map(root.outerTypeParameters, mapper);
const id = getTypeListId(typeArguments);
let result = root.instantiations!.get(id);
if (!result) {
const newMapper = createTypeMapper(root.outerTypeParameters, typeArguments);
result = instantiateConditionalType(root, newMapper);
root.instantiations!.set(id, result);
}
return result;
}
return type;
}
function instantiateConditionalType(root: ConditionalRoot, mapper: TypeMapper): Type {
// Check if we have a conditional type where the check type is a naked type parameter. If so,
// the conditional type is distributive over union types and when T is instantiated to a union
// type A | B, we produce (A extends U ? X : Y) | (B extends U ? X : Y).
if (root.isDistributive) {
const checkType = <TypeParameter>root.checkType;
const instantiatedType = mapper(checkType);
if (checkType !== instantiatedType && instantiatedType.flags & (TypeFlags.Union | TypeFlags.Never)) {
return mapType(instantiatedType, t => getConditionalType(root, createReplacementMapper(checkType, t, mapper)));
}
}
return getConditionalType(root, mapper);
}
function instantiateType(type: Type, mapper: TypeMapper | undefined): Type;
function instantiateType(type: Type | undefined, mapper: TypeMapper | undefined): Type | undefined;
function instantiateType(type: Type | undefined, mapper: TypeMapper | undefined): Type | undefined {
if (!type || !mapper || mapper === identityMapper) {
return type;
}
if (instantiationDepth === 50) {
// We have reached 50 recursive type instantiations and there is a very high likelyhood we're dealing
// with a combination of infinite generic types that perpetually generate new type identities. We stop
// the recursion here by yielding the error type.
error(currentNode, Diagnostics.Type_instantiation_is_excessively_deep_and_possibly_infinite);
return errorType;
}
instantiationDepth++;
const result = instantiateTypeWorker(type, mapper);
instantiationDepth--;
return result;
}
function instantiateTypeWorker(type: Type, mapper: TypeMapper): Type {
const flags = type.flags;
if (flags & TypeFlags.TypeParameter) {
return mapper(type);
}
if (flags & TypeFlags.Object) {
const objectFlags = (<ObjectType>type).objectFlags;
if (objectFlags & ObjectFlags.Anonymous) {
// If the anonymous type originates in a declaration of a function, method, class, or
// interface, in an object type literal, or in an object literal expression, we may need
// to instantiate the type because it might reference a type parameter.
return type.symbol && type.symbol.flags & (SymbolFlags.Function | SymbolFlags.Method | SymbolFlags.Class | SymbolFlags.TypeLiteral | SymbolFlags.ObjectLiteral) && type.symbol.declarations ?
getAnonymousTypeInstantiation(<AnonymousType>type, mapper) : type;
}
if (objectFlags & ObjectFlags.Mapped) {
return getAnonymousTypeInstantiation(<AnonymousType>type, mapper);
}
if (objectFlags & ObjectFlags.Reference) {
const typeArguments = (<TypeReference>type).typeArguments;
const newTypeArguments = instantiateTypes(typeArguments, mapper);
return newTypeArguments !== typeArguments ? createTypeReference((<TypeReference>type).target, newTypeArguments) : type;
}
return type;
}
if (flags & TypeFlags.Union && !(flags & TypeFlags.Primitive)) {
const types = (<UnionType>type).types;
const newTypes = instantiateTypes(types, mapper);
return newTypes !== types ? getUnionType(newTypes, UnionReduction.Literal, type.aliasSymbol, instantiateTypes(type.aliasTypeArguments, mapper)) : type;
}
if (flags & TypeFlags.Intersection) {
const types = (<IntersectionType>type).types;
const newTypes = instantiateTypes(types, mapper);
return newTypes !== types ? getIntersectionType(newTypes, type.aliasSymbol, instantiateTypes(type.aliasTypeArguments, mapper)) : type;
}
if (flags & TypeFlags.Index) {
return getIndexType(instantiateType((<IndexType>type).type, mapper));
}
if (flags & TypeFlags.IndexedAccess) {
return getIndexedAccessType(instantiateType((<IndexedAccessType>type).objectType, mapper), instantiateType((<IndexedAccessType>type).indexType, mapper));
}
if (flags & TypeFlags.Conditional) {
return getConditionalTypeInstantiation(<ConditionalType>type, combineTypeMappers((<ConditionalType>type).mapper, mapper));
}
if (flags & TypeFlags.Substitution) {
const maybeVariable = instantiateType((<SubstitutionType>type).typeVariable, mapper);
if (maybeVariable.flags & TypeFlags.TypeVariable) {
return getSubstitutionType(maybeVariable as TypeVariable, instantiateType((<SubstitutionType>type).substitute, mapper));
}
else {
return maybeVariable;
}
}
return type;
}
function getPermissiveInstantiation(type: Type) {
return type.flags & (TypeFlags.Primitive | TypeFlags.AnyOrUnknown | TypeFlags.Never) ? type :
type.permissiveInstantiation || (type.permissiveInstantiation = instantiateType(type, permissiveMapper));
}
function getRestrictiveInstantiation(type: Type) {
return type.flags & (TypeFlags.Primitive | TypeFlags.AnyOrUnknown | TypeFlags.Never) ? type :
type.restrictiveInstantiation || (type.restrictiveInstantiation = instantiateType(type, restrictiveMapper));
}
function instantiateIndexInfo(info: IndexInfo | undefined, mapper: TypeMapper): IndexInfo | undefined {
return info && createIndexInfo(instantiateType(info.type, mapper), info.isReadonly, info.declaration);
}
// Returns true if the given expression contains (at any level of nesting) a function or arrow expression
// that is subject to contextual typing.
function isContextSensitive(node: Expression | MethodDeclaration | ObjectLiteralElementLike | JsxAttributeLike | JsxChild): boolean {
Debug.assert(node.kind !== SyntaxKind.MethodDeclaration || isObjectLiteralMethod(node));
switch (node.kind) {
case SyntaxKind.FunctionExpression:
case SyntaxKind.ArrowFunction:
case SyntaxKind.MethodDeclaration:
return isContextSensitiveFunctionLikeDeclaration(<FunctionExpression | ArrowFunction | MethodDeclaration>node);
case SyntaxKind.ObjectLiteralExpression:
return some((<ObjectLiteralExpression>node).properties, isContextSensitive);
case SyntaxKind.ArrayLiteralExpression:
return some((<ArrayLiteralExpression>node).elements, isContextSensitive);
case SyntaxKind.ConditionalExpression:
return isContextSensitive((<ConditionalExpression>node).whenTrue) ||
isContextSensitive((<ConditionalExpression>node).whenFalse);
case SyntaxKind.BinaryExpression:
return (<BinaryExpression>node).operatorToken.kind === SyntaxKind.BarBarToken &&
(isContextSensitive((<BinaryExpression>node).left) || isContextSensitive((<BinaryExpression>node).right));
case SyntaxKind.PropertyAssignment:
return isContextSensitive((<PropertyAssignment>node).initializer);
case SyntaxKind.ParenthesizedExpression:
return isContextSensitive((<ParenthesizedExpression>node).expression);
case SyntaxKind.JsxAttributes:
return some((<JsxAttributes>node).properties, isContextSensitive) || isJsxOpeningElement(node.parent) && some(node.parent.parent.children, isContextSensitive);
case SyntaxKind.JsxAttribute: {
// If there is no initializer, JSX attribute has a boolean value of true which is not context sensitive.
const { initializer } = node as JsxAttribute;
return !!initializer && isContextSensitive(initializer);
}
case SyntaxKind.JsxExpression: {
// It is possible to that node.expression is undefined (e.g <div x={} />)
const { expression } = node as JsxExpression;
return !!expression && isContextSensitive(expression);
}
}
return false;
}
function isContextSensitiveFunctionLikeDeclaration(node: FunctionLikeDeclaration): boolean {
// Functions with type parameters are not context sensitive.
if (node.typeParameters) {
return false;
}
// Functions with any parameters that lack type annotations are context sensitive.
if (some(node.parameters, p => !getEffectiveTypeAnnotationNode(p))) {
return true;
}
if (node.kind !== SyntaxKind.ArrowFunction) {
// If the first parameter is not an explicit 'this' parameter, then the function has
// an implicit 'this' parameter which is subject to contextual typing.
const parameter = firstOrUndefined(node.parameters);
if (!(parameter && parameterIsThisKeyword(parameter))) {
return true;
}
}
return hasContextSensitiveReturnExpression(node);
}
function hasContextSensitiveReturnExpression(node: FunctionLikeDeclaration) {
// TODO(anhans): A block should be context-sensitive if it has a context-sensitive return value.
return !!node.body && node.body.kind !== SyntaxKind.Block && isContextSensitive(node.body);
}
function isContextSensitiveFunctionOrObjectLiteralMethod(func: Node): func is FunctionExpression | ArrowFunction | MethodDeclaration {
return (isInJSFile(func) && isFunctionDeclaration(func) || isFunctionExpressionOrArrowFunction(func) || isObjectLiteralMethod(func)) &&
isContextSensitiveFunctionLikeDeclaration(func);
}
function getTypeWithoutSignatures(type: Type): Type {
if (type.flags & TypeFlags.Object) {
const resolved = resolveStructuredTypeMembers(<ObjectType>type);
if (resolved.constructSignatures.length || resolved.callSignatures.length) {
const result = createObjectType(ObjectFlags.Anonymous, type.symbol);
result.members = resolved.members;
result.properties = resolved.properties;
result.callSignatures = emptyArray;
result.constructSignatures = emptyArray;
return result;
}
}
else if (type.flags & TypeFlags.Intersection) {
return getIntersectionType(map((<IntersectionType>type).types, getTypeWithoutSignatures));
}
return type;
}
// TYPE CHECKING
function isTypeIdenticalTo(source: Type, target: Type): boolean {
return isTypeRelatedTo(source, target, identityRelation);
}
function compareTypesIdentical(source: Type, target: Type): Ternary {
return isTypeRelatedTo(source, target, identityRelation) ? Ternary.True : Ternary.False;
}
function compareTypesAssignable(source: Type, target: Type): Ternary {
return isTypeRelatedTo(source, target, assignableRelation) ? Ternary.True : Ternary.False;
}
function compareTypesSubtypeOf(source: Type, target: Type): Ternary {
return isTypeRelatedTo(source, target, subtypeRelation) ? Ternary.True : Ternary.False;
}
function isTypeSubtypeOf(source: Type, target: Type): boolean {
return isTypeRelatedTo(source, target, subtypeRelation);
}
function isTypeAssignableTo(source: Type, target: Type): boolean {
return isTypeRelatedTo(source, target, assignableRelation);
}
// An object type S is considered to be derived from an object type T if
// S is a union type and every constituent of S is derived from T,
// T is a union type and S is derived from at least one constituent of T, or
// S is a type variable with a base constraint that is derived from T,
// T is one of the global types Object and Function and S is a subtype of T, or
// T occurs directly or indirectly in an 'extends' clause of S.
// Note that this check ignores type parameters and only considers the
// inheritance hierarchy.
function isTypeDerivedFrom(source: Type, target: Type): boolean {
return source.flags & TypeFlags.Union ? every((<UnionType>source).types, t => isTypeDerivedFrom(t, target)) :
target.flags & TypeFlags.Union ? some((<UnionType>target).types, t => isTypeDerivedFrom(source, t)) :
source.flags & TypeFlags.InstantiableNonPrimitive ? isTypeDerivedFrom(getBaseConstraintOfType(source) || emptyObjectType, target) :
target === globalObjectType ? !!(source.flags & (TypeFlags.Object | TypeFlags.NonPrimitive)) :
target === globalFunctionType ? !!(source.flags & TypeFlags.Object) && isFunctionObjectType(source as ObjectType) :
hasBaseType(source, getTargetType(target));
}
/**
* This is *not* a bi-directional relationship.
* If one needs to check both directions for comparability, use a second call to this function or 'checkTypeComparableTo'.
*
* A type S is comparable to a type T if some (but not necessarily all) of the possible values of S are also possible values of T.
* It is used to check following cases:
* - the types of the left and right sides of equality/inequality operators (`===`, `!==`, `==`, `!=`).
* - the types of `case` clause expressions and their respective `switch` expressions.
* - the type of an expression in a type assertion with the type being asserted.
*/
function isTypeComparableTo(source: Type, target: Type): boolean {
return isTypeRelatedTo(source, target, comparableRelation);
}
function areTypesComparable(type1: Type, type2: Type): boolean {
return isTypeComparableTo(type1, type2) || isTypeComparableTo(type2, type1);
}
function checkTypeAssignableTo(source: Type, target: Type, errorNode: Node | undefined, headMessage?: DiagnosticMessage, containingMessageChain?: () => DiagnosticMessageChain | undefined, errorOutputObject?: { error?: Diagnostic }): boolean {
return checkTypeRelatedTo(source, target, assignableRelation, errorNode, headMessage, containingMessageChain, errorOutputObject);
}
/**
* Like `checkTypeAssignableTo`, but if it would issue an error, instead performs structural comparisons of the types using the given expression node to
* attempt to issue more specific errors on, for example, specific object literal properties or tuple members.
*/
function checkTypeAssignableToAndOptionallyElaborate(source: Type, target: Type, errorNode: Node | undefined, expr: Expression | undefined, headMessage?: DiagnosticMessage, containingMessageChain?: () => DiagnosticMessageChain | undefined): boolean {
return checkTypeRelatedToAndOptionallyElaborate(source, target, assignableRelation, errorNode, expr, headMessage, containingMessageChain);
}
function checkTypeRelatedToAndOptionallyElaborate(source: Type, target: Type, relation: Map<RelationComparisonResult>, errorNode: Node | undefined, expr: Expression | undefined, headMessage?: DiagnosticMessage, containingMessageChain?: () => DiagnosticMessageChain | undefined): boolean {
if (isTypeRelatedTo(source, target, relation)) return true;
if (!errorNode || !elaborateError(expr, source, target, relation, headMessage)) {
return checkTypeRelatedTo(source, target, relation, errorNode, headMessage, containingMessageChain);
}
return false;
}
function isOrHasGenericConditional(type: Type): boolean {
return !!(type.flags & TypeFlags.Conditional || (type.flags & TypeFlags.Intersection && some((type as IntersectionType).types, isOrHasGenericConditional)));
}
function elaborateError(node: Expression | undefined, source: Type, target: Type, relation: Map<RelationComparisonResult>, headMessage: DiagnosticMessage | undefined): boolean {
if (!node || isOrHasGenericConditional(target)) return false;
if (!checkTypeRelatedTo(source, target, relation, /*errorNode*/ undefined) && elaborateDidYouMeanToCallOrConstruct(node, source, target, relation, headMessage)) {
return true;
}
switch (node.kind) {
case SyntaxKind.JsxExpression:
case SyntaxKind.ParenthesizedExpression:
return elaborateError((node as ParenthesizedExpression | JsxExpression).expression, source, target, relation, headMessage);
case SyntaxKind.BinaryExpression:
switch ((node as BinaryExpression).operatorToken.kind) {
case SyntaxKind.EqualsToken:
case SyntaxKind.CommaToken:
return elaborateError((node as BinaryExpression).right, source, target, relation, headMessage);
}
break;
case SyntaxKind.ObjectLiteralExpression:
return elaborateObjectLiteral(node as ObjectLiteralExpression, source, target, relation);
case SyntaxKind.ArrayLiteralExpression:
return elaborateArrayLiteral(node as ArrayLiteralExpression, source, target, relation);
case SyntaxKind.JsxAttributes:
return elaborateJsxComponents(node as JsxAttributes, source, target, relation);
case SyntaxKind.ArrowFunction:
return elaborateArrowFunction(node as ArrowFunction, source, target, relation);
}
return false;
}
function elaborateDidYouMeanToCallOrConstruct(node: Expression, source: Type, target: Type, relation: Map<RelationComparisonResult>, headMessage: DiagnosticMessage | undefined): boolean {
const callSignatures = getSignaturesOfType(source, SignatureKind.Call);
const constructSignatures = getSignaturesOfType(source, SignatureKind.Construct);
for (const signatures of [constructSignatures, callSignatures]) {
if (some(signatures, s => {
const returnType = getReturnTypeOfSignature(s);
return !(returnType.flags & (TypeFlags.Any | TypeFlags.Never)) && checkTypeRelatedTo(returnType, target, relation, /*errorNode*/ undefined);
})) {
const resultObj: { error?: Diagnostic } = {};
checkTypeAssignableTo(source, target, node, headMessage, /*containingChain*/ undefined, resultObj);
const diagnostic = resultObj.error!;
addRelatedInfo(diagnostic, createDiagnosticForNode(
node,
signatures === constructSignatures ? Diagnostics.Did_you_mean_to_use_new_with_this_expression : Diagnostics.Did_you_mean_to_call_this_expression
));
return true;
}
}
return false;
}
function elaborateArrowFunction(node: ArrowFunction, source: Type, target: Type, relation: Map<RelationComparisonResult>): boolean {
// Don't elaborate blocks
if (isBlock(node.body)) {
return false;
}
// Or functions with annotated parameter types
if (some(node.parameters, ts.hasType)) {
return false;
}
const sourceSig = getSingleCallSignature(source);
if (!sourceSig) {
return false;
}
const targetSignatures = getSignaturesOfType(target, SignatureKind.Call);
if (!length(targetSignatures)) {
return false;
}
const returnExpression = node.body;
const sourceReturn = getReturnTypeOfSignature(sourceSig);
const targetReturn = getUnionType(map(targetSignatures, getReturnTypeOfSignature));
if (!checkTypeRelatedTo(sourceReturn, targetReturn, relation, /*errorNode*/ undefined)) {
const elaborated = returnExpression && elaborateError(returnExpression, sourceReturn, targetReturn, relation, /*headMessage*/ undefined);
if (elaborated) {
return elaborated;
}
const resultObj: { error?: Diagnostic } = {};
checkTypeRelatedTo(sourceReturn, targetReturn, relation, returnExpression, /*message*/ undefined, /*chain*/ undefined, resultObj);
if (resultObj.error) {
if (target.symbol && length(target.symbol.declarations)) {
addRelatedInfo(resultObj.error, createDiagnosticForNode(
target.symbol.declarations[0],
Diagnostics.The_expected_type_comes_from_the_return_type_of_this_signature,
));
}
return true;
}
}
return false;
}
type ElaborationIterator = IterableIterator<{ errorNode: Node, innerExpression: Expression | undefined, nameType: Type, errorMessage?: DiagnosticMessage | undefined }>;
/**
* For every element returned from the iterator, checks that element to issue an error on a property of that element's type
* If that element would issue an error, we first attempt to dive into that element's inner expression and issue a more specific error by recuring into `elaborateError`
* Otherwise, we issue an error on _every_ element which fail the assignability check
*/
function elaborateElementwise(iterator: ElaborationIterator, source: Type, target: Type, relation: Map<RelationComparisonResult>) {
// Assignability failure - check each prop individually, and if that fails, fall back on the bad error span
let reportedError = false;
for (let status = iterator.next(); !status.done; status = iterator.next()) {
const { errorNode: prop, innerExpression: next, nameType, errorMessage } = status.value;
const targetPropType = getIndexedAccessType(target, nameType, /*accessNode*/ undefined, errorType);
if (targetPropType === errorType || targetPropType.flags & TypeFlags.IndexedAccess) continue; // Don't elaborate on indexes on generic variables
const sourcePropType = getIndexedAccessType(source, nameType, /*accessNode*/ undefined, errorType);
if (sourcePropType !== errorType && targetPropType !== errorType && !checkTypeRelatedTo(sourcePropType, targetPropType, relation, /*errorNode*/ undefined)) {
const elaborated = next && elaborateError(next, sourcePropType, targetPropType, relation, /*headMessage*/ undefined);
if (elaborated) {
reportedError = true;
}
else {
// Issue error on the prop itself, since the prop couldn't elaborate the error
const resultObj: { error?: Diagnostic } = {};
// Use the expression type, if available
const specificSource = next ? checkExpressionForMutableLocation(next, CheckMode.Normal, sourcePropType) : sourcePropType;
const result = checkTypeRelatedTo(specificSource, targetPropType, relation, prop, errorMessage, /*containingChain*/ undefined, resultObj);
if (result && specificSource !== sourcePropType) {
// If for whatever reason the expression type doesn't yield an error, make sure we still issue an error on the sourcePropType
checkTypeRelatedTo(sourcePropType, targetPropType, relation, prop, errorMessage, /*containingChain*/ undefined, resultObj);
}
if (resultObj.error) {
const reportedDiag = resultObj.error;
const propertyName = isTypeUsableAsPropertyName(nameType) ? getPropertyNameFromType(nameType) : undefined;
const targetProp = propertyName !== undefined ? getPropertyOfType(target, propertyName) : undefined;
let issuedElaboration = false;
if (!targetProp) {
const indexInfo = isTypeAssignableToKind(nameType, TypeFlags.NumberLike) && getIndexInfoOfType(target, IndexKind.Number) ||
getIndexInfoOfType(target, IndexKind.String) ||
undefined;
if (indexInfo && indexInfo.declaration && !getSourceFileOfNode(indexInfo.declaration).hasNoDefaultLib) {
issuedElaboration = true;
addRelatedInfo(reportedDiag, createDiagnosticForNode(indexInfo.declaration, Diagnostics.The_expected_type_comes_from_this_index_signature));
}
}
if (!issuedElaboration && (targetProp && length(targetProp.declarations) || target.symbol && length(target.symbol.declarations))) {
const targetNode = targetProp && length(targetProp.declarations) ? targetProp.declarations[0] : target.symbol.declarations[0];
if (!getSourceFileOfNode(targetNode).hasNoDefaultLib) {
addRelatedInfo(reportedDiag, createDiagnosticForNode(
targetNode,
Diagnostics.The_expected_type_comes_from_property_0_which_is_declared_here_on_type_1,
propertyName && !(nameType.flags & TypeFlags.UniqueESSymbol) ? unescapeLeadingUnderscores(propertyName) : typeToString(nameType),
typeToString(target)
));
}
}
}
reportedError = true;
}
}
}
return reportedError;
}
function *generateJsxAttributes(node: JsxAttributes): ElaborationIterator {
if (!length(node.properties)) return;
for (const prop of node.properties) {
if (isJsxSpreadAttribute(prop)) continue;
yield { errorNode: prop.name, innerExpression: prop.initializer, nameType: getLiteralType(idText(prop.name)) };
}
}
function *generateJsxChildren(node: JsxElement, getInvalidTextDiagnostic: () => DiagnosticMessage): ElaborationIterator {
if (!length(node.children)) return;
let memberOffset = 0;
for (let i = 0; i < node.children.length; i++) {
const child = node.children[i];
const nameType = getLiteralType(i - memberOffset);
const elem = getElaborationElementForJsxChild(child, nameType, getInvalidTextDiagnostic);
if (elem) {
yield elem;
}
else {
memberOffset++;
}
}
}
function getElaborationElementForJsxChild(child: JsxChild, nameType: LiteralType, getInvalidTextDiagnostic: () => DiagnosticMessage) {
switch (child.kind) {
case SyntaxKind.JsxExpression:
// child is of the type of the expression
return { errorNode: child, innerExpression: child.expression, nameType };
case SyntaxKind.JsxText:
if (child.containsOnlyWhiteSpaces) {
break; // Whitespace only jsx text isn't real jsx text
}
// child is a string
return { errorNode: child, innerExpression: undefined, nameType, errorMessage: getInvalidTextDiagnostic() };
case SyntaxKind.JsxElement:
case SyntaxKind.JsxSelfClosingElement:
case SyntaxKind.JsxFragment:
// child is of type JSX.Element
return { errorNode: child, innerExpression: child, nameType };
default:
return Debug.assertNever(child, "Found invalid jsx child");
}
}
function elaborateJsxComponents(node: JsxAttributes, source: Type, target: Type, relation: Map<RelationComparisonResult>) {
let result = elaborateElementwise(generateJsxAttributes(node), source, target, relation);
let invalidTextDiagnostic: DiagnosticMessage | undefined;
if (isJsxOpeningElement(node.parent) && isJsxElement(node.parent.parent)) {
const containingElement = node.parent.parent;
const childPropName = getJsxElementChildrenPropertyName(getJsxNamespaceAt(node));
const childrenPropName = childPropName === undefined ? "children" : unescapeLeadingUnderscores(childPropName);
const childrenNameType = getLiteralType(childrenPropName);
const childrenTargetType = getIndexedAccessType(target, childrenNameType);
const validChildren = filter(containingElement.children, i => !isJsxText(i) || !i.containsOnlyWhiteSpaces);
if (!length(validChildren)) {
return result;
}
const moreThanOneRealChildren = length(validChildren) > 1;
const arrayLikeTargetParts = filterType(childrenTargetType, isArrayOrTupleLikeType);
const nonArrayLikeTargetParts = filterType(childrenTargetType, t => !isArrayOrTupleLikeType(t));
if (moreThanOneRealChildren) {
if (arrayLikeTargetParts !== neverType) {
const realSource = createTupleType(checkJsxChildren(containingElement, CheckMode.Normal));
result = elaborateElementwise(generateJsxChildren(containingElement, getInvalidTextualChildDiagnostic), realSource, arrayLikeTargetParts, relation) || result;
}
else if (!isTypeRelatedTo(getIndexedAccessType(source, childrenNameType), childrenTargetType, relation)) {
// arity mismatch
result = true;
error(
containingElement.openingElement.tagName,
Diagnostics.This_JSX_tag_s_0_prop_expects_a_single_child_of_type_1_but_multiple_children_were_provided,
childrenPropName,
typeToString(childrenTargetType)
);
}
}
else {
if (nonArrayLikeTargetParts !== neverType) {
const child = validChildren[0];
const elem = getElaborationElementForJsxChild(child, childrenNameType, getInvalidTextualChildDiagnostic);
if (elem) {
result = elaborateElementwise(
(function*() { yield elem; })(),
source,
target,
relation
) || result;
}
}
else if (!isTypeRelatedTo(getIndexedAccessType(source, childrenNameType), childrenTargetType, relation)) {
// arity mismatch
result = true;
error(
containingElement.openingElement.tagName,
Diagnostics.This_JSX_tag_s_0_prop_expects_type_1_which_requires_multiple_children_but_only_a_single_child_was_provided,
childrenPropName,
typeToString(childrenTargetType)
);
}
}
}
return result;
function getInvalidTextualChildDiagnostic() {
if (!invalidTextDiagnostic) {
const tagNameText = getTextOfNode(node.parent.tagName);
const childPropName = getJsxElementChildrenPropertyName(getJsxNamespaceAt(node));
const childrenPropName = childPropName === undefined ? "children" : unescapeLeadingUnderscores(childPropName);
const childrenTargetType = getIndexedAccessType(target, getLiteralType(childrenPropName));
const diagnostic = Diagnostics._0_components_don_t_accept_text_as_child_elements_Text_in_JSX_has_the_type_string_but_the_expected_type_of_1_is_2;
invalidTextDiagnostic = { ...diagnostic, key: "!!ALREADY FORMATTED!!", message: formatMessage(/*_dummy*/ undefined, diagnostic, tagNameText, childrenPropName, typeToString(childrenTargetType)) };
}
return invalidTextDiagnostic;
}
}
function *generateLimitedTupleElements(node: ArrayLiteralExpression, target: Type): ElaborationIterator {
const len = length(node.elements);
if (!len) return;
for (let i = 0; i < len; i++) {
// Skip elements which do not exist in the target - a length error on the tuple overall is likely better than an error on a mismatched index signature
if (isTupleLikeType(target) && !getPropertyOfType(target, ("" + i) as __String)) continue;
const elem = node.elements[i];
if (isOmittedExpression(elem)) continue;
const nameType = getLiteralType(i);
yield { errorNode: elem, innerExpression: elem, nameType };
}
}
function elaborateArrayLiteral(node: ArrayLiteralExpression, source: Type, target: Type, relation: Map<RelationComparisonResult>) {
if (isTupleLikeType(source)) {
return elaborateElementwise(generateLimitedTupleElements(node, target), source, target, relation);
}
// recreate a tuple from the elements, if possible
const tupleizedType = checkArrayLiteral(node, CheckMode.Contextual, /*forceTuple*/ true);
if (isTupleLikeType(tupleizedType)) {
return elaborateElementwise(generateLimitedTupleElements(node, target), tupleizedType, target, relation);
}
return false;
}
function *generateObjectLiteralElements(node: ObjectLiteralExpression): ElaborationIterator {
if (!length(node.properties)) return;
for (const prop of node.properties) {
if (isSpreadAssignment(prop)) continue;
const type = getLiteralTypeFromProperty(getSymbolOfNode(prop), TypeFlags.StringOrNumberLiteralOrUnique);
if (!type || (type.flags & TypeFlags.Never)) {
continue;
}
switch (prop.kind) {
case SyntaxKind.SetAccessor:
case SyntaxKind.GetAccessor:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.ShorthandPropertyAssignment:
yield { errorNode: prop.name, innerExpression: undefined, nameType: type };
break;
case SyntaxKind.PropertyAssignment:
yield { errorNode: prop.name, innerExpression: prop.initializer, nameType: type, errorMessage: isComputedNonLiteralName(prop.name) ? Diagnostics.Type_of_computed_property_s_value_is_0_which_is_not_assignable_to_type_1 : undefined };
break;
default:
Debug.assertNever(prop);
}
}
}
function elaborateObjectLiteral(node: ObjectLiteralExpression, source: Type, target: Type, relation: Map<RelationComparisonResult>) {
return elaborateElementwise(generateObjectLiteralElements(node), source, target, relation);
}
/**
* This is *not* a bi-directional relationship.
* If one needs to check both directions for comparability, use a second call to this function or 'isTypeComparableTo'.
*/
function checkTypeComparableTo(source: Type, target: Type, errorNode: Node, headMessage?: DiagnosticMessage, containingMessageChain?: () => DiagnosticMessageChain | undefined): boolean {
return checkTypeRelatedTo(source, target, comparableRelation, errorNode, headMessage, containingMessageChain);
}
function isSignatureAssignableTo(source: Signature,
target: Signature,
ignoreReturnTypes: boolean): boolean {
return compareSignaturesRelated(source, target, CallbackCheck.None, ignoreReturnTypes, /*reportErrors*/ false,
/*errorReporter*/ undefined, compareTypesAssignable) !== Ternary.False;
}
type ErrorReporter = (message: DiagnosticMessage, arg0?: string, arg1?: string) => void;
/**
* See signatureRelatedTo, compareSignaturesIdentical
*/
function compareSignaturesRelated(source: Signature,
target: Signature,
callbackCheck: CallbackCheck,
ignoreReturnTypes: boolean,
reportErrors: boolean,
errorReporter: ErrorReporter | undefined,
compareTypes: TypeComparer): Ternary {
// TODO (drosen): De-duplicate code between related functions.
if (source === target) {
return Ternary.True;
}
const targetCount = getParameterCount(target);
if (!hasEffectiveRestParameter(target) && getMinArgumentCount(source) > targetCount) {
return Ternary.False;
}
if (source.typeParameters && source.typeParameters !== target.typeParameters) {
target = getCanonicalSignature(target);
source = instantiateSignatureInContextOf(source, target, /*contextualMapper*/ undefined, compareTypes);
}
const sourceCount = getParameterCount(source);
const sourceRestType = getNonArrayRestType(source);
const targetRestType = getNonArrayRestType(target);
if (sourceRestType && targetRestType && sourceCount !== targetCount) {
// We're not able to relate misaligned complex rest parameters
return Ternary.False;
}
const kind = target.declaration ? target.declaration.kind : SyntaxKind.Unknown;
const strictVariance = !callbackCheck && strictFunctionTypes && kind !== SyntaxKind.MethodDeclaration &&
kind !== SyntaxKind.MethodSignature && kind !== SyntaxKind.Constructor;
let result = Ternary.True;
const sourceThisType = getThisTypeOfSignature(source);
if (sourceThisType && sourceThisType !== voidType) {
const targetThisType = getThisTypeOfSignature(target);
if (targetThisType) {
// void sources are assignable to anything.
const related = !strictVariance && compareTypes(sourceThisType, targetThisType, /*reportErrors*/ false)
|| compareTypes(targetThisType, sourceThisType, reportErrors);
if (!related) {
if (reportErrors) {
errorReporter!(Diagnostics.The_this_types_of_each_signature_are_incompatible);
}
return Ternary.False;
}
result &= related;
}
}
const paramCount = sourceRestType || targetRestType ? Math.min(sourceCount, targetCount) : Math.max(sourceCount, targetCount);
const restIndex = sourceRestType || targetRestType ? paramCount - 1 : -1;
for (let i = 0; i < paramCount; i++) {
const sourceType = i === restIndex ? getRestTypeAtPosition(source, i) : getTypeAtPosition(source, i);
const targetType = i === restIndex ? getRestTypeAtPosition(target, i) : getTypeAtPosition(target, i);
// In order to ensure that any generic type Foo<T> is at least co-variant with respect to T no matter
// how Foo uses T, we need to relate parameters bi-variantly (given that parameters are input positions,
// they naturally relate only contra-variantly). However, if the source and target parameters both have
// function types with a single call signature, we know we are relating two callback parameters. In
// that case it is sufficient to only relate the parameters of the signatures co-variantly because,
// similar to return values, callback parameters are output positions. This means that a Promise<T>,
// where T is used only in callback parameter positions, will be co-variant (as opposed to bi-variant)
// with respect to T.
const sourceSig = callbackCheck ? undefined : getSingleCallSignature(getNonNullableType(sourceType));
const targetSig = callbackCheck ? undefined : getSingleCallSignature(getNonNullableType(targetType));
const callbacks = sourceSig && targetSig && !signatureHasTypePredicate(sourceSig) && !signatureHasTypePredicate(targetSig) &&
(getFalsyFlags(sourceType) & TypeFlags.Nullable) === (getFalsyFlags(targetType) & TypeFlags.Nullable);
const related = callbacks ?
// TODO: GH#18217 It will work if they're both `undefined`, but not if only one is
compareSignaturesRelated(targetSig!, sourceSig!, strictVariance ? CallbackCheck.Strict : CallbackCheck.Bivariant, /*ignoreReturnTypes*/ false, reportErrors, errorReporter, compareTypes) :
!callbackCheck && !strictVariance && compareTypes(sourceType, targetType, /*reportErrors*/ false) || compareTypes(targetType, sourceType, reportErrors);
if (!related) {
if (reportErrors) {
errorReporter!(Diagnostics.Types_of_parameters_0_and_1_are_incompatible,
unescapeLeadingUnderscores(getParameterNameAtPosition(source, i)),
unescapeLeadingUnderscores(getParameterNameAtPosition(target, i)));
}
return Ternary.False;
}
result &= related;
}
if (!ignoreReturnTypes) {
const targetReturnType = (target.declaration && isJSConstructor(target.declaration)) ?
getJSClassType(target.declaration.symbol)! : getReturnTypeOfSignature(target);
if (targetReturnType === voidType) {
return result;
}
const sourceReturnType = (source.declaration && isJSConstructor(source.declaration)) ?
getJSClassType(source.declaration.symbol)! : getReturnTypeOfSignature(source);
// The following block preserves behavior forbidding boolean returning functions from being assignable to type guard returning functions
const targetTypePredicate = getTypePredicateOfSignature(target);
if (targetTypePredicate) {
const sourceTypePredicate = getTypePredicateOfSignature(source);
if (sourceTypePredicate) {
result &= compareTypePredicateRelatedTo(sourceTypePredicate, targetTypePredicate, source.declaration!, target.declaration!, reportErrors, errorReporter, compareTypes); // TODO: GH#18217
}
else if (isIdentifierTypePredicate(targetTypePredicate)) {
if (reportErrors) {
errorReporter!(Diagnostics.Signature_0_must_be_a_type_predicate, signatureToString(source));
}
return Ternary.False;
}
}
else {
// When relating callback signatures, we still need to relate return types bi-variantly as otherwise
// the containing type wouldn't be co-variant. For example, interface Foo<T> { add(cb: () => T): void }
// wouldn't be co-variant for T without this rule.
result &= callbackCheck === CallbackCheck.Bivariant && compareTypes(targetReturnType, sourceReturnType, /*reportErrors*/ false) ||
compareTypes(sourceReturnType, targetReturnType, reportErrors);
}
}
return result;
}
function compareTypePredicateRelatedTo(
source: TypePredicate,
target: TypePredicate,
sourceDeclaration: SignatureDeclaration | JSDocSignature,
targetDeclaration: SignatureDeclaration | JSDocSignature,
reportErrors: boolean,
errorReporter: ErrorReporter | undefined,
compareTypes: (s: Type, t: Type, reportErrors?: boolean) => Ternary): Ternary {
if (source.kind !== target.kind) {
if (reportErrors) {
errorReporter!(Diagnostics.A_this_based_type_guard_is_not_compatible_with_a_parameter_based_type_guard);
errorReporter!(Diagnostics.Type_predicate_0_is_not_assignable_to_1, typePredicateToString(source), typePredicateToString(target));
}
return Ternary.False;
}
if (source.kind === TypePredicateKind.Identifier) {
const targetPredicate = target as IdentifierTypePredicate;
const sourceIndex = source.parameterIndex - (getThisParameter(sourceDeclaration) ? 1 : 0);
const targetIndex = targetPredicate.parameterIndex - (getThisParameter(targetDeclaration) ? 1 : 0);
if (sourceIndex !== targetIndex) {
if (reportErrors) {
errorReporter!(Diagnostics.Parameter_0_is_not_in_the_same_position_as_parameter_1, source.parameterName, targetPredicate.parameterName);
errorReporter!(Diagnostics.Type_predicate_0_is_not_assignable_to_1, typePredicateToString(source), typePredicateToString(target));
}
return Ternary.False;
}
}
const related = compareTypes(source.type, target.type, reportErrors);
if (related === Ternary.False && reportErrors) {
errorReporter!(Diagnostics.Type_predicate_0_is_not_assignable_to_1, typePredicateToString(source), typePredicateToString(target));
}
return related;
}
function isImplementationCompatibleWithOverload(implementation: Signature, overload: Signature): boolean {
const erasedSource = getErasedSignature(implementation);
const erasedTarget = getErasedSignature(overload);
// First see if the return types are compatible in either direction.
const sourceReturnType = getReturnTypeOfSignature(erasedSource);
const targetReturnType = getReturnTypeOfSignature(erasedTarget);
if (targetReturnType === voidType
|| isTypeRelatedTo(targetReturnType, sourceReturnType, assignableRelation)
|| isTypeRelatedTo(sourceReturnType, targetReturnType, assignableRelation)) {
return isSignatureAssignableTo(erasedSource, erasedTarget, /*ignoreReturnTypes*/ true);
}
return false;
}
function isEmptyResolvedType(t: ResolvedType) {
return t.properties.length === 0 &&
t.callSignatures.length === 0 &&
t.constructSignatures.length === 0 &&
!t.stringIndexInfo &&
!t.numberIndexInfo;
}
function isEmptyObjectType(type: Type): boolean {
return type.flags & TypeFlags.Object ? !isGenericMappedType(type) && isEmptyResolvedType(resolveStructuredTypeMembers(<ObjectType>type)) :
type.flags & TypeFlags.NonPrimitive ? true :
type.flags & TypeFlags.Union ? some((<UnionType>type).types, isEmptyObjectType) :
type.flags & TypeFlags.Intersection ? every((<UnionType>type).types, isEmptyObjectType) :
false;
}
function isEmptyAnonymousObjectType(type: Type) {
return !!(getObjectFlags(type) & ObjectFlags.Anonymous) && isEmptyObjectType(type);
}
function isEnumTypeRelatedTo(sourceSymbol: Symbol, targetSymbol: Symbol, errorReporter?: ErrorReporter) {
if (sourceSymbol === targetSymbol) {
return true;
}
const id = getSymbolId(sourceSymbol) + "," + getSymbolId(targetSymbol);
const relation = enumRelation.get(id);
if (relation !== undefined && !(relation === RelationComparisonResult.Failed && errorReporter)) {
return relation === RelationComparisonResult.Succeeded;
}
if (sourceSymbol.escapedName !== targetSymbol.escapedName || !(sourceSymbol.flags & SymbolFlags.RegularEnum) || !(targetSymbol.flags & SymbolFlags.RegularEnum)) {
enumRelation.set(id, RelationComparisonResult.FailedAndReported);
return false;
}
const targetEnumType = getTypeOfSymbol(targetSymbol);
for (const property of getPropertiesOfType(getTypeOfSymbol(sourceSymbol))) {
if (property.flags & SymbolFlags.EnumMember) {
const targetProperty = getPropertyOfType(targetEnumType, property.escapedName);
if (!targetProperty || !(targetProperty.flags & SymbolFlags.EnumMember)) {
if (errorReporter) {
errorReporter(Diagnostics.Property_0_is_missing_in_type_1, symbolName(property),
typeToString(getDeclaredTypeOfSymbol(targetSymbol), /*enclosingDeclaration*/ undefined, TypeFormatFlags.UseFullyQualifiedType));
enumRelation.set(id, RelationComparisonResult.FailedAndReported);
}
else {
enumRelation.set(id, RelationComparisonResult.Failed);
}
return false;
}
}
}
enumRelation.set(id, RelationComparisonResult.Succeeded);
return true;
}
function isSimpleTypeRelatedTo(source: Type, target: Type, relation: Map<RelationComparisonResult>, errorReporter?: ErrorReporter) {
const s = source.flags;
const t = target.flags;
if (t & TypeFlags.AnyOrUnknown || s & TypeFlags.Never || source === wildcardType) return true;
if (t & TypeFlags.Never) return false;
if (s & TypeFlags.StringLike && t & TypeFlags.String) return true;
if (s & TypeFlags.StringLiteral && s & TypeFlags.EnumLiteral &&
t & TypeFlags.StringLiteral && !(t & TypeFlags.EnumLiteral) &&
(<StringLiteralType>source).value === (<StringLiteralType>target).value) return true;
if (s & TypeFlags.NumberLike && t & TypeFlags.Number) return true;
if (s & TypeFlags.NumberLiteral && s & TypeFlags.EnumLiteral &&
t & TypeFlags.NumberLiteral && !(t & TypeFlags.EnumLiteral) &&
(<NumberLiteralType>source).value === (<NumberLiteralType>target).value) return true;
if (s & TypeFlags.BigIntLike && t & TypeFlags.BigInt) return true;
if (s & TypeFlags.BooleanLike && t & TypeFlags.Boolean) return true;
if (s & TypeFlags.ESSymbolLike && t & TypeFlags.ESSymbol) return true;
if (s & TypeFlags.Enum && t & TypeFlags.Enum && isEnumTypeRelatedTo(source.symbol, target.symbol, errorReporter)) return true;
if (s & TypeFlags.EnumLiteral && t & TypeFlags.EnumLiteral) {
if (s & TypeFlags.Union && t & TypeFlags.Union && isEnumTypeRelatedTo(source.symbol, target.symbol, errorReporter)) return true;
if (s & TypeFlags.Literal && t & TypeFlags.Literal &&
(<LiteralType>source).value === (<LiteralType>target).value &&
isEnumTypeRelatedTo(getParentOfSymbol(source.symbol)!, getParentOfSymbol(target.symbol)!, errorReporter)) return true;
}
if (s & TypeFlags.Undefined && (!strictNullChecks || t & (TypeFlags.Undefined | TypeFlags.Void))) return true;
if (s & TypeFlags.Null && (!strictNullChecks || t & TypeFlags.Null)) return true;
if (s & TypeFlags.Object && t & TypeFlags.NonPrimitive) return true;
if (relation === assignableRelation || relation === comparableRelation) {
if (s & TypeFlags.Any) return true;
// Type number or any numeric literal type is assignable to any numeric enum type or any
// numeric enum literal type. This rule exists for backwards compatibility reasons because
// bit-flag enum types sometimes look like literal enum types with numeric literal values.
if (s & (TypeFlags.Number | TypeFlags.NumberLiteral) && !(s & TypeFlags.EnumLiteral) && (
t & TypeFlags.Enum || t & TypeFlags.NumberLiteral && t & TypeFlags.EnumLiteral)) return true;
}
return false;
}
function isTypeRelatedTo(source: Type, target: Type, relation: Map<RelationComparisonResult>) {
if (isFreshLiteralType(source)) {
source = (<FreshableType>source).regularType;
}
if (isFreshLiteralType(target)) {
target = (<FreshableType>target).regularType;
}
if (source === target ||
relation === comparableRelation && !(target.flags & TypeFlags.Never) && isSimpleTypeRelatedTo(target, source, relation) ||
relation !== identityRelation && isSimpleTypeRelatedTo(source, target, relation)) {
return true;
}
if (source.flags & TypeFlags.Object && target.flags & TypeFlags.Object) {
const related = relation.get(getRelationKey(source, target, relation));
if (related !== undefined) {
return related === RelationComparisonResult.Succeeded;
}
}
if (source.flags & TypeFlags.StructuredOrInstantiable || target.flags & TypeFlags.StructuredOrInstantiable) {
return checkTypeRelatedTo(source, target, relation, /*errorNode*/ undefined);
}
return false;
}
function isIgnoredJsxProperty(source: Type, sourceProp: Symbol, targetMemberType: Type | undefined) {
return getObjectFlags(source) & ObjectFlags.JsxAttributes && !(isUnhyphenatedJsxName(sourceProp.escapedName) || targetMemberType);
}
/**
* Checks if 'source' is related to 'target' (e.g.: is a assignable to).
* @param source The left-hand-side of the relation.
* @param target The right-hand-side of the relation.
* @param relation The relation considered. One of 'identityRelation', 'subtypeRelation', 'assignableRelation', or 'comparableRelation'.
* Used as both to determine which checks are performed and as a cache of previously computed results.
* @param errorNode The suggested node upon which all errors will be reported, if defined. This may or may not be the actual node used.
* @param headMessage If the error chain should be prepended by a head message, then headMessage will be used.
* @param containingMessageChain A chain of errors to prepend any new errors found.
*/
function checkTypeRelatedTo(
source: Type,
target: Type,
relation: Map<RelationComparisonResult>,
errorNode: Node | undefined,
headMessage?: DiagnosticMessage,
containingMessageChain?: () => DiagnosticMessageChain | undefined,
errorOutputContainer?: { error?: Diagnostic }
): boolean {
let errorInfo: DiagnosticMessageChain | undefined;
let relatedInfo: [DiagnosticRelatedInformation, ...DiagnosticRelatedInformation[]] | undefined;
let maybeKeys: string[];
let sourceStack: Type[];
let targetStack: Type[];
let maybeCount = 0;
let depth = 0;
let expandingFlags = ExpandingFlags.None;
let overflow = false;
let suppressNextError = false;
Debug.assert(relation !== identityRelation || !errorNode, "no error reporting in identity checking");
const result = isRelatedTo(source, target, /*reportErrors*/ !!errorNode, headMessage);
if (overflow) {
error(errorNode, Diagnostics.Excessive_stack_depth_comparing_types_0_and_1, typeToString(source), typeToString(target));
}
else if (errorInfo) {
if (containingMessageChain) {
const chain = containingMessageChain();
if (chain) {
errorInfo = concatenateDiagnosticMessageChains(chain, errorInfo);
}
}
let relatedInformation: DiagnosticRelatedInformation[] | undefined;
// Check if we should issue an extra diagnostic to produce a quickfix for a slightly incorrect import statement
if (headMessage && errorNode && !result && source.symbol) {
const links = getSymbolLinks(source.symbol);
if (links.originatingImport && !isImportCall(links.originatingImport)) {
const helpfulRetry = checkTypeRelatedTo(getTypeOfSymbol(links.target!), target, relation, /*errorNode*/ undefined);
if (helpfulRetry) {
// Likely an incorrect import. Issue a helpful diagnostic to produce a quickfix to change the import
const diag = createDiagnosticForNode(links.originatingImport, Diagnostics.Type_originates_at_this_import_A_namespace_style_import_cannot_be_called_or_constructed_and_will_cause_a_failure_at_runtime_Consider_using_a_default_import_or_import_require_here_instead);
relatedInformation = append(relatedInformation, diag); // Cause the error to appear with the error that triggered it
}
}
}
const diag = createDiagnosticForNodeFromMessageChain(errorNode!, errorInfo, relatedInformation);
if (relatedInfo) {
addRelatedInfo(diag, ...relatedInfo);
}
if (errorOutputContainer) {
errorOutputContainer.error = diag;
}
diagnostics.add(diag); // TODO: GH#18217
}
return result !== Ternary.False;
function reportError(message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number, arg3?: string | number): void {
Debug.assert(!!errorNode);
errorInfo = chainDiagnosticMessages(errorInfo, message, arg0, arg1, arg2, arg3);
}
function associateRelatedInfo(info: DiagnosticRelatedInformation) {
Debug.assert(!!errorInfo);
if (!relatedInfo) {
relatedInfo = [info];
}
else {
relatedInfo.push(info);
}
}
function reportRelationError(message: DiagnosticMessage | undefined, source: Type, target: Type) {
let sourceType = typeToString(source);
let targetType = typeToString(target);
if (sourceType === targetType) {
sourceType = typeToString(source, /*enclosingDeclaration*/ undefined, TypeFormatFlags.UseFullyQualifiedType);
targetType = typeToString(target, /*enclosingDeclaration*/ undefined, TypeFormatFlags.UseFullyQualifiedType);
}
if (!message) {
if (relation === comparableRelation) {
message = Diagnostics.Type_0_is_not_comparable_to_type_1;
}
else if (sourceType === targetType) {
message = Diagnostics.Type_0_is_not_assignable_to_type_1_Two_different_types_with_this_name_exist_but_they_are_unrelated;
}
else {
message = Diagnostics.Type_0_is_not_assignable_to_type_1;
}
}
reportError(message, sourceType, targetType);
}
function tryElaborateErrorsForPrimitivesAndObjects(source: Type, target: Type) {
const sourceType = typeToString(source);
const targetType = typeToString(target);
if ((globalStringType === source && stringType === target) ||
(globalNumberType === source && numberType === target) ||
(globalBooleanType === source && booleanType === target) ||
(getGlobalESSymbolType(/*reportErrors*/ false) === source && esSymbolType === target)) {
reportError(Diagnostics._0_is_a_primitive_but_1_is_a_wrapper_object_Prefer_using_0_when_possible, targetType, sourceType);
}
}
function isUnionOrIntersectionTypeWithoutNullableConstituents(type: Type): boolean {
if (!(type.flags & TypeFlags.UnionOrIntersection)) {
return false;
}
// at this point we know that this is union or intersection type possibly with nullable constituents.
// check if we still will have compound type if we ignore nullable components.
let seenNonNullable = false;
for (const t of (<UnionOrIntersectionType>type).types) {
if (t.flags & TypeFlags.Nullable) {
continue;
}
if (seenNonNullable) {
return true;
}
seenNonNullable = true;
}
return false;
}
/**
* Compare two types and return
* * Ternary.True if they are related with no assumptions,
* * Ternary.Maybe if they are related with assumptions of other relationships, or
* * Ternary.False if they are not related.
*/
function isRelatedTo(source: Type, target: Type, reportErrors = false, headMessage?: DiagnosticMessage, isApparentIntersectionConstituent?: boolean): Ternary {
if (isFreshLiteralType(source)) {
source = (<FreshableType>source).regularType;
}
if (isFreshLiteralType(target)) {
target = (<FreshableType>target).regularType;
}
if (source.flags & TypeFlags.Substitution) {
source = (<SubstitutionType>source).substitute;
}
if (target.flags & TypeFlags.Substitution) {
target = (<SubstitutionType>target).typeVariable;
}
if (source.flags & TypeFlags.IndexedAccess) {
source = getSimplifiedType(source);
}
if (target.flags & TypeFlags.IndexedAccess) {
target = getSimplifiedType(target);
}
// Try to see if we're relating something like `Foo` -> `Bar | null | undefined`.
// If so, reporting the `null` and `undefined` in the type is hardly useful.
// First, see if we're even relating an object type to a union.
// Then see if the target is stripped down to a single non-union type.
// Note
// * We actually want to remove null and undefined naively here (rather than using getNonNullableType),
// since we don't want to end up with a worse error like "`Foo` is not assignable to `NonNullable<T>`"
// when dealing with generics.
// * We also don't deal with primitive source types, since we already halt elaboration below.
if (target.flags & TypeFlags.Union && source.flags & TypeFlags.Object &&
(target as UnionType).types.length <= 3 && maybeTypeOfKind(target, TypeFlags.Nullable)) {
const nullStrippedTarget = extractTypesOfKind(target, ~TypeFlags.Nullable);
if (!(nullStrippedTarget.flags & (TypeFlags.Union | TypeFlags.Never))) {
target = nullStrippedTarget;
}
}
// both types are the same - covers 'they are the same primitive type or both are Any' or the same type parameter cases
if (source === target) return Ternary.True;
if (relation === identityRelation) {
return isIdenticalTo(source, target);
}
if (relation === comparableRelation && !(target.flags & TypeFlags.Never) && isSimpleTypeRelatedTo(target, source, relation) ||
isSimpleTypeRelatedTo(source, target, relation, reportErrors ? reportError : undefined)) return Ternary.True;
const isComparingJsxAttributes = !!(getObjectFlags(source) & ObjectFlags.JsxAttributes);
if (isObjectLiteralType(source) && getObjectFlags(source) & ObjectFlags.FreshLiteral) {
const discriminantType = target.flags & TypeFlags.Union ? findMatchingDiscriminantType(source, target as UnionType) : undefined;
if (hasExcessProperties(<FreshObjectLiteralType>source, target, discriminantType, reportErrors)) {
if (reportErrors) {
reportRelationError(headMessage, source, target);
}
return Ternary.False;
}
// Above we check for excess properties with respect to the entire target type. When union
// and intersection types are further deconstructed on the target side, we don't want to
// make the check again (as it might fail for a partial target type). Therefore we obtain
// the regular source type and proceed with that.
if (isUnionOrIntersectionTypeWithoutNullableConstituents(target) && !discriminantType) {
source = getRegularTypeOfObjectLiteral(source);
}
}
if (relation !== comparableRelation && !isApparentIntersectionConstituent &&
source.flags & (TypeFlags.Primitive | TypeFlags.Object | TypeFlags.Intersection) && source !== globalObjectType &&
target.flags & (TypeFlags.Object | TypeFlags.Intersection) && isWeakType(target) &&
(getPropertiesOfType(source).length > 0 || typeHasCallOrConstructSignatures(source)) &&
!hasCommonProperties(source, target, isComparingJsxAttributes)) {
if (reportErrors) {
const calls = getSignaturesOfType(source, SignatureKind.Call);
const constructs = getSignaturesOfType(source, SignatureKind.Construct);
if (calls.length > 0 && isRelatedTo(getReturnTypeOfSignature(calls[0]), target, /*reportErrors*/ false) ||
constructs.length > 0 && isRelatedTo(getReturnTypeOfSignature(constructs[0]), target, /*reportErrors*/ false)) {
reportError(Diagnostics.Value_of_type_0_has_no_properties_in_common_with_type_1_Did_you_mean_to_call_it, typeToString(source), typeToString(target));
}
else {
reportError(Diagnostics.Type_0_has_no_properties_in_common_with_type_1, typeToString(source), typeToString(target));
}
}
return Ternary.False;
}
let result = Ternary.False;
const saveErrorInfo = errorInfo;
let isIntersectionConstituent = !!isApparentIntersectionConstituent;
// Note that these checks are specifically ordered to produce correct results. In particular,
// we need to deconstruct unions before intersections (because unions are always at the top),
// and we need to handle "each" relations before "some" relations for the same kind of type.
if (source.flags & TypeFlags.Union) {
result = relation === comparableRelation ?
someTypeRelatedToType(source as UnionType, target, reportErrors && !(source.flags & TypeFlags.Primitive)) :
eachTypeRelatedToType(source as UnionType, target, reportErrors && !(source.flags & TypeFlags.Primitive));
}
else {
if (target.flags & TypeFlags.Union) {
result = typeRelatedToSomeType(source, <UnionType>target, reportErrors && !(source.flags & TypeFlags.Primitive) && !(target.flags & TypeFlags.Primitive));
}
else if (target.flags & TypeFlags.Intersection) {
isIntersectionConstituent = true; // set here to affect the following trio of checks
result = typeRelatedToEachType(source, target as IntersectionType, reportErrors);
}
else if (source.flags & TypeFlags.Intersection) {
// Check to see if any constituents of the intersection are immediately related to the target.
//
// Don't report errors though. Checking whether a constituent is related to the source is not actually
// useful and leads to some confusing error messages. Instead it is better to let the below checks
// take care of this, or to not elaborate at all. For instance,
//
// - For an object type (such as 'C = A & B'), users are usually more interested in structural errors.
//
// - For a union type (such as '(A | B) = (C & D)'), it's better to hold onto the whole intersection
// than to report that 'D' is not assignable to 'A' or 'B'.
//
// - For a primitive type or type parameter (such as 'number = A & B') there is no point in
// breaking the intersection apart.
result = someTypeRelatedToType(<IntersectionType>source, target, /*reportErrors*/ false);
}
if (!result && (source.flags & TypeFlags.StructuredOrInstantiable || target.flags & TypeFlags.StructuredOrInstantiable)) {
if (result = recursiveTypeRelatedTo(source, target, reportErrors, isIntersectionConstituent)) {
errorInfo = saveErrorInfo;
}
}
}
if (!result && source.flags & TypeFlags.Intersection) {
// The combined constraint of an intersection type is the intersection of the constraints of
// the constituents. When an intersection type contains instantiable types with union type
// constraints, there are situations where we need to examine the combined constraint. One is
// when the target is a union type. Another is when the intersection contains types belonging
// to one of the disjoint domains. For example, given type variables T and U, each with the
// constraint 'string | number', the combined constraint of 'T & U' is 'string | number' and
// we need to check this constraint against a union on the target side. Also, given a type
// variable V constrained to 'string | number', 'V & number' has a combined constraint of
// 'string & number | number & number' which reduces to just 'number'.
const constraint = getUnionConstraintOfIntersection(<IntersectionType>source, !!(target.flags & TypeFlags.Union));
if (constraint) {
if (result = isRelatedTo(constraint, target, reportErrors, /*headMessage*/ undefined, isIntersectionConstituent)) {
errorInfo = saveErrorInfo;
}
}
}
if (!result && reportErrors) {
const maybeSuppress = suppressNextError;
suppressNextError = false;
if (source.flags & TypeFlags.Object && target.flags & TypeFlags.Primitive) {
tryElaborateErrorsForPrimitivesAndObjects(source, target);
}
else if (source.symbol && source.flags & TypeFlags.Object && globalObjectType === source) {
reportError(Diagnostics.The_Object_type_is_assignable_to_very_few_other_types_Did_you_mean_to_use_the_any_type_instead);
}
else if (isComparingJsxAttributes && target.flags & TypeFlags.Intersection) {
const targetTypes = (target as IntersectionType).types;
const intrinsicAttributes = getJsxType(JsxNames.IntrinsicAttributes, errorNode);
const intrinsicClassAttributes = getJsxType(JsxNames.IntrinsicClassAttributes, errorNode);
if (intrinsicAttributes !== errorType && intrinsicClassAttributes !== errorType &&
(contains(targetTypes, intrinsicAttributes) || contains(targetTypes, intrinsicClassAttributes))) {
// do not report top error
return result;
}
}
if (!headMessage && maybeSuppress) {
// Used by, eg, missing property checking to replace the top-level message with a more informative one
return result;
}
reportRelationError(headMessage, source, target);
}
return result;
}
function isIdenticalTo(source: Type, target: Type): Ternary {
let result: Ternary;
const flags = source.flags & target.flags;
if (flags & TypeFlags.Object || flags & TypeFlags.IndexedAccess || flags & TypeFlags.Conditional || flags & TypeFlags.Index || flags & TypeFlags.Substitution) {
return recursiveTypeRelatedTo(source, target, /*reportErrors*/ false, /*isIntersectionConstituent*/ false);
}
if (flags & (TypeFlags.Union | TypeFlags.Intersection)) {
if (result = eachTypeRelatedToSomeType(<UnionOrIntersectionType>source, <UnionOrIntersectionType>target)) {
if (result &= eachTypeRelatedToSomeType(<UnionOrIntersectionType>target, <UnionOrIntersectionType>source)) {
return result;
}
}
}
return Ternary.False;
}
function hasExcessProperties(source: FreshObjectLiteralType, target: Type, discriminant: Type | undefined, reportErrors: boolean): boolean {
if (!noImplicitAny && getObjectFlags(target) & ObjectFlags.JSLiteral) {
return false; // Disable excess property checks on JS literals to simulate having an implicit "index signature" - but only outside of noImplicitAny
}
if (isExcessPropertyCheckTarget(target)) {
const isComparingJsxAttributes = !!(getObjectFlags(source) & ObjectFlags.JsxAttributes);
if ((relation === assignableRelation || relation === comparableRelation) &&
(isTypeSubsetOf(globalObjectType, target) || (!isComparingJsxAttributes && isEmptyObjectType(target)))) {
return false;
}
if (discriminant) {
// check excess properties against discriminant type only, not the entire union
return hasExcessProperties(source, discriminant, /*discriminant*/ undefined, reportErrors);
}
for (const prop of getPropertiesOfObjectType(source)) {
if (shouldCheckAsExcessProperty(prop, source.symbol) && !isKnownProperty(target, prop.escapedName, isComparingJsxAttributes)) {
if (reportErrors) {
// Report error in terms of object types in the target as those are the only ones
// we check in isKnownProperty.
const errorTarget = filterType(target, isExcessPropertyCheckTarget);
// We know *exactly* where things went wrong when comparing the types.
// Use this property as the error node as this will be more helpful in
// reasoning about what went wrong.
if (!errorNode) return Debug.fail();
if (isJsxAttributes(errorNode) || isJsxOpeningLikeElement(errorNode) || isJsxOpeningLikeElement(errorNode.parent)) {
// JsxAttributes has an object-literal flag and undergo same type-assignablity check as normal object-literal.
// However, using an object-literal error message will be very confusing to the users so we give different a message.
// TODO: Spelling suggestions for excess jsx attributes (needs new diagnostic messages)
reportError(Diagnostics.Property_0_does_not_exist_on_type_1, symbolToString(prop), typeToString(errorTarget));
}
else {
// use the property's value declaration if the property is assigned inside the literal itself
const objectLiteralDeclaration = source.symbol && firstOrUndefined(source.symbol.declarations);
let suggestion;
if (prop.valueDeclaration && findAncestor(prop.valueDeclaration, d => d === objectLiteralDeclaration)) {
const propDeclaration = prop.valueDeclaration as ObjectLiteralElementLike;
Debug.assertNode(propDeclaration, isObjectLiteralElementLike);
errorNode = propDeclaration;
const name = propDeclaration.name!;
if (isIdentifier(name)) {
suggestion = getSuggestionForNonexistentProperty(name, errorTarget);
}
}
if (suggestion !== undefined) {
reportError(Diagnostics.Object_literal_may_only_specify_known_properties_but_0_does_not_exist_in_type_1_Did_you_mean_to_write_2,
symbolToString(prop), typeToString(errorTarget), suggestion);
}
else {
reportError(Diagnostics.Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1,
symbolToString(prop), typeToString(errorTarget));
}
}
}
return true;
}
}
}
return false;
}
function shouldCheckAsExcessProperty(prop: Symbol, container: Symbol) {
return prop.valueDeclaration && container.valueDeclaration && prop.valueDeclaration.parent === container.valueDeclaration;
}
function eachTypeRelatedToSomeType(source: UnionOrIntersectionType, target: UnionOrIntersectionType): Ternary {
let result = Ternary.True;
const sourceTypes = source.types;
for (const sourceType of sourceTypes) {
const related = typeRelatedToSomeType(sourceType, target, /*reportErrors*/ false);
if (!related) {
return Ternary.False;
}
result &= related;
}
return result;
}
function typeRelatedToSomeType(source: Type, target: UnionOrIntersectionType, reportErrors: boolean): Ternary {
const targetTypes = target.types;
if (target.flags & TypeFlags.Union && containsType(targetTypes, source)) {
return Ternary.True;
}
for (const type of targetTypes) {
const related = isRelatedTo(source, type, /*reportErrors*/ false);
if (related) {
return related;
}
}
if (reportErrors) {
const bestMatchingType =
findMatchingDiscriminantType(source, target) ||
findMatchingTypeReferenceOrTypeAliasReference(source, target) ||
findBestTypeForObjectLiteral(source, target) ||
findBestTypeForInvokable(source, target) ||
findMostOverlappyType(source, target);
isRelatedTo(source, bestMatchingType || targetTypes[targetTypes.length - 1], /*reportErrors*/ true);
}
return Ternary.False;
}
function findMatchingTypeReferenceOrTypeAliasReference(source: Type, unionTarget: UnionOrIntersectionType) {
const sourceObjectFlags = getObjectFlags(source);
if (sourceObjectFlags & (ObjectFlags.Reference | ObjectFlags.Anonymous) && unionTarget.flags & TypeFlags.Union) {
return find(unionTarget.types, target => {
if (target.flags & TypeFlags.Object) {
const overlapObjFlags = sourceObjectFlags & getObjectFlags(target);
if (overlapObjFlags & ObjectFlags.Reference) {
return (source as TypeReference).target === (target as TypeReference).target;
}
if (overlapObjFlags & ObjectFlags.Anonymous) {
return !!(source as AnonymousType).aliasSymbol && (source as AnonymousType).aliasSymbol === (target as AnonymousType).aliasSymbol;
}
}
return false;
});
}
}
function findBestTypeForObjectLiteral(source: Type, unionTarget: UnionOrIntersectionType) {
if (getObjectFlags(source) & ObjectFlags.ObjectLiteral && forEachType(unionTarget, isArrayLikeType)) {
return find(unionTarget.types, t => !isArrayLikeType(t));
}
}
function findBestTypeForInvokable(source: Type, unionTarget: UnionOrIntersectionType) {
let signatureKind = SignatureKind.Call;
const hasSignatures = getSignaturesOfType(source, signatureKind).length > 0 ||
(signatureKind = SignatureKind.Construct, getSignaturesOfType(source, signatureKind).length > 0);
if (hasSignatures) {
return find(unionTarget.types, t => getSignaturesOfType(t, signatureKind).length > 0);
}
}
function findMostOverlappyType(source: Type, unionTarget: UnionOrIntersectionType) {
let bestMatch: Type | undefined;
let matchingCount = 0;
for (const target of unionTarget.types) {
const overlap = getIntersectionType([getIndexType(source), getIndexType(target)]);
if (overlap.flags & TypeFlags.Index) {
// perfect overlap of keys
bestMatch = target;
matchingCount = Infinity;
}
else if (overlap.flags & TypeFlags.Union) {
// We only want to account for literal types otherwise.
// If we have a union of index types, it seems likely that we
// needed to elaborate between two generic mapped types anyway.
const len = length(filter((overlap as UnionType).types, isUnitType));
if (len >= matchingCount) {
bestMatch = target;
matchingCount = len;
}
}
else if (isUnitType(overlap) && 1 >= matchingCount) {
bestMatch = target;
matchingCount = 1;
}
}
return bestMatch;
}
// Keep this up-to-date with the same logic within `getApparentTypeOfContextualType`, since they should behave similarly
function findMatchingDiscriminantType(source: Type, target: Type) {
if (target.flags & TypeFlags.Union) {
const sourceProperties = getPropertiesOfObjectType(source);
if (sourceProperties) {
const sourcePropertiesFiltered = findDiscriminantProperties(sourceProperties, target);
if (sourcePropertiesFiltered) {
return discriminateTypeByDiscriminableItems(<UnionType>target, map(sourcePropertiesFiltered, p => ([() => getTypeOfSymbol(p), p.escapedName] as [() => Type, __String])), isRelatedTo);
}
}
}
return undefined;
}
function typeRelatedToEachType(source: Type, target: IntersectionType, reportErrors: boolean): Ternary {
let result = Ternary.True;
const targetTypes = target.types;
for (const targetType of targetTypes) {
const related = isRelatedTo(source, targetType, reportErrors, /*headMessage*/ undefined, /*isIntersectionConstituent*/ true);
if (!related) {
return Ternary.False;
}
result &= related;
}
return result;
}
function someTypeRelatedToType(source: UnionOrIntersectionType, target: Type, reportErrors: boolean): Ternary {
const sourceTypes = source.types;
if (source.flags & TypeFlags.Union && containsType(sourceTypes, target)) {
return Ternary.True;
}
const len = sourceTypes.length;
for (let i = 0; i < len; i++) {
const related = isRelatedTo(sourceTypes[i], target, reportErrors && i === len - 1);
if (related) {
return related;
}
}
return Ternary.False;
}
function eachTypeRelatedToType(source: UnionOrIntersectionType, target: Type, reportErrors: boolean): Ternary {
let result = Ternary.True;
const sourceTypes = source.types;
for (const sourceType of sourceTypes) {
const related = isRelatedTo(sourceType, target, reportErrors);
if (!related) {
return Ternary.False;
}
result &= related;
}
return result;
}
function typeArgumentsRelatedTo(sources: ReadonlyArray<Type> = emptyArray, targets: ReadonlyArray<Type> = emptyArray, variances: ReadonlyArray<Variance> = emptyArray, reportErrors: boolean): Ternary {
if (sources.length !== targets.length && relation === identityRelation) {
return Ternary.False;
}
const length = sources.length <= targets.length ? sources.length : targets.length;
let result = Ternary.True;
for (let i = 0; i < length; i++) {
// When variance information isn't available we default to covariance. This happens
// in the process of computing variance information for recursive types and when
// comparing 'this' type arguments.
const variance = i < variances.length ? variances[i] : Variance.Covariant;
// We ignore arguments for independent type parameters (because they're never witnessed).
if (variance !== Variance.Independent) {
const s = sources[i];
const t = targets[i];
let related = Ternary.True;
if (variance === Variance.Covariant) {
related = isRelatedTo(s, t, reportErrors);
}
else if (variance === Variance.Contravariant) {
related = isRelatedTo(t, s, reportErrors);
}
else if (variance === Variance.Bivariant) {
// In the bivariant case we first compare contravariantly without reporting
// errors. Then, if that doesn't succeed, we compare covariantly with error
// reporting. Thus, error elaboration will be based on the the covariant check,
// which is generally easier to reason about.
related = isRelatedTo(t, s, /*reportErrors*/ false);
if (!related) {
related = isRelatedTo(s, t, reportErrors);
}
}
else {
// In the invariant case we first compare covariantly, and only when that
// succeeds do we proceed to compare contravariantly. Thus, error elaboration
// will typically be based on the covariant check.
related = isRelatedTo(s, t, reportErrors);
if (related) {
related &= isRelatedTo(t, s, reportErrors);
}
}
if (!related) {
return Ternary.False;
}
result &= related;
}
}
return result;
}
// Determine if possibly recursive types are related. First, check if the result is already available in the global cache.
// Second, check if we have already started a comparison of the given two types in which case we assume the result to be true.
// Third, check if both types are part of deeply nested chains of generic type instantiations and if so assume the types are
// equal and infinitely expanding. Fourth, if we have reached a depth of 100 nested comparisons, assume we have runaway recursion
// and issue an error. Otherwise, actually compare the structure of the two types.
function recursiveTypeRelatedTo(source: Type, target: Type, reportErrors: boolean, isIntersectionConstituent: boolean): Ternary {
if (overflow) {
return Ternary.False;
}
const id = getRelationKey(source, target, relation);
const related = relation.get(id);
if (related !== undefined) {
if (reportErrors && related === RelationComparisonResult.Failed) {
// We are elaborating errors and the cached result is an unreported failure. The result will be reported
// as a failure, and should be updated as a reported failure by the bottom of this function.
}
else {
return related === RelationComparisonResult.Succeeded ? Ternary.True : Ternary.False;
}
}
if (!maybeKeys) {
maybeKeys = [];
sourceStack = [];
targetStack = [];
}
else {
for (let i = 0; i < maybeCount; i++) {
// If source and target are already being compared, consider them related with assumptions
if (id === maybeKeys[i]) {
return Ternary.Maybe;
}
}
if (depth === 100) {
overflow = true;
return Ternary.False;
}
}
const maybeStart = maybeCount;
maybeKeys[maybeCount] = id;
maybeCount++;
sourceStack[depth] = source;
targetStack[depth] = target;
depth++;
const saveExpandingFlags = expandingFlags;
if (!(expandingFlags & ExpandingFlags.Source) && isDeeplyNestedType(source, sourceStack, depth)) expandingFlags |= ExpandingFlags.Source;
if (!(expandingFlags & ExpandingFlags.Target) && isDeeplyNestedType(target, targetStack, depth)) expandingFlags |= ExpandingFlags.Target;
const result = expandingFlags !== ExpandingFlags.Both ? structuredTypeRelatedTo(source, target, reportErrors, isIntersectionConstituent) : Ternary.Maybe;
expandingFlags = saveExpandingFlags;
depth--;
if (result) {
if (result === Ternary.True || depth === 0) {
// If result is definitely true, record all maybe keys as having succeeded
for (let i = maybeStart; i < maybeCount; i++) {
relation.set(maybeKeys[i], RelationComparisonResult.Succeeded);
}
maybeCount = maybeStart;
}
}
else {
// A false result goes straight into global cache (when something is false under
// assumptions it will also be false without assumptions)
relation.set(id, reportErrors ? RelationComparisonResult.FailedAndReported : RelationComparisonResult.Failed);
maybeCount = maybeStart;
}
return result;
}
function structuredTypeRelatedTo(source: Type, target: Type, reportErrors: boolean, isIntersectionConstituent: boolean): Ternary {
const flags = source.flags & target.flags;
if (relation === identityRelation && !(flags & TypeFlags.Object)) {
if (flags & TypeFlags.Index) {
return isRelatedTo((<IndexType>source).type, (<IndexType>target).type, /*reportErrors*/ false);
}
let result = Ternary.False;
if (flags & TypeFlags.IndexedAccess) {
if (result = isRelatedTo((<IndexedAccessType>source).objectType, (<IndexedAccessType>target).objectType, /*reportErrors*/ false)) {
if (result &= isRelatedTo((<IndexedAccessType>source).indexType, (<IndexedAccessType>target).indexType, /*reportErrors*/ false)) {
return result;
}
}
}
if (flags & TypeFlags.Conditional) {
if ((<ConditionalType>source).root.isDistributive === (<ConditionalType>target).root.isDistributive) {
if (result = isRelatedTo((<ConditionalType>source).checkType, (<ConditionalType>target).checkType, /*reportErrors*/ false)) {
if (result &= isRelatedTo((<ConditionalType>source).extendsType, (<ConditionalType>target).extendsType, /*reportErrors*/ false)) {
if (result &= isRelatedTo(getTrueTypeFromConditionalType(<ConditionalType>source), getTrueTypeFromConditionalType(<ConditionalType>target), /*reportErrors*/ false)) {
if (result &= isRelatedTo(getFalseTypeFromConditionalType(<ConditionalType>source), getFalseTypeFromConditionalType(<ConditionalType>target), /*reportErrors*/ false)) {
return result;
}
}
}
}
}
}
if (flags & TypeFlags.Substitution) {
return isRelatedTo((<SubstitutionType>source).substitute, (<SubstitutionType>target).substitute, /*reportErrors*/ false);
}
return Ternary.False;
}
let result: Ternary;
let originalErrorInfo: DiagnosticMessageChain | undefined;
let varianceCheckFailed = false;
const saveErrorInfo = errorInfo;
// We limit alias variance probing to only object and conditional types since their alias behavior
// is more predictable than other, interned types, which may or may not have an alias depending on
// the order in which things were checked.
if (source.flags & (TypeFlags.Object | TypeFlags.Conditional) && source.aliasSymbol &&
source.aliasTypeArguments && source.aliasSymbol === target.aliasSymbol &&
!(source.aliasTypeArgumentsContainsMarker || target.aliasTypeArgumentsContainsMarker)) {
const variances = getAliasVariances(source.aliasSymbol);
const varianceResult = relateVariances(source.aliasTypeArguments, target.aliasTypeArguments, variances);
if (varianceResult !== undefined) {
return varianceResult;
}
}
if (target.flags & TypeFlags.TypeParameter) {
// A source type { [P in Q]: X } is related to a target type T if keyof T is related to Q and X is related to T[Q].
if (getObjectFlags(source) & ObjectFlags.Mapped && isRelatedTo(getIndexType(target), getConstraintTypeFromMappedType(<MappedType>source))) {
if (!(getMappedTypeModifiers(<MappedType>source) & MappedTypeModifiers.IncludeOptional)) {
const templateType = getTemplateTypeFromMappedType(<MappedType>source);
const indexedAccessType = getIndexedAccessType(target, getTypeParameterFromMappedType(<MappedType>source));
if (result = isRelatedTo(templateType, indexedAccessType, reportErrors)) {
return result;
}
}
}
}
else if (target.flags & TypeFlags.Index) {
// A keyof S is related to a keyof T if T is related to S.
if (source.flags & TypeFlags.Index) {
if (result = isRelatedTo((<IndexType>target).type, (<IndexType>source).type, /*reportErrors*/ false)) {
return result;
}
}
// A type S is assignable to keyof T if S is assignable to keyof C, where C is the
// simplified form of T or, if T doesn't simplify, the constraint of T.
const simplified = getSimplifiedType((<IndexType>target).type);
const constraint = simplified !== (<IndexType>target).type ? simplified : getConstraintOfType((<IndexType>target).type);
if (constraint) {
// We require Ternary.True here such that circular constraints don't cause
// false positives. For example, given 'T extends { [K in keyof T]: string }',
// 'keyof T' has itself as its constraint and produces a Ternary.Maybe when
// related to other types.
if (isRelatedTo(source, getIndexType(constraint, (target as IndexType).stringsOnly), reportErrors) === Ternary.True) {
return Ternary.True;
}
}
}
else if (target.flags & TypeFlags.IndexedAccess) {
// A type S is related to a type T[K], where T and K aren't both type variables, if S is related to C,
// where C is the base constraint of T[K]
if (relation !== identityRelation &&
!(isGenericObjectType((<IndexedAccessType>target).objectType) && isGenericIndexType((<IndexedAccessType>target).indexType))) {
const constraint = getBaseConstraintOfType(target);
if (constraint && constraint !== target) {
if (result = isRelatedTo(source, constraint, reportErrors)) {
return result;
}
}
}
}
else if (isGenericMappedType(target)) {
// A source type T is related to a target type { [P in X]: T[P] }
const template = getTemplateTypeFromMappedType(target);
const modifiers = getMappedTypeModifiers(target);
if (!(modifiers & MappedTypeModifiers.ExcludeOptional)) {
if (template.flags & TypeFlags.IndexedAccess && (<IndexedAccessType>template).objectType === source &&
(<IndexedAccessType>template).indexType === getTypeParameterFromMappedType(target)) {
return Ternary.True;
}
// A source type T is related to a target type { [P in Q]: X } if Q is related to keyof T and T[Q] is related to X.
if (!isGenericMappedType(source) && isRelatedTo(getConstraintTypeFromMappedType(target), getIndexType(source))) {
const indexedAccessType = getIndexedAccessType(source, getTypeParameterFromMappedType(target));
const templateType = getTemplateTypeFromMappedType(target);
if (result = isRelatedTo(indexedAccessType, templateType, reportErrors)) {
return result;
}
}
originalErrorInfo = errorInfo;
errorInfo = saveErrorInfo;
}
}
if (source.flags & TypeFlags.TypeVariable) {
if (source.flags & TypeFlags.IndexedAccess && target.flags & TypeFlags.IndexedAccess) {
// A type S[K] is related to a type T[J] if S is related to T and K is related to J.
if (result = isRelatedTo((<IndexedAccessType>source).objectType, (<IndexedAccessType>target).objectType, reportErrors)) {
result &= isRelatedTo((<IndexedAccessType>source).indexType, (<IndexedAccessType>target).indexType, reportErrors);
}
if (result) {
errorInfo = saveErrorInfo;
return result;
}
}
const constraint = getConstraintOfType(<TypeParameter>source);
if (!constraint || (source.flags & TypeFlags.TypeParameter && constraint.flags & TypeFlags.Any)) {
// A type variable with no constraint is not related to the non-primitive object type.
if (result = isRelatedTo(emptyObjectType, extractTypesOfKind(target, ~TypeFlags.NonPrimitive))) {
errorInfo = saveErrorInfo;
return result;
}
}
// hi-speed no-this-instantiation check (less accurate, but avoids costly `this`-instantiation when the constraint will suffice), see #28231 for report on why this is needed
else if (result = isRelatedTo(constraint, target, /*reportErrors*/ false, /*headMessage*/ undefined, isIntersectionConstituent)) {
errorInfo = saveErrorInfo;
return result;
}
// slower, fuller, this-instantiated check (necessary when comparing raw `this` types from base classes), see `subclassWithPolymorphicThisIsAssignable.ts` test for example
else if (result = isRelatedTo(getTypeWithThisArgument(constraint, source), target, reportErrors, /*headMessage*/ undefined, isIntersectionConstituent)) {
errorInfo = saveErrorInfo;
return result;
}
}
else if (source.flags & TypeFlags.Index) {
if (result = isRelatedTo(keyofConstraintType, target, reportErrors)) {
errorInfo = saveErrorInfo;
return result;
}
}
else if (source.flags & TypeFlags.Conditional) {
if (target.flags & TypeFlags.Conditional) {
// Two conditional types 'T1 extends U1 ? X1 : Y1' and 'T2 extends U2 ? X2 : Y2' are related if
// one of T1 and T2 is related to the other, U1 and U2 are identical types, X1 is related to X2,
// and Y1 is related to Y2.
if (isTypeIdenticalTo((<ConditionalType>source).extendsType, (<ConditionalType>target).extendsType) &&
(isRelatedTo((<ConditionalType>source).checkType, (<ConditionalType>target).checkType) || isRelatedTo((<ConditionalType>target).checkType, (<ConditionalType>source).checkType))) {
if (result = isRelatedTo(getTrueTypeFromConditionalType(<ConditionalType>source), getTrueTypeFromConditionalType(<ConditionalType>target), reportErrors)) {
result &= isRelatedTo(getFalseTypeFromConditionalType(<ConditionalType>source), getFalseTypeFromConditionalType(<ConditionalType>target), reportErrors);
}
if (result) {
errorInfo = saveErrorInfo;
return result;
}
}
}
else {
const distributiveConstraint = getConstraintOfDistributiveConditionalType(<ConditionalType>source);
if (distributiveConstraint) {
if (result = isRelatedTo(distributiveConstraint, target, reportErrors)) {
errorInfo = saveErrorInfo;
return result;
}
}
const defaultConstraint = getDefaultConstraintOfConditionalType(<ConditionalType>source);
if (defaultConstraint) {
if (result = isRelatedTo(defaultConstraint, target, reportErrors)) {
errorInfo = saveErrorInfo;
return result;
}
}
}
}
else {
// An empty object type is related to any mapped type that includes a '?' modifier.
if (relation !== subtypeRelation && isPartialMappedType(target) && isEmptyObjectType(source)) {
return Ternary.True;
}
if (isGenericMappedType(target)) {
if (isGenericMappedType(source)) {
if (result = mappedTypeRelatedTo(source, target, reportErrors)) {
errorInfo = saveErrorInfo;
return result;
}
}
return Ternary.False;
}
const sourceIsPrimitive = !!(source.flags & TypeFlags.Primitive);
if (relation !== identityRelation) {
source = getApparentType(source);
}
if (getObjectFlags(source) & ObjectFlags.Reference && getObjectFlags(target) & ObjectFlags.Reference && (<TypeReference>source).target === (<TypeReference>target).target &&
!(getObjectFlags(source) & ObjectFlags.MarkerType || getObjectFlags(target) & ObjectFlags.MarkerType)) {
// We have type references to the same generic type, and the type references are not marker
// type references (which are intended by be compared structurally). Obtain the variance
// information for the type parameters and relate the type arguments accordingly.
const variances = getVariances((<TypeReference>source).target);
const varianceResult = relateVariances((<TypeReference>source).typeArguments, (<TypeReference>target).typeArguments, variances);
if (varianceResult !== undefined) {
return varianceResult;
}
}
else if (isReadonlyArrayType(target) ? isArrayType(source) || isTupleType(source) : isArrayType(target) && isTupleType(source) && !source.target.readonly) {
return isRelatedTo(getIndexTypeOfType(source, IndexKind.Number) || anyType, getIndexTypeOfType(target, IndexKind.Number) || anyType, reportErrors);
}
// Consider a fresh empty object literal type "closed" under the subtype relationship - this way `{} <- {[idx: string]: any} <- fresh({})`
// and not `{} <- fresh({}) <- {[idx: string]: any}`
else if (relation === subtypeRelation && isEmptyObjectType(target) && getObjectFlags(target) & ObjectFlags.FreshLiteral && !isEmptyObjectType(source)) {
return Ternary.False;
}
// Even if relationship doesn't hold for unions, intersections, or generic type references,
// it may hold in a structural comparison.
// In a check of the form X = A & B, we will have previously checked if A relates to X or B relates
// to X. Failing both of those we want to check if the aggregation of A and B's members structurally
// relates to X. Thus, we include intersection types on the source side here.
if (source.flags & (TypeFlags.Object | TypeFlags.Intersection) && target.flags & TypeFlags.Object) {
// Report structural errors only if we haven't reported any errors yet
const reportStructuralErrors = reportErrors && errorInfo === saveErrorInfo && !sourceIsPrimitive;
result = propertiesRelatedTo(source, target, reportStructuralErrors);
if (result) {
result &= signaturesRelatedTo(source, target, SignatureKind.Call, reportStructuralErrors);
if (result) {
result &= signaturesRelatedTo(source, target, SignatureKind.Construct, reportStructuralErrors);
if (result) {
result &= indexTypesRelatedTo(source, target, IndexKind.String, sourceIsPrimitive, reportStructuralErrors);
if (result) {
result &= indexTypesRelatedTo(source, target, IndexKind.Number, sourceIsPrimitive, reportStructuralErrors);
}
}
}
}
if (varianceCheckFailed && result) {
errorInfo = originalErrorInfo || errorInfo || saveErrorInfo; // Use variance error (there is no structural one) and return false
}
else if (result) {
return result;
}
}
}
return Ternary.False;
function isNonGeneric(type: Type) {
// If we're already in identity relationship checking, we should use `isRelatedTo`
// to catch the `Maybe` from an excessively deep type (which we then assume means
// that the type could possibly contain a generic)
if (relation === identityRelation) {
return isRelatedTo(type, getPermissiveInstantiation(type)) === Ternary.True;
}
return isTypeIdenticalTo(type, getPermissiveInstantiation(type));
}
function relateVariances(sourceTypeArguments: ReadonlyArray<Type> | undefined, targetTypeArguments: ReadonlyArray<Type> | undefined, variances: Variance[]) {
if (result = typeArgumentsRelatedTo(sourceTypeArguments, targetTypeArguments, variances, reportErrors)) {
return result;
}
const allowStructuralFallback = (targetTypeArguments && hasCovariantVoidArgument(targetTypeArguments, variances)) || isNonGeneric(source) || isNonGeneric(target);
varianceCheckFailed = !allowStructuralFallback;
// The type arguments did not relate appropriately, but it may be because we have no variance
// information (in which case typeArgumentsRelatedTo defaulted to covariance for all type
// arguments). It might also be the case that the target type has a 'void' type argument for
// a covariant type parameter that is only used in return positions within the generic type
// (in which case any type argument is permitted on the source side). In those cases we proceed
// with a structural comparison. Otherwise, we know for certain the instantiations aren't
// related and we can return here.
if (variances !== emptyArray && !allowStructuralFallback) {
// In some cases generic types that are covariant in regular type checking mode become
// invariant in --strictFunctionTypes mode because one or more type parameters are used in
// both co- and contravariant positions. In order to make it easier to diagnose *why* such
// types are invariant, if any of the type parameters are invariant we reset the reported
// errors and instead force a structural comparison (which will include elaborations that
// reveal the reason).
// We can switch on `reportErrors` here, since varianceCheckFailed guarantees we return `False`,
// we can return `False` early here to skip calculating the structural error message we don't need.
if (varianceCheckFailed && !(reportErrors && some(variances, v => v === Variance.Invariant))) {
return Ternary.False;
}
// We remember the original error information so we can restore it in case the structural
// comparison unexpectedly succeeds. This can happen when the structural comparison result
// is a Ternary.Maybe for example caused by the recursion depth limiter.
originalErrorInfo = errorInfo;
errorInfo = saveErrorInfo;
}
}
}
// A type [P in S]: X is related to a type [Q in T]: Y if T is related to S and X' is
// related to Y, where X' is an instantiation of X in which P is replaced with Q. Notice
// that S and T are contra-variant whereas X and Y are co-variant.
function mappedTypeRelatedTo(source: MappedType, target: MappedType, reportErrors: boolean): Ternary {
const modifiersRelated = relation === comparableRelation || (relation === identityRelation ? getMappedTypeModifiers(source) === getMappedTypeModifiers(target) :
getCombinedMappedTypeOptionality(source) <= getCombinedMappedTypeOptionality(target));
if (modifiersRelated) {
let result: Ternary;
if (result = isRelatedTo(getConstraintTypeFromMappedType(target), getConstraintTypeFromMappedType(source), reportErrors)) {
const mapper = createTypeMapper([getTypeParameterFromMappedType(source)], [getTypeParameterFromMappedType(target)]);
return result & isRelatedTo(instantiateType(getTemplateTypeFromMappedType(source), mapper), getTemplateTypeFromMappedType(target), reportErrors);
}
}
return Ternary.False;
}
function propertiesRelatedTo(source: Type, target: Type, reportErrors: boolean): Ternary {
if (relation === identityRelation) {
return propertiesIdenticalTo(source, target);
}
const requireOptionalProperties = relation === subtypeRelation && !isObjectLiteralType(source) && !isEmptyArrayLiteralType(source) && !isTupleType(source);
const unmatchedProperty = getUnmatchedProperty(source, target, requireOptionalProperties, /*matchDiscriminantProperties*/ false);
if (unmatchedProperty) {
if (reportErrors) {
const props = arrayFrom(getUnmatchedProperties(source, target, requireOptionalProperties, /*matchDiscriminantProperties*/ false));
if (!headMessage || (headMessage.code !== Diagnostics.Class_0_incorrectly_implements_interface_1.code &&
headMessage.code !== Diagnostics.Class_0_incorrectly_implements_class_1_Did_you_mean_to_extend_1_and_inherit_its_members_as_a_subclass.code)) {
suppressNextError = true; // Retain top-level error for interface implementing issues, otherwise omit it
}
if (props.length === 1) {
const propName = symbolToString(unmatchedProperty);
reportError(Diagnostics.Property_0_is_missing_in_type_1_but_required_in_type_2, propName, typeToString(source), typeToString(target));
if (length(unmatchedProperty.declarations)) {
associateRelatedInfo(createDiagnosticForNode(unmatchedProperty.declarations[0], Diagnostics._0_is_declared_here, propName));
}
}
else if (props.length > 5) { // arbitrary cutoff for too-long list form
reportError(Diagnostics.Type_0_is_missing_the_following_properties_from_type_1_Colon_2_and_3_more, typeToString(source), typeToString(target), map(props.slice(0, 4), p => symbolToString(p)).join(", "), props.length - 4);
}
else {
reportError(Diagnostics.Type_0_is_missing_the_following_properties_from_type_1_Colon_2, typeToString(source), typeToString(target), map(props, p => symbolToString(p)).join(", "));
}
}
return Ternary.False;
}
if (isObjectLiteralType(target)) {
for (const sourceProp of getPropertiesOfType(source)) {
if (!getPropertyOfObjectType(target, sourceProp.escapedName)) {
const sourceType = getTypeOfSymbol(sourceProp);
if (!(sourceType === undefinedType || sourceType === undefinedWideningType)) {
if (reportErrors) {
reportError(Diagnostics.Property_0_does_not_exist_on_type_1, symbolToString(sourceProp), typeToString(target));
}
return Ternary.False;
}
}
}
}
let result = Ternary.True;
if (isTupleType(target)) {
const targetRestType = getRestTypeOfTupleType(target);
if (targetRestType) {
if (!isTupleType(source)) {
return Ternary.False;
}
const sourceRestType = getRestTypeOfTupleType(source);
if (sourceRestType && !isRelatedTo(sourceRestType, targetRestType, reportErrors)) {
if (reportErrors) {
reportError(Diagnostics.Rest_signatures_are_incompatible);
}
return Ternary.False;
}
const targetCount = getTypeReferenceArity(target) - 1;
const sourceCount = getTypeReferenceArity(source) - (sourceRestType ? 1 : 0);
for (let i = targetCount; i < sourceCount; i++) {
const related = isRelatedTo((<TypeReference>source).typeArguments![i], targetRestType, reportErrors);
if (!related) {
if (reportErrors) {
reportError(Diagnostics.Property_0_is_incompatible_with_rest_element_type, "" + i);
}
return Ternary.False;
}
result &= related;
}
}
}
const properties = getPropertiesOfObjectType(target);
for (const targetProp of properties) {
if (!(targetProp.flags & SymbolFlags.Prototype)) {
const sourceProp = getPropertyOfType(source, targetProp.escapedName);
if (sourceProp && sourceProp !== targetProp) {
if (isIgnoredJsxProperty(source, sourceProp, getTypeOfSymbol(targetProp))) {
continue;
}
const sourcePropFlags = getDeclarationModifierFlagsFromSymbol(sourceProp);
const targetPropFlags = getDeclarationModifierFlagsFromSymbol(targetProp);
if (sourcePropFlags & ModifierFlags.Private || targetPropFlags & ModifierFlags.Private) {
const hasDifferingDeclarations = sourceProp.valueDeclaration !== targetProp.valueDeclaration;
if (getCheckFlags(sourceProp) & CheckFlags.ContainsPrivate && hasDifferingDeclarations) {
if (reportErrors) {
reportError(Diagnostics.Property_0_has_conflicting_declarations_and_is_inaccessible_in_type_1, symbolToString(sourceProp), typeToString(source));
}
return Ternary.False;
}
if (hasDifferingDeclarations) {
if (reportErrors) {
if (sourcePropFlags & ModifierFlags.Private && targetPropFlags & ModifierFlags.Private) {
reportError(Diagnostics.Types_have_separate_declarations_of_a_private_property_0, symbolToString(targetProp));
}
else {
reportError(Diagnostics.Property_0_is_private_in_type_1_but_not_in_type_2, symbolToString(targetProp),
typeToString(sourcePropFlags & ModifierFlags.Private ? source : target),
typeToString(sourcePropFlags & ModifierFlags.Private ? target : source));
}
}
return Ternary.False;
}
}
else if (targetPropFlags & ModifierFlags.Protected) {
if (!isValidOverrideOf(sourceProp, targetProp)) {
if (reportErrors) {
reportError(Diagnostics.Property_0_is_protected_but_type_1_is_not_a_class_derived_from_2, symbolToString(targetProp),
typeToString(getDeclaringClass(sourceProp) || source), typeToString(getDeclaringClass(targetProp) || target));
}
return Ternary.False;
}
}
else if (sourcePropFlags & ModifierFlags.Protected) {
if (reportErrors) {
reportError(Diagnostics.Property_0_is_protected_in_type_1_but_public_in_type_2,
symbolToString(targetProp), typeToString(source), typeToString(target));
}
return Ternary.False;
}
const related = isRelatedTo(getTypeOfSymbol(sourceProp), getTypeOfSymbol(targetProp), reportErrors);
if (!related) {
if (reportErrors) {
reportError(Diagnostics.Types_of_property_0_are_incompatible, symbolToString(targetProp));
}
return Ternary.False;
}
result &= related;
// When checking for comparability, be more lenient with optional properties.
if (relation !== comparableRelation && sourceProp.flags & SymbolFlags.Optional && !(targetProp.flags & SymbolFlags.Optional)) {
// TypeScript 1.0 spec (April 2014): 3.8.3
// S is a subtype of a type T, and T is a supertype of S if ...
// S' and T are object types and, for each member M in T..
// M is a property and S' contains a property N where
// if M is a required property, N is also a required property
// (M - property in T)
// (N - property in S)
if (reportErrors) {
reportError(Diagnostics.Property_0_is_optional_in_type_1_but_required_in_type_2,
symbolToString(targetProp), typeToString(source), typeToString(target));
}
return Ternary.False;
}
}
}
}
return result;
}
function propertiesIdenticalTo(source: Type, target: Type): Ternary {
if (!(source.flags & TypeFlags.Object && target.flags & TypeFlags.Object)) {
return Ternary.False;
}
const sourceProperties = getPropertiesOfObjectType(source);
const targetProperties = getPropertiesOfObjectType(target);
if (sourceProperties.length !== targetProperties.length) {
return Ternary.False;
}
let result = Ternary.True;
for (const sourceProp of sourceProperties) {
const targetProp = getPropertyOfObjectType(target, sourceProp.escapedName);
if (!targetProp) {
return Ternary.False;
}
const related = compareProperties(sourceProp, targetProp, isRelatedTo);
if (!related) {
return Ternary.False;
}
result &= related;
}
return result;
}
function signaturesRelatedTo(source: Type, target: Type, kind: SignatureKind, reportErrors: boolean): Ternary {
if (relation === identityRelation) {
return signaturesIdenticalTo(source, target, kind);
}
if (target === anyFunctionType || source === anyFunctionType) {
return Ternary.True;
}
const sourceIsJSConstructor = source.symbol && isJSConstructor(source.symbol.valueDeclaration);
const targetIsJSConstructor = target.symbol && isJSConstructor(target.symbol.valueDeclaration);
const sourceSignatures = getSignaturesOfType(source, (sourceIsJSConstructor && kind === SignatureKind.Construct) ?
SignatureKind.Call : kind);
const targetSignatures = getSignaturesOfType(target, (targetIsJSConstructor && kind === SignatureKind.Construct) ?
SignatureKind.Call : kind);
if (kind === SignatureKind.Construct && sourceSignatures.length && targetSignatures.length) {
if (isAbstractConstructorType(source) && !isAbstractConstructorType(target)) {
// An abstract constructor type is not assignable to a non-abstract constructor type
// as it would otherwise be possible to new an abstract class. Note that the assignability
// check we perform for an extends clause excludes construct signatures from the target,
// so this check never proceeds.
if (reportErrors) {
reportError(Diagnostics.Cannot_assign_an_abstract_constructor_type_to_a_non_abstract_constructor_type);
}
return Ternary.False;
}
if (!constructorVisibilitiesAreCompatible(sourceSignatures[0], targetSignatures[0], reportErrors)) {
return Ternary.False;
}
}
let result = Ternary.True;
const saveErrorInfo = errorInfo;
if (getObjectFlags(source) & ObjectFlags.Instantiated && getObjectFlags(target) & ObjectFlags.Instantiated && source.symbol === target.symbol) {
// We have instantiations of the same anonymous type (which typically will be the type of a
// method). Simply do a pairwise comparison of the signatures in the two signature lists instead
// of the much more expensive N * M comparison matrix we explore below. We erase type parameters
// as they are known to always be the same.
for (let i = 0; i < targetSignatures.length; i++) {
const related = signatureRelatedTo(sourceSignatures[i], targetSignatures[i], /*erase*/ true, reportErrors);
if (!related) {
return Ternary.False;
}
result &= related;
}
}
else if (sourceSignatures.length === 1 && targetSignatures.length === 1) {
// For simple functions (functions with a single signature) we only erase type parameters for
// the comparable relation. Otherwise, if the source signature is generic, we instantiate it
// in the context of the target signature before checking the relationship. Ideally we'd do
// this regardless of the number of signatures, but the potential costs are prohibitive due
// to the quadratic nature of the logic below.
const eraseGenerics = relation === comparableRelation || !!compilerOptions.noStrictGenericChecks;
result = signatureRelatedTo(sourceSignatures[0], targetSignatures[0], eraseGenerics, reportErrors);
}
else {
outer: for (const t of targetSignatures) {
// Only elaborate errors from the first failure
let shouldElaborateErrors = reportErrors;
for (const s of sourceSignatures) {
const related = signatureRelatedTo(s, t, /*erase*/ true, shouldElaborateErrors);
if (related) {
result &= related;
errorInfo = saveErrorInfo;
continue outer;
}
shouldElaborateErrors = false;
}
if (shouldElaborateErrors) {
reportError(Diagnostics.Type_0_provides_no_match_for_the_signature_1,
typeToString(source),
signatureToString(t, /*enclosingDeclaration*/ undefined, /*flags*/ undefined, kind));
}
return Ternary.False;
}
}
return result;
}
/**
* See signatureAssignableTo, compareSignaturesIdentical
*/
function signatureRelatedTo(source: Signature, target: Signature, erase: boolean, reportErrors: boolean): Ternary {
return compareSignaturesRelated(erase ? getErasedSignature(source) : source, erase ? getErasedSignature(target) : target,
CallbackCheck.None, /*ignoreReturnTypes*/ false, reportErrors, reportError, isRelatedTo);
}
function signaturesIdenticalTo(source: Type, target: Type, kind: SignatureKind): Ternary {
const sourceSignatures = getSignaturesOfType(source, kind);
const targetSignatures = getSignaturesOfType(target, kind);
if (sourceSignatures.length !== targetSignatures.length) {
return Ternary.False;
}
let result = Ternary.True;
for (let i = 0; i < sourceSignatures.length; i++) {
const related = compareSignaturesIdentical(sourceSignatures[i], targetSignatures[i], /*partialMatch*/ false, /*ignoreThisTypes*/ false, /*ignoreReturnTypes*/ false, isRelatedTo);
if (!related) {
return Ternary.False;
}
result &= related;
}
return result;
}
function eachPropertyRelatedTo(source: Type, target: Type, kind: IndexKind, reportErrors: boolean): Ternary {
let result = Ternary.True;
for (const prop of getPropertiesOfObjectType(source)) {
if (isIgnoredJsxProperty(source, prop, /*targetMemberType*/ undefined)) {
continue;
}
// Skip over symbol-named members
if (prop.nameType && prop.nameType.flags & TypeFlags.UniqueESSymbol) {
continue;
}
if (kind === IndexKind.String || isNumericLiteralName(prop.escapedName)) {
const related = isRelatedTo(getTypeOfSymbol(prop), target, reportErrors);
if (!related) {
if (reportErrors) {
reportError(Diagnostics.Property_0_is_incompatible_with_index_signature, symbolToString(prop));
}
return Ternary.False;
}
result &= related;
}
}
return result;
}
function indexInfoRelatedTo(sourceInfo: IndexInfo, targetInfo: IndexInfo, reportErrors: boolean) {
const related = isRelatedTo(sourceInfo.type, targetInfo.type, reportErrors);
if (!related && reportErrors) {
reportError(Diagnostics.Index_signatures_are_incompatible);
}
return related;
}
function indexTypesRelatedTo(source: Type, target: Type, kind: IndexKind, sourceIsPrimitive: boolean, reportErrors: boolean): Ternary {
if (relation === identityRelation) {
return indexTypesIdenticalTo(source, target, kind);
}
const targetInfo = getIndexInfoOfType(target, kind);
if (!targetInfo || targetInfo.type.flags & TypeFlags.AnyOrUnknown && !sourceIsPrimitive) {
// Index signature of type any permits assignment from everything but primitives
return Ternary.True;
}
const sourceInfo = getIndexInfoOfType(source, kind) ||
kind === IndexKind.Number && getIndexInfoOfType(source, IndexKind.String);
if (sourceInfo) {
return indexInfoRelatedTo(sourceInfo, targetInfo, reportErrors);
}
if (isGenericMappedType(source)) {
// A generic mapped type { [P in K]: T } is related to an index signature { [x: string]: U }
// if T is related to U.
return (kind === IndexKind.String && isRelatedTo(getTemplateTypeFromMappedType(source), targetInfo.type, reportErrors)) as any as Ternary; // TODO: GH#18217
}
if (isObjectTypeWithInferableIndex(source)) {
let related = Ternary.True;
if (kind === IndexKind.String) {
const sourceNumberInfo = getIndexInfoOfType(source, IndexKind.Number);
if (sourceNumberInfo) {
related = indexInfoRelatedTo(sourceNumberInfo, targetInfo, reportErrors);
}
}
if (related) {
related &= eachPropertyRelatedTo(source, targetInfo.type, kind, reportErrors);
}
return related;
}
if (reportErrors) {
reportError(Diagnostics.Index_signature_is_missing_in_type_0, typeToString(source));
}
return Ternary.False;
}
function indexTypesIdenticalTo(source: Type, target: Type, indexKind: IndexKind): Ternary {
const targetInfo = getIndexInfoOfType(target, indexKind);
const sourceInfo = getIndexInfoOfType(source, indexKind);
if (!sourceInfo && !targetInfo) {
return Ternary.True;
}
if (sourceInfo && targetInfo && sourceInfo.isReadonly === targetInfo.isReadonly) {
return isRelatedTo(sourceInfo.type, targetInfo.type);
}
return Ternary.False;
}
function constructorVisibilitiesAreCompatible(sourceSignature: Signature, targetSignature: Signature, reportErrors: boolean) {
if (!sourceSignature.declaration || !targetSignature.declaration) {
return true;
}
const sourceAccessibility = getSelectedModifierFlags(sourceSignature.declaration, ModifierFlags.NonPublicAccessibilityModifier);
const targetAccessibility = getSelectedModifierFlags(targetSignature.declaration, ModifierFlags.NonPublicAccessibilityModifier);
// A public, protected and private signature is assignable to a private signature.
if (targetAccessibility === ModifierFlags.Private) {
return true;
}
// A public and protected signature is assignable to a protected signature.
if (targetAccessibility === ModifierFlags.Protected && sourceAccessibility !== ModifierFlags.Private) {
return true;
}
// Only a public signature is assignable to public signature.
if (targetAccessibility !== ModifierFlags.Protected && !sourceAccessibility) {
return true;
}
if (reportErrors) {
reportError(Diagnostics.Cannot_assign_a_0_constructor_type_to_a_1_constructor_type, visibilityToString(sourceAccessibility), visibilityToString(targetAccessibility));
}
return false;
}
}
function discriminateTypeByDiscriminableItems(target: UnionType, discriminators: [() => Type, __String][], related: (source: Type, target: Type) => boolean | Ternary): Type | undefined;
function discriminateTypeByDiscriminableItems(target: UnionType, discriminators: [() => Type, __String][], related: (source: Type, target: Type) => boolean | Ternary, defaultValue: Type): Type;
function discriminateTypeByDiscriminableItems(target: UnionType, discriminators: [() => Type, __String][], related: (source: Type, target: Type) => boolean | Ternary, defaultValue?: Type) {
let match: Type | undefined;
for (const [getDiscriminatingType, propertyName] of discriminators) {
for (const type of target.types) {
const targetType = getTypeOfPropertyOfType(type, propertyName);
if (targetType && related(getDiscriminatingType(), targetType)) {
if (match) {
if (type === match) continue; // Finding multiple fields which discriminate to the same type is fine
return defaultValue;
}
match = type;
}
}
}
return match || defaultValue;
}
/**
* A type is 'weak' if it is an object type with at least one optional property
* and no required properties, call/construct signatures or index signatures
*/
function isWeakType(type: Type): boolean {
if (type.flags & TypeFlags.Object) {
const resolved = resolveStructuredTypeMembers(<ObjectType>type);
return resolved.callSignatures.length === 0 && resolved.constructSignatures.length === 0 &&
!resolved.stringIndexInfo && !resolved.numberIndexInfo &&
resolved.properties.length > 0 &&
every(resolved.properties, p => !!(p.flags & SymbolFlags.Optional));
}
if (type.flags & TypeFlags.Intersection) {
return every((<IntersectionType>type).types, isWeakType);
}
return false;
}
function hasCommonProperties(source: Type, target: Type, isComparingJsxAttributes: boolean) {
for (const prop of getPropertiesOfType(source)) {
if (isKnownProperty(target, prop.escapedName, isComparingJsxAttributes)) {
return true;
}
}
return false;
}
// Return a type reference where the source type parameter is replaced with the target marker
// type, and flag the result as a marker type reference.
function getMarkerTypeReference(type: GenericType, source: TypeParameter, target: Type) {
const result = createTypeReference(type, map(type.typeParameters, t => t === source ? target : t));
result.objectFlags |= ObjectFlags.MarkerType;
return result;
}
function getAliasVariances(symbol: Symbol) {
const links = getSymbolLinks(symbol);
return getVariancesWorker(links.typeParameters, links, (_links, param, marker) => {
const type = getTypeAliasInstantiation(symbol, instantiateTypes(links.typeParameters!, makeUnaryTypeMapper(param, marker)));
type.aliasTypeArgumentsContainsMarker = true;
return type;
});
}
// Return an array containing the variance of each type parameter. The variance is effectively
// a digest of the type comparisons that occur for each type argument when instantiations of the
// generic type are structurally compared. We infer the variance information by comparing
// instantiations of the generic type for type arguments with known relations. The function
// returns the emptyArray singleton if we're not in strictFunctionTypes mode or if the function
// has been invoked recursively for the given generic type.
function getVariancesWorker<TCache extends { variances?: Variance[] }>(typeParameters: ReadonlyArray<TypeParameter> = emptyArray, cache: TCache, createMarkerType: (input: TCache, param: TypeParameter, marker: Type) => Type): Variance[] {
let variances = cache.variances;
if (!variances) {
// The emptyArray singleton is used to signal a recursive invocation.
cache.variances = emptyArray;
variances = [];
for (const tp of typeParameters) {
// We first compare instantiations where the type parameter is replaced with
// marker types that have a known subtype relationship. From this we can infer
// invariance, covariance, contravariance or bivariance.
const typeWithSuper = createMarkerType(cache, tp, markerSuperType);
const typeWithSub = createMarkerType(cache, tp, markerSubType);
let variance = (isTypeAssignableTo(typeWithSub, typeWithSuper) ? Variance.Covariant : 0) |
(isTypeAssignableTo(typeWithSuper, typeWithSub) ? Variance.Contravariant : 0);
// If the instantiations appear to be related bivariantly it may be because the
// type parameter is independent (i.e. it isn't witnessed anywhere in the generic
// type). To determine this we compare instantiations where the type parameter is
// replaced with marker types that are known to be unrelated.
if (variance === Variance.Bivariant && isTypeAssignableTo(createMarkerType(cache, tp, markerOtherType), typeWithSuper)) {
variance = Variance.Independent;
}
variances.push(variance);
}
cache.variances = variances;
}
return variances;
}
function getVariances(type: GenericType): Variance[] {
// Arrays and tuples are known to be covariant, no need to spend time computing this (emptyArray implies covariance for all parameters)
if (type === globalArrayType || type === globalReadonlyArrayType || type.objectFlags & ObjectFlags.Tuple) {
return emptyArray;
}
return getVariancesWorker(type.typeParameters, type, getMarkerTypeReference);
}
// Return true if the given type reference has a 'void' type argument for a covariant type parameter.
// See comment at call in recursiveTypeRelatedTo for when this case matters.
function hasCovariantVoidArgument(typeArguments: ReadonlyArray<Type>, variances: Variance[]): boolean {
for (let i = 0; i < variances.length; i++) {
if (variances[i] === Variance.Covariant && typeArguments[i].flags & TypeFlags.Void) {
return true;
}
}
return false;
}
function isUnconstrainedTypeParameter(type: Type) {
return type.flags & TypeFlags.TypeParameter && !getConstraintOfTypeParameter(<TypeParameter>type);
}
function isTypeReferenceWithGenericArguments(type: Type): boolean {
return !!(getObjectFlags(type) & ObjectFlags.Reference) && some((<TypeReference>type).typeArguments, t => isUnconstrainedTypeParameter(t) || isTypeReferenceWithGenericArguments(t));
}
/**
* getTypeReferenceId(A<T, number, U>) returns "111=0-12=1"
* where A.id=111 and number.id=12
*/
function getTypeReferenceId(type: TypeReference, typeParameters: Type[], depth = 0) {
let result = "" + type.target.id;
for (const t of type.typeArguments!) {
if (isUnconstrainedTypeParameter(t)) {
let index = typeParameters.indexOf(t);
if (index < 0) {
index = typeParameters.length;
typeParameters.push(t);
}
result += "=" + index;
}
else if (depth < 4 && isTypeReferenceWithGenericArguments(t)) {
result += "<" + getTypeReferenceId(t as TypeReference, typeParameters, depth + 1) + ">";
}
else {
result += "-" + t.id;
}
}
return result;
}
/**
* To improve caching, the relation key for two generic types uses the target's id plus ids of the type parameters.
* For other cases, the types ids are used.
*/
function getRelationKey(source: Type, target: Type, relation: Map<RelationComparisonResult>) {
if (relation === identityRelation && source.id > target.id) {
const temp = source;
source = target;
target = temp;
}
if (isTypeReferenceWithGenericArguments(source) && isTypeReferenceWithGenericArguments(target)) {
const typeParameters: Type[] = [];
return getTypeReferenceId(<TypeReference>source, typeParameters) + "," + getTypeReferenceId(<TypeReference>target, typeParameters);
}
return source.id + "," + target.id;
}
// Invoke the callback for each underlying property symbol of the given symbol and return the first
// value that isn't undefined.
function forEachProperty<T>(prop: Symbol, callback: (p: Symbol) => T): T | undefined {
if (getCheckFlags(prop) & CheckFlags.Synthetic) {
for (const t of (<TransientSymbol>prop).containingType!.types) {
const p = getPropertyOfType(t, prop.escapedName);
const result = p && forEachProperty(p, callback);
if (result) {
return result;
}
}
return undefined;
}
return callback(prop);
}
// Return the declaring class type of a property or undefined if property not declared in class
function getDeclaringClass(prop: Symbol) {
return prop.parent && prop.parent.flags & SymbolFlags.Class ? getDeclaredTypeOfSymbol(getParentOfSymbol(prop)!) : undefined;
}
// Return true if some underlying source property is declared in a class that derives
// from the given base class.
function isPropertyInClassDerivedFrom(prop: Symbol, baseClass: Type | undefined) {
return forEachProperty(prop, sp => {
const sourceClass = getDeclaringClass(sp);
return sourceClass ? hasBaseType(sourceClass, baseClass) : false;
});
}
// Return true if source property is a valid override of protected parts of target property.
function isValidOverrideOf(sourceProp: Symbol, targetProp: Symbol) {
return !forEachProperty(targetProp, tp => getDeclarationModifierFlagsFromSymbol(tp) & ModifierFlags.Protected ?
!isPropertyInClassDerivedFrom(sourceProp, getDeclaringClass(tp)) : false);
}
// Return true if the given class derives from each of the declaring classes of the protected
// constituents of the given property.
function isClassDerivedFromDeclaringClasses(checkClass: Type, prop: Symbol) {
return forEachProperty(prop, p => getDeclarationModifierFlagsFromSymbol(p) & ModifierFlags.Protected ?
!hasBaseType(checkClass, getDeclaringClass(p)) : false) ? undefined : checkClass;
}
// Return true if the given type is deeply nested. We consider this to be the case when structural type comparisons
// for 5 or more occurrences or instantiations of the type have been recorded on the given stack. It is possible,
// though highly unlikely, for this test to be true in a situation where a chain of instantiations is not infinitely
// expanding. Effectively, we will generate a false positive when two types are structurally equal to at least 5
// levels, but unequal at some level beyond that.
function isDeeplyNestedType(type: Type, stack: Type[], depth: number): boolean {
// We track all object types that have an associated symbol (representing the origin of the type)
if (depth >= 5 && type.flags & TypeFlags.Object) {
const symbol = type.symbol;
if (symbol) {
let count = 0;
for (let i = 0; i < depth; i++) {
const t = stack[i];
if (t.flags & TypeFlags.Object && t.symbol === symbol) {
count++;
if (count >= 5) return true;
}
}
}
}
return false;
}
function isPropertyIdenticalTo(sourceProp: Symbol, targetProp: Symbol): boolean {
return compareProperties(sourceProp, targetProp, compareTypesIdentical) !== Ternary.False;
}
function compareProperties(sourceProp: Symbol, targetProp: Symbol, compareTypes: (source: Type, target: Type) => Ternary): Ternary {
// Two members are considered identical when
// - they are public properties with identical names, optionality, and types,
// - they are private or protected properties originating in the same declaration and having identical types
if (sourceProp === targetProp) {
return Ternary.True;
}
const sourcePropAccessibility = getDeclarationModifierFlagsFromSymbol(sourceProp) & ModifierFlags.NonPublicAccessibilityModifier;
const targetPropAccessibility = getDeclarationModifierFlagsFromSymbol(targetProp) & ModifierFlags.NonPublicAccessibilityModifier;
if (sourcePropAccessibility !== targetPropAccessibility) {
return Ternary.False;
}
if (sourcePropAccessibility) {
if (getTargetSymbol(sourceProp) !== getTargetSymbol(targetProp)) {
return Ternary.False;
}
}
else {
if ((sourceProp.flags & SymbolFlags.Optional) !== (targetProp.flags & SymbolFlags.Optional)) {
return Ternary.False;
}
}
if (isReadonlySymbol(sourceProp) !== isReadonlySymbol(targetProp)) {
return Ternary.False;
}
return compareTypes(getTypeOfSymbol(sourceProp), getTypeOfSymbol(targetProp));
}
function isMatchingSignature(source: Signature, target: Signature, partialMatch: boolean) {
const sourceParameterCount = getParameterCount(source);
const targetParameterCount = getParameterCount(target);
const sourceMinArgumentCount = getMinArgumentCount(source);
const targetMinArgumentCount = getMinArgumentCount(target);
const sourceHasRestParameter = hasEffectiveRestParameter(source);
const targetHasRestParameter = hasEffectiveRestParameter(target);
// A source signature matches a target signature if the two signatures have the same number of required,
// optional, and rest parameters.
if (sourceParameterCount === targetParameterCount &&
sourceMinArgumentCount === targetMinArgumentCount &&
sourceHasRestParameter === targetHasRestParameter) {
return true;
}
// A source signature partially matches a target signature if the target signature has no fewer required
// parameters
if (partialMatch && sourceMinArgumentCount <= targetMinArgumentCount) {
return true;
}
return false;
}
/**
* See signatureRelatedTo, compareSignaturesIdentical
*/
function compareSignaturesIdentical(source: Signature, target: Signature, partialMatch: boolean, ignoreThisTypes: boolean, ignoreReturnTypes: boolean, compareTypes: (s: Type, t: Type) => Ternary): Ternary {
// TODO (drosen): De-duplicate code between related functions.
if (source === target) {
return Ternary.True;
}
if (!(isMatchingSignature(source, target, partialMatch))) {
return Ternary.False;
}
// Check that the two signatures have the same number of type parameters. We might consider
// also checking that any type parameter constraints match, but that would require instantiating
// the constraints with a common set of type arguments to get relatable entities in places where
// type parameters occur in the constraints. The complexity of doing that doesn't seem worthwhile,
// particularly as we're comparing erased versions of the signatures below.
if (length(source.typeParameters) !== length(target.typeParameters)) {
return Ternary.False;
}
// Spec 1.0 Section 3.8.3 & 3.8.4:
// M and N (the signatures) are instantiated using type Any as the type argument for all type parameters declared by M and N
source = getErasedSignature(source);
target = getErasedSignature(target);
let result = Ternary.True;
if (!ignoreThisTypes) {
const sourceThisType = getThisTypeOfSignature(source);
if (sourceThisType) {
const targetThisType = getThisTypeOfSignature(target);
if (targetThisType) {
const related = compareTypes(sourceThisType, targetThisType);
if (!related) {
return Ternary.False;
}
result &= related;
}
}
}
const targetLen = getParameterCount(target);
for (let i = 0; i < targetLen; i++) {
const s = getTypeAtPosition(source, i);
const t = getTypeAtPosition(target, i);
const related = compareTypes(t, s);
if (!related) {
return Ternary.False;
}
result &= related;
}
if (!ignoreReturnTypes) {
const sourceTypePredicate = getTypePredicateOfSignature(source);
const targetTypePredicate = getTypePredicateOfSignature(target);
result &= sourceTypePredicate !== undefined || targetTypePredicate !== undefined
? compareTypePredicatesIdentical(sourceTypePredicate, targetTypePredicate, compareTypes)
// If they're both type predicates their return types will both be `boolean`, so no need to compare those.
: compareTypes(getReturnTypeOfSignature(source), getReturnTypeOfSignature(target));
}
return result;
}
function compareTypePredicatesIdentical(source: TypePredicate | undefined, target: TypePredicate | undefined, compareTypes: (s: Type, t: Type) => Ternary): Ternary {
return source === undefined || target === undefined || !typePredicateKindsMatch(source, target) ? Ternary.False : compareTypes(source.type, target.type);
}
function literalTypesWithSameBaseType(types: Type[]): boolean {
let commonBaseType: Type | undefined;
for (const t of types) {
const baseType = getBaseTypeOfLiteralType(t);
if (!commonBaseType) {
commonBaseType = baseType;
}
if (baseType === t || baseType !== commonBaseType) {
return false;
}
}
return true;
}
// When the candidate types are all literal types with the same base type, return a union
// of those literal types. Otherwise, return the leftmost type for which no type to the
// right is a supertype.
function getSupertypeOrUnion(types: Type[]): Type {
return literalTypesWithSameBaseType(types) ?
getUnionType(types) :
reduceLeft(types, (s, t) => isTypeSubtypeOf(s, t) ? t : s)!;
}
function getCommonSupertype(types: Type[]): Type {
if (!strictNullChecks) {
return getSupertypeOrUnion(types);
}
const primaryTypes = filter(types, t => !(t.flags & TypeFlags.Nullable));
return primaryTypes.length ?
getNullableType(getSupertypeOrUnion(primaryTypes), getFalsyFlagsOfTypes(types) & TypeFlags.Nullable) :
getUnionType(types, UnionReduction.Subtype);
}
// Return the leftmost type for which no type to the right is a subtype.
function getCommonSubtype(types: Type[]) {
return reduceLeft(types, (s, t) => isTypeSubtypeOf(t, s) ? t : s)!;
}
function isArrayType(type: Type): boolean {
return !!(getObjectFlags(type) & ObjectFlags.Reference) && ((<TypeReference>type).target === globalArrayType || (<TypeReference>type).target === globalReadonlyArrayType);
}
function isReadonlyArrayType(type: Type): boolean {
return !!(getObjectFlags(type) & ObjectFlags.Reference) && (<TypeReference>type).target === globalReadonlyArrayType;
}
function getElementTypeOfArrayType(type: Type): Type | undefined {
return isArrayType(type) && (type as TypeReference).typeArguments ? (type as TypeReference).typeArguments![0] : undefined;
}
function isArrayLikeType(type: Type): boolean {
// A type is array-like if it is a reference to the global Array or global ReadonlyArray type,
// or if it is not the undefined or null type and if it is assignable to ReadonlyArray<any>
return isArrayType(type) || !(type.flags & TypeFlags.Nullable) && isTypeAssignableTo(type, anyReadonlyArrayType);
}
function isEmptyArrayLiteralType(type: Type): boolean {
const elementType = isArrayType(type) ? (<TypeReference>type).typeArguments![0] : undefined;
return elementType === undefinedWideningType || elementType === implicitNeverType;
}
function isTupleLikeType(type: Type): boolean {
return isTupleType(type) || !!getPropertyOfType(type, "0" as __String);
}
function isArrayOrTupleLikeType(type: Type): boolean {
return isArrayLikeType(type) || isTupleLikeType(type);
}
function getTupleElementType(type: Type, index: number) {
const propType = getTypeOfPropertyOfType(type, "" + index as __String);
if (propType) {
return propType;
}
if (everyType(type, isTupleType) && !everyType(type, t => !(<TupleTypeReference>t).target.hasRestElement)) {
return mapType(type, t => getRestTypeOfTupleType(<TupleTypeReference>t) || undefinedType);
}
return undefined;
}
function isNeitherUnitTypeNorNever(type: Type): boolean {
return !(type.flags & (TypeFlags.Unit | TypeFlags.Never));
}
function isUnitType(type: Type): boolean {
return !!(type.flags & TypeFlags.Unit);
}
function isLiteralType(type: Type): boolean {
return type.flags & TypeFlags.Boolean ? true :
type.flags & TypeFlags.Union ? type.flags & TypeFlags.EnumLiteral ? true : every((<UnionType>type).types, isUnitType) :
isUnitType(type);
}
function getBaseTypeOfLiteralType(type: Type): Type {
return type.flags & TypeFlags.EnumLiteral ? getBaseTypeOfEnumLiteralType(<LiteralType>type) :
type.flags & TypeFlags.StringLiteral ? stringType :
type.flags & TypeFlags.NumberLiteral ? numberType :
type.flags & TypeFlags.BigIntLiteral ? bigintType :
type.flags & TypeFlags.BooleanLiteral ? booleanType :
type.flags & TypeFlags.Union ? getUnionType(sameMap((<UnionType>type).types, getBaseTypeOfLiteralType)) :
type;
}
function getWidenedLiteralType(type: Type): Type {
return type.flags & TypeFlags.EnumLiteral && isFreshLiteralType(type) ? getBaseTypeOfEnumLiteralType(<LiteralType>type) :
type.flags & TypeFlags.StringLiteral && isFreshLiteralType(type) ? stringType :
type.flags & TypeFlags.NumberLiteral && isFreshLiteralType(type) ? numberType :
type.flags & TypeFlags.BigIntLiteral && isFreshLiteralType(type) ? bigintType :
type.flags & TypeFlags.BooleanLiteral && isFreshLiteralType(type) ? booleanType :
type.flags & TypeFlags.Union ? getUnionType(sameMap((<UnionType>type).types, getWidenedLiteralType)) :
type;
}
function getWidenedUniqueESSymbolType(type: Type): Type {
return type.flags & TypeFlags.UniqueESSymbol ? esSymbolType :
type.flags & TypeFlags.Union ? getUnionType(sameMap((<UnionType>type).types, getWidenedUniqueESSymbolType)) :
type;
}
function getWidenedLiteralLikeTypeForContextualType(type: Type, contextualType: Type | undefined) {
if (!isLiteralOfContextualType(type, contextualType)) {
type = getWidenedUniqueESSymbolType(getWidenedLiteralType(type));
}
return type;
}
/**
* Check if a Type was written as a tuple type literal.
* Prefer using isTupleLikeType() unless the use of `elementTypes` is required.
*/
function isTupleType(type: Type): type is TupleTypeReference {
return !!(getObjectFlags(type) & ObjectFlags.Reference && (<TypeReference>type).target.objectFlags & ObjectFlags.Tuple);
}
function getRestTypeOfTupleType(type: TupleTypeReference) {
return type.target.hasRestElement ? type.typeArguments![type.target.typeParameters!.length - 1] : undefined;
}
function getRestArrayTypeOfTupleType(type: TupleTypeReference) {
const restType = getRestTypeOfTupleType(type);
return restType && createArrayType(restType);
}
function getLengthOfTupleType(type: TupleTypeReference) {
return getTypeReferenceArity(type) - (type.target.hasRestElement ? 1 : 0);
}
function isZeroBigInt({value}: BigIntLiteralType) {
return value.base10Value === "0";
}
function getFalsyFlagsOfTypes(types: Type[]): TypeFlags {
let result: TypeFlags = 0;
for (const t of types) {
result |= getFalsyFlags(t);
}
return result;
}
// Returns the String, Number, Boolean, StringLiteral, NumberLiteral, BooleanLiteral, Void, Undefined, or Null
// flags for the string, number, boolean, "", 0, false, void, undefined, or null types respectively. Returns
// no flags for all other types (including non-falsy literal types).
function getFalsyFlags(type: Type): TypeFlags {
return type.flags & TypeFlags.Union ? getFalsyFlagsOfTypes((<UnionType>type).types) :
type.flags & TypeFlags.StringLiteral ? (<StringLiteralType>type).value === "" ? TypeFlags.StringLiteral : 0 :
type.flags & TypeFlags.NumberLiteral ? (<NumberLiteralType>type).value === 0 ? TypeFlags.NumberLiteral : 0 :
type.flags & TypeFlags.BigIntLiteral ? isZeroBigInt(<BigIntLiteralType>type) ? TypeFlags.BigIntLiteral : 0 :
type.flags & TypeFlags.BooleanLiteral ? (type === falseType || type === regularFalseType) ? TypeFlags.BooleanLiteral : 0 :
type.flags & TypeFlags.PossiblyFalsy;
}
function removeDefinitelyFalsyTypes(type: Type): Type {
return getFalsyFlags(type) & TypeFlags.DefinitelyFalsy ?
filterType(type, t => !(getFalsyFlags(t) & TypeFlags.DefinitelyFalsy)) :
type;
}
function extractDefinitelyFalsyTypes(type: Type): Type {
return mapType(type, getDefinitelyFalsyPartOfType);
}
function getDefinitelyFalsyPartOfType(type: Type): Type {
return type.flags & TypeFlags.String ? emptyStringType :
type.flags & TypeFlags.Number ? zeroType :
type.flags & TypeFlags.BigInt ? zeroBigIntType :
type === regularFalseType ||
type === falseType ||
type.flags & (TypeFlags.Void | TypeFlags.Undefined | TypeFlags.Null) ||
type.flags & TypeFlags.StringLiteral && (<StringLiteralType>type).value === "" ||
type.flags & TypeFlags.NumberLiteral && (<NumberLiteralType>type).value === 0 ||
type.flags & TypeFlags.BigIntLiteral && isZeroBigInt(<BigIntLiteralType>type) ? type :
neverType;
}
/**
* Add undefined or null or both to a type if they are missing.
* @param type - type to add undefined and/or null to if not present
* @param flags - Either TypeFlags.Undefined or TypeFlags.Null, or both
*/
function getNullableType(type: Type, flags: TypeFlags): Type {
const missing = (flags & ~type.flags) & (TypeFlags.Undefined | TypeFlags.Null);
return missing === 0 ? type :
missing === TypeFlags.Undefined ? getUnionType([type, undefinedType]) :
missing === TypeFlags.Null ? getUnionType([type, nullType]) :
getUnionType([type, undefinedType, nullType]);
}
function getOptionalType(type: Type): Type {
Debug.assert(strictNullChecks);
return type.flags & TypeFlags.Undefined ? type : getUnionType([type, undefinedType]);
}
function getGlobalNonNullableTypeInstantiation(type: Type) {
if (!deferredGlobalNonNullableTypeAlias) {
deferredGlobalNonNullableTypeAlias = getGlobalSymbol("NonNullable" as __String, SymbolFlags.TypeAlias, /*diagnostic*/ undefined) || unknownSymbol;
}
// Use NonNullable global type alias if available to improve quick info/declaration emit
if (deferredGlobalNonNullableTypeAlias !== unknownSymbol) {
return getTypeAliasInstantiation(deferredGlobalNonNullableTypeAlias, [type]);
}
return getTypeWithFacts(type, TypeFacts.NEUndefinedOrNull); // Type alias unavailable, fall back to non-higher-order behavior
}
function getNonNullableType(type: Type): Type {
return strictNullChecks ? getGlobalNonNullableTypeInstantiation(type) : type;
}
/**
* Return true if type was inferred from an object literal, written as an object type literal, or is the shape of a module
* with no call or construct signatures.
*/
function isObjectTypeWithInferableIndex(type: Type) {
return type.symbol && (type.symbol.flags & (SymbolFlags.ObjectLiteral | SymbolFlags.TypeLiteral | SymbolFlags.ValueModule)) !== 0 &&
!typeHasCallOrConstructSignatures(type);
}
function createSymbolWithType(source: Symbol, type: Type | undefined) {
const symbol = createSymbol(source.flags, source.escapedName);
symbol.declarations = source.declarations;
symbol.parent = source.parent;
symbol.type = type;
symbol.target = source;
if (source.valueDeclaration) {
symbol.valueDeclaration = source.valueDeclaration;
}
if (source.nameType) {
symbol.nameType = source.nameType;
}
return symbol;
}
function transformTypeOfMembers(type: Type, f: (propertyType: Type) => Type) {
const members = createSymbolTable();
for (const property of getPropertiesOfObjectType(type)) {
const original = getTypeOfSymbol(property);
const updated = f(original);
members.set(property.escapedName, updated === original ? property : createSymbolWithType(property, updated));
}
return members;
}
/**
* If the the provided object literal is subject to the excess properties check,
* create a new that is exempt. Recursively mark object literal members as exempt.
* Leave signatures alone since they are not subject to the check.
*/
function getRegularTypeOfObjectLiteral(type: Type): Type {
if (!(isObjectLiteralType(type) && getObjectFlags(type) & ObjectFlags.FreshLiteral)) {
return type;
}
const regularType = (<FreshObjectLiteralType>type).regularType;
if (regularType) {
return regularType;
}
const resolved = <ResolvedType>type;
const members = transformTypeOfMembers(type, getRegularTypeOfObjectLiteral);
const regularNew = createAnonymousType(resolved.symbol,
members,
resolved.callSignatures,
resolved.constructSignatures,
resolved.stringIndexInfo,
resolved.numberIndexInfo);
regularNew.flags = resolved.flags;
regularNew.objectFlags |= resolved.objectFlags & ~ObjectFlags.FreshLiteral;
(<FreshObjectLiteralType>type).regularType = regularNew;
return regularNew;
}
function createWideningContext(parent: WideningContext | undefined, propertyName: __String | undefined, siblings: Type[] | undefined): WideningContext {
return { parent, propertyName, siblings, resolvedProperties: undefined };
}
function getSiblingsOfContext(context: WideningContext): Type[] {
if (!context.siblings) {
const siblings: Type[] = [];
for (const type of getSiblingsOfContext(context.parent!)) {
if (isObjectLiteralType(type)) {
const prop = getPropertyOfObjectType(type, context.propertyName!);
if (prop) {
forEachType(getTypeOfSymbol(prop), t => {
siblings.push(t);
});
}
}
}
context.siblings = siblings;
}
return context.siblings;
}
function getPropertiesOfContext(context: WideningContext): Symbol[] {
if (!context.resolvedProperties) {
const names = createMap<Symbol>() as UnderscoreEscapedMap<Symbol>;
for (const t of getSiblingsOfContext(context)) {
if (isObjectLiteralType(t) && !(getObjectFlags(t) & ObjectFlags.ContainsSpread)) {
for (const prop of getPropertiesOfType(t)) {
names.set(prop.escapedName, prop);
}
}
}
context.resolvedProperties = arrayFrom(names.values());
}
return context.resolvedProperties;
}
function getWidenedProperty(prop: Symbol, context: WideningContext | undefined): Symbol {
if (!(prop.flags & SymbolFlags.Property)) {
// Since get accessors already widen their return value there is no need to
// widen accessor based properties here.
return prop;
}
const original = getTypeOfSymbol(prop);
const propContext = context && createWideningContext(context, prop.escapedName, /*siblings*/ undefined);
const widened = getWidenedTypeWithContext(original, propContext);
return widened === original ? prop : createSymbolWithType(prop, widened);
}
function getUndefinedProperty(prop: Symbol) {
const cached = undefinedProperties.get(prop.escapedName);
if (cached) {
return cached;
}
const result = createSymbolWithType(prop, undefinedType);
result.flags |= SymbolFlags.Optional;
undefinedProperties.set(prop.escapedName, result);
return result;
}
function getWidenedTypeOfObjectLiteral(type: Type, context: WideningContext | undefined): Type {
const members = createSymbolTable();
for (const prop of getPropertiesOfObjectType(type)) {
members.set(prop.escapedName, getWidenedProperty(prop, context));
}
if (context) {
for (const prop of getPropertiesOfContext(context)) {
if (!members.has(prop.escapedName)) {
members.set(prop.escapedName, getUndefinedProperty(prop));
}
}
}
const stringIndexInfo = getIndexInfoOfType(type, IndexKind.String);
const numberIndexInfo = getIndexInfoOfType(type, IndexKind.Number);
const result = createAnonymousType(type.symbol, members, emptyArray, emptyArray,
stringIndexInfo && createIndexInfo(getWidenedType(stringIndexInfo.type), stringIndexInfo.isReadonly),
numberIndexInfo && createIndexInfo(getWidenedType(numberIndexInfo.type), numberIndexInfo.isReadonly));
result.objectFlags |= (getObjectFlags(type) & ObjectFlags.JSLiteral); // Retain js literal flag through widening
return result;
}
function getWidenedType(type: Type) {
return getWidenedTypeWithContext(type, /*context*/ undefined);
}
function getWidenedTypeWithContext(type: Type, context: WideningContext | undefined): Type {
if (getObjectFlags(type) & ObjectFlags.RequiresWidening) {
if (type.flags & TypeFlags.Nullable) {
return anyType;
}
if (isObjectLiteralType(type)) {
return getWidenedTypeOfObjectLiteral(type, context);
}
if (type.flags & TypeFlags.Union) {
const unionContext = context || createWideningContext(/*parent*/ undefined, /*propertyName*/ undefined, (<UnionType>type).types);
const widenedTypes = sameMap((<UnionType>type).types, t => t.flags & TypeFlags.Nullable ? t : getWidenedTypeWithContext(t, unionContext));
// Widening an empty object literal transitions from a highly restrictive type to
// a highly inclusive one. For that reason we perform subtype reduction here if the
// union includes empty object types (e.g. reducing {} | string to just {}).
return getUnionType(widenedTypes, some(widenedTypes, isEmptyObjectType) ? UnionReduction.Subtype : UnionReduction.Literal);
}
if (type.flags & TypeFlags.Intersection) {
return getIntersectionType(sameMap((<IntersectionType>type).types, getWidenedType));
}
if (isArrayType(type) || isTupleType(type)) {
return createTypeReference((<TypeReference>type).target, sameMap((<TypeReference>type).typeArguments, getWidenedType));
}
}
return type;
}
/**
* Reports implicit any errors that occur as a result of widening 'null' and 'undefined'
* to 'any'. A call to reportWideningErrorsInType is normally accompanied by a call to
* getWidenedType. But in some cases getWidenedType is called without reporting errors
* (type argument inference is an example).
*
* The return value indicates whether an error was in fact reported. The particular circumstances
* are on a best effort basis. Currently, if the null or undefined that causes widening is inside
* an object literal property (arbitrarily deeply), this function reports an error. If no error is
* reported, reportImplicitAnyError is a suitable fallback to report a general error.
*/
function reportWideningErrorsInType(type: Type): boolean {
let errorReported = false;
if (getObjectFlags(type) & ObjectFlags.ContainsWideningType) {
if (type.flags & TypeFlags.Union) {
if (some((<UnionType>type).types, isEmptyObjectType)) {
errorReported = true;
}
else {
for (const t of (<UnionType>type).types) {
if (reportWideningErrorsInType(t)) {
errorReported = true;
}
}
}
}
if (isArrayType(type) || isTupleType(type)) {
for (const t of (<TypeReference>type).typeArguments!) {
if (reportWideningErrorsInType(t)) {
errorReported = true;
}
}
}
if (isObjectLiteralType(type)) {
for (const p of getPropertiesOfObjectType(type)) {
const t = getTypeOfSymbol(p);
if (getObjectFlags(t) & ObjectFlags.ContainsWideningType) {
if (!reportWideningErrorsInType(t)) {
error(p.valueDeclaration, Diagnostics.Object_literal_s_property_0_implicitly_has_an_1_type, symbolToString(p), typeToString(getWidenedType(t)));
}
errorReported = true;
}
}
}
}
return errorReported;
}
function reportImplicitAny(declaration: Declaration, type: Type) {
const typeAsString = typeToString(getWidenedType(type));
if (isInJSFile(declaration) && !isCheckJsEnabledForFile(getSourceFileOfNode(declaration), compilerOptions)) {
// Only report implicit any errors/suggestions in TS and ts-check JS files
return;
}
let diagnostic: DiagnosticMessage;
switch (declaration.kind) {
case SyntaxKind.BinaryExpression:
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.PropertySignature:
diagnostic = noImplicitAny ? Diagnostics.Member_0_implicitly_has_an_1_type : Diagnostics.Member_0_implicitly_has_an_1_type_but_a_better_type_may_be_inferred_from_usage;
break;
case SyntaxKind.Parameter:
const param = declaration as ParameterDeclaration;
if (isIdentifier(param.name) &&
(isCallSignatureDeclaration(param.parent) || isMethodSignature(param.parent) || isFunctionTypeNode(param.parent)) &&
param.parent.parameters.indexOf(param) > -1 &&
(resolveName(param, param.name.escapedText, SymbolFlags.Type, undefined, param.name.escapedText, /*isUse*/ true) ||
param.name.originalKeywordKind && isTypeNodeKind(param.name.originalKeywordKind))) {
const newName = "arg" + param.parent.parameters.indexOf(param);
errorOrSuggestion(noImplicitAny, declaration, Diagnostics.Parameter_has_a_name_but_no_type_Did_you_mean_0_Colon_1, newName, declarationNameToString(param.name));
return;
}
diagnostic = (<ParameterDeclaration>declaration).dotDotDotToken ?
noImplicitAny ? Diagnostics.Rest_parameter_0_implicitly_has_an_any_type : Diagnostics.Rest_parameter_0_implicitly_has_an_any_type_but_a_better_type_may_be_inferred_from_usage :
noImplicitAny ? Diagnostics.Parameter_0_implicitly_has_an_1_type : Diagnostics.Parameter_0_implicitly_has_an_1_type_but_a_better_type_may_be_inferred_from_usage;
break;
case SyntaxKind.BindingElement:
diagnostic = Diagnostics.Binding_element_0_implicitly_has_an_1_type;
if (!noImplicitAny) {
// Don't issue a suggestion for binding elements since the codefix doesn't yet support them.
return;
}
break;
case SyntaxKind.JSDocFunctionType:
error(declaration, Diagnostics.Function_type_which_lacks_return_type_annotation_implicitly_has_an_0_return_type, typeAsString);
return;
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.MethodSignature:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
case SyntaxKind.FunctionExpression:
case SyntaxKind.ArrowFunction:
if (noImplicitAny && !(declaration as NamedDeclaration).name) {
error(declaration, Diagnostics.Function_expression_which_lacks_return_type_annotation_implicitly_has_an_0_return_type, typeAsString);
return;
}
diagnostic = noImplicitAny ? Diagnostics._0_which_lacks_return_type_annotation_implicitly_has_an_1_return_type : Diagnostics._0_implicitly_has_an_1_return_type_but_a_better_type_may_be_inferred_from_usage;
break;
case SyntaxKind.MappedType:
if (noImplicitAny) {
error(declaration, Diagnostics.Mapped_object_type_implicitly_has_an_any_template_type);
}
return;
default:
diagnostic = noImplicitAny ? Diagnostics.Variable_0_implicitly_has_an_1_type : Diagnostics.Variable_0_implicitly_has_an_1_type_but_a_better_type_may_be_inferred_from_usage;
}
errorOrSuggestion(noImplicitAny, declaration, diagnostic, declarationNameToString(getNameOfDeclaration(declaration)), typeAsString);
}
function reportErrorsFromWidening(declaration: Declaration, type: Type) {
if (produceDiagnostics && noImplicitAny && getObjectFlags(type) & ObjectFlags.ContainsWideningType) {
// Report implicit any error within type if possible, otherwise report error on declaration
if (!reportWideningErrorsInType(type)) {
reportImplicitAny(declaration, type);
}
}
}
function forEachMatchingParameterType(source: Signature, target: Signature, callback: (s: Type, t: Type) => void) {
const sourceCount = getParameterCount(source);
const targetCount = getParameterCount(target);
const sourceRestType = getEffectiveRestType(source);
const targetRestType = getEffectiveRestType(target);
const targetNonRestCount = targetRestType ? targetCount - 1 : targetCount;
const paramCount = sourceRestType ? targetNonRestCount : Math.min(sourceCount, targetNonRestCount);
const sourceThisType = getThisTypeOfSignature(source);
if (sourceThisType) {
const targetThisType = getThisTypeOfSignature(target);
if (targetThisType) {
callback(sourceThisType, targetThisType);
}
}
for (let i = 0; i < paramCount; i++) {
callback(getTypeAtPosition(source, i), getTypeAtPosition(target, i));
}
if (targetRestType) {
callback(getRestTypeAtPosition(source, paramCount), targetRestType);
}
}
function createInferenceContext(typeParameters: ReadonlyArray<TypeParameter>, signature: Signature | undefined, flags: InferenceFlags, compareTypes?: TypeComparer, baseInferences?: InferenceInfo[]): InferenceContext {
const inferences = baseInferences ? baseInferences.map(cloneInferenceInfo) : typeParameters.map(createInferenceInfo);
const context = mapper as InferenceContext;
context.typeParameters = typeParameters;
context.signature = signature;
context.inferences = inferences;
context.flags = flags;
context.compareTypes = compareTypes || compareTypesAssignable;
return context;
function mapper(t: Type): Type {
for (let i = 0; i < inferences.length; i++) {
if (t === inferences[i].typeParameter) {
if (!(context.flags & InferenceFlags.NoFixing)) {
inferences[i].isFixed = true;
}
return getInferredType(context, i);
}
}
return t;
}
}
function createInferenceInfo(typeParameter: TypeParameter): InferenceInfo {
return {
typeParameter,
candidates: undefined,
contraCandidates: undefined,
inferredType: undefined,
priority: undefined,
topLevel: true,
isFixed: false
};
}
function cloneInferenceInfo(inference: InferenceInfo): InferenceInfo {
return {
typeParameter: inference.typeParameter,
candidates: inference.candidates && inference.candidates.slice(),
contraCandidates: inference.contraCandidates && inference.contraCandidates.slice(),
inferredType: inference.inferredType,
priority: inference.priority,
topLevel: inference.topLevel,
isFixed: inference.isFixed
};
}
// Return true if the given type could possibly reference a type parameter for which
// we perform type inference (i.e. a type parameter of a generic function). We cache
// results for union and intersection types for performance reasons.
function couldContainTypeVariables(type: Type): boolean {
const objectFlags = getObjectFlags(type);
return !!(type.flags & TypeFlags.Instantiable ||
objectFlags & ObjectFlags.Reference && forEach((<TypeReference>type).typeArguments, couldContainTypeVariables) ||
objectFlags & ObjectFlags.Anonymous && type.symbol && type.symbol.flags & (SymbolFlags.Function | SymbolFlags.Method | SymbolFlags.TypeLiteral | SymbolFlags.Class) ||
objectFlags & ObjectFlags.Mapped ||
type.flags & TypeFlags.UnionOrIntersection && couldUnionOrIntersectionContainTypeVariables(<UnionOrIntersectionType>type));
}
function couldUnionOrIntersectionContainTypeVariables(type: UnionOrIntersectionType): boolean {
if (type.couldContainTypeVariables === undefined) {
type.couldContainTypeVariables = some(type.types, couldContainTypeVariables);
}
return type.couldContainTypeVariables;
}
function isTypeParameterAtTopLevel(type: Type, typeParameter: TypeParameter): boolean {
return type === typeParameter || !!(type.flags & TypeFlags.UnionOrIntersection) && some((<UnionOrIntersectionType>type).types, t => isTypeParameterAtTopLevel(t, typeParameter));
}
/** Create an object with properties named in the string literal type. Every property has type `any` */
function createEmptyObjectTypeFromStringLiteral(type: Type) {
const members = createSymbolTable();
forEachType(type, t => {
if (!(t.flags & TypeFlags.StringLiteral)) {
return;
}
const name = escapeLeadingUnderscores((t as StringLiteralType).value);
const literalProp = createSymbol(SymbolFlags.Property, name);
literalProp.type = anyType;
if (t.symbol) {
literalProp.declarations = t.symbol.declarations;
literalProp.valueDeclaration = t.symbol.valueDeclaration;
}
members.set(name, literalProp);
});
const indexInfo = type.flags & TypeFlags.String ? createIndexInfo(emptyObjectType, /*isReadonly*/ false) : undefined;
return createAnonymousType(undefined, members, emptyArray, emptyArray, indexInfo, undefined);
}
/**
* Infer a suitable input type for a homomorphic mapped type { [P in keyof T]: X }. We construct
* an object type with the same set of properties as the source type, where the type of each
* property is computed by inferring from the source property type to X for the type
* variable T[P] (i.e. we treat the type T[P] as the type variable we're inferring for).
*/
function inferTypeForHomomorphicMappedType(source: Type, target: MappedType, constraint: IndexType): Type | undefined {
const key = source.id + "," + target.id + "," + constraint.id;
if (reverseMappedCache.has(key)) {
return reverseMappedCache.get(key);
}
reverseMappedCache.set(key, undefined);
const type = createReverseMappedType(source, target, constraint);
reverseMappedCache.set(key, type);
return type;
}
function createReverseMappedType(source: Type, target: MappedType, constraint: IndexType) {
const properties = getPropertiesOfType(source);
if (properties.length === 0 && !getIndexInfoOfType(source, IndexKind.String)) {
return undefined;
}
// If any property contains context sensitive functions that have been skipped, the source type
// is incomplete and we can't infer a meaningful input type.
for (const prop of properties) {
if (getObjectFlags(getTypeOfSymbol(prop)) & ObjectFlags.ContainsAnyFunctionType) {
return undefined;
}
}
// For arrays and tuples we infer new arrays and tuples where the reverse mapping has been
// applied to the element type(s).
if (isArrayType(source)) {
return createArrayType(inferReverseMappedType((<TypeReference>source).typeArguments![0], target, constraint), isReadonlyArrayType(source));
}
if (isTupleType(source)) {
const elementTypes = map(source.typeArguments || emptyArray, t => inferReverseMappedType(t, target, constraint));
const minLength = getMappedTypeModifiers(target) & MappedTypeModifiers.IncludeOptional ?
getTypeReferenceArity(source) - (source.target.hasRestElement ? 1 : 0) : source.target.minLength;
return createTupleType(elementTypes, minLength, source.target.hasRestElement, source.target.readonly, source.target.associatedNames);
}
// For all other object types we infer a new object type where the reverse mapping has been
// applied to the type of each property.
const reversed = createObjectType(ObjectFlags.ReverseMapped | ObjectFlags.Anonymous, /*symbol*/ undefined) as ReverseMappedType;
reversed.source = source;
reversed.mappedType = target;
reversed.constraintType = constraint;
return reversed;
}
function getTypeOfReverseMappedSymbol(symbol: ReverseMappedSymbol) {
return inferReverseMappedType(symbol.propertyType, symbol.mappedType, symbol.constraintType);
}
function inferReverseMappedType(sourceType: Type, target: MappedType, constraint: IndexType): Type {
const typeParameter = <TypeParameter>getIndexedAccessType(constraint.type, getTypeParameterFromMappedType(target));
const templateType = getTemplateTypeFromMappedType(target);
const inference = createInferenceInfo(typeParameter);
inferTypes([inference], sourceType, templateType);
return getTypeFromInference(inference);
}
function* getUnmatchedProperties(source: Type, target: Type, requireOptionalProperties: boolean, matchDiscriminantProperties: boolean) {
const properties = target.flags & TypeFlags.Intersection ? getPropertiesOfUnionOrIntersectionType(<IntersectionType>target) : getPropertiesOfObjectType(target);
for (const targetProp of properties) {
if (requireOptionalProperties || !(targetProp.flags & SymbolFlags.Optional)) {
const sourceProp = getPropertyOfType(source, targetProp.escapedName);
if (!sourceProp) {
yield targetProp;
}
else if (matchDiscriminantProperties) {
const targetType = getTypeOfSymbol(targetProp);
if (targetType.flags & TypeFlags.Unit) {
const sourceType = getTypeOfSymbol(sourceProp);
if (!(sourceType.flags & TypeFlags.Any || getRegularTypeOfLiteralType(sourceType) === getRegularTypeOfLiteralType(targetType))) {
yield targetProp;
}
}
}
}
}
}
function getUnmatchedProperty(source: Type, target: Type, requireOptionalProperties: boolean, matchDiscriminantProperties: boolean): Symbol | undefined {
return getUnmatchedProperties(source, target, requireOptionalProperties, matchDiscriminantProperties).next().value;
}
function tupleTypesDefinitelyUnrelated(source: TupleTypeReference, target: TupleTypeReference) {
return target.target.minLength > source.target.minLength ||
!getRestTypeOfTupleType(target) && (!!getRestTypeOfTupleType(source) || getLengthOfTupleType(target) < getLengthOfTupleType(source));
}
function typesDefinitelyUnrelated(source: Type, target: Type) {
// Two tuple types with incompatible arities are definitely unrelated.
// Two object types that each have a property that is unmatched in the other are definitely unrelated.
return isTupleType(source) && isTupleType(target) && tupleTypesDefinitelyUnrelated(source, target) ||
!!getUnmatchedProperty(source, target, /*requireOptionalProperties*/ false, /*matchDiscriminantProperties*/ true) &&
!!getUnmatchedProperty(target, source, /*requireOptionalProperties*/ false, /*matchDiscriminantProperties*/ true);
}
function getTypeFromInference(inference: InferenceInfo) {
return inference.candidates ? getUnionType(inference.candidates, UnionReduction.Subtype) :
inference.contraCandidates ? getIntersectionType(inference.contraCandidates) :
emptyObjectType;
}
function inferTypes(inferences: InferenceInfo[], originalSource: Type, originalTarget: Type, priority: InferencePriority = 0) {
let symbolStack: Symbol[];
let visited: Map<boolean>;
let contravariant = false;
let bivariant = false;
let propagationType: Type;
let allowComplexConstraintInference = true;
inferFromTypes(originalSource, originalTarget);
function inferFromTypes(source: Type, target: Type): void {
if (!couldContainTypeVariables(target)) {
return;
}
if (source === wildcardType) {
// We are inferring from an 'any' type. We want to infer this type for every type parameter
// referenced in the target type, so we record it as the propagation type and infer from the
// target to itself. Then, as we find candidates we substitute the propagation type.
const savePropagationType = propagationType;
propagationType = source;
inferFromTypes(target, target);
propagationType = savePropagationType;
return;
}
if (source.aliasSymbol && source.aliasTypeArguments && source.aliasSymbol === target.aliasSymbol) {
// Source and target are types originating in the same generic type alias declaration.
// Simply infer from source type arguments to target type arguments.
const sourceTypes = source.aliasTypeArguments;
const targetTypes = target.aliasTypeArguments!;
for (let i = 0; i < sourceTypes.length; i++) {
inferFromTypes(sourceTypes[i], targetTypes[i]);
}
return;
}
if (source.flags & TypeFlags.Union && target.flags & TypeFlags.Union && !(source.flags & TypeFlags.EnumLiteral && target.flags & TypeFlags.EnumLiteral) ||
source.flags & TypeFlags.Intersection && target.flags & TypeFlags.Intersection) {
// Source and target are both unions or both intersections. If source and target
// are the same type, just relate each constituent type to itself.
if (source === target) {
for (const t of (<UnionOrIntersectionType>source).types) {
inferFromTypes(t, t);
}
return;
}
// Find each source constituent type that has an identically matching target constituent
// type, and for each such type infer from the type to itself. When inferring from a
// type to itself we effectively find all type parameter occurrences within that type
// and infer themselves as their type arguments. We have special handling for numeric
// and string literals because the number and string types are not represented as unions
// of all their possible values.
let matchingTypes: Type[] | undefined;
for (const t of (<UnionOrIntersectionType>source).types) {
if (typeIdenticalToSomeType(t, (<UnionOrIntersectionType>target).types)) {
(matchingTypes || (matchingTypes = [])).push(t);
inferFromTypes(t, t);
}
else if (t.flags & (TypeFlags.NumberLiteral | TypeFlags.StringLiteral)) {
const b = getBaseTypeOfLiteralType(t);
if (typeIdenticalToSomeType(b, (<UnionOrIntersectionType>target).types)) {
(matchingTypes || (matchingTypes = [])).push(t, b);
}
}
}
// Next, to improve the quality of inferences, reduce the source and target types by
// removing the identically matched constituents. For example, when inferring from
// 'string | string[]' to 'string | T' we reduce the types to 'string[]' and 'T'.
if (matchingTypes) {
source = removeTypesFromUnionOrIntersection(<UnionOrIntersectionType>source, matchingTypes);
target = removeTypesFromUnionOrIntersection(<UnionOrIntersectionType>target, matchingTypes);
}
}
if (target.flags & TypeFlags.TypeVariable) {
// If target is a type parameter, make an inference, unless the source type contains
// the anyFunctionType (the wildcard type that's used to avoid contextually typing functions).
// Because the anyFunctionType is internal, it should not be exposed to the user by adding
// it as an inference candidate. Hopefully, a better candidate will come along that does
// not contain anyFunctionType when we come back to this argument for its second round
// of inference. Also, we exclude inferences for silentNeverType (which is used as a wildcard
// when constructing types from type parameters that had no inference candidates).
if (getObjectFlags(source) & ObjectFlags.ContainsAnyFunctionType || source === silentNeverType || (priority & InferencePriority.ReturnType && (source === autoType || source === autoArrayType))) {
return;
}
const inference = getInferenceInfoForType(target);
if (inference) {
if (!inference.isFixed) {
if (inference.priority === undefined || priority < inference.priority) {
inference.candidates = undefined;
inference.contraCandidates = undefined;
inference.priority = priority;
}
if (priority === inference.priority) {
const candidate = propagationType || source;
// We make contravariant inferences only if we are in a pure contravariant position,
// i.e. only if we have not descended into a bivariant position.
if (contravariant && !bivariant) {
inference.contraCandidates = appendIfUnique(inference.contraCandidates, candidate);
}
else {
inference.candidates = appendIfUnique(inference.candidates, candidate);
}
}
if (!(priority & InferencePriority.ReturnType) && target.flags & TypeFlags.TypeParameter && !isTypeParameterAtTopLevel(originalTarget, <TypeParameter>target)) {
inference.topLevel = false;
}
}
return;
}
else {
// Infer to the simplified version of an indexed access, if possible, to (hopefully) expose more bare type parameters to the inference engine
const simplified = getSimplifiedType(target);
if (simplified !== target) {
inferFromTypesOnce(source, simplified);
}
else if (target.flags & TypeFlags.IndexedAccess) {
const indexType = getSimplifiedType((target as IndexedAccessType).indexType);
// Generally simplifications of instantiable indexes are avoided to keep relationship checking correct, however if our target is an access, we can consider
// that key of that access to be "instantiated", since we're looking to find the infernce goal in any way we can.
if (indexType.flags & TypeFlags.Instantiable) {
const simplified = distributeIndexOverObjectType(getSimplifiedType((target as IndexedAccessType).objectType), indexType);
if (simplified && simplified !== target) {
inferFromTypesOnce(source, simplified);
}
}
}
}
}
else if (target.flags & TypeFlags.Substitution) {
inferFromTypes(source, (target as SubstitutionType).typeVariable);
}
if (getObjectFlags(source) & ObjectFlags.Reference && getObjectFlags(target) & ObjectFlags.Reference && (<TypeReference>source).target === (<TypeReference>target).target) {
// If source and target are references to the same generic type, infer from type arguments
const sourceTypes = (<TypeReference>source).typeArguments || emptyArray;
const targetTypes = (<TypeReference>target).typeArguments || emptyArray;
const count = sourceTypes.length < targetTypes.length ? sourceTypes.length : targetTypes.length;
const variances = getVariances((<TypeReference>source).target);
for (let i = 0; i < count; i++) {
if (i < variances.length && variances[i] === Variance.Contravariant) {
inferFromContravariantTypes(sourceTypes[i], targetTypes[i]);
}
else {
inferFromTypes(sourceTypes[i], targetTypes[i]);
}
}
}
else if (source.flags & TypeFlags.Index && target.flags & TypeFlags.Index) {
contravariant = !contravariant;
inferFromTypes((<IndexType>source).type, (<IndexType>target).type);
contravariant = !contravariant;
}
else if ((isLiteralType(source) || source.flags & TypeFlags.String) && target.flags & TypeFlags.Index) {
const empty = createEmptyObjectTypeFromStringLiteral(source);
contravariant = !contravariant;
const savePriority = priority;
priority |= InferencePriority.LiteralKeyof;
inferFromTypes(empty, (target as IndexType).type);
priority = savePriority;
contravariant = !contravariant;
}
else if (source.flags & TypeFlags.IndexedAccess && target.flags & TypeFlags.IndexedAccess) {
inferFromTypes((<IndexedAccessType>source).objectType, (<IndexedAccessType>target).objectType);
inferFromTypes((<IndexedAccessType>source).indexType, (<IndexedAccessType>target).indexType);
}
else if (source.flags & TypeFlags.Conditional && target.flags & TypeFlags.Conditional) {
inferFromTypes((<ConditionalType>source).checkType, (<ConditionalType>target).checkType);
inferFromTypes((<ConditionalType>source).extendsType, (<ConditionalType>target).extendsType);
inferFromTypes(getTrueTypeFromConditionalType(<ConditionalType>source), getTrueTypeFromConditionalType(<ConditionalType>target));
inferFromTypes(getFalseTypeFromConditionalType(<ConditionalType>source), getFalseTypeFromConditionalType(<ConditionalType>target));
}
else if (target.flags & TypeFlags.Conditional) {
inferFromTypes(source, getTrueTypeFromConditionalType(<ConditionalType>target));
inferFromTypes(source, getFalseTypeFromConditionalType(<ConditionalType>target));
}
else if (target.flags & TypeFlags.UnionOrIntersection) {
for (const t of (<UnionOrIntersectionType>target).types) {
const savePriority = priority;
// Inferences directly to naked type variables are given lower priority as they are
// less specific. For example, when inferring from Promise<string> to T | Promise<T>,
// we want to infer string for T, not Promise<string> | string.
if (getInferenceInfoForType(t)) {
priority |= InferencePriority.NakedTypeVariable;
}
inferFromTypes(source, t);
priority = savePriority;
}
}
else if (source.flags & TypeFlags.Union) {
// Source is a union or intersection type, infer from each constituent type
const sourceTypes = (<UnionOrIntersectionType>source).types;
for (const sourceType of sourceTypes) {
inferFromTypes(sourceType, target);
}
}
else {
if (!(priority & InferencePriority.NoConstraints && source.flags & (TypeFlags.Intersection | TypeFlags.Instantiable))) {
const apparentSource = getApparentType(source);
// getApparentType can return _any_ type, since an indexed access or conditional may simplify to any other type.
// If that occurs and it doesn't simplify to an object or intersection, we'll need to restart `inferFromTypes`
// with the simplified source.
if (apparentSource !== source && allowComplexConstraintInference && !(apparentSource.flags & (TypeFlags.Object | TypeFlags.Intersection))) {
// TODO: The `allowComplexConstraintInference` flag is a hack! This forbids inference from complex constraints within constraints!
// This isn't required algorithmically, but rather is used to lower the memory burden caused by performing inference
// that is _too good_ in projects with complicated constraints (eg, fp-ts). In such cases, if we did not limit ourselves
// here, we might produce more valid inferences for types, causing us to do more checks and perform more instantiations
// (in addition to the extra stack depth here) which, in turn, can push the already close process over its limit.
// TL;DR: If we ever become generally more memory efficient (or our resource budget ever increases), we should just
// remove this `allowComplexConstraintInference` flag.
allowComplexConstraintInference = false;
return inferFromTypes(apparentSource, target);
}
source = apparentSource;
}
if (source.flags & (TypeFlags.Object | TypeFlags.Intersection)) {
const key = source.id + "," + target.id;
if (visited && visited.get(key)) {
return;
}
(visited || (visited = createMap<boolean>())).set(key, true);
// If we are already processing another target type with the same associated symbol (such as
// an instantiation of the same generic type), we do not explore this target as it would yield
// no further inferences. We exclude the static side of classes from this check since it shares
// its symbol with the instance side which would lead to false positives.
const isNonConstructorObject = target.flags & TypeFlags.Object &&
!(getObjectFlags(target) & ObjectFlags.Anonymous && target.symbol && target.symbol.flags & SymbolFlags.Class);
const symbol = isNonConstructorObject ? target.symbol : undefined;
if (symbol) {
if (contains(symbolStack, symbol)) {
return;
}
(symbolStack || (symbolStack = [])).push(symbol);
inferFromObjectTypes(source, target);
symbolStack.pop();
}
else {
inferFromObjectTypes(source, target);
}
}
}
function inferFromTypesOnce(source: Type, target: Type) {
const key = source.id + "," + target.id;
if (!visited || !visited.get(key)) {
(visited || (visited = createMap<boolean>())).set(key, true);
inferFromTypes(source, target);
}
}
}
function inferFromContravariantTypes(source: Type, target: Type) {
if (strictFunctionTypes || priority & InferencePriority.AlwaysStrict) {
contravariant = !contravariant;
inferFromTypes(source, target);
contravariant = !contravariant;
}
else {
inferFromTypes(source, target);
}
}
function getInferenceInfoForType(type: Type) {
if (type.flags & TypeFlags.TypeVariable) {
for (const inference of inferences) {
if (type === inference.typeParameter) {
return inference;
}
}
}
return undefined;
}
function inferToMappedType(source: Type, target: MappedType, constraintType: Type): boolean {
if (constraintType.flags & TypeFlags.Union) {
let result = false;
for (const type of (constraintType as UnionType).types) {
result = inferToMappedType(source, target, type) || result;
}
return result;
}
if (constraintType.flags & TypeFlags.Index) {
// We're inferring from some source type S to a homomorphic mapped type { [P in keyof T]: X },
// where T is a type variable. Use inferTypeForHomomorphicMappedType to infer a suitable source
// type and then make a secondary inference from that type to T. We make a secondary inference
// such that direct inferences to T get priority over inferences to Partial<T>, for example.
const inference = getInferenceInfoForType((<IndexType>constraintType).type);
if (inference && !inference.isFixed) {
const inferredType = inferTypeForHomomorphicMappedType(source, target, <IndexType>constraintType);
if (inferredType) {
const savePriority = priority;
priority |= InferencePriority.HomomorphicMappedType;
inferFromTypes(inferredType, inference.typeParameter);
priority = savePriority;
}
}
return true;
}
if (constraintType.flags & TypeFlags.TypeParameter) {
// We're inferring from some source type S to a mapped type { [P in K]: X }, where K is a type
// parameter. First infer from 'keyof S' to K.
const savePriority = priority;
priority |= InferencePriority.MappedTypeConstraint;
inferFromTypes(getIndexType(source), constraintType);
priority = savePriority;
// If K is constrained to a type C, also infer to C. Thus, for a mapped type { [P in K]: X },
// where K extends keyof T, we make the same inferences as for a homomorphic mapped type
// { [P in keyof T]: X }. This enables us to make meaningful inferences when the target is a
// Pick<T, K>.
const extendedConstraint = getConstraintOfType(constraintType);
if (extendedConstraint && inferToMappedType(source, target, extendedConstraint)) {
return true;
}
// If no inferences can be made to K's constraint, infer from a union of the property types
// in the source to the template type X.
const valueTypes = compact([
getIndexTypeOfType(source, IndexKind.String),
getIndexTypeOfType(source, IndexKind.Number),
...map(getPropertiesOfType(source), getTypeOfSymbol)
]);
inferFromTypes(getUnionType(valueTypes), getTemplateTypeFromMappedType(target));
return true;
}
return false;
}
function inferFromObjectTypes(source: Type, target: Type) {
if (isGenericMappedType(source) && isGenericMappedType(target)) {
// The source and target types are generic types { [P in S]: X } and { [P in T]: Y }, so we infer
// from S to T and from X to Y.
inferFromTypes(getConstraintTypeFromMappedType(source), getConstraintTypeFromMappedType(target));
inferFromTypes(getTemplateTypeFromMappedType(source), getTemplateTypeFromMappedType(target));
}
if (getObjectFlags(target) & ObjectFlags.Mapped) {
const constraintType = getConstraintTypeFromMappedType(<MappedType>target);
if (inferToMappedType(source, <MappedType>target, constraintType)) {
return;
}
}
// Infer from the members of source and target only if the two types are possibly related
if (!typesDefinitelyUnrelated(source, target)) {
inferFromProperties(source, target);
inferFromSignatures(source, target, SignatureKind.Call);
inferFromSignatures(source, target, SignatureKind.Construct);
inferFromIndexTypes(source, target);
}
}
function inferFromProperties(source: Type, target: Type) {
if (isArrayType(source) || isTupleType(source)) {
if (isTupleType(target)) {
const sourceLength = isTupleType(source) ? getLengthOfTupleType(source) : 0;
const targetLength = getLengthOfTupleType(target);
const sourceRestType = isTupleType(source) ? getRestTypeOfTupleType(source) : getElementTypeOfArrayType(source);
const targetRestType = getRestTypeOfTupleType(target);
const fixedLength = targetLength < sourceLength || sourceRestType ? targetLength : sourceLength;
for (let i = 0; i < fixedLength; i++) {
inferFromTypes(i < sourceLength ? (<TypeReference>source).typeArguments![i] : sourceRestType!, target.typeArguments![i]);
}
if (targetRestType) {
const types = fixedLength < sourceLength ? (<TypeReference>source).typeArguments!.slice(fixedLength, sourceLength) : [];
if (sourceRestType) {
types.push(sourceRestType);
}
if (types.length) {
inferFromTypes(getUnionType(types), targetRestType);
}
}
return;
}
if (isArrayType(target)) {
inferFromIndexTypes(source, target);
return;
}
}
const properties = getPropertiesOfObjectType(target);
for (const targetProp of properties) {
const sourceProp = getPropertyOfType(source, targetProp.escapedName);
if (sourceProp) {
inferFromTypes(getTypeOfSymbol(sourceProp), getTypeOfSymbol(targetProp));
}
}
}
function inferFromSignatures(source: Type, target: Type, kind: SignatureKind) {
const sourceSignatures = getSignaturesOfType(source, kind);
const targetSignatures = getSignaturesOfType(target, kind);
const sourceLen = sourceSignatures.length;
const targetLen = targetSignatures.length;
const len = sourceLen < targetLen ? sourceLen : targetLen;
const skipParameters = !!(getObjectFlags(source) & ObjectFlags.ContainsAnyFunctionType);
for (let i = 0; i < len; i++) {
inferFromSignature(getBaseSignature(sourceSignatures[sourceLen - len + i]), getBaseSignature(targetSignatures[targetLen - len + i]), skipParameters);
}
}
function inferFromSignature(source: Signature, target: Signature, skipParameters: boolean) {
if (!skipParameters) {
const saveBivariant = bivariant;
const kind = target.declaration ? target.declaration.kind : SyntaxKind.Unknown;
// Once we descend into a bivariant signature we remain bivariant for all nested inferences
bivariant = bivariant || kind === SyntaxKind.MethodDeclaration || kind === SyntaxKind.MethodSignature || kind === SyntaxKind.Constructor;
forEachMatchingParameterType(source, target, inferFromContravariantTypes);
bivariant = saveBivariant;
}
const sourceTypePredicate = getTypePredicateOfSignature(source);
const targetTypePredicate = getTypePredicateOfSignature(target);
if (sourceTypePredicate && targetTypePredicate && sourceTypePredicate.kind === targetTypePredicate.kind) {
inferFromTypes(sourceTypePredicate.type, targetTypePredicate.type);
}
else {
inferFromTypes(getReturnTypeOfSignature(source), getReturnTypeOfSignature(target));
}
}
function inferFromIndexTypes(source: Type, target: Type) {
const targetStringIndexType = getIndexTypeOfType(target, IndexKind.String);
if (targetStringIndexType) {
const sourceIndexType = getIndexTypeOfType(source, IndexKind.String) ||
getImplicitIndexTypeOfType(source, IndexKind.String);
if (sourceIndexType) {
inferFromTypes(sourceIndexType, targetStringIndexType);
}
}
const targetNumberIndexType = getIndexTypeOfType(target, IndexKind.Number);
if (targetNumberIndexType) {
const sourceIndexType = getIndexTypeOfType(source, IndexKind.Number) ||
getIndexTypeOfType(source, IndexKind.String) ||
getImplicitIndexTypeOfType(source, IndexKind.Number);
if (sourceIndexType) {
inferFromTypes(sourceIndexType, targetNumberIndexType);
}
}
}
}
function typeIdenticalToSomeType(type: Type, types: Type[]): boolean {
for (const t of types) {
if (isTypeIdenticalTo(t, type)) {
return true;
}
}
return false;
}
/**
* Return a new union or intersection type computed by removing a given set of types
* from a given union or intersection type.
*/
function removeTypesFromUnionOrIntersection(type: UnionOrIntersectionType, typesToRemove: Type[]) {
const reducedTypes: Type[] = [];
for (const t of type.types) {
if (!typeIdenticalToSomeType(t, typesToRemove)) {
reducedTypes.push(t);
}
}
return type.flags & TypeFlags.Union ? getUnionType(reducedTypes) : getIntersectionType(reducedTypes);
}
function hasPrimitiveConstraint(type: TypeParameter): boolean {
const constraint = getConstraintOfTypeParameter(type);
return !!constraint && maybeTypeOfKind(constraint.flags & TypeFlags.Conditional ? getDefaultConstraintOfConditionalType(constraint as ConditionalType) : constraint, TypeFlags.Primitive | TypeFlags.Index);
}
function isObjectLiteralType(type: Type) {
return !!(getObjectFlags(type) & ObjectFlags.ObjectLiteral);
}
function widenObjectLiteralCandidates(candidates: Type[]): Type[] {
if (candidates.length > 1) {
const objectLiterals = filter(candidates, isObjectLiteralType);
if (objectLiterals.length) {
const objectLiteralsType = getWidenedType(getUnionType(objectLiterals, UnionReduction.Subtype));
return concatenate(filter(candidates, t => !isObjectLiteralType(t)), [objectLiteralsType]);
}
}
return candidates;
}
function getContravariantInference(inference: InferenceInfo) {
return inference.priority! & InferencePriority.PriorityImpliesCombination ? getIntersectionType(inference.contraCandidates!) : getCommonSubtype(inference.contraCandidates!);
}
function getCovariantInference(inference: InferenceInfo, signature: Signature) {
// Extract all object literal types and replace them with a single widened and normalized type.
const candidates = widenObjectLiteralCandidates(inference.candidates!);
// We widen inferred literal types if
// all inferences were made to top-level occurrences of the type parameter, and
// the type parameter has no constraint or its constraint includes no primitive or literal types, and
// the type parameter was fixed during inference or does not occur at top-level in the return type.
const primitiveConstraint = hasPrimitiveConstraint(inference.typeParameter);
const widenLiteralTypes = !primitiveConstraint && inference.topLevel &&
(inference.isFixed || !isTypeParameterAtTopLevel(getReturnTypeOfSignature(signature), inference.typeParameter));
const baseCandidates = primitiveConstraint ? sameMap(candidates, getRegularTypeOfLiteralType) :
widenLiteralTypes ? sameMap(candidates, getWidenedLiteralType) :
candidates;
// If all inferences were made from a position that implies a combined result, infer a union type.
// Otherwise, infer a common supertype.
const unwidenedType = inference.priority! & InferencePriority.PriorityImpliesCombination ?
getUnionType(baseCandidates, UnionReduction.Subtype) :
getCommonSupertype(baseCandidates);
return getWidenedType(unwidenedType);
}
function getInferredType(context: InferenceContext, index: number): Type {
const inference = context.inferences[index];
let inferredType = inference.inferredType;
if (!inferredType) {
const signature = context.signature;
if (signature) {
const inferredCovariantType = inference.candidates ? getCovariantInference(inference, signature) : undefined;
if (inference.contraCandidates) {
const inferredContravariantType = getContravariantInference(inference);
// If we have both co- and contra-variant inferences, we prefer the contra-variant inference
// unless the co-variant inference is a subtype and not 'never'.
inferredType = inferredCovariantType && !(inferredCovariantType.flags & TypeFlags.Never) &&
isTypeSubtypeOf(inferredCovariantType, inferredContravariantType) ?
inferredCovariantType : inferredContravariantType;
}
else if (inferredCovariantType) {
inferredType = inferredCovariantType;
}
else if (context.flags & InferenceFlags.NoDefault) {
// We use silentNeverType as the wildcard that signals no inferences.
inferredType = silentNeverType;
}
else {
// Infer either the default or the empty object type when no inferences were
// made. It is important to remember that in this case, inference still
// succeeds, meaning there is no error for not having inference candidates. An
// inference error only occurs when there are *conflicting* candidates, i.e.
// candidates with no common supertype.
const defaultType = getDefaultFromTypeParameter(inference.typeParameter);
if (defaultType) {
// Instantiate the default type. Any forward reference to a type
// parameter should be instantiated to the empty object type.
inferredType = instantiateType(defaultType,
combineTypeMappers(
createBackreferenceMapper(context.typeParameters, index),
context));
}
else {
inferredType = getDefaultTypeArgumentType(!!(context.flags & InferenceFlags.AnyDefault));
}
}
}
else {
inferredType = getTypeFromInference(inference);
}
inference.inferredType = inferredType;
const constraint = getConstraintOfTypeParameter(inference.typeParameter);
if (constraint) {
context.flags |= InferenceFlags.NoFixing;
const instantiatedConstraint = instantiateType(constraint, context);
if (!context.compareTypes(inferredType, getTypeWithThisArgument(instantiatedConstraint, inferredType))) {
inference.inferredType = inferredType = instantiatedConstraint;
}
context.flags &= ~InferenceFlags.NoFixing;
}
}
return inferredType;
}
function getDefaultTypeArgumentType(isInJavaScriptFile: boolean): Type {
return isInJavaScriptFile ? anyType : emptyObjectType;
}
function getInferredTypes(context: InferenceContext): Type[] {
const result: Type[] = [];
for (let i = 0; i < context.inferences.length; i++) {
result.push(getInferredType(context, i));
}
return result;
}
// EXPRESSION TYPE CHECKING
function getCannotFindNameDiagnosticForName(name: __String): DiagnosticMessage {
switch (name) {
case "document":
case "console":
return Diagnostics.Cannot_find_name_0_Do_you_need_to_change_your_target_library_Try_changing_the_lib_compiler_option_to_include_dom;
case "$":
return compilerOptions.types
? Diagnostics.Cannot_find_name_0_Do_you_need_to_install_type_definitions_for_jQuery_Try_npm_i_types_Slashjquery_and_then_add_jquery_to_the_types_field_in_your_tsconfig
: Diagnostics.Cannot_find_name_0_Do_you_need_to_install_type_definitions_for_jQuery_Try_npm_i_types_Slashjquery;
case "describe":
case "suite":
case "it":
case "test":
return compilerOptions.types
? Diagnostics.Cannot_find_name_0_Do_you_need_to_install_type_definitions_for_a_test_runner_Try_npm_i_types_Slashjest_or_npm_i_types_Slashmocha_and_then_add_jest_or_mocha_to_the_types_field_in_your_tsconfig
: Diagnostics.Cannot_find_name_0_Do_you_need_to_install_type_definitions_for_a_test_runner_Try_npm_i_types_Slashjest_or_npm_i_types_Slashmocha;
case "process":
case "require":
case "Buffer":
case "module":
return compilerOptions.types
? Diagnostics.Cannot_find_name_0_Do_you_need_to_install_type_definitions_for_node_Try_npm_i_types_Slashnode_and_then_add_node_to_the_types_field_in_your_tsconfig
: Diagnostics.Cannot_find_name_0_Do_you_need_to_install_type_definitions_for_node_Try_npm_i_types_Slashnode;
case "Map":
case "Set":
case "Promise":
case "Symbol":
case "WeakMap":
case "WeakSet":
case "Iterator":
case "AsyncIterator":
return Diagnostics.Cannot_find_name_0_Do_you_need_to_change_your_target_library_Try_changing_the_lib_compiler_option_to_es2015_or_later;
default: return Diagnostics.Cannot_find_name_0;
}
}
function getResolvedSymbol(node: Identifier): Symbol {
const links = getNodeLinks(node);
if (!links.resolvedSymbol) {
links.resolvedSymbol = !nodeIsMissing(node) &&
resolveName(
node,
node.escapedText,
SymbolFlags.Value | SymbolFlags.ExportValue,
getCannotFindNameDiagnosticForName(node.escapedText),
node,
!isWriteOnlyAccess(node),
/*excludeGlobals*/ false,
Diagnostics.Cannot_find_name_0_Did_you_mean_1) || unknownSymbol;
}
return links.resolvedSymbol;
}
function isInTypeQuery(node: Node): boolean {
// TypeScript 1.0 spec (April 2014): 3.6.3
// A type query consists of the keyword typeof followed by an expression.
// The expression is restricted to a single identifier or a sequence of identifiers separated by periods
return !!findAncestor(
node,
n => n.kind === SyntaxKind.TypeQuery ? true : n.kind === SyntaxKind.Identifier || n.kind === SyntaxKind.QualifiedName ? false : "quit");
}
// Return the flow cache key for a "dotted name" (i.e. a sequence of identifiers
// separated by dots). The key consists of the id of the symbol referenced by the
// leftmost identifier followed by zero or more property names separated by dots.
// The result is undefined if the reference isn't a dotted name. We prefix nodes
// occurring in an apparent type position with '@' because the control flow type
// of such nodes may be based on the apparent type instead of the declared type.
function getFlowCacheKey(node: Node): string | undefined {
switch (node.kind) {
case SyntaxKind.Identifier:
const symbol = getResolvedSymbol(<Identifier>node);
return symbol !== unknownSymbol ? (isConstraintPosition(node) ? "@" : "") + getSymbolId(symbol) : undefined;
case SyntaxKind.ThisKeyword:
return "0";
case SyntaxKind.NonNullExpression:
case SyntaxKind.ParenthesizedExpression:
return getFlowCacheKey((<NonNullExpression | ParenthesizedExpression>node).expression);
case SyntaxKind.PropertyAccessExpression:
case SyntaxKind.ElementAccessExpression:
const propName = getAccessedPropertyName(<AccessExpression>node);
if (propName !== undefined) {
const key = getFlowCacheKey((<AccessExpression>node).expression);
return key && key + "." + propName;
}
}
return undefined;
}
function isMatchingReference(source: Node, target: Node): boolean {
switch (target.kind) {
case SyntaxKind.ParenthesizedExpression:
case SyntaxKind.NonNullExpression:
return isMatchingReference(source, (target as NonNullExpression | ParenthesizedExpression).expression);
}
switch (source.kind) {
case SyntaxKind.Identifier:
return target.kind === SyntaxKind.Identifier && getResolvedSymbol(<Identifier>source) === getResolvedSymbol(<Identifier>target) ||
(target.kind === SyntaxKind.VariableDeclaration || target.kind === SyntaxKind.BindingElement) &&
getExportSymbolOfValueSymbolIfExported(getResolvedSymbol(<Identifier>source)) === getSymbolOfNode(target);
case SyntaxKind.ThisKeyword:
return target.kind === SyntaxKind.ThisKeyword;
case SyntaxKind.SuperKeyword:
return target.kind === SyntaxKind.SuperKeyword;
case SyntaxKind.NonNullExpression:
case SyntaxKind.ParenthesizedExpression:
return isMatchingReference((source as NonNullExpression | ParenthesizedExpression).expression, target);
case SyntaxKind.PropertyAccessExpression:
case SyntaxKind.ElementAccessExpression:
return isAccessExpression(target) &&
getAccessedPropertyName(<AccessExpression>source) === getAccessedPropertyName(target) &&
isMatchingReference((<AccessExpression>source).expression, target.expression);
}
return false;
}
function getAccessedPropertyName(access: AccessExpression): __String | undefined {
return access.kind === SyntaxKind.PropertyAccessExpression ? access.name.escapedText :
isStringLiteral(access.argumentExpression) || isNumericLiteral(access.argumentExpression) ? escapeLeadingUnderscores(access.argumentExpression.text) :
undefined;
}
function containsMatchingReference(source: Node, target: Node) {
while (isAccessExpression(source)) {
source = source.expression;
if (isMatchingReference(source, target)) {
return true;
}
}
return false;
}
// Return true if target is a property access xxx.yyy, source is a property access xxx.zzz, the declared
// type of xxx is a union type, and yyy is a property that is possibly a discriminant. We consider a property
// a possible discriminant if its type differs in the constituents of containing union type, and if every
// choice is a unit type or a union of unit types.
function containsMatchingReferenceDiscriminant(source: Node, target: Node) {
let name;
return isAccessExpression(target) &&
containsMatchingReference(source, target.expression) &&
(name = getAccessedPropertyName(target)) !== undefined &&
isDiscriminantProperty(getDeclaredTypeOfReference(target.expression), name);
}
function getDeclaredTypeOfReference(expr: Node): Type | undefined {
if (expr.kind === SyntaxKind.Identifier) {
return getTypeOfSymbol(getResolvedSymbol(<Identifier>expr));
}
if (isAccessExpression(expr)) {
const type = getDeclaredTypeOfReference(expr.expression);
if (type) {
const propName = getAccessedPropertyName(expr);
return propName !== undefined ? getTypeOfPropertyOfType(type, propName) : undefined;
}
}
return undefined;
}
function isDiscriminantType(type: Type): boolean {
return !!(type.flags & TypeFlags.Union &&
(type.flags & (TypeFlags.Boolean | TypeFlags.EnumLiteral) || !isGenericIndexType(type)));
}
function isDiscriminantProperty(type: Type | undefined, name: __String) {
if (type && type.flags & TypeFlags.Union) {
const prop = getUnionOrIntersectionProperty(<UnionType>type, name);
if (prop && getCheckFlags(prop) & CheckFlags.SyntheticProperty) {
if ((<TransientSymbol>prop).isDiscriminantProperty === undefined) {
(<TransientSymbol>prop).isDiscriminantProperty =
((<TransientSymbol>prop).checkFlags & CheckFlags.Discriminant) === CheckFlags.Discriminant &&
isDiscriminantType(getTypeOfSymbol(prop));
}
return !!(<TransientSymbol>prop).isDiscriminantProperty;
}
}
return false;
}
function isSyntheticThisPropertyAccess(expr: Node) {
return isAccessExpression(expr) && expr.expression.kind === SyntaxKind.ThisKeyword && !!(expr.expression.flags & NodeFlags.Synthesized);
}
function findDiscriminantProperties(sourceProperties: Symbol[], target: Type): Symbol[] | undefined {
let result: Symbol[] | undefined;
for (const sourceProperty of sourceProperties) {
if (isDiscriminantProperty(target, sourceProperty.escapedName)) {
if (result) {
result.push(sourceProperty);
continue;
}
result = [sourceProperty];
}
}
return result;
}
function isOrContainsMatchingReference(source: Node, target: Node) {
return isMatchingReference(source, target) || containsMatchingReference(source, target);
}
function hasMatchingArgument(callExpression: CallExpression, reference: Node) {
if (callExpression.arguments) {
for (const argument of callExpression.arguments) {
if (isOrContainsMatchingReference(reference, argument)) {
return true;
}
}
}
if (callExpression.expression.kind === SyntaxKind.PropertyAccessExpression &&
isOrContainsMatchingReference(reference, (<PropertyAccessExpression>callExpression.expression).expression)) {
return true;
}
return false;
}
function getFlowNodeId(flow: FlowNode): number {
if (!flow.id) {
flow.id = nextFlowId;
nextFlowId++;
}
return flow.id;
}
function typeMaybeAssignableTo(source: Type, target: Type) {
if (!(source.flags & TypeFlags.Union)) {
return isTypeAssignableTo(source, target);
}
for (const t of (<UnionType>source).types) {
if (isTypeAssignableTo(t, target)) {
return true;
}
}
return false;
}
// Remove those constituent types of declaredType to which no constituent type of assignedType is assignable.
// For example, when a variable of type number | string | boolean is assigned a value of type number | boolean,
// we remove type string.
function getAssignmentReducedType(declaredType: UnionType, assignedType: Type) {
if (declaredType !== assignedType) {
if (assignedType.flags & TypeFlags.Never) {
return assignedType;
}
let reducedType = filterType(declaredType, t => typeMaybeAssignableTo(assignedType, t));
if (assignedType.flags & TypeFlags.BooleanLiteral && isFreshLiteralType(assignedType)) {
reducedType = mapType(reducedType, getFreshTypeOfLiteralType); // Ensure that if the assignment is a fresh type, that we narrow to fresh types
}
// Our crude heuristic produces an invalid result in some cases: see GH#26130.
// For now, when that happens, we give up and don't narrow at all. (This also
// means we'll never narrow for erroneous assignments where the assigned type
// is not assignable to the declared type.)
if (isTypeAssignableTo(assignedType, reducedType)) {
return reducedType;
}
}
return declaredType;
}
function getTypeFactsOfTypes(types: Type[]): TypeFacts {
let result: TypeFacts = TypeFacts.None;
for (const t of types) {
result |= getTypeFacts(t);
}
return result;
}
function isFunctionObjectType(type: ObjectType): boolean {
// We do a quick check for a "bind" property before performing the more expensive subtype
// check. This gives us a quicker out in the common case where an object type is not a function.
const resolved = resolveStructuredTypeMembers(type);
return !!(resolved.callSignatures.length || resolved.constructSignatures.length ||
resolved.members.get("bind" as __String) && isTypeSubtypeOf(type, globalFunctionType));
}
function getTypeFacts(type: Type): TypeFacts {
const flags = type.flags;
if (flags & TypeFlags.String) {
return strictNullChecks ? TypeFacts.StringStrictFacts : TypeFacts.StringFacts;
}
if (flags & TypeFlags.StringLiteral) {
const isEmpty = (<StringLiteralType>type).value === "";
return strictNullChecks ?
isEmpty ? TypeFacts.EmptyStringStrictFacts : TypeFacts.NonEmptyStringStrictFacts :
isEmpty ? TypeFacts.EmptyStringFacts : TypeFacts.NonEmptyStringFacts;
}
if (flags & (TypeFlags.Number | TypeFlags.Enum)) {
return strictNullChecks ? TypeFacts.NumberStrictFacts : TypeFacts.NumberFacts;
}
if (flags & TypeFlags.NumberLiteral) {
const isZero = (<NumberLiteralType>type).value === 0;
return strictNullChecks ?
isZero ? TypeFacts.ZeroNumberStrictFacts : TypeFacts.NonZeroNumberStrictFacts :
isZero ? TypeFacts.ZeroNumberFacts : TypeFacts.NonZeroNumberFacts;
}
if (flags & TypeFlags.BigInt) {
return strictNullChecks ? TypeFacts.BigIntStrictFacts : TypeFacts.BigIntFacts;
}
if (flags & TypeFlags.BigIntLiteral) {
const isZero = isZeroBigInt(<BigIntLiteralType>type);
return strictNullChecks ?
isZero ? TypeFacts.ZeroBigIntStrictFacts : TypeFacts.NonZeroBigIntStrictFacts :
isZero ? TypeFacts.ZeroBigIntFacts : TypeFacts.NonZeroBigIntFacts;
}
if (flags & TypeFlags.Boolean) {
return strictNullChecks ? TypeFacts.BooleanStrictFacts : TypeFacts.BooleanFacts;
}
if (flags & TypeFlags.BooleanLike) {
return strictNullChecks ?
(type === falseType || type === regularFalseType) ? TypeFacts.FalseStrictFacts : TypeFacts.TrueStrictFacts :
(type === falseType || type === regularFalseType) ? TypeFacts.FalseFacts : TypeFacts.TrueFacts;
}
if (flags & TypeFlags.Object) {
return getObjectFlags(type) & ObjectFlags.Anonymous && isEmptyObjectType(<ObjectType>type) ?
strictNullChecks ? TypeFacts.EmptyObjectStrictFacts : TypeFacts.EmptyObjectFacts :
isFunctionObjectType(<ObjectType>type) ?
strictNullChecks ? TypeFacts.FunctionStrictFacts : TypeFacts.FunctionFacts :
strictNullChecks ? TypeFacts.ObjectStrictFacts : TypeFacts.ObjectFacts;
}
if (flags & (TypeFlags.Void | TypeFlags.Undefined)) {
return TypeFacts.UndefinedFacts;
}
if (flags & TypeFlags.Null) {
return TypeFacts.NullFacts;
}
if (flags & TypeFlags.ESSymbolLike) {
return strictNullChecks ? TypeFacts.SymbolStrictFacts : TypeFacts.SymbolFacts;
}
if (flags & TypeFlags.NonPrimitive) {
return strictNullChecks ? TypeFacts.ObjectStrictFacts : TypeFacts.ObjectFacts;
}
if (flags & TypeFlags.Instantiable) {
return getTypeFacts(getBaseConstraintOfType(type) || emptyObjectType);
}
if (flags & TypeFlags.UnionOrIntersection) {
return getTypeFactsOfTypes((<UnionOrIntersectionType>type).types);
}
return TypeFacts.All;
}
function getTypeWithFacts(type: Type, include: TypeFacts) {
return filterType(type, t => (getTypeFacts(t) & include) !== 0);
}
function getTypeWithDefault(type: Type, defaultExpression: Expression) {
if (defaultExpression) {
const defaultType = getTypeOfExpression(defaultExpression);
return getUnionType([getTypeWithFacts(type, TypeFacts.NEUndefined), defaultType]);
}
return type;
}
function getTypeOfDestructuredProperty(type: Type, name: PropertyName) {
const nameType = getLiteralTypeFromPropertyName(name);
if (!isTypeUsableAsPropertyName(nameType)) return errorType;
const text = getPropertyNameFromType(nameType);
return getConstraintForLocation(getTypeOfPropertyOfType(type, text), name) ||
isNumericLiteralName(text) && getIndexTypeOfType(type, IndexKind.Number) ||
getIndexTypeOfType(type, IndexKind.String) ||
errorType;
}
function getTypeOfDestructuredArrayElement(type: Type, index: number) {
return everyType(type, isTupleLikeType) && getTupleElementType(type, index) ||
checkIteratedTypeOrElementType(type, /*errorNode*/ undefined, /*allowStringInput*/ false, /*allowAsyncIterables*/ false) ||
errorType;
}
function getTypeOfDestructuredSpreadExpression(type: Type) {
return createArrayType(checkIteratedTypeOrElementType(type, /*errorNode*/ undefined, /*allowStringInput*/ false, /*allowAsyncIterables*/ false) || errorType);
}
function getAssignedTypeOfBinaryExpression(node: BinaryExpression): Type {
const isDestructuringDefaultAssignment =
node.parent.kind === SyntaxKind.ArrayLiteralExpression && isDestructuringAssignmentTarget(node.parent) ||
node.parent.kind === SyntaxKind.PropertyAssignment && isDestructuringAssignmentTarget(node.parent.parent);
return isDestructuringDefaultAssignment ?
getTypeWithDefault(getAssignedType(node), node.right) :
getTypeOfExpression(node.right);
}
function isDestructuringAssignmentTarget(parent: Node) {
return parent.parent.kind === SyntaxKind.BinaryExpression && (parent.parent as BinaryExpression).left === parent ||
parent.parent.kind === SyntaxKind.ForOfStatement && (parent.parent as ForOfStatement).initializer === parent;
}
function getAssignedTypeOfArrayLiteralElement(node: ArrayLiteralExpression, element: Expression): Type {
return getTypeOfDestructuredArrayElement(getAssignedType(node), node.elements.indexOf(element));
}
function getAssignedTypeOfSpreadExpression(node: SpreadElement): Type {
return getTypeOfDestructuredSpreadExpression(getAssignedType(<ArrayLiteralExpression>node.parent));
}
function getAssignedTypeOfPropertyAssignment(node: PropertyAssignment | ShorthandPropertyAssignment): Type {
return getTypeOfDestructuredProperty(getAssignedType(node.parent), node.name);
}
function getAssignedTypeOfShorthandPropertyAssignment(node: ShorthandPropertyAssignment): Type {
return getTypeWithDefault(getAssignedTypeOfPropertyAssignment(node), node.objectAssignmentInitializer!);
}
function getAssignedType(node: Expression): Type {
const { parent } = node;
switch (parent.kind) {
case SyntaxKind.ForInStatement:
return stringType;
case SyntaxKind.ForOfStatement:
return checkRightHandSideOfForOf((<ForOfStatement>parent).expression, (<ForOfStatement>parent).awaitModifier) || errorType;
case SyntaxKind.BinaryExpression:
return getAssignedTypeOfBinaryExpression(<BinaryExpression>parent);
case SyntaxKind.DeleteExpression:
return undefinedType;
case SyntaxKind.ArrayLiteralExpression:
return getAssignedTypeOfArrayLiteralElement(<ArrayLiteralExpression>parent, node);
case SyntaxKind.SpreadElement:
return getAssignedTypeOfSpreadExpression(<SpreadElement>parent);
case SyntaxKind.PropertyAssignment:
return getAssignedTypeOfPropertyAssignment(<PropertyAssignment>parent);
case SyntaxKind.ShorthandPropertyAssignment:
return getAssignedTypeOfShorthandPropertyAssignment(<ShorthandPropertyAssignment>parent);
}
return errorType;
}
function getInitialTypeOfBindingElement(node: BindingElement): Type {
const pattern = node.parent;
const parentType = getInitialType(<VariableDeclaration | BindingElement>pattern.parent);
const type = pattern.kind === SyntaxKind.ObjectBindingPattern ?
getTypeOfDestructuredProperty(parentType, node.propertyName || <Identifier>node.name) :
!node.dotDotDotToken ?
getTypeOfDestructuredArrayElement(parentType, pattern.elements.indexOf(node)) :
getTypeOfDestructuredSpreadExpression(parentType);
return getTypeWithDefault(type, node.initializer!);
}
function getTypeOfInitializer(node: Expression) {
// Return the cached type if one is available. If the type of the variable was inferred
// from its initializer, we'll already have cached the type. Otherwise we compute it now
// without caching such that transient types are reflected.
const links = getNodeLinks(node);
return links.resolvedType || getTypeOfExpression(node);
}
function getInitialTypeOfVariableDeclaration(node: VariableDeclaration) {
if (node.initializer) {
return getTypeOfInitializer(node.initializer);
}
if (node.parent.parent.kind === SyntaxKind.ForInStatement) {
return stringType;
}
if (node.parent.parent.kind === SyntaxKind.ForOfStatement) {
return checkRightHandSideOfForOf(node.parent.parent.expression, node.parent.parent.awaitModifier) || errorType;
}
return errorType;
}
function getInitialType(node: VariableDeclaration | BindingElement) {
return node.kind === SyntaxKind.VariableDeclaration ?
getInitialTypeOfVariableDeclaration(node) :
getInitialTypeOfBindingElement(node);
}
function getInitialOrAssignedType(node: VariableDeclaration | BindingElement | Expression, reference: Node) {
return getConstraintForLocation(node.kind === SyntaxKind.VariableDeclaration || node.kind === SyntaxKind.BindingElement ?
getInitialType(<VariableDeclaration | BindingElement>node) :
getAssignedType(node), reference);
}
function isEmptyArrayAssignment(node: VariableDeclaration | BindingElement | Expression) {
return node.kind === SyntaxKind.VariableDeclaration && (<VariableDeclaration>node).initializer &&
isEmptyArrayLiteral((<VariableDeclaration>node).initializer!) ||
node.kind !== SyntaxKind.BindingElement && node.parent.kind === SyntaxKind.BinaryExpression &&
isEmptyArrayLiteral((<BinaryExpression>node.parent).right);
}
function getReferenceCandidate(node: Expression): Expression {
switch (node.kind) {
case SyntaxKind.ParenthesizedExpression:
return getReferenceCandidate((<ParenthesizedExpression>node).expression);
case SyntaxKind.BinaryExpression:
switch ((<BinaryExpression>node).operatorToken.kind) {
case SyntaxKind.EqualsToken:
return getReferenceCandidate((<BinaryExpression>node).left);
case SyntaxKind.CommaToken:
return getReferenceCandidate((<BinaryExpression>node).right);
}
}
return node;
}
function getReferenceRoot(node: Node): Node {
const { parent } = node;
return parent.kind === SyntaxKind.ParenthesizedExpression ||
parent.kind === SyntaxKind.BinaryExpression && (<BinaryExpression>parent).operatorToken.kind === SyntaxKind.EqualsToken && (<BinaryExpression>parent).left === node ||
parent.kind === SyntaxKind.BinaryExpression && (<BinaryExpression>parent).operatorToken.kind === SyntaxKind.CommaToken && (<BinaryExpression>parent).right === node ?
getReferenceRoot(parent) : node;
}
function getTypeOfSwitchClause(clause: CaseClause | DefaultClause) {
if (clause.kind === SyntaxKind.CaseClause) {
return getRegularTypeOfLiteralType(getTypeOfExpression(clause.expression));
}
return neverType;
}
function getSwitchClauseTypes(switchStatement: SwitchStatement): Type[] {
const links = getNodeLinks(switchStatement);
if (!links.switchTypes) {
links.switchTypes = [];
for (const clause of switchStatement.caseBlock.clauses) {
links.switchTypes.push(getTypeOfSwitchClause(clause));
}
}
return links.switchTypes;
}
// Get the types from all cases in a switch on `typeof`. An
// `undefined` element denotes an explicit `default` clause.
function getSwitchClauseTypeOfWitnesses(switchStatement: SwitchStatement): (string | undefined)[] {
const witnesses: (string | undefined)[] = [];
for (const clause of switchStatement.caseBlock.clauses) {
if (clause.kind === SyntaxKind.CaseClause) {
if (clause.expression.kind === SyntaxKind.StringLiteral) {
witnesses.push((clause.expression as StringLiteral).text);
continue;
}
return emptyArray;
}
witnesses.push(/*explicitDefaultStatement*/ undefined);
}
return witnesses;
}
function eachTypeContainedIn(source: Type, types: Type[]) {
return source.flags & TypeFlags.Union ? !forEach((<UnionType>source).types, t => !contains(types, t)) : contains(types, source);
}
function isTypeSubsetOf(source: Type, target: Type) {
return source === target || target.flags & TypeFlags.Union && isTypeSubsetOfUnion(source, <UnionType>target);
}
function isTypeSubsetOfUnion(source: Type, target: UnionType) {
if (source.flags & TypeFlags.Union) {
for (const t of (<UnionType>source).types) {
if (!containsType(target.types, t)) {
return false;
}
}
return true;
}
if (source.flags & TypeFlags.EnumLiteral && getBaseTypeOfEnumLiteralType(<LiteralType>source) === target) {
return true;
}
return containsType(target.types, source);
}
function forEachType<T>(type: Type, f: (t: Type) => T | undefined): T | undefined {
return type.flags & TypeFlags.Union ? forEach((<UnionType>type).types, f) : f(type);
}
function everyType(type: Type, f: (t: Type) => boolean): boolean {
return type.flags & TypeFlags.Union ? every((<UnionType>type).types, f) : f(type);
}
function filterType(type: Type, f: (t: Type) => boolean): Type {
if (type.flags & TypeFlags.Union) {
const types = (<UnionType>type).types;
const filtered = filter(types, f);
return filtered === types ? type : getUnionTypeFromSortedList(filtered, (<UnionType>type).objectFlags);
}
return f(type) ? type : neverType;
}
// Apply a mapping function to a type and return the resulting type. If the source type
// is a union type, the mapping function is applied to each constituent type and a union
// of the resulting types is returned.
function mapType(type: Type, mapper: (t: Type) => Type, noReductions?: boolean): Type;
function mapType(type: Type, mapper: (t: Type) => Type | undefined, noReductions?: boolean): Type | undefined;
function mapType(type: Type, mapper: (t: Type) => Type | undefined, noReductions?: boolean): Type | undefined {
if (type.flags & TypeFlags.Never) {
return type;
}
if (!(type.flags & TypeFlags.Union)) {
return mapper(type);
}
const types = (<UnionType>type).types;
let mappedType: Type | undefined;
let mappedTypes: Type[] | undefined;
for (const current of types) {
const t = mapper(current);
if (t) {
if (!mappedType) {
mappedType = t;
}
else if (!mappedTypes) {
mappedTypes = [mappedType, t];
}
else {
mappedTypes.push(t);
}
}
}
return mappedTypes ? getUnionType(mappedTypes, noReductions ? UnionReduction.None : UnionReduction.Literal) : mappedType;
}
function extractTypesOfKind(type: Type, kind: TypeFlags) {
return filterType(type, t => (t.flags & kind) !== 0);
}
// Return a new type in which occurrences of the string and number primitive types in
// typeWithPrimitives have been replaced with occurrences of string literals and numeric
// literals in typeWithLiterals, respectively.
function replacePrimitivesWithLiterals(typeWithPrimitives: Type, typeWithLiterals: Type) {
if (isTypeSubsetOf(stringType, typeWithPrimitives) && maybeTypeOfKind(typeWithLiterals, TypeFlags.StringLiteral) ||
isTypeSubsetOf(numberType, typeWithPrimitives) && maybeTypeOfKind(typeWithLiterals, TypeFlags.NumberLiteral) ||
isTypeSubsetOf(bigintType, typeWithPrimitives) && maybeTypeOfKind(typeWithLiterals, TypeFlags.BigIntLiteral)) {
return mapType(typeWithPrimitives, t =>
t.flags & TypeFlags.String ? extractTypesOfKind(typeWithLiterals, TypeFlags.String | TypeFlags.StringLiteral) :
t.flags & TypeFlags.Number ? extractTypesOfKind(typeWithLiterals, TypeFlags.Number | TypeFlags.NumberLiteral) :
t.flags & TypeFlags.BigInt ? extractTypesOfKind(typeWithLiterals, TypeFlags.BigInt | TypeFlags.BigIntLiteral) :
t);
}
return typeWithPrimitives;
}
function isIncomplete(flowType: FlowType) {
return flowType.flags === 0;
}
function getTypeFromFlowType(flowType: FlowType) {
return flowType.flags === 0 ? (<IncompleteType>flowType).type : <Type>flowType;
}
function createFlowType(type: Type, incomplete: boolean): FlowType {
return incomplete ? { flags: 0, type } : type;
}
// An evolving array type tracks the element types that have so far been seen in an
// 'x.push(value)' or 'x[n] = value' operation along the control flow graph. Evolving
// array types are ultimately converted into manifest array types (using getFinalArrayType)
// and never escape the getFlowTypeOfReference function.
function createEvolvingArrayType(elementType: Type): EvolvingArrayType {
const result = <EvolvingArrayType>createObjectType(ObjectFlags.EvolvingArray);
result.elementType = elementType;
return result;
}
function getEvolvingArrayType(elementType: Type): EvolvingArrayType {
return evolvingArrayTypes[elementType.id] || (evolvingArrayTypes[elementType.id] = createEvolvingArrayType(elementType));
}
// When adding evolving array element types we do not perform subtype reduction. Instead,
// we defer subtype reduction until the evolving array type is finalized into a manifest
// array type.
function addEvolvingArrayElementType(evolvingArrayType: EvolvingArrayType, node: Expression): EvolvingArrayType {
const elementType = getBaseTypeOfLiteralType(getContextFreeTypeOfExpression(node));
return isTypeSubsetOf(elementType, evolvingArrayType.elementType) ? evolvingArrayType : getEvolvingArrayType(getUnionType([evolvingArrayType.elementType, elementType]));
}
function createFinalArrayType(elementType: Type) {
return elementType.flags & TypeFlags.Never ?
autoArrayType :
createArrayType(elementType.flags & TypeFlags.Union ?
getUnionType((<UnionType>elementType).types, UnionReduction.Subtype) :
elementType);
}
// We perform subtype reduction upon obtaining the final array type from an evolving array type.
function getFinalArrayType(evolvingArrayType: EvolvingArrayType): Type {
return evolvingArrayType.finalArrayType || (evolvingArrayType.finalArrayType = createFinalArrayType(evolvingArrayType.elementType));
}
function finalizeEvolvingArrayType(type: Type): Type {
return getObjectFlags(type) & ObjectFlags.EvolvingArray ? getFinalArrayType(<EvolvingArrayType>type) : type;
}
function getElementTypeOfEvolvingArrayType(type: Type) {
return getObjectFlags(type) & ObjectFlags.EvolvingArray ? (<EvolvingArrayType>type).elementType : neverType;
}
function isEvolvingArrayTypeList(types: Type[]) {
let hasEvolvingArrayType = false;
for (const t of types) {
if (!(t.flags & TypeFlags.Never)) {
if (!(getObjectFlags(t) & ObjectFlags.EvolvingArray)) {
return false;
}
hasEvolvingArrayType = true;
}
}
return hasEvolvingArrayType;
}
// At flow control branch or loop junctions, if the type along every antecedent code path
// is an evolving array type, we construct a combined evolving array type. Otherwise we
// finalize all evolving array types.
function getUnionOrEvolvingArrayType(types: Type[], subtypeReduction: UnionReduction) {
return isEvolvingArrayTypeList(types) ?
getEvolvingArrayType(getUnionType(map(types, getElementTypeOfEvolvingArrayType))) :
getUnionType(sameMap(types, finalizeEvolvingArrayType), subtypeReduction);
}
// Return true if the given node is 'x' in an 'x.length', x.push(value)', 'x.unshift(value)' or
// 'x[n] = value' operation, where 'n' is an expression of type any, undefined, or a number-like type.
function isEvolvingArrayOperationTarget(node: Node) {
const root = getReferenceRoot(node);
const parent = root.parent;
const isLengthPushOrUnshift = parent.kind === SyntaxKind.PropertyAccessExpression && (
(<PropertyAccessExpression>parent).name.escapedText === "length" ||
parent.parent.kind === SyntaxKind.CallExpression && isPushOrUnshiftIdentifier((<PropertyAccessExpression>parent).name));
const isElementAssignment = parent.kind === SyntaxKind.ElementAccessExpression &&
(<ElementAccessExpression>parent).expression === root &&
parent.parent.kind === SyntaxKind.BinaryExpression &&
(<BinaryExpression>parent.parent).operatorToken.kind === SyntaxKind.EqualsToken &&
(<BinaryExpression>parent.parent).left === parent &&
!isAssignmentTarget(parent.parent) &&
isTypeAssignableToKind(getTypeOfExpression((<ElementAccessExpression>parent).argumentExpression), TypeFlags.NumberLike);
return isLengthPushOrUnshift || isElementAssignment;
}
function maybeTypePredicateCall(node: CallExpression) {
const links = getNodeLinks(node);
if (links.maybeTypePredicate === undefined) {
links.maybeTypePredicate = getMaybeTypePredicate(node);
}
return links.maybeTypePredicate;
}
function getMaybeTypePredicate(node: CallExpression) {
if (node.expression.kind !== SyntaxKind.SuperKeyword) {
const funcType = checkNonNullExpression(node.expression);
if (funcType !== silentNeverType) {
const apparentType = getApparentType(funcType);
return apparentType !== errorType && some(getSignaturesOfType(apparentType, SignatureKind.Call), signatureHasTypePredicate);
}
}
return false;
}
function reportFlowControlError(node: Node) {
const block = <Block | ModuleBlock | SourceFile>findAncestor(node, isFunctionOrModuleBlock);
const sourceFile = getSourceFileOfNode(node);
const span = getSpanOfTokenAtPosition(sourceFile, block.statements.pos);
diagnostics.add(createFileDiagnostic(sourceFile, span.start, span.length, Diagnostics.The_containing_function_or_module_body_is_too_large_for_control_flow_analysis));
}
function getFlowTypeOfReference(reference: Node, declaredType: Type, initialType = declaredType, flowContainer?: Node, couldBeUninitialized?: boolean) {
let key: string | undefined;
let flowDepth = 0;
if (flowAnalysisDisabled) {
return errorType;
}
if (!reference.flowNode || !couldBeUninitialized && !(declaredType.flags & TypeFlags.Narrowable)) {
return declaredType;
}
const sharedFlowStart = sharedFlowCount;
const evolvedType = getTypeFromFlowType(getTypeAtFlowNode(reference.flowNode));
sharedFlowCount = sharedFlowStart;
// When the reference is 'x' in an 'x.length', 'x.push(value)', 'x.unshift(value)' or x[n] = value' operation,
// we give type 'any[]' to 'x' instead of using the type determined by control flow analysis such that operations
// on empty arrays are possible without implicit any errors and new element types can be inferred without
// type mismatch errors.
const resultType = getObjectFlags(evolvedType) & ObjectFlags.EvolvingArray && isEvolvingArrayOperationTarget(reference) ? autoArrayType : finalizeEvolvingArrayType(evolvedType);
if (reference.parent && reference.parent.kind === SyntaxKind.NonNullExpression && getTypeWithFacts(resultType, TypeFacts.NEUndefinedOrNull).flags & TypeFlags.Never) {
return declaredType;
}
return resultType;
function getTypeAtFlowNode(flow: FlowNode): FlowType {
if (flowDepth === 2000) {
// We have made 2000 recursive invocations. To avoid overflowing the call stack we report an error
// and disable further control flow analysis in the containing function or module body.
flowAnalysisDisabled = true;
reportFlowControlError(reference);
return errorType;
}
flowDepth++;
while (true) {
const flags = flow.flags;
if (flags & FlowFlags.Shared) {
// We cache results of flow type resolution for shared nodes that were previously visited in
// the same getFlowTypeOfReference invocation. A node is considered shared when it is the
// antecedent of more than one node.
for (let i = sharedFlowStart; i < sharedFlowCount; i++) {
if (sharedFlowNodes[i] === flow) {
flowDepth--;
return sharedFlowTypes[i];
}
}
}
let type: FlowType | undefined;
if (flags & FlowFlags.AfterFinally) {
// block flow edge: finally -> pre-try (for larger explanation check comment in binder.ts - bindTryStatement
(<AfterFinallyFlow>flow).locked = true;
type = getTypeAtFlowNode((<AfterFinallyFlow>flow).antecedent);
(<AfterFinallyFlow>flow).locked = false;
}
else if (flags & FlowFlags.PreFinally) {
// locked pre-finally flows are filtered out in getTypeAtFlowBranchLabel
// so here just redirect to antecedent
flow = (<PreFinallyFlow>flow).antecedent;
continue;
}
else if (flags & FlowFlags.Assignment) {
type = getTypeAtFlowAssignment(<FlowAssignment>flow);
if (!type) {
flow = (<FlowAssignment>flow).antecedent;
continue;
}
}
else if (flags & FlowFlags.Condition) {
type = getTypeAtFlowCondition(<FlowCondition>flow);
}
else if (flags & FlowFlags.SwitchClause) {
type = getTypeAtSwitchClause(<FlowSwitchClause>flow);
}
else if (flags & FlowFlags.Label) {
if ((<FlowLabel>flow).antecedents!.length === 1) {
flow = (<FlowLabel>flow).antecedents![0];
continue;
}
type = flags & FlowFlags.BranchLabel ?
getTypeAtFlowBranchLabel(<FlowLabel>flow) :
getTypeAtFlowLoopLabel(<FlowLabel>flow);
}
else if (flags & FlowFlags.ArrayMutation) {
type = getTypeAtFlowArrayMutation(<FlowArrayMutation>flow);
if (!type) {
flow = (<FlowArrayMutation>flow).antecedent;
continue;
}
}
else if (flags & FlowFlags.Start) {
// Check if we should continue with the control flow of the containing function.
const container = (<FlowStart>flow).container;
if (container && container !== flowContainer &&
reference.kind !== SyntaxKind.PropertyAccessExpression &&
reference.kind !== SyntaxKind.ElementAccessExpression &&
reference.kind !== SyntaxKind.ThisKeyword) {
flow = container.flowNode!;
continue;
}
// At the top of the flow we have the initial type.
type = initialType;
}
else {
// Unreachable code errors are reported in the binding phase. Here we
// simply return the non-auto declared type to reduce follow-on errors.
type = convertAutoToAny(declaredType);
}
if (flags & FlowFlags.Shared) {
// Record visited node and the associated type in the cache.
sharedFlowNodes[sharedFlowCount] = flow;
sharedFlowTypes[sharedFlowCount] = type;
sharedFlowCount++;
}
flowDepth--;
return type;
}
}
function getTypeAtFlowAssignment(flow: FlowAssignment) {
const node = flow.node;
// Assignments only narrow the computed type if the declared type is a union type. Thus, we
// only need to evaluate the assigned type if the declared type is a union type.
if (isMatchingReference(reference, node)) {
if (getAssignmentTargetKind(node) === AssignmentKind.Compound) {
const flowType = getTypeAtFlowNode(flow.antecedent);
return createFlowType(getBaseTypeOfLiteralType(getTypeFromFlowType(flowType)), isIncomplete(flowType));
}
if (declaredType === autoType || declaredType === autoArrayType) {
if (isEmptyArrayAssignment(node)) {
return getEvolvingArrayType(neverType);
}
const assignedType = getBaseTypeOfLiteralType(getInitialOrAssignedType(node, reference));
return isTypeAssignableTo(assignedType, declaredType) ? assignedType : anyArrayType;
}
if (declaredType.flags & TypeFlags.Union) {
return getAssignmentReducedType(<UnionType>declaredType, getInitialOrAssignedType(node, reference));
}
return declaredType;
}
// We didn't have a direct match. However, if the reference is a dotted name, this
// may be an assignment to a left hand part of the reference. For example, for a
// reference 'x.y.z', we may be at an assignment to 'x.y' or 'x'. In that case,
// return the declared type.
if (containsMatchingReference(reference, node)) {
// A matching dotted name might also be an expando property on a function *expression*,
// in which case we continue control flow analysis back to the function's declaration
if (isVariableDeclaration(node) && (isInJSFile(node) || isVarConst(node))) {
const init = getDeclaredExpandoInitializer(node);
if (init && (init.kind === SyntaxKind.FunctionExpression || init.kind === SyntaxKind.ArrowFunction)) {
return getTypeAtFlowNode(flow.antecedent);
}
}
return declaredType;
}
// for (const _ in ref) acts as a nonnull on ref
if (isVariableDeclaration(node) && node.parent.parent.kind === SyntaxKind.ForInStatement && isMatchingReference(reference, node.parent.parent.expression)) {
return getNonNullableTypeIfNeeded(getTypeFromFlowType(getTypeAtFlowNode(flow.antecedent)));
}
// Assignment doesn't affect reference
return undefined;
}
function getTypeAtFlowArrayMutation(flow: FlowArrayMutation): FlowType | undefined {
if (declaredType === autoType || declaredType === autoArrayType) {
const node = flow.node;
const expr = node.kind === SyntaxKind.CallExpression ?
(<PropertyAccessExpression>node.expression).expression :
(<ElementAccessExpression>node.left).expression;
if (isMatchingReference(reference, getReferenceCandidate(expr))) {
const flowType = getTypeAtFlowNode(flow.antecedent);
const type = getTypeFromFlowType(flowType);
if (getObjectFlags(type) & ObjectFlags.EvolvingArray) {
let evolvedType = <EvolvingArrayType>type;
if (node.kind === SyntaxKind.CallExpression) {
for (const arg of node.arguments) {
evolvedType = addEvolvingArrayElementType(evolvedType, arg);
}
}
else {
// We must get the context free expression type so as to not recur in an uncached fashion on the LHS (which causes exponential blowup in compile time)
const indexType = getContextFreeTypeOfExpression((<ElementAccessExpression>node.left).argumentExpression);
if (isTypeAssignableToKind(indexType, TypeFlags.NumberLike)) {
evolvedType = addEvolvingArrayElementType(evolvedType, node.right);
}
}
return evolvedType === type ? flowType : createFlowType(evolvedType, isIncomplete(flowType));
}
return flowType;
}
}
return undefined;
}
function getTypeAtFlowCondition(flow: FlowCondition): FlowType {
const flowType = getTypeAtFlowNode(flow.antecedent);
const type = getTypeFromFlowType(flowType);
if (type.flags & TypeFlags.Never) {
return flowType;
}
// If we have an antecedent type (meaning we're reachable in some way), we first
// attempt to narrow the antecedent type. If that produces the never type, and if
// the antecedent type is incomplete (i.e. a transient type in a loop), then we
// take the type guard as an indication that control *could* reach here once we
// have the complete type. We proceed by switching to the silent never type which
// doesn't report errors when operators are applied to it. Note that this is the
// *only* place a silent never type is ever generated.
const assumeTrue = (flow.flags & FlowFlags.TrueCondition) !== 0;
const nonEvolvingType = finalizeEvolvingArrayType(type);
const narrowedType = narrowType(nonEvolvingType, flow.expression, assumeTrue);
if (narrowedType === nonEvolvingType) {
return flowType;
}
const incomplete = isIncomplete(flowType);
const resultType = incomplete && narrowedType.flags & TypeFlags.Never ? silentNeverType : narrowedType;
return createFlowType(resultType, incomplete);
}
function getTypeAtSwitchClause(flow: FlowSwitchClause): FlowType {
const expr = flow.switchStatement.expression;
const flowType = getTypeAtFlowNode(flow.antecedent);
let type = getTypeFromFlowType(flowType);
if (isMatchingReference(reference, expr)) {
type = narrowTypeBySwitchOnDiscriminant(type, flow.switchStatement, flow.clauseStart, flow.clauseEnd);
}
else if (isMatchingReferenceDiscriminant(expr, type)) {
type = narrowTypeByDiscriminant(
type,
expr as AccessExpression,
t => narrowTypeBySwitchOnDiscriminant(t, flow.switchStatement, flow.clauseStart, flow.clauseEnd));
}
else if (expr.kind === SyntaxKind.TypeOfExpression && isMatchingReference(reference, (expr as TypeOfExpression).expression)) {
type = narrowBySwitchOnTypeOf(type, flow.switchStatement, flow.clauseStart, flow.clauseEnd);
}
else if (containsMatchingReferenceDiscriminant(reference, expr)) {
type = declaredType;
}
return createFlowType(type, isIncomplete(flowType));
}
function getTypeAtFlowBranchLabel(flow: FlowLabel): FlowType {
const antecedentTypes: Type[] = [];
let subtypeReduction = false;
let seenIncomplete = false;
for (const antecedent of flow.antecedents!) {
if (antecedent.flags & FlowFlags.PreFinally && (<PreFinallyFlow>antecedent).lock.locked) {
// if flow correspond to branch from pre-try to finally and this branch is locked - this means that
// we initially have started following the flow outside the finally block.
// in this case we should ignore this branch.
continue;
}
const flowType = getTypeAtFlowNode(antecedent);
const type = getTypeFromFlowType(flowType);
// If the type at a particular antecedent path is the declared type and the
// reference is known to always be assigned (i.e. when declared and initial types
// are the same), there is no reason to process more antecedents since the only
// possible outcome is subtypes that will be removed in the final union type anyway.
if (type === declaredType && declaredType === initialType) {
return type;
}
pushIfUnique(antecedentTypes, type);
// If an antecedent type is not a subset of the declared type, we need to perform
// subtype reduction. This happens when a "foreign" type is injected into the control
// flow using the instanceof operator or a user defined type predicate.
if (!isTypeSubsetOf(type, declaredType)) {
subtypeReduction = true;
}
if (isIncomplete(flowType)) {
seenIncomplete = true;
}
}
return createFlowType(getUnionOrEvolvingArrayType(antecedentTypes, subtypeReduction ? UnionReduction.Subtype : UnionReduction.Literal), seenIncomplete);
}
function getTypeAtFlowLoopLabel(flow: FlowLabel): FlowType {
// If we have previously computed the control flow type for the reference at
// this flow loop junction, return the cached type.
const id = getFlowNodeId(flow);
const cache = flowLoopCaches[id] || (flowLoopCaches[id] = createMap<Type>());
if (!key) {
key = getFlowCacheKey(reference);
// No cache key is generated when binding patterns are in unnarrowable situations
if (!key) {
return declaredType;
}
}
const cached = cache.get(key);
if (cached) {
return cached;
}
// If this flow loop junction and reference are already being processed, return
// the union of the types computed for each branch so far, marked as incomplete.
// It is possible to see an empty array in cases where loops are nested and the
// back edge of the outer loop reaches an inner loop that is already being analyzed.
// In such cases we restart the analysis of the inner loop, which will then see
// a non-empty in-process array for the outer loop and eventually terminate because
// the first antecedent of a loop junction is always the non-looping control flow
// path that leads to the top.
for (let i = flowLoopStart; i < flowLoopCount; i++) {
if (flowLoopNodes[i] === flow && flowLoopKeys[i] === key && flowLoopTypes[i].length) {
return createFlowType(getUnionOrEvolvingArrayType(flowLoopTypes[i], UnionReduction.Literal), /*incomplete*/ true);
}
}
// Add the flow loop junction and reference to the in-process stack and analyze
// each antecedent code path.
const antecedentTypes: Type[] = [];
let subtypeReduction = false;
let firstAntecedentType: FlowType | undefined;
flowLoopNodes[flowLoopCount] = flow;
flowLoopKeys[flowLoopCount] = key;
flowLoopTypes[flowLoopCount] = antecedentTypes;
for (const antecedent of flow.antecedents!) {
flowLoopCount++;
const flowType = getTypeAtFlowNode(antecedent);
flowLoopCount--;
if (!firstAntecedentType) {
firstAntecedentType = flowType;
}
const type = getTypeFromFlowType(flowType);
// If we see a value appear in the cache it is a sign that control flow analysis
// was restarted and completed by checkExpressionCached. We can simply pick up
// the resulting type and bail out.
const cached = cache.get(key);
if (cached) {
return cached;
}
pushIfUnique(antecedentTypes, type);
// If an antecedent type is not a subset of the declared type, we need to perform
// subtype reduction. This happens when a "foreign" type is injected into the control
// flow using the instanceof operator or a user defined type predicate.
if (!isTypeSubsetOf(type, declaredType)) {
subtypeReduction = true;
}
// If the type at a particular antecedent path is the declared type there is no
// reason to process more antecedents since the only possible outcome is subtypes
// that will be removed in the final union type anyway.
if (type === declaredType) {
break;
}
}
// The result is incomplete if the first antecedent (the non-looping control flow path)
// is incomplete.
const result = getUnionOrEvolvingArrayType(antecedentTypes, subtypeReduction ? UnionReduction.Subtype : UnionReduction.Literal);
if (isIncomplete(firstAntecedentType!)) {
return createFlowType(result, /*incomplete*/ true);
}
cache.set(key, result);
return result;
}
function isMatchingReferenceDiscriminant(expr: Expression, computedType: Type) {
if (!(computedType.flags & TypeFlags.Union) || !isAccessExpression(expr)) {
return false;
}
const name = getAccessedPropertyName(expr);
if (name === undefined) {
return false;
}
return isMatchingReference(reference, expr.expression) && isDiscriminantProperty(computedType, name);
}
function narrowTypeByDiscriminant(type: Type, access: AccessExpression, narrowType: (t: Type) => Type): Type {
const propName = getAccessedPropertyName(access);
if (propName === undefined) {
return type;
}
const propType = getTypeOfPropertyOfType(type, propName);
const narrowedPropType = propType && narrowType(propType);
return propType === narrowedPropType ? type : filterType(type, t => isTypeComparableTo(getTypeOfPropertyOrIndexSignature(t, propName), narrowedPropType!));
}
function narrowTypeByTruthiness(type: Type, expr: Expression, assumeTrue: boolean): Type {
if (isMatchingReference(reference, expr)) {
return getTypeWithFacts(type, assumeTrue ? TypeFacts.Truthy : TypeFacts.Falsy);
}
if (isMatchingReferenceDiscriminant(expr, declaredType)) {
return narrowTypeByDiscriminant(type, <AccessExpression>expr, t => getTypeWithFacts(t, assumeTrue ? TypeFacts.Truthy : TypeFacts.Falsy));
}
if (containsMatchingReferenceDiscriminant(reference, expr)) {
return declaredType;
}
return type;
}
function isTypePresencePossible(type: Type, propName: __String, assumeTrue: boolean) {
if (getIndexInfoOfType(type, IndexKind.String)) {
return true;
}
const prop = getPropertyOfType(type, propName);
if (prop) {
return prop.flags & SymbolFlags.Optional ? true : assumeTrue;
}
return !assumeTrue;
}
function narrowByInKeyword(type: Type, literal: LiteralExpression, assumeTrue: boolean) {
if ((type.flags & (TypeFlags.Union | TypeFlags.Object)) || (type.flags & TypeFlags.TypeParameter && (type as TypeParameter).isThisType)) {
const propName = escapeLeadingUnderscores(literal.text);
return filterType(type, t => isTypePresencePossible(t, propName, assumeTrue));
}
return type;
}
function narrowTypeByBinaryExpression(type: Type, expr: BinaryExpression, assumeTrue: boolean): Type {
switch (expr.operatorToken.kind) {
case SyntaxKind.EqualsToken:
return narrowTypeByTruthiness(type, expr.left, assumeTrue);
case SyntaxKind.EqualsEqualsToken:
case SyntaxKind.ExclamationEqualsToken:
case SyntaxKind.EqualsEqualsEqualsToken:
case SyntaxKind.ExclamationEqualsEqualsToken:
const operator = expr.operatorToken.kind;
const left = getReferenceCandidate(expr.left);
const right = getReferenceCandidate(expr.right);
if (left.kind === SyntaxKind.TypeOfExpression && isStringLiteralLike(right)) {
return narrowTypeByTypeof(type, <TypeOfExpression>left, operator, right, assumeTrue);
}
if (right.kind === SyntaxKind.TypeOfExpression && isStringLiteralLike(left)) {
return narrowTypeByTypeof(type, <TypeOfExpression>right, operator, left, assumeTrue);
}
if (isMatchingReference(reference, left)) {
return narrowTypeByEquality(type, operator, right, assumeTrue);
}
if (isMatchingReference(reference, right)) {
return narrowTypeByEquality(type, operator, left, assumeTrue);
}
if (isMatchingReferenceDiscriminant(left, declaredType)) {
return narrowTypeByDiscriminant(type, <AccessExpression>left, t => narrowTypeByEquality(t, operator, right, assumeTrue));
}
if (isMatchingReferenceDiscriminant(right, declaredType)) {
return narrowTypeByDiscriminant(type, <AccessExpression>right, t => narrowTypeByEquality(t, operator, left, assumeTrue));
}
if (containsMatchingReferenceDiscriminant(reference, left) || containsMatchingReferenceDiscriminant(reference, right)) {
return declaredType;
}
break;
case SyntaxKind.InstanceOfKeyword:
return narrowTypeByInstanceof(type, expr, assumeTrue);
case SyntaxKind.InKeyword:
const target = getReferenceCandidate(expr.right);
if (isStringLiteralLike(expr.left) && isMatchingReference(reference, target)) {
return narrowByInKeyword(type, expr.left, assumeTrue);
}
break;
case SyntaxKind.CommaToken:
return narrowType(type, expr.right, assumeTrue);
}
return type;
}
function narrowTypeByEquality(type: Type, operator: SyntaxKind, value: Expression, assumeTrue: boolean): Type {
if (type.flags & TypeFlags.Any) {
return type;
}
if (operator === SyntaxKind.ExclamationEqualsToken || operator === SyntaxKind.ExclamationEqualsEqualsToken) {
assumeTrue = !assumeTrue;
}
const valueType = getTypeOfExpression(value);
if ((type.flags & TypeFlags.Unknown) && (operator === SyntaxKind.EqualsEqualsEqualsToken) && assumeTrue) {
if (valueType.flags & (TypeFlags.Primitive | TypeFlags.NonPrimitive)) {
return valueType;
}
if (valueType.flags & TypeFlags.Object) {
return nonPrimitiveType;
}
return type;
}
if (valueType.flags & TypeFlags.Nullable) {
if (!strictNullChecks) {
return type;
}
const doubleEquals = operator === SyntaxKind.EqualsEqualsToken || operator === SyntaxKind.ExclamationEqualsToken;
const facts = doubleEquals ?
assumeTrue ? TypeFacts.EQUndefinedOrNull : TypeFacts.NEUndefinedOrNull :
valueType.flags & TypeFlags.Null ?
assumeTrue ? TypeFacts.EQNull : TypeFacts.NENull :
assumeTrue ? TypeFacts.EQUndefined : TypeFacts.NEUndefined;
return getTypeWithFacts(type, facts);
}
if (type.flags & TypeFlags.NotUnionOrUnit) {
return type;
}
if (assumeTrue) {
const narrowedType = filterType(type, t => areTypesComparable(t, valueType));
return narrowedType.flags & TypeFlags.Never ? type : replacePrimitivesWithLiterals(narrowedType, valueType);
}
if (isUnitType(valueType)) {
const regularType = getRegularTypeOfLiteralType(valueType);
return filterType(type, t => getRegularTypeOfLiteralType(t) !== regularType);
}
return type;
}
function narrowTypeByTypeof(type: Type, typeOfExpr: TypeOfExpression, operator: SyntaxKind, literal: LiteralExpression, assumeTrue: boolean): Type {
// We have '==', '!=', '====', or !==' operator with 'typeof xxx' and string literal operands
const target = getReferenceCandidate(typeOfExpr.expression);
if (!isMatchingReference(reference, target)) {
// For a reference of the form 'x.y', a 'typeof x === ...' type guard resets the
// narrowed type of 'y' to its declared type.
if (containsMatchingReference(reference, target)) {
return declaredType;
}
return type;
}
if (operator === SyntaxKind.ExclamationEqualsToken || operator === SyntaxKind.ExclamationEqualsEqualsToken) {
assumeTrue = !assumeTrue;
}
if (type.flags & TypeFlags.Any && literal.text === "function") {
return type;
}
const facts = assumeTrue ?
typeofEQFacts.get(literal.text) || TypeFacts.TypeofEQHostObject :
typeofNEFacts.get(literal.text) || TypeFacts.TypeofNEHostObject;
return getTypeWithFacts(assumeTrue ? mapType(type, narrowTypeForTypeof) : type, facts);
function narrowTypeForTypeof(type: Type) {
if (type.flags & TypeFlags.Unknown && literal.text === "object") {
return getUnionType([nonPrimitiveType, nullType]);
}
// We narrow a non-union type to an exact primitive type if the non-union type
// is a supertype of that primitive type. For example, type 'any' can be narrowed
// to one of the primitive types.
const targetType = literal.text === "function" ? globalFunctionType : typeofTypesByName.get(literal.text);
if (targetType) {
if (isTypeSubtypeOf(type, targetType)) {
return type;
}
if (isTypeSubtypeOf(targetType, type)) {
return targetType;
}
if (type.flags & TypeFlags.Instantiable) {
const constraint = getBaseConstraintOfType(type) || anyType;
if (isTypeSubtypeOf(targetType, constraint)) {
return getIntersectionType([type, targetType]);
}
}
}
return type;
}
}
function narrowTypeBySwitchOnDiscriminant(type: Type, switchStatement: SwitchStatement, clauseStart: number, clauseEnd: number) {
// We only narrow if all case expressions specify
// values with unit types, except for the case where
// `type` is unknown. In this instance we map object
// types to the nonPrimitive type and narrow with that.
const switchTypes = getSwitchClauseTypes(switchStatement);
if (!switchTypes.length) {
return type;
}
const clauseTypes = switchTypes.slice(clauseStart, clauseEnd);
const hasDefaultClause = clauseStart === clauseEnd || contains(clauseTypes, neverType);
if ((type.flags & TypeFlags.Unknown) && !hasDefaultClause) {
let groundClauseTypes: Type[] | undefined;
for (let i = 0; i < clauseTypes.length; i += 1) {
const t = clauseTypes[i];
if (t.flags & (TypeFlags.Primitive | TypeFlags.NonPrimitive)) {
if (groundClauseTypes !== undefined) {
groundClauseTypes.push(t);
}
}
else if (t.flags & TypeFlags.Object) {
if (groundClauseTypes === undefined) {
groundClauseTypes = clauseTypes.slice(0, i);
}
groundClauseTypes.push(nonPrimitiveType);
}
else {
return type;
}
}
return getUnionType(groundClauseTypes === undefined ? clauseTypes : groundClauseTypes);
}
const discriminantType = getUnionType(clauseTypes);
const caseType =
discriminantType.flags & TypeFlags.Never ? neverType :
replacePrimitivesWithLiterals(filterType(type, t => areTypesComparable(discriminantType, t)), discriminantType);
if (!hasDefaultClause) {
return caseType;
}
const defaultType = filterType(type, t => !(isUnitType(t) && contains(switchTypes, getRegularTypeOfLiteralType(t))));
return caseType.flags & TypeFlags.Never ? defaultType : getUnionType([caseType, defaultType]);
}
function getImpliedTypeFromTypeofCase(type: Type, text: string) {
switch (text) {
case "function":
return type.flags & TypeFlags.Any ? type : globalFunctionType;
case "object":
return type.flags & TypeFlags.Unknown ? getUnionType([nonPrimitiveType, nullType]) : type;
default:
return typeofTypesByName.get(text) || type;
}
}
function narrowTypeForTypeofSwitch(candidate: Type) {
return (type: Type) => {
if (isTypeSubtypeOf(candidate, type)) {
return candidate;
}
if (type.flags & TypeFlags.Instantiable) {
const constraint = getBaseConstraintOfType(type) || anyType;
if (isTypeSubtypeOf(candidate, constraint)) {
return getIntersectionType([type, candidate]);
}
}
return type;
};
}
function narrowBySwitchOnTypeOf(type: Type, switchStatement: SwitchStatement, clauseStart: number, clauseEnd: number): Type {
const switchWitnesses = getSwitchClauseTypeOfWitnesses(switchStatement);
if (!switchWitnesses.length) {
return type;
}
// Equal start and end denotes implicit fallthrough; undefined marks explicit default clause
const defaultCaseLocation = findIndex(switchWitnesses, elem => elem === undefined);
const hasDefaultClause = clauseStart === clauseEnd || (defaultCaseLocation >= clauseStart && defaultCaseLocation < clauseEnd);
let clauseWitnesses: string[];
let switchFacts: TypeFacts;
if (defaultCaseLocation > -1) {
// We no longer need the undefined denoting an
// explicit default case. Remove the undefined and
// fix-up clauseStart and clauseEnd. This means
// that we don't have to worry about undefined
// in the witness array.
const witnesses = <string[]>switchWitnesses.filter(witness => witness !== undefined);
// The adjusted clause start and end after removing the `default` statement.
const fixedClauseStart = defaultCaseLocation < clauseStart ? clauseStart - 1 : clauseStart;
const fixedClauseEnd = defaultCaseLocation < clauseEnd ? clauseEnd - 1 : clauseEnd;
clauseWitnesses = witnesses.slice(fixedClauseStart, fixedClauseEnd);
switchFacts = getFactsFromTypeofSwitch(fixedClauseStart, fixedClauseEnd, witnesses, hasDefaultClause);
}
else {
clauseWitnesses = <string[]>switchWitnesses.slice(clauseStart, clauseEnd);
switchFacts = getFactsFromTypeofSwitch(clauseStart, clauseEnd, <string[]>switchWitnesses, hasDefaultClause);
}
if (hasDefaultClause) {
return filterType(type, t => (getTypeFacts(t) & switchFacts) === switchFacts);
}
/*
The implied type is the raw type suggested by a
value being caught in this clause.
When the clause contains a default case we ignore
the implied type and try to narrow using any facts
we can learn: see `switchFacts`.
Example:
switch (typeof x) {
case 'number':
case 'string': break;
default: break;
case 'number':
case 'boolean': break
}
In the first clause (case `number` and `string`) the
implied type is number | string.
In the default clause we de not compute an implied type.
In the third clause (case `number` and `boolean`)
the naive implied type is number | boolean, however
we use the type facts to narrow the implied type to
boolean. We know that number cannot be selected
because it is caught in the first clause.
*/
let impliedType = getTypeWithFacts(getUnionType(clauseWitnesses.map(text => getImpliedTypeFromTypeofCase(type, text))), switchFacts);
if (impliedType.flags & TypeFlags.Union) {
impliedType = getAssignmentReducedType(impliedType as UnionType, getBaseConstraintOrType(type));
}
return getTypeWithFacts(mapType(type, narrowTypeForTypeofSwitch(impliedType)), switchFacts);
}
function narrowTypeByInstanceof(type: Type, expr: BinaryExpression, assumeTrue: boolean): Type {
const left = getReferenceCandidate(expr.left);
if (!isMatchingReference(reference, left)) {
// For a reference of the form 'x.y', an 'x instanceof T' type guard resets the
// narrowed type of 'y' to its declared type. We do this because preceding 'x.y'
// references might reference a different 'y' property. However, we make an exception
// for property accesses where x is a synthetic 'this' expression, indicating that we
// were called from isPropertyInitializedInConstructor. Without this exception,
// initializations of 'this' properties that occur before a 'this instanceof XXX'
// check would not be considered.
if (containsMatchingReference(reference, left) && !isSyntheticThisPropertyAccess(reference)) {
return declaredType;
}
return type;
}
// Check that right operand is a function type with a prototype property
const rightType = getTypeOfExpression(expr.right);
if (!isTypeDerivedFrom(rightType, globalFunctionType)) {
return type;
}
let targetType: Type | undefined;
const prototypeProperty = getPropertyOfType(rightType, "prototype" as __String);
if (prototypeProperty) {
// Target type is type of the prototype property
const prototypePropertyType = getTypeOfSymbol(prototypeProperty);
if (!isTypeAny(prototypePropertyType)) {
targetType = prototypePropertyType;
}
}
// Don't narrow from 'any' if the target type is exactly 'Object' or 'Function'
if (isTypeAny(type) && (targetType === globalObjectType || targetType === globalFunctionType)) {
return type;
}
if (!targetType) {
const constructSignatures = getSignaturesOfType(rightType, SignatureKind.Construct);
targetType = constructSignatures.length ?
getUnionType(map(constructSignatures, signature => getReturnTypeOfSignature(getErasedSignature(signature)))) :
emptyObjectType;
}
return getNarrowedType(type, targetType, assumeTrue, isTypeDerivedFrom);
}
function getNarrowedType(type: Type, candidate: Type, assumeTrue: boolean, isRelated: (source: Type, target: Type) => boolean) {
if (!assumeTrue) {
return filterType(type, t => !isRelated(t, candidate));
}
// If the current type is a union type, remove all constituents that couldn't be instances of
// the candidate type. If one or more constituents remain, return a union of those.
if (type.flags & TypeFlags.Union) {
const assignableType = filterType(type, t => isRelated(t, candidate));
if (!(assignableType.flags & TypeFlags.Never)) {
return assignableType;
}
}
// If the candidate type is a subtype of the target type, narrow to the candidate type.
// Otherwise, if the target type is assignable to the candidate type, keep the target type.
// Otherwise, if the candidate type is assignable to the target type, narrow to the candidate
// type. Otherwise, the types are completely unrelated, so narrow to an intersection of the
// two types.
return isTypeSubtypeOf(candidate, type) ? candidate :
isTypeAssignableTo(type, candidate) ? type :
isTypeAssignableTo(candidate, type) ? candidate :
getIntersectionType([type, candidate]);
}
function narrowTypeByTypePredicate(type: Type, callExpression: CallExpression, assumeTrue: boolean): Type {
if (!hasMatchingArgument(callExpression, reference) || !maybeTypePredicateCall(callExpression)) {
return type;
}
const signature = getResolvedSignature(callExpression);
const predicate = getTypePredicateOfSignature(signature);
if (!predicate) {
return type;
}
// Don't narrow from 'any' if the predicate type is exactly 'Object' or 'Function'
if (isTypeAny(type) && (predicate.type === globalObjectType || predicate.type === globalFunctionType)) {
return type;
}
if (isIdentifierTypePredicate(predicate)) {
const predicateArgument = callExpression.arguments[predicate.parameterIndex - (signature.thisParameter ? 1 : 0)];
if (predicateArgument) {
if (isMatchingReference(reference, predicateArgument)) {
return getNarrowedType(type, predicate.type, assumeTrue, isTypeSubtypeOf);
}
if (containsMatchingReference(reference, predicateArgument)) {
return declaredType;
}
}
}
else {
const invokedExpression = skipParentheses(callExpression.expression);
if (isAccessExpression(invokedExpression)) {
const possibleReference = skipParentheses(invokedExpression.expression);
if (isMatchingReference(reference, possibleReference)) {
return getNarrowedType(type, predicate.type, assumeTrue, isTypeSubtypeOf);
}
if (containsMatchingReference(reference, possibleReference)) {
return declaredType;
}
}
}
return type;
}
// Narrow the given type based on the given expression having the assumed boolean value. The returned type
// will be a subtype or the same type as the argument.
function narrowType(type: Type, expr: Expression, assumeTrue: boolean): Type {
switch (expr.kind) {
case SyntaxKind.Identifier:
case SyntaxKind.ThisKeyword:
case SyntaxKind.SuperKeyword:
case SyntaxKind.PropertyAccessExpression:
case SyntaxKind.ElementAccessExpression:
return narrowTypeByTruthiness(type, expr, assumeTrue);
case SyntaxKind.CallExpression:
return narrowTypeByTypePredicate(type, <CallExpression>expr, assumeTrue);
case SyntaxKind.ParenthesizedExpression:
return narrowType(type, (<ParenthesizedExpression>expr).expression, assumeTrue);
case SyntaxKind.BinaryExpression:
return narrowTypeByBinaryExpression(type, <BinaryExpression>expr, assumeTrue);
case SyntaxKind.PrefixUnaryExpression:
if ((<PrefixUnaryExpression>expr).operator === SyntaxKind.ExclamationToken) {
return narrowType(type, (<PrefixUnaryExpression>expr).operand, !assumeTrue);
}
break;
}
return type;
}
}
function getTypeOfSymbolAtLocation(symbol: Symbol, location: Node) {
symbol = symbol.exportSymbol || symbol;
// If we have an identifier or a property access at the given location, if the location is
// an dotted name expression, and if the location is not an assignment target, obtain the type
// of the expression (which will reflect control flow analysis). If the expression indeed
// resolved to the given symbol, return the narrowed type.
if (location.kind === SyntaxKind.Identifier) {
if (isRightSideOfQualifiedNameOrPropertyAccess(location)) {
location = location.parent;
}
if (isExpressionNode(location) && !isAssignmentTarget(location)) {
const type = getTypeOfExpression(<Expression>location);
if (getExportSymbolOfValueSymbolIfExported(getNodeLinks(location).resolvedSymbol) === symbol) {
return type;
}
}
}
// The location isn't a reference to the given symbol, meaning we're being asked
// a hypothetical question of what type the symbol would have if there was a reference
// to it at the given location. Since we have no control flow information for the
// hypothetical reference (control flow information is created and attached by the
// binder), we simply return the declared type of the symbol.
return getTypeOfSymbol(symbol);
}
function getControlFlowContainer(node: Node): Node {
return findAncestor(node.parent, node =>
isFunctionLike(node) && !getImmediatelyInvokedFunctionExpression(node) ||
node.kind === SyntaxKind.ModuleBlock ||
node.kind === SyntaxKind.SourceFile ||
node.kind === SyntaxKind.PropertyDeclaration)!;
}
// Check if a parameter is assigned anywhere within its declaring function.
function isParameterAssigned(symbol: Symbol) {
const func = <FunctionLikeDeclaration>getRootDeclaration(symbol.valueDeclaration).parent;
const links = getNodeLinks(func);
if (!(links.flags & NodeCheckFlags.AssignmentsMarked)) {
links.flags |= NodeCheckFlags.AssignmentsMarked;
if (!hasParentWithAssignmentsMarked(func)) {
markParameterAssignments(func);
}
}
return symbol.isAssigned || false;
}
function hasParentWithAssignmentsMarked(node: Node) {
return !!findAncestor(node.parent, node => isFunctionLike(node) && !!(getNodeLinks(node).flags & NodeCheckFlags.AssignmentsMarked));
}
function markParameterAssignments(node: Node) {
if (node.kind === SyntaxKind.Identifier) {
if (isAssignmentTarget(node)) {
const symbol = getResolvedSymbol(<Identifier>node);
if (symbol.valueDeclaration && getRootDeclaration(symbol.valueDeclaration).kind === SyntaxKind.Parameter) {
symbol.isAssigned = true;
}
}
}
else {
forEachChild(node, markParameterAssignments);
}
}
function isConstVariable(symbol: Symbol) {
return symbol.flags & SymbolFlags.Variable && (getDeclarationNodeFlagsFromSymbol(symbol) & NodeFlags.Const) !== 0 && getTypeOfSymbol(symbol) !== autoArrayType;
}
/** remove undefined from the annotated type of a parameter when there is an initializer (that doesn't include undefined) */
function removeOptionalityFromDeclaredType(declaredType: Type, declaration: VariableLikeDeclaration): Type {
const annotationIncludesUndefined = strictNullChecks &&
declaration.kind === SyntaxKind.Parameter &&
declaration.initializer &&
getFalsyFlags(declaredType) & TypeFlags.Undefined &&
!(getFalsyFlags(checkExpression(declaration.initializer)) & TypeFlags.Undefined);
return annotationIncludesUndefined ? getTypeWithFacts(declaredType, TypeFacts.NEUndefined) : declaredType;
}
function isConstraintPosition(node: Node) {
const parent = node.parent;
return parent.kind === SyntaxKind.PropertyAccessExpression ||
parent.kind === SyntaxKind.CallExpression && (<CallExpression>parent).expression === node ||
parent.kind === SyntaxKind.ElementAccessExpression && (<ElementAccessExpression>parent).expression === node ||
parent.kind === SyntaxKind.BindingElement && (<BindingElement>parent).name === node && !!(<BindingElement>parent).initializer;
}
function typeHasNullableConstraint(type: Type) {
return type.flags & TypeFlags.InstantiableNonPrimitive && maybeTypeOfKind(getBaseConstraintOfType(type) || emptyObjectType, TypeFlags.Nullable);
}
function getConstraintForLocation(type: Type, node: Node): Type;
function getConstraintForLocation(type: Type | undefined, node: Node): Type | undefined;
function getConstraintForLocation(type: Type, node: Node): Type | undefined {
// When a node is the left hand expression of a property access, element access, or call expression,
// and the type of the node includes type variables with constraints that are nullable, we fetch the
// apparent type of the node *before* performing control flow analysis such that narrowings apply to
// the constraint type.
if (type && isConstraintPosition(node) && forEachType(type, typeHasNullableConstraint)) {
return mapType(getWidenedType(type), getBaseConstraintOrType);
}
return type;
}
function markAliasReferenced(symbol: Symbol, location: Node) {
if (isNonLocalAlias(symbol, /*excludes*/ SymbolFlags.Value) && !isInTypeQuery(location) && !isConstEnumOrConstEnumOnlyModule(resolveAlias(symbol))) {
markAliasSymbolAsReferenced(symbol);
}
}
function checkIdentifier(node: Identifier): Type {
const symbol = getResolvedSymbol(node);
if (symbol === unknownSymbol) {
return errorType;
}
// As noted in ECMAScript 6 language spec, arrow functions never have an arguments objects.
// Although in down-level emit of arrow function, we emit it using function expression which means that
// arguments objects will be bound to the inner object; emitting arrow function natively in ES6, arguments objects
// will be bound to non-arrow function that contain this arrow function. This results in inconsistent behavior.
// To avoid that we will give an error to users if they use arguments objects in arrow function so that they
// can explicitly bound arguments objects
if (symbol === argumentsSymbol) {
const container = getContainingFunction(node)!;
if (languageVersion < ScriptTarget.ES2015) {
if (container.kind === SyntaxKind.ArrowFunction) {
error(node, Diagnostics.The_arguments_object_cannot_be_referenced_in_an_arrow_function_in_ES3_and_ES5_Consider_using_a_standard_function_expression);
}
else if (hasModifier(container, ModifierFlags.Async)) {
error(node, Diagnostics.The_arguments_object_cannot_be_referenced_in_an_async_function_or_method_in_ES3_and_ES5_Consider_using_a_standard_function_or_method);
}
}
getNodeLinks(container).flags |= NodeCheckFlags.CaptureArguments;
return getTypeOfSymbol(symbol);
}
// We should only mark aliases as referenced if there isn't a local value declaration
// for the symbol. Also, don't mark any property access expression LHS - checkPropertyAccessExpression will handle that
if (!(node.parent && isPropertyAccessExpression(node.parent) && node.parent.expression === node)) {
markAliasReferenced(symbol, node);
}
const localOrExportSymbol = getExportSymbolOfValueSymbolIfExported(symbol);
let declaration: Declaration | undefined = localOrExportSymbol.valueDeclaration;
if (localOrExportSymbol.flags & SymbolFlags.Class) {
// Due to the emit for class decorators, any reference to the class from inside of the class body
// must instead be rewritten to point to a temporary variable to avoid issues with the double-bind
// behavior of class names in ES6.
if (declaration.kind === SyntaxKind.ClassDeclaration
&& nodeIsDecorated(declaration as ClassDeclaration)) {
let container = getContainingClass(node);
while (container !== undefined) {
if (container === declaration && container.name !== node) {
getNodeLinks(declaration).flags |= NodeCheckFlags.ClassWithConstructorReference;
getNodeLinks(node).flags |= NodeCheckFlags.ConstructorReferenceInClass;
break;
}
container = getContainingClass(container);
}
}
else if (declaration.kind === SyntaxKind.ClassExpression) {
// When we emit a class expression with static members that contain a reference
// to the constructor in the initializer, we will need to substitute that
// binding with an alias as the class name is not in scope.
let container = getThisContainer(node, /*includeArrowFunctions*/ false);
while (container.kind !== SyntaxKind.SourceFile) {
if (container.parent === declaration) {
if (container.kind === SyntaxKind.PropertyDeclaration && hasModifier(container, ModifierFlags.Static)) {
getNodeLinks(declaration).flags |= NodeCheckFlags.ClassWithConstructorReference;
getNodeLinks(node).flags |= NodeCheckFlags.ConstructorReferenceInClass;
}
break;
}
container = getThisContainer(container, /*includeArrowFunctions*/ false);
}
}
}
checkNestedBlockScopedBinding(node, symbol);
const type = getConstraintForLocation(getTypeOfSymbol(localOrExportSymbol), node);
const assignmentKind = getAssignmentTargetKind(node);
if (assignmentKind) {
if (!(localOrExportSymbol.flags & SymbolFlags.Variable) &&
!(isInJSFile(node) && localOrExportSymbol.flags & SymbolFlags.ValueModule)) {
error(node, Diagnostics.Cannot_assign_to_0_because_it_is_not_a_variable, symbolToString(symbol));
return errorType;
}
if (isReadonlySymbol(localOrExportSymbol)) {
if (localOrExportSymbol.flags & SymbolFlags.Variable) {
error(node, Diagnostics.Cannot_assign_to_0_because_it_is_a_constant, symbolToString(symbol));
}
else {
error(node, Diagnostics.Cannot_assign_to_0_because_it_is_a_read_only_property, symbolToString(symbol));
}
return errorType;
}
}
const isAlias = localOrExportSymbol.flags & SymbolFlags.Alias;
// We only narrow variables and parameters occurring in a non-assignment position. For all other
// entities we simply return the declared type.
if (localOrExportSymbol.flags & SymbolFlags.Variable) {
if (assignmentKind === AssignmentKind.Definite) {
return type;
}
}
else if (isAlias) {
declaration = find<Declaration>(symbol.declarations, isSomeImportDeclaration);
}
else {
return type;
}
if (!declaration) {
return type;
}
// The declaration container is the innermost function that encloses the declaration of the variable
// or parameter. The flow container is the innermost function starting with which we analyze the control
// flow graph to determine the control flow based type.
const isParameter = getRootDeclaration(declaration).kind === SyntaxKind.Parameter;
const declarationContainer = getControlFlowContainer(declaration);
let flowContainer = getControlFlowContainer(node);
const isOuterVariable = flowContainer !== declarationContainer;
const isSpreadDestructuringAssignmentTarget = node.parent && node.parent.parent && isSpreadAssignment(node.parent) && isDestructuringAssignmentTarget(node.parent.parent);
const isModuleExports = symbol.flags & SymbolFlags.ModuleExports;
// When the control flow originates in a function expression or arrow function and we are referencing
// a const variable or parameter from an outer function, we extend the origin of the control flow
// analysis to include the immediately enclosing function.
while (flowContainer !== declarationContainer && (flowContainer.kind === SyntaxKind.FunctionExpression ||
flowContainer.kind === SyntaxKind.ArrowFunction || isObjectLiteralOrClassExpressionMethod(flowContainer)) &&
(isConstVariable(localOrExportSymbol) || isParameter && !isParameterAssigned(localOrExportSymbol))) {
flowContainer = getControlFlowContainer(flowContainer);
}
// We only look for uninitialized variables in strict null checking mode, and only when we can analyze
// the entire control flow graph from the variable's declaration (i.e. when the flow container and
// declaration container are the same).
const assumeInitialized = isParameter || isAlias || isOuterVariable || isSpreadDestructuringAssignmentTarget || isModuleExports ||
type !== autoType && type !== autoArrayType && (!strictNullChecks || (type.flags & TypeFlags.AnyOrUnknown) !== 0 ||
isInTypeQuery(node) || node.parent.kind === SyntaxKind.ExportSpecifier) ||
node.parent.kind === SyntaxKind.NonNullExpression ||
declaration.kind === SyntaxKind.VariableDeclaration && (<VariableDeclaration>declaration).exclamationToken ||
declaration.flags & NodeFlags.Ambient;
const initialType = assumeInitialized ? (isParameter ? removeOptionalityFromDeclaredType(type, declaration as VariableLikeDeclaration) : type) :
type === autoType || type === autoArrayType ? undefinedType :
getOptionalType(type);
const flowType = getFlowTypeOfReference(node, type, initialType, flowContainer, !assumeInitialized);
// A variable is considered uninitialized when it is possible to analyze the entire control flow graph
// from declaration to use, and when the variable's declared type doesn't include undefined but the
// control flow based type does include undefined.
if (!isEvolvingArrayOperationTarget(node) && (type === autoType || type === autoArrayType)) {
if (flowType === autoType || flowType === autoArrayType) {
if (noImplicitAny) {
error(getNameOfDeclaration(declaration), Diagnostics.Variable_0_implicitly_has_type_1_in_some_locations_where_its_type_cannot_be_determined, symbolToString(symbol), typeToString(flowType));
error(node, Diagnostics.Variable_0_implicitly_has_an_1_type, symbolToString(symbol), typeToString(flowType));
}
return convertAutoToAny(flowType);
}
}
else if (!assumeInitialized && !(getFalsyFlags(type) & TypeFlags.Undefined) && getFalsyFlags(flowType) & TypeFlags.Undefined) {
error(node, Diagnostics.Variable_0_is_used_before_being_assigned, symbolToString(symbol));
// Return the declared type to reduce follow-on errors
return type;
}
return assignmentKind ? getBaseTypeOfLiteralType(flowType) : flowType;
}
function isInsideFunction(node: Node, threshold: Node): boolean {
return !!findAncestor(node, n => n === threshold ? "quit" : isFunctionLike(n));
}
function getPartOfForStatementContainingNode(node: Node, container: ForStatement) {
return findAncestor(node, n => n === container ? "quit" : n === container.initializer || n === container.condition || n === container.incrementor || n === container.statement);
}
function checkNestedBlockScopedBinding(node: Identifier, symbol: Symbol): void {
if (languageVersion >= ScriptTarget.ES2015 ||
(symbol.flags & (SymbolFlags.BlockScopedVariable | SymbolFlags.Class)) === 0 ||
symbol.valueDeclaration.parent.kind === SyntaxKind.CatchClause) {
return;
}
// 1. walk from the use site up to the declaration and check
// if there is anything function like between declaration and use-site (is binding/class is captured in function).
// 2. walk from the declaration up to the boundary of lexical environment and check
// if there is an iteration statement in between declaration and boundary (is binding/class declared inside iteration statement)
const container = getEnclosingBlockScopeContainer(symbol.valueDeclaration);
const usedInFunction = isInsideFunction(node.parent, container);
let current = container;
let containedInIterationStatement = false;
while (current && !nodeStartsNewLexicalEnvironment(current)) {
if (isIterationStatement(current, /*lookInLabeledStatements*/ false)) {
containedInIterationStatement = true;
break;
}
current = current.parent;
}
if (containedInIterationStatement) {
if (usedInFunction) {
// mark iteration statement as containing block-scoped binding captured in some function
let capturesBlockScopeBindingInLoopBody = true;
if (isForStatement(container) &&
getAncestor(symbol.valueDeclaration, SyntaxKind.VariableDeclarationList)!.parent === container) {
const part = getPartOfForStatementContainingNode(node.parent, container);
if (part) {
const links = getNodeLinks(part);
links.flags |= NodeCheckFlags.ContainsCapturedBlockScopeBinding;
const capturedBindings = links.capturedBlockScopeBindings || (links.capturedBlockScopeBindings = []);
pushIfUnique(capturedBindings, symbol);
if (part === container.initializer) {
capturesBlockScopeBindingInLoopBody = false; // Initializer is outside of loop body
}
}
}
if (capturesBlockScopeBindingInLoopBody) {
getNodeLinks(current).flags |= NodeCheckFlags.LoopWithCapturedBlockScopedBinding;
}
}
// mark variables that are declared in loop initializer and reassigned inside the body of ForStatement.
// if body of ForStatement will be converted to function then we'll need a extra machinery to propagate reassigned values back.
if (container.kind === SyntaxKind.ForStatement &&
getAncestor(symbol.valueDeclaration, SyntaxKind.VariableDeclarationList)!.parent === container &&
isAssignedInBodyOfForStatement(node, <ForStatement>container)) {
getNodeLinks(symbol.valueDeclaration).flags |= NodeCheckFlags.NeedsLoopOutParameter;
}
// set 'declared inside loop' bit on the block-scoped binding
getNodeLinks(symbol.valueDeclaration).flags |= NodeCheckFlags.BlockScopedBindingInLoop;
}
if (usedInFunction) {
getNodeLinks(symbol.valueDeclaration).flags |= NodeCheckFlags.CapturedBlockScopedBinding;
}
}
function isBindingCapturedByNode(node: Node, decl: VariableDeclaration | BindingElement) {
const links = getNodeLinks(node);
return !!links && contains(links.capturedBlockScopeBindings, getSymbolOfNode(decl));
}
function isAssignedInBodyOfForStatement(node: Identifier, container: ForStatement): boolean {
// skip parenthesized nodes
let current: Node = node;
while (current.parent.kind === SyntaxKind.ParenthesizedExpression) {
current = current.parent;
}
// check if node is used as LHS in some assignment expression
let isAssigned = false;
if (isAssignmentTarget(current)) {
isAssigned = true;
}
else if ((current.parent.kind === SyntaxKind.PrefixUnaryExpression || current.parent.kind === SyntaxKind.PostfixUnaryExpression)) {
const expr = <PrefixUnaryExpression | PostfixUnaryExpression>current.parent;
isAssigned = expr.operator === SyntaxKind.PlusPlusToken || expr.operator === SyntaxKind.MinusMinusToken;
}
if (!isAssigned) {
return false;
}
// at this point we know that node is the target of assignment
// now check that modification happens inside the statement part of the ForStatement
return !!findAncestor(current, n => n === container ? "quit" : n === container.statement);
}
function captureLexicalThis(node: Node, container: Node): void {
getNodeLinks(node).flags |= NodeCheckFlags.LexicalThis;
if (container.kind === SyntaxKind.PropertyDeclaration || container.kind === SyntaxKind.Constructor) {
const classNode = container.parent;
getNodeLinks(classNode).flags |= NodeCheckFlags.CaptureThis;
}
else {
getNodeLinks(container).flags |= NodeCheckFlags.CaptureThis;
}
}
function findFirstSuperCall(n: Node): SuperCall | undefined {
if (isSuperCall(n)) {
return n;
}
else if (isFunctionLike(n)) {
return undefined;
}
return forEachChild(n, findFirstSuperCall);
}
/**
* Return a cached result if super-statement is already found.
* Otherwise, find a super statement in a given constructor function and cache the result in the node-links of the constructor
*
* @param constructor constructor-function to look for super statement
*/
function getSuperCallInConstructor(constructor: ConstructorDeclaration): SuperCall | undefined {
const links = getNodeLinks(constructor);
// Only trying to find super-call if we haven't yet tried to find one. Once we try, we will record the result
if (links.hasSuperCall === undefined) {
links.superCall = findFirstSuperCall(constructor.body!);
links.hasSuperCall = links.superCall ? true : false;
}
return links.superCall!;
}
/**
* Check if the given class-declaration extends null then return true.
* Otherwise, return false
* @param classDecl a class declaration to check if it extends null
*/
function classDeclarationExtendsNull(classDecl: ClassDeclaration): boolean {
const classSymbol = getSymbolOfNode(classDecl);
const classInstanceType = <InterfaceType>getDeclaredTypeOfSymbol(classSymbol);
const baseConstructorType = getBaseConstructorTypeOfClass(classInstanceType);
return baseConstructorType === nullWideningType;
}
function checkThisBeforeSuper(node: Node, container: Node, diagnosticMessage: DiagnosticMessage) {
const containingClassDecl = <ClassDeclaration>container.parent;
const baseTypeNode = getClassExtendsHeritageElement(containingClassDecl);
// If a containing class does not have extends clause or the class extends null
// skip checking whether super statement is called before "this" accessing.
if (baseTypeNode && !classDeclarationExtendsNull(containingClassDecl)) {
const superCall = getSuperCallInConstructor(<ConstructorDeclaration>container);
// We should give an error in the following cases:
// - No super-call
// - "this" is accessing before super-call.
// i.e super(this)
// this.x; super();
// We want to make sure that super-call is done before accessing "this" so that
// "this" is not accessed as a parameter of the super-call.
if (!superCall || superCall.end > node.pos) {
// In ES6, super inside constructor of class-declaration has to precede "this" accessing
error(node, diagnosticMessage);
}
}
}
function checkThisExpression(node: Node): Type {
// Stop at the first arrow function so that we can
// tell whether 'this' needs to be captured.
let container = getThisContainer(node, /* includeArrowFunctions */ true);
let capturedByArrowFunction = false;
if (container.kind === SyntaxKind.Constructor) {
checkThisBeforeSuper(node, container, Diagnostics.super_must_be_called_before_accessing_this_in_the_constructor_of_a_derived_class);
}
// Now skip arrow functions to get the "real" owner of 'this'.
if (container.kind === SyntaxKind.ArrowFunction) {
container = getThisContainer(container, /* includeArrowFunctions */ false);
capturedByArrowFunction = true;
}
switch (container.kind) {
case SyntaxKind.ModuleDeclaration:
error(node, Diagnostics.this_cannot_be_referenced_in_a_module_or_namespace_body);
// do not return here so in case if lexical this is captured - it will be reflected in flags on NodeLinks
break;
case SyntaxKind.EnumDeclaration:
error(node, Diagnostics.this_cannot_be_referenced_in_current_location);
// do not return here so in case if lexical this is captured - it will be reflected in flags on NodeLinks
break;
case SyntaxKind.Constructor:
if (isInConstructorArgumentInitializer(node, container)) {
error(node, Diagnostics.this_cannot_be_referenced_in_constructor_arguments);
// do not return here so in case if lexical this is captured - it will be reflected in flags on NodeLinks
}
break;
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.PropertySignature:
if (hasModifier(container, ModifierFlags.Static)) {
error(node, Diagnostics.this_cannot_be_referenced_in_a_static_property_initializer);
// do not return here so in case if lexical this is captured - it will be reflected in flags on NodeLinks
}
break;
case SyntaxKind.ComputedPropertyName:
error(node, Diagnostics.this_cannot_be_referenced_in_a_computed_property_name);
break;
}
// When targeting es6, mark that we'll need to capture `this` in its lexically bound scope.
if (capturedByArrowFunction && languageVersion < ScriptTarget.ES2015) {
captureLexicalThis(node, container);
}
const type = tryGetThisTypeAt(node, /*includeGlobalThis*/ true, container);
if (noImplicitThis) {
const globalThisType = getTypeOfSymbol(globalThisSymbol);
if (type === globalThisType && capturedByArrowFunction) {
error(node, Diagnostics.The_containing_arrow_function_captures_the_global_value_of_this);
}
else if (!type) {
// With noImplicitThis, functions may not reference 'this' if it has type 'any'
const diag = error(node, Diagnostics.this_implicitly_has_type_any_because_it_does_not_have_a_type_annotation);
if (!isSourceFile(container)) {
const outsideThis = tryGetThisTypeAt(container);
if (outsideThis && outsideThis !== globalThisType) {
addRelatedInfo(diag, createDiagnosticForNode(container, Diagnostics.An_outer_value_of_this_is_shadowed_by_this_container));
}
}
}
}
return type || anyType;
}
function tryGetThisTypeAt(node: Node, includeGlobalThis = true, container = getThisContainer(node, /*includeArrowFunctions*/ false)): Type | undefined {
const isInJS = isInJSFile(node);
if (isFunctionLike(container) &&
(!isInParameterInitializerBeforeContainingFunction(node) || getThisParameter(container))) {
// Note: a parameter initializer should refer to class-this unless function-this is explicitly annotated.
// If this is a function in a JS file, it might be a class method.
const className = getClassNameFromPrototypeMethod(container);
if (isInJS && className) {
const classSymbol = checkExpression(className).symbol;
if (classSymbol && classSymbol.members && (classSymbol.flags & SymbolFlags.Function)) {
const classType = getJSClassType(classSymbol);
if (classType) {
return getFlowTypeOfReference(node, classType);
}
}
}
// Check if it's a constructor definition, can be either a variable decl or function decl
// i.e.
// * /** @constructor */ function [name]() { ... }
// * /** @constructor */ var x = function() { ... }
else if (isInJS &&
(container.kind === SyntaxKind.FunctionExpression || container.kind === SyntaxKind.FunctionDeclaration) &&
getJSDocClassTag(container)) {
const classType = getJSClassType(getMergedSymbol(container.symbol));
if (classType) {
return getFlowTypeOfReference(node, classType);
}
}
const thisType = getThisTypeOfDeclaration(container) || getContextualThisParameterType(container);
if (thisType) {
return getFlowTypeOfReference(node, thisType);
}
}
if (isClassLike(container.parent)) {
const symbol = getSymbolOfNode(container.parent);
const type = hasModifier(container, ModifierFlags.Static) ? getTypeOfSymbol(symbol) : (<InterfaceType>getDeclaredTypeOfSymbol(symbol)).thisType!;
return getFlowTypeOfReference(node, type);
}
if (isInJS) {
const type = getTypeForThisExpressionFromJSDoc(container);
if (type && type !== errorType) {
return getFlowTypeOfReference(node, type);
}
}
if (isSourceFile(container)) {
// look up in the source file's locals or exports
if (container.commonJsModuleIndicator) {
const fileSymbol = getSymbolOfNode(container);
return fileSymbol && getTypeOfSymbol(fileSymbol);
}
else if (includeGlobalThis) {
return getTypeOfSymbol(globalThisSymbol);
}
}
}
function getClassNameFromPrototypeMethod(container: Node) {
// Check if it's the RHS of a x.prototype.y = function [name]() { .... }
if (container.kind === SyntaxKind.FunctionExpression &&
isBinaryExpression(container.parent) &&
getAssignmentDeclarationKind(container.parent) === AssignmentDeclarationKind.PrototypeProperty) {
// Get the 'x' of 'x.prototype.y = container'
return ((container.parent // x.prototype.y = container
.left as PropertyAccessExpression) // x.prototype.y
.expression as PropertyAccessExpression) // x.prototype
.expression; // x
}
// x.prototype = { method() { } }
else if (container.kind === SyntaxKind.MethodDeclaration &&
container.parent.kind === SyntaxKind.ObjectLiteralExpression &&
isBinaryExpression(container.parent.parent) &&
getAssignmentDeclarationKind(container.parent.parent) === AssignmentDeclarationKind.Prototype) {
return (container.parent.parent.left as PropertyAccessExpression).expression;
}
// x.prototype = { method: function() { } }
else if (container.kind === SyntaxKind.FunctionExpression &&
container.parent.kind === SyntaxKind.PropertyAssignment &&
container.parent.parent.kind === SyntaxKind.ObjectLiteralExpression &&
isBinaryExpression(container.parent.parent.parent) &&
getAssignmentDeclarationKind(container.parent.parent.parent) === AssignmentDeclarationKind.Prototype) {
return (container.parent.parent.parent.left as PropertyAccessExpression).expression;
}
// Object.defineProperty(x, "method", { value: function() { } });
// Object.defineProperty(x, "method", { set: (x: () => void) => void });
// Object.defineProperty(x, "method", { get: () => function() { }) });
else if (container.kind === SyntaxKind.FunctionExpression &&
isPropertyAssignment(container.parent) &&
isIdentifier(container.parent.name) &&
(container.parent.name.escapedText === "value" || container.parent.name.escapedText === "get" || container.parent.name.escapedText === "set") &&
isObjectLiteralExpression(container.parent.parent) &&
isCallExpression(container.parent.parent.parent) &&
container.parent.parent.parent.arguments[2] === container.parent.parent &&
getAssignmentDeclarationKind(container.parent.parent.parent) === AssignmentDeclarationKind.ObjectDefinePrototypeProperty) {
return (container.parent.parent.parent.arguments[0] as PropertyAccessExpression).expression;
}
// Object.defineProperty(x, "method", { value() { } });
// Object.defineProperty(x, "method", { set(x: () => void) {} });
// Object.defineProperty(x, "method", { get() { return () => {} } });
else if (isMethodDeclaration(container) &&
isIdentifier(container.name) &&
(container.name.escapedText === "value" || container.name.escapedText === "get" || container.name.escapedText === "set") &&
isObjectLiteralExpression(container.parent) &&
isCallExpression(container.parent.parent) &&
container.parent.parent.arguments[2] === container.parent &&
getAssignmentDeclarationKind(container.parent.parent) === AssignmentDeclarationKind.ObjectDefinePrototypeProperty) {
return (container.parent.parent.arguments[0] as PropertyAccessExpression).expression;
}
}
function getTypeForThisExpressionFromJSDoc(node: Node) {
const jsdocType = getJSDocType(node);
if (jsdocType && jsdocType.kind === SyntaxKind.JSDocFunctionType) {
const jsDocFunctionType = <JSDocFunctionType>jsdocType;
if (jsDocFunctionType.parameters.length > 0 &&
jsDocFunctionType.parameters[0].name &&
(jsDocFunctionType.parameters[0].name as Identifier).escapedText === InternalSymbolName.This) {
return getTypeFromTypeNode(jsDocFunctionType.parameters[0].type!);
}
}
const thisTag = getJSDocThisTag(node);
if (thisTag && thisTag.typeExpression) {
return getTypeFromTypeNode(thisTag.typeExpression);
}
}
function isInConstructorArgumentInitializer(node: Node, constructorDecl: Node): boolean {
return !!findAncestor(node, n => isFunctionLikeDeclaration(n) ? "quit" : n.kind === SyntaxKind.Parameter && n.parent === constructorDecl);
}
function checkSuperExpression(node: Node): Type {
const isCallExpression = node.parent.kind === SyntaxKind.CallExpression && (<CallExpression>node.parent).expression === node;
let container = getSuperContainer(node, /*stopOnFunctions*/ true);
let needToCaptureLexicalThis = false;
// adjust the container reference in case if super is used inside arrow functions with arbitrarily deep nesting
if (!isCallExpression) {
while (container && container.kind === SyntaxKind.ArrowFunction) {
container = getSuperContainer(container, /*stopOnFunctions*/ true);
needToCaptureLexicalThis = languageVersion < ScriptTarget.ES2015;
}
}
const canUseSuperExpression = isLegalUsageOfSuperExpression(container);
let nodeCheckFlag: NodeCheckFlags = 0;
if (!canUseSuperExpression) {
// issue more specific error if super is used in computed property name
// class A { foo() { return "1" }}
// class B {
// [super.foo()]() {}
// }
const current = findAncestor(node, n => n === container ? "quit" : n.kind === SyntaxKind.ComputedPropertyName);
if (current && current.kind === SyntaxKind.ComputedPropertyName) {
error(node, Diagnostics.super_cannot_be_referenced_in_a_computed_property_name);
}
else if (isCallExpression) {
error(node, Diagnostics.Super_calls_are_not_permitted_outside_constructors_or_in_nested_functions_inside_constructors);
}
else if (!container || !container.parent || !(isClassLike(container.parent) || container.parent.kind === SyntaxKind.ObjectLiteralExpression)) {
error(node, Diagnostics.super_can_only_be_referenced_in_members_of_derived_classes_or_object_literal_expressions);
}
else {
error(node, Diagnostics.super_property_access_is_permitted_only_in_a_constructor_member_function_or_member_accessor_of_a_derived_class);
}
return errorType;
}
if (!isCallExpression && container.kind === SyntaxKind.Constructor) {
checkThisBeforeSuper(node, container, Diagnostics.super_must_be_called_before_accessing_a_property_of_super_in_the_constructor_of_a_derived_class);
}
if (hasModifier(container, ModifierFlags.Static) || isCallExpression) {
nodeCheckFlag = NodeCheckFlags.SuperStatic;
}
else {
nodeCheckFlag = NodeCheckFlags.SuperInstance;
}
getNodeLinks(node).flags |= nodeCheckFlag;
// Due to how we emit async functions, we need to specialize the emit for an async method that contains a `super` reference.
// This is due to the fact that we emit the body of an async function inside of a generator function. As generator
// functions cannot reference `super`, we emit a helper inside of the method body, but outside of the generator. This helper
// uses an arrow function, which is permitted to reference `super`.
//
// There are two primary ways we can access `super` from within an async method. The first is getting the value of a property
// or indexed access on super, either as part of a right-hand-side expression or call expression. The second is when setting the value
// of a property or indexed access, either as part of an assignment expression or destructuring assignment.
//
// The simplest case is reading a value, in which case we will emit something like the following:
//
// // ts
// ...
// async asyncMethod() {
// let x = await super.asyncMethod();
// return x;
// }
// ...
//
// // js
// ...
// asyncMethod() {
// const _super = Object.create(null, {
// asyncMethod: { get: () => super.asyncMethod },
// });
// return __awaiter(this, arguments, Promise, function *() {
// let x = yield _super.asyncMethod.call(this);
// return x;
// });
// }
// ...
//
// The more complex case is when we wish to assign a value, especially as part of a destructuring assignment. As both cases
// are legal in ES6, but also likely less frequent, we only emit setters if there is an assignment:
//
// // ts
// ...
// async asyncMethod(ar: Promise<any[]>) {
// [super.a, super.b] = await ar;
// }
// ...
//
// // js
// ...
// asyncMethod(ar) {
// const _super = Object.create(null, {
// a: { get: () => super.a, set: (v) => super.a = v },
// b: { get: () => super.b, set: (v) => super.b = v }
// };
// return __awaiter(this, arguments, Promise, function *() {
// [_super.a, _super.b] = yield ar;
// });
// }
// ...
//
// Creating an object that has getter and setters instead of just an accessor function is required for destructuring assignments
// as a call expression cannot be used as the target of a destructuring assignment while a property access can.
//
// For element access expressions (`super[x]`), we emit a generic helper that forwards the element access in both situations.
if (container.kind === SyntaxKind.MethodDeclaration && hasModifier(container, ModifierFlags.Async)) {
if (isSuperProperty(node.parent) && isAssignmentTarget(node.parent)) {
getNodeLinks(container).flags |= NodeCheckFlags.AsyncMethodWithSuperBinding;
}
else {
getNodeLinks(container).flags |= NodeCheckFlags.AsyncMethodWithSuper;
}
}
if (needToCaptureLexicalThis) {
// call expressions are allowed only in constructors so they should always capture correct 'this'
// super property access expressions can also appear in arrow functions -
// in this case they should also use correct lexical this
captureLexicalThis(node.parent, container);
}
if (container.parent.kind === SyntaxKind.ObjectLiteralExpression) {
if (languageVersion < ScriptTarget.ES2015) {
error(node, Diagnostics.super_is_only_allowed_in_members_of_object_literal_expressions_when_option_target_is_ES2015_or_higher);
return errorType;
}
else {
// for object literal assume that type of 'super' is 'any'
return anyType;
}
}
// at this point the only legal case for parent is ClassLikeDeclaration
const classLikeDeclaration = <ClassLikeDeclaration>container.parent;
if (!getClassExtendsHeritageElement(classLikeDeclaration)) {
error(node, Diagnostics.super_can_only_be_referenced_in_a_derived_class);
return errorType;
}
const classType = <InterfaceType>getDeclaredTypeOfSymbol(getSymbolOfNode(classLikeDeclaration));
const baseClassType = classType && getBaseTypes(classType)[0];
if (!baseClassType) {
return errorType;
}
if (container.kind === SyntaxKind.Constructor && isInConstructorArgumentInitializer(node, container)) {
// issue custom error message for super property access in constructor arguments (to be aligned with old compiler)
error(node, Diagnostics.super_cannot_be_referenced_in_constructor_arguments);
return errorType;
}
return nodeCheckFlag === NodeCheckFlags.SuperStatic
? getBaseConstructorTypeOfClass(classType)
: getTypeWithThisArgument(baseClassType, classType.thisType);
function isLegalUsageOfSuperExpression(container: Node): boolean {
if (!container) {
return false;
}
if (isCallExpression) {
// TS 1.0 SPEC (April 2014): 4.8.1
// Super calls are only permitted in constructors of derived classes
return container.kind === SyntaxKind.Constructor;
}
else {
// TS 1.0 SPEC (April 2014)
// 'super' property access is allowed
// - In a constructor, instance member function, instance member accessor, or instance member variable initializer where this references a derived class instance
// - In a static member function or static member accessor
// topmost container must be something that is directly nested in the class declaration\object literal expression
if (isClassLike(container.parent) || container.parent.kind === SyntaxKind.ObjectLiteralExpression) {
if (hasModifier(container, ModifierFlags.Static)) {
return container.kind === SyntaxKind.MethodDeclaration ||
container.kind === SyntaxKind.MethodSignature ||
container.kind === SyntaxKind.GetAccessor ||
container.kind === SyntaxKind.SetAccessor;
}
else {
return container.kind === SyntaxKind.MethodDeclaration ||
container.kind === SyntaxKind.MethodSignature ||
container.kind === SyntaxKind.GetAccessor ||
container.kind === SyntaxKind.SetAccessor ||
container.kind === SyntaxKind.PropertyDeclaration ||
container.kind === SyntaxKind.PropertySignature ||
container.kind === SyntaxKind.Constructor;
}
}
}
return false;
}
}
function getContainingObjectLiteral(func: SignatureDeclaration): ObjectLiteralExpression | undefined {
return (func.kind === SyntaxKind.MethodDeclaration ||
func.kind === SyntaxKind.GetAccessor ||
func.kind === SyntaxKind.SetAccessor) && func.parent.kind === SyntaxKind.ObjectLiteralExpression ? func.parent :
func.kind === SyntaxKind.FunctionExpression && func.parent.kind === SyntaxKind.PropertyAssignment ? <ObjectLiteralExpression>func.parent.parent :
undefined;
}
function getThisTypeArgument(type: Type): Type | undefined {
return getObjectFlags(type) & ObjectFlags.Reference && (<TypeReference>type).target === globalThisType ? (<TypeReference>type).typeArguments![0] : undefined;
}
function getThisTypeFromContextualType(type: Type): Type | undefined {
return mapType(type, t => {
return t.flags & TypeFlags.Intersection ? forEach((<IntersectionType>t).types, getThisTypeArgument) : getThisTypeArgument(t);
});
}
function getContextualThisParameterType(func: SignatureDeclaration): Type | undefined {
if (func.kind === SyntaxKind.ArrowFunction) {
return undefined;
}
if (isContextSensitiveFunctionOrObjectLiteralMethod(func)) {
const contextualSignature = getContextualSignature(func);
if (contextualSignature) {
const thisParameter = contextualSignature.thisParameter;
if (thisParameter) {
return getTypeOfSymbol(thisParameter);
}
}
}
const inJs = isInJSFile(func);
if (noImplicitThis || inJs) {
const containingLiteral = getContainingObjectLiteral(func);
if (containingLiteral) {
// We have an object literal method. Check if the containing object literal has a contextual type
// that includes a ThisType<T>. If so, T is the contextual type for 'this'. We continue looking in
// any directly enclosing object literals.
const contextualType = getApparentTypeOfContextualType(containingLiteral);
let literal = containingLiteral;
let type = contextualType;
while (type) {
const thisType = getThisTypeFromContextualType(type);
if (thisType) {
return instantiateType(thisType, getContextualMapper(containingLiteral));
}
if (literal.parent.kind !== SyntaxKind.PropertyAssignment) {
break;
}
literal = <ObjectLiteralExpression>literal.parent.parent;
type = getApparentTypeOfContextualType(literal);
}
// There was no contextual ThisType<T> for the containing object literal, so the contextual type
// for 'this' is the non-null form of the contextual type for the containing object literal or
// the type of the object literal itself.
return contextualType ? getNonNullableType(contextualType) : checkExpressionCached(containingLiteral);
}
// In an assignment of the form 'obj.xxx = function(...)' or 'obj[xxx] = function(...)', the
// contextual type for 'this' is 'obj'.
const parent = func.parent;
if (parent.kind === SyntaxKind.BinaryExpression && (<BinaryExpression>parent).operatorToken.kind === SyntaxKind.EqualsToken) {
const target = (<BinaryExpression>parent).left;
if (target.kind === SyntaxKind.PropertyAccessExpression || target.kind === SyntaxKind.ElementAccessExpression) {
const { expression } = target as AccessExpression;
// Don't contextually type `this` as `exports` in `exports.Point = function(x, y) { this.x = x; this.y = y; }`
if (inJs && isIdentifier(expression)) {
const sourceFile = getSourceFileOfNode(parent);
if (sourceFile.commonJsModuleIndicator && getResolvedSymbol(expression) === sourceFile.symbol) {
return undefined;
}
}
return checkExpressionCached(expression);
}
}
}
return undefined;
}
// Return contextual type of parameter or undefined if no contextual type is available
function getContextuallyTypedParameterType(parameter: ParameterDeclaration): Type | undefined {
const func = parameter.parent;
if (!isContextSensitiveFunctionOrObjectLiteralMethod(func)) {
return undefined;
}
const iife = getImmediatelyInvokedFunctionExpression(func);
if (iife && iife.arguments) {
const args = getEffectiveCallArguments(iife);
const indexOfParameter = func.parameters.indexOf(parameter);
if (parameter.dotDotDotToken) {
return getSpreadArgumentType(args, indexOfParameter, args.length, anyType, /*context*/ undefined);
}
const links = getNodeLinks(iife);
const cached = links.resolvedSignature;
links.resolvedSignature = anySignature;
const type = indexOfParameter < args.length ?
getWidenedLiteralType(checkExpression(args[indexOfParameter])) :
parameter.initializer ? undefined : undefinedWideningType;
links.resolvedSignature = cached;
return type;
}
const contextualSignature = getContextualSignature(func);
if (contextualSignature) {
const index = func.parameters.indexOf(parameter) - (getThisParameter(func) ? 1 : 0);
return parameter.dotDotDotToken && lastOrUndefined(func.parameters) === parameter ?
getRestTypeAtPosition(contextualSignature, index) :
tryGetTypeAtPosition(contextualSignature, index);
}
}
function getContextualTypeForVariableLikeDeclaration(declaration: VariableLikeDeclaration): Type | undefined {
const typeNode = getEffectiveTypeAnnotationNode(declaration);
if (typeNode) {
return getTypeFromTypeNode(typeNode);
}
switch (declaration.kind) {
case SyntaxKind.Parameter:
return getContextuallyTypedParameterType(declaration);
case SyntaxKind.BindingElement:
return getContextualTypeForBindingElement(declaration);
// By default, do nothing and return undefined - only parameters and binding elements have context implied by a parent
}
}
function getContextualTypeForBindingElement(declaration: BindingElement): Type | undefined {
const parentDeclaration = declaration.parent.parent;
const name = declaration.propertyName || declaration.name;
const parentType = getContextualTypeForVariableLikeDeclaration(parentDeclaration);
if (parentType && !isBindingPattern(name) && !isComputedNonLiteralName(name)) {
const nameType = getLiteralTypeFromPropertyName(name);
if (isTypeUsableAsPropertyName(nameType)) {
const text = getPropertyNameFromType(nameType);
return getTypeOfPropertyOfType(parentType, text);
}
}
}
// In a variable, parameter or property declaration with a type annotation,
// the contextual type of an initializer expression is the type of the variable, parameter or property.
// Otherwise, in a parameter declaration of a contextually typed function expression,
// the contextual type of an initializer expression is the contextual type of the parameter.
// Otherwise, in a variable or parameter declaration with a binding pattern name,
// the contextual type of an initializer expression is the type implied by the binding pattern.
// Otherwise, in a binding pattern inside a variable or parameter declaration,
// the contextual type of an initializer expression is the type annotation of the containing declaration, if present.
function getContextualTypeForInitializerExpression(node: Expression): Type | undefined {
const declaration = <VariableLikeDeclaration>node.parent;
if (hasInitializer(declaration) && node === declaration.initializer) {
const result = getContextualTypeForVariableLikeDeclaration(declaration);
if (result) {
return result;
}
if (isBindingPattern(declaration.name)) { // This is less a contextual type and more an implied shape - in some cases, this may be undesirable
return getTypeFromBindingPattern(declaration.name, /*includePatternInType*/ true, /*reportErrors*/ false);
}
}
return undefined;
}
function getContextualTypeForReturnExpression(node: Expression): Type | undefined {
const func = getContainingFunction(node);
if (func) {
const functionFlags = getFunctionFlags(func);
if (functionFlags & FunctionFlags.Generator) { // AsyncGenerator function or Generator function
return undefined;
}
const contextualReturnType = getContextualReturnType(func);
if (contextualReturnType) {
if (functionFlags & FunctionFlags.Async) { // Async function
const contextualAwaitedType = getAwaitedTypeOfPromise(contextualReturnType);
return contextualAwaitedType && getUnionType([contextualAwaitedType, createPromiseLikeType(contextualAwaitedType)]);
}
return contextualReturnType; // Regular function
}
}
return undefined;
}
function getContextualTypeForAwaitOperand(node: AwaitExpression): Type | undefined {
const contextualType = getContextualType(node);
if (contextualType) {
const contextualAwaitedType = getAwaitedType(contextualType);
return contextualAwaitedType && getUnionType([contextualAwaitedType, createPromiseLikeType(contextualAwaitedType)]);
}
return undefined;
}
function getContextualTypeForYieldOperand(node: YieldExpression): Type | undefined {
const func = getContainingFunction(node);
if (func) {
const functionFlags = getFunctionFlags(func);
const contextualReturnType = getContextualReturnType(func);
if (contextualReturnType) {
return node.asteriskToken
? contextualReturnType
: getIteratedTypeOfGenerator(contextualReturnType, (functionFlags & FunctionFlags.Async) !== 0);
}
}
return undefined;
}
function isInParameterInitializerBeforeContainingFunction(node: Node) {
let inBindingInitializer = false;
while (node.parent && !isFunctionLike(node.parent)) {
if (isParameter(node.parent) && (inBindingInitializer || node.parent.initializer === node)) {
return true;
}
if (isBindingElement(node.parent) && node.parent.initializer === node) {
inBindingInitializer = true;
}
node = node.parent;
}
return false;
}
function getContextualReturnType(functionDecl: SignatureDeclaration): Type | undefined {
// If the containing function has a return type annotation, is a constructor, or is a get accessor whose
// corresponding set accessor has a type annotation, return statements in the function are contextually typed
const returnType = getReturnTypeFromAnnotation(functionDecl);
if (returnType) {
return returnType;
}
// Otherwise, if the containing function is contextually typed by a function type with exactly one call signature
// and that call signature is non-generic, return statements are contextually typed by the return type of the signature
const signature = getContextualSignatureForFunctionLikeDeclaration(<FunctionExpression>functionDecl);
if (signature && !isResolvingReturnTypeOfSignature(signature)) {
return getReturnTypeOfSignature(signature);
}
return undefined;
}
// In a typed function call, an argument or substitution expression is contextually typed by the type of the corresponding parameter.
function getContextualTypeForArgument(callTarget: CallLikeExpression, arg: Expression): Type | undefined {
const args = getEffectiveCallArguments(callTarget);
const argIndex = args.indexOf(arg); // -1 for e.g. the expression of a CallExpression, or the tag of a TaggedTemplateExpression
return argIndex === -1 ? undefined : getContextualTypeForArgumentAtIndex(callTarget, argIndex);
}
function getContextualTypeForArgumentAtIndex(callTarget: CallLikeExpression, argIndex: number): Type {
// If we're already in the process of resolving the given signature, don't resolve again as
// that could cause infinite recursion. Instead, return anySignature.
const signature = getNodeLinks(callTarget).resolvedSignature === resolvingSignature ? resolvingSignature : getResolvedSignature(callTarget);
if (isJsxOpeningLikeElement(callTarget) && argIndex === 0) {
return getEffectiveFirstArgumentForJsxSignature(signature, callTarget);
}
return getTypeAtPosition(signature, argIndex);
}
function getContextualTypeForSubstitutionExpression(template: TemplateExpression, substitutionExpression: Expression) {
if (template.parent.kind === SyntaxKind.TaggedTemplateExpression) {
return getContextualTypeForArgument(<TaggedTemplateExpression>template.parent, substitutionExpression);
}
return undefined;
}
function getContextualTypeForBinaryOperand(node: Expression): Type | undefined {
const binaryExpression = <BinaryExpression>node.parent;
const { left, operatorToken, right } = binaryExpression;
switch (operatorToken.kind) {
case SyntaxKind.EqualsToken:
if (node !== right) {
return undefined;
}
const contextSensitive = getIsContextSensitiveAssignmentOrContextType(binaryExpression);
if (!contextSensitive) {
return undefined;
}
return contextSensitive === true ? getTypeOfExpression(left) : contextSensitive;
case SyntaxKind.BarBarToken:
// When an || expression has a contextual type, the operands are contextually typed by that type. When an ||
// expression has no contextual type, the right operand is contextually typed by the type of the left operand,
// except for the special case of Javascript declarations of the form `namespace.prop = namespace.prop || {}`
const type = getContextualType(binaryExpression);
return !type && node === right && !isDefaultedExpandoInitializer(binaryExpression) ?
getTypeOfExpression(left) : type;
case SyntaxKind.AmpersandAmpersandToken:
case SyntaxKind.CommaToken:
return node === right ? getContextualType(binaryExpression) : undefined;
default:
return undefined;
}
}
// In an assignment expression, the right operand is contextually typed by the type of the left operand.
// Don't do this for assignment declarations unless there is a type tag on the assignment, to avoid circularity from checking the right operand.
function getIsContextSensitiveAssignmentOrContextType(binaryExpression: BinaryExpression): boolean | Type {
const kind = getAssignmentDeclarationKind(binaryExpression);
switch (kind) {
case AssignmentDeclarationKind.None:
return true;
case AssignmentDeclarationKind.Property:
case AssignmentDeclarationKind.ExportsProperty:
case AssignmentDeclarationKind.Prototype:
case AssignmentDeclarationKind.PrototypeProperty:
// If `binaryExpression.left` was assigned a symbol, then this is a new declaration; otherwise it is an assignment to an existing declaration.
// See `bindStaticPropertyAssignment` in `binder.ts`.
if (!binaryExpression.left.symbol) {
return true;
}
else {
const decl = binaryExpression.left.symbol.valueDeclaration;
if (!decl) {
return false;
}
const lhs = binaryExpression.left as PropertyAccessExpression;
const overallAnnotation = getEffectiveTypeAnnotationNode(decl);
if (overallAnnotation) {
return getTypeFromTypeNode(overallAnnotation);
}
else if (isIdentifier(lhs.expression)) {
const id = lhs.expression;
const parentSymbol = resolveName(id, id.escapedText, SymbolFlags.Value, undefined, id.escapedText, /*isUse*/ true);
if (parentSymbol) {
const annotated = getEffectiveTypeAnnotationNode(parentSymbol.valueDeclaration);
if (annotated) {
const type = getTypeOfPropertyOfContextualType(getTypeFromTypeNode(annotated), lhs.name.escapedText);
return type || false;
}
return false;
}
}
return !isInJSFile(decl);
}
case AssignmentDeclarationKind.ModuleExports:
case AssignmentDeclarationKind.ThisProperty:
if (!binaryExpression.symbol) return true;
if (binaryExpression.symbol.valueDeclaration) {
const annotated = getEffectiveTypeAnnotationNode(binaryExpression.symbol.valueDeclaration);
if (annotated) {
const type = getTypeFromTypeNode(annotated);
if (type) {
return type;
}
}
}
if (kind === AssignmentDeclarationKind.ModuleExports) return false;
const thisAccess = binaryExpression.left as PropertyAccessExpression;
if (!isObjectLiteralMethod(getThisContainer(thisAccess.expression, /*includeArrowFunctions*/ false))) {
return false;
}
const thisType = checkThisExpression(thisAccess.expression);
return thisType && getTypeOfPropertyOfContextualType(thisType, thisAccess.name.escapedText) || false;
case AssignmentDeclarationKind.ObjectDefinePropertyValue:
case AssignmentDeclarationKind.ObjectDefinePropertyExports:
case AssignmentDeclarationKind.ObjectDefinePrototypeProperty:
return Debug.fail("Does not apply");
default:
return Debug.assertNever(kind);
}
}
function getTypeOfPropertyOfContextualType(type: Type, name: __String) {
return mapType(type, t => {
if (t.flags & TypeFlags.StructuredType) {
const prop = getPropertyOfType(t, name);
if (prop) {
return getTypeOfSymbol(prop);
}
if (isTupleType(t)) {
const restType = getRestTypeOfTupleType(t);
if (restType && isNumericLiteralName(name) && +name >= 0) {
return restType;
}
}
return isNumericLiteralName(name) && getIndexTypeOfContextualType(t, IndexKind.Number) ||
getIndexTypeOfContextualType(t, IndexKind.String);
}
return undefined;
}, /*noReductions*/ true);
}
function getIndexTypeOfContextualType(type: Type, kind: IndexKind) {
return mapType(type, t => getIndexTypeOfStructuredType(t, kind), /*noReductions*/ true);
}
// In an object literal contextually typed by a type T, the contextual type of a property assignment is the type of
// the matching property in T, if one exists. Otherwise, it is the type of the numeric index signature in T, if one
// exists. Otherwise, it is the type of the string index signature in T, if one exists.
function getContextualTypeForObjectLiteralMethod(node: MethodDeclaration): Type | undefined {
Debug.assert(isObjectLiteralMethod(node));
if (node.flags & NodeFlags.InWithStatement) {
// We cannot answer semantic questions within a with block, do not proceed any further
return undefined;
}
return getContextualTypeForObjectLiteralElement(node);
}
function getContextualTypeForObjectLiteralElement(element: ObjectLiteralElementLike) {
const objectLiteral = <ObjectLiteralExpression>element.parent;
const type = getApparentTypeOfContextualType(objectLiteral);
if (type) {
if (!hasNonBindableDynamicName(element)) {
// For a (non-symbol) computed property, there is no reason to look up the name
// in the type. It will just be "__computed", which does not appear in any
// SymbolTable.
const symbolName = getSymbolOfNode(element).escapedName;
const propertyType = getTypeOfPropertyOfContextualType(type, symbolName);
if (propertyType) {
return propertyType;
}
}
return isNumericName(element.name!) && getIndexTypeOfContextualType(type, IndexKind.Number) ||
getIndexTypeOfContextualType(type, IndexKind.String);
}
return undefined;
}
// In an array literal contextually typed by a type T, the contextual type of an element expression at index N is
// the type of the property with the numeric name N in T, if one exists. Otherwise, if T has a numeric index signature,
// it is the type of the numeric index signature in T. Otherwise, in ES6 and higher, the contextual type is the iterated
// type of T.
function getContextualTypeForElementExpression(arrayContextualType: Type | undefined, index: number): Type | undefined {
return arrayContextualType && (
getTypeOfPropertyOfContextualType(arrayContextualType, "" + index as __String)
|| getIteratedTypeOrElementType(arrayContextualType, /*errorNode*/ undefined, /*allowStringInput*/ false, /*allowAsyncIterables*/ false, /*checkAssignability*/ false));
}
// In a contextually typed conditional expression, the true/false expressions are contextually typed by the same type.
function getContextualTypeForConditionalOperand(node: Expression): Type | undefined {
const conditional = <ConditionalExpression>node.parent;
return node === conditional.whenTrue || node === conditional.whenFalse ? getContextualType(conditional) : undefined;
}
function getContextualTypeForChildJsxExpression(node: JsxElement, child: JsxChild) {
const attributesType = getApparentTypeOfContextualType(node.openingElement.tagName);
// JSX expression is in children of JSX Element, we will look for an "children" atttribute (we get the name from JSX.ElementAttributesProperty)
const jsxChildrenPropertyName = getJsxElementChildrenPropertyName(getJsxNamespaceAt(node));
if (!(attributesType && !isTypeAny(attributesType) && jsxChildrenPropertyName && jsxChildrenPropertyName !== "")) {
return undefined;
}
const childIndex = node.children.indexOf(child);
const childFieldType = getTypeOfPropertyOfContextualType(attributesType, jsxChildrenPropertyName);
return childFieldType && mapType(childFieldType, t => {
if (isArrayLikeType(t)) {
return getIndexedAccessType(t, getLiteralType(childIndex));
}
else {
return t;
}
}, /*noReductions*/ true);
}
function getContextualTypeForJsxExpression(node: JsxExpression): Type | undefined {
const exprParent = node.parent;
return isJsxAttributeLike(exprParent)
? getContextualType(node)
: isJsxElement(exprParent)
? getContextualTypeForChildJsxExpression(exprParent, node)
: undefined;
}
function getContextualTypeForJsxAttribute(attribute: JsxAttribute | JsxSpreadAttribute): Type | undefined {
// When we trying to resolve JsxOpeningLikeElement as a stateless function element, we will already give its attributes a contextual type
// which is a type of the parameter of the signature we are trying out.
// If there is no contextual type (e.g. we are trying to resolve stateful component), get attributes type from resolving element's tagName
if (isJsxAttribute(attribute)) {
const attributesType = getApparentTypeOfContextualType(attribute.parent);
if (!attributesType || isTypeAny(attributesType)) {
return undefined;
}
return getTypeOfPropertyOfContextualType(attributesType, attribute.name.escapedText);
}
else {
return getContextualType(attribute.parent);
}
}
// Return true if the given expression is possibly a discriminant value. We limit the kinds of
// expressions we check to those that don't depend on their contextual type in order not to cause
// recursive (and possibly infinite) invocations of getContextualType.
function isPossiblyDiscriminantValue(node: Expression): boolean {
switch (node.kind) {
case SyntaxKind.StringLiteral:
case SyntaxKind.NumericLiteral:
case SyntaxKind.BigIntLiteral:
case SyntaxKind.NoSubstitutionTemplateLiteral:
case SyntaxKind.TrueKeyword:
case SyntaxKind.FalseKeyword:
case SyntaxKind.NullKeyword:
case SyntaxKind.Identifier:
case SyntaxKind.UndefinedKeyword:
return true;
case SyntaxKind.PropertyAccessExpression:
case SyntaxKind.ParenthesizedExpression:
return isPossiblyDiscriminantValue((<PropertyAccessExpression | ParenthesizedExpression>node).expression);
case SyntaxKind.JsxExpression:
return !(node as JsxExpression).expression || isPossiblyDiscriminantValue((node as JsxExpression).expression!);
}
return false;
}
function discriminateContextualTypeByObjectMembers(node: ObjectLiteralExpression, contextualType: UnionType) {
return discriminateTypeByDiscriminableItems(contextualType,
map(
filter(node.properties, p => !!p.symbol && p.kind === SyntaxKind.PropertyAssignment && isPossiblyDiscriminantValue(p.initializer) && isDiscriminantProperty(contextualType, p.symbol.escapedName)),
prop => ([() => checkExpression((prop as PropertyAssignment).initializer), prop.symbol.escapedName] as [() => Type, __String])
),
isTypeAssignableTo,
contextualType
);
}
function discriminateContextualTypeByJSXAttributes(node: JsxAttributes, contextualType: UnionType) {
return discriminateTypeByDiscriminableItems(contextualType,
map(
filter(node.properties, p => !!p.symbol && p.kind === SyntaxKind.JsxAttribute && isDiscriminantProperty(contextualType, p.symbol.escapedName) && (!p.initializer || isPossiblyDiscriminantValue(p.initializer))),
prop => ([!(prop as JsxAttribute).initializer ? (() => trueType) : (() => checkExpression((prop as JsxAttribute).initializer!)), prop.symbol.escapedName] as [() => Type, __String])
),
isTypeAssignableTo,
contextualType
);
}
// Return the contextual type for a given expression node. During overload resolution, a contextual type may temporarily
// be "pushed" onto a node using the contextualType property.
function getApparentTypeOfContextualType(node: Expression): Type | undefined {
const contextualType = instantiateContextualType(getContextualType(node), node);
if (contextualType) {
const apparentType = mapType(contextualType, getApparentType, /*noReductions*/ true);
if (apparentType.flags & TypeFlags.Union) {
if (isObjectLiteralExpression(node)) {
return discriminateContextualTypeByObjectMembers(node, apparentType as UnionType);
}
else if (isJsxAttributes(node)) {
return discriminateContextualTypeByJSXAttributes(node, apparentType as UnionType);
}
}
return apparentType;
}
}
// If the given contextual type contains instantiable types and if a mapper representing
// return type inferences is available, instantiate those types using that mapper.
function instantiateContextualType(contextualType: Type | undefined, node: Expression): Type | undefined {
if (contextualType && maybeTypeOfKind(contextualType, TypeFlags.Instantiable)) {
const returnMapper = (<InferenceContext>getContextualMapper(node)).returnMapper;
if (returnMapper) {
return instantiateInstantiableTypes(contextualType, returnMapper);
}
}
return contextualType;
}
// This function is similar to instantiateType, except that (a) it only instantiates types that
// are classified as instantiable (i.e. it doesn't instantiate object types), and (b) it performs
// no reductions on instantiated union types.
function instantiateInstantiableTypes(type: Type, mapper: TypeMapper): Type {
if (type.flags & TypeFlags.Instantiable) {
return instantiateType(type, mapper);
}
if (type.flags & TypeFlags.Union) {
return getUnionType(map((<UnionType>type).types, t => instantiateInstantiableTypes(t, mapper)), UnionReduction.None);
}
if (type.flags & TypeFlags.Intersection) {
return getIntersectionType(map((<IntersectionType>type).types, t => instantiateInstantiableTypes(t, mapper)));
}
return type;
}
/**
* Woah! Do you really want to use this function?
*
* Unless you're trying to get the *non-apparent* type for a
* value-literal type or you're authoring relevant portions of this algorithm,
* you probably meant to use 'getApparentTypeOfContextualType'.
* Otherwise this may not be very useful.
*
* In cases where you *are* working on this function, you should understand
* when it is appropriate to use 'getContextualType' and 'getApparentTypeOfContextualType'.
*
* - Use 'getContextualType' when you are simply going to propagate the result to the expression.
* - Use 'getApparentTypeOfContextualType' when you're going to need the members of the type.
*
* @param node the expression whose contextual type will be returned.
* @returns the contextual type of an expression.
*/
function getContextualType(node: Expression): Type | undefined {
if (node.flags & NodeFlags.InWithStatement) {
// We cannot answer semantic questions within a with block, do not proceed any further
return undefined;
}
if (node.contextualType) {
return node.contextualType;
}
const { parent } = node;
switch (parent.kind) {
case SyntaxKind.VariableDeclaration:
case SyntaxKind.Parameter:
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.PropertySignature:
case SyntaxKind.BindingElement:
return getContextualTypeForInitializerExpression(node);
case SyntaxKind.ArrowFunction:
case SyntaxKind.ReturnStatement:
return getContextualTypeForReturnExpression(node);
case SyntaxKind.YieldExpression:
return getContextualTypeForYieldOperand(<YieldExpression>parent);
case SyntaxKind.AwaitExpression:
return getContextualTypeForAwaitOperand(<AwaitExpression>parent);
case SyntaxKind.CallExpression:
case SyntaxKind.NewExpression:
return getContextualTypeForArgument(<CallExpression | NewExpression>parent, node);
case SyntaxKind.TypeAssertionExpression:
case SyntaxKind.AsExpression:
return isConstTypeReference((<AssertionExpression>parent).type) ? undefined : getTypeFromTypeNode((<AssertionExpression>parent).type);
case SyntaxKind.BinaryExpression:
return getContextualTypeForBinaryOperand(node);
case SyntaxKind.PropertyAssignment:
case SyntaxKind.ShorthandPropertyAssignment:
return getContextualTypeForObjectLiteralElement(<PropertyAssignment | ShorthandPropertyAssignment>parent);
case SyntaxKind.SpreadAssignment:
return getApparentTypeOfContextualType(parent.parent as ObjectLiteralExpression);
case SyntaxKind.ArrayLiteralExpression: {
const arrayLiteral = <ArrayLiteralExpression>parent;
const type = getApparentTypeOfContextualType(arrayLiteral);
return getContextualTypeForElementExpression(type, indexOfNode(arrayLiteral.elements, node));
}
case SyntaxKind.ConditionalExpression:
return getContextualTypeForConditionalOperand(node);
case SyntaxKind.TemplateSpan:
Debug.assert(parent.parent.kind === SyntaxKind.TemplateExpression);
return getContextualTypeForSubstitutionExpression(<TemplateExpression>parent.parent, node);
case SyntaxKind.ParenthesizedExpression: {
// Like in `checkParenthesizedExpression`, an `/** @type {xyz} */` comment before a parenthesized expression acts as a type cast.
const tag = isInJSFile(parent) ? getJSDocTypeTag(parent) : undefined;
return tag ? getTypeFromTypeNode(tag.typeExpression!.type) : getContextualType(<ParenthesizedExpression>parent);
}
case SyntaxKind.JsxExpression:
return getContextualTypeForJsxExpression(<JsxExpression>parent);
case SyntaxKind.JsxAttribute:
case SyntaxKind.JsxSpreadAttribute:
return getContextualTypeForJsxAttribute(<JsxAttribute | JsxSpreadAttribute>parent);
case SyntaxKind.JsxOpeningElement:
case SyntaxKind.JsxSelfClosingElement:
return getContextualJsxElementAttributesType(<JsxOpeningLikeElement>parent);
}
return undefined;
}
function getContextualMapper(node: Node) {
const ancestor = findAncestor(node, n => !!n.contextualMapper);
return ancestor ? ancestor.contextualMapper! : identityMapper;
}
function getContextualJsxElementAttributesType(node: JsxOpeningLikeElement) {
if (isJsxOpeningElement(node) && node.parent.contextualType) {
// Contextually applied type is moved from attributes up to the outer jsx attributes so when walking up from the children they get hit
// _However_ to hit them from the _attributes_ we must look for them here; otherwise we'll used the declared type
// (as below) instead!
return node.parent.contextualType;
}
return getContextualTypeForArgumentAtIndex(node, 0);
}
function getEffectiveFirstArgumentForJsxSignature(signature: Signature, node: JsxOpeningLikeElement) {
return getJsxReferenceKind(node) !== JsxReferenceKind.Component ? getJsxPropsTypeFromCallSignature(signature, node) : getJsxPropsTypeFromClassType(signature, node);
}
function getJsxPropsTypeFromCallSignature(sig: Signature, context: JsxOpeningLikeElement) {
let propsType = getTypeOfFirstParameterOfSignatureWithFallback(sig, emptyObjectType);
propsType = getJsxManagedAttributesFromLocatedAttributes(context, getJsxNamespaceAt(context), propsType);
const intrinsicAttribs = getJsxType(JsxNames.IntrinsicAttributes, context);
if (intrinsicAttribs !== errorType) {
propsType = intersectTypes(intrinsicAttribs, propsType);
}
return propsType;
}
function getJsxPropsTypeForSignatureFromMember(sig: Signature, forcedLookupLocation: __String) {
if (sig.unionSignatures) {
// JSX Elements using the legacy `props`-field based lookup (eg, react class components) need to treat the `props` member as an input
// instead of an output position when resolving the signature. We need to go back to the input signatures of the composite signature,
// get the type of `props` on each return type individually, and then _intersect them_, rather than union them (as would normally occur
// for a union signature). It's an unfortunate quirk of looking in the output of the signature for the type we want to use for the input.
// The default behavior of `getTypeOfFirstParameterOfSignatureWithFallback` when no `props` member name is defined is much more sane.
const results: Type[] = [];
for (const signature of sig.unionSignatures) {
const instance = getReturnTypeOfSignature(signature);
if (isTypeAny(instance)) {
return instance;
}
const propType = getTypeOfPropertyOfType(instance, forcedLookupLocation);
if (!propType) {
return;
}
results.push(propType);
}
return getIntersectionType(results);
}
const instanceType = getReturnTypeOfSignature(sig);
return isTypeAny(instanceType) ? instanceType : getTypeOfPropertyOfType(instanceType, forcedLookupLocation);
}
function getStaticTypeOfReferencedJsxConstructor(context: JsxOpeningLikeElement) {
if (isJsxIntrinsicIdentifier(context.tagName)) {
const result = getIntrinsicAttributesTypeFromJsxOpeningLikeElement(context);
const fakeSignature = createSignatureForJSXIntrinsic(context, result);
return getOrCreateTypeFromSignature(fakeSignature);
}
const tagType = checkExpressionCached(context.tagName);
if (tagType.flags & TypeFlags.StringLiteral) {
const result = getIntrinsicAttributesTypeFromStringLiteralType(tagType as StringLiteralType, context);
if (!result) {
return errorType;
}
const fakeSignature = createSignatureForJSXIntrinsic(context, result);
return getOrCreateTypeFromSignature(fakeSignature);
}
return tagType;
}
function getJsxManagedAttributesFromLocatedAttributes(context: JsxOpeningLikeElement, ns: Symbol, attributesType: Type) {
const managedSym = getJsxLibraryManagedAttributes(ns);
if (managedSym) {
const declaredManagedType = getDeclaredTypeOfSymbol(managedSym);
const ctorType = getStaticTypeOfReferencedJsxConstructor(context);
if (length((declaredManagedType as GenericType).typeParameters) >= 2) {
const args = fillMissingTypeArguments([ctorType, attributesType], (declaredManagedType as GenericType).typeParameters, 2, isInJSFile(context));
return createTypeReference((declaredManagedType as GenericType), args);
}
else if (length(declaredManagedType.aliasTypeArguments) >= 2) {
const args = fillMissingTypeArguments([ctorType, attributesType], declaredManagedType.aliasTypeArguments!, 2, isInJSFile(context));
return getTypeAliasInstantiation(declaredManagedType.aliasSymbol!, args);
}
}
return attributesType;
}
function getJsxPropsTypeFromClassType(sig: Signature, context: JsxOpeningLikeElement) {
const ns = getJsxNamespaceAt(context);
const forcedLookupLocation = getJsxElementPropertiesName(ns);
let attributesType = forcedLookupLocation === undefined
// If there is no type ElementAttributesProperty, return the type of the first parameter of the signature, which should be the props type
? getTypeOfFirstParameterOfSignatureWithFallback(sig, emptyObjectType)
: forcedLookupLocation === ""
// If there is no e.g. 'props' member in ElementAttributesProperty, use the element class type instead
? getReturnTypeOfSignature(sig)
// Otherwise get the type of the property on the signature return type
: getJsxPropsTypeForSignatureFromMember(sig, forcedLookupLocation);
if (!attributesType) {
// There is no property named 'props' on this instance type
if (!!forcedLookupLocation && !!length(context.attributes.properties)) {
error(context, Diagnostics.JSX_element_class_does_not_support_attributes_because_it_does_not_have_a_0_property, unescapeLeadingUnderscores(forcedLookupLocation));
}
return emptyObjectType;
}
attributesType = getJsxManagedAttributesFromLocatedAttributes(context, ns, attributesType);
if (isTypeAny(attributesType)) {
// Props is of type 'any' or unknown
return attributesType;
}
else {
// Normal case -- add in IntrinsicClassElements<T> and IntrinsicElements
let apparentAttributesType = attributesType;
const intrinsicClassAttribs = getJsxType(JsxNames.IntrinsicClassAttributes, context);
if (intrinsicClassAttribs !== errorType) {
const typeParams = getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(intrinsicClassAttribs.symbol);
const hostClassType = getReturnTypeOfSignature(sig);
apparentAttributesType = intersectTypes(
typeParams
? createTypeReference(<GenericType>intrinsicClassAttribs, fillMissingTypeArguments([hostClassType], typeParams, getMinTypeArgumentCount(typeParams), isInJSFile(context)))
: intrinsicClassAttribs,
apparentAttributesType
);
}
const intrinsicAttribs = getJsxType(JsxNames.IntrinsicAttributes, context);
if (intrinsicAttribs !== errorType) {
apparentAttributesType = intersectTypes(intrinsicAttribs, apparentAttributesType);
}
return apparentAttributesType;
}
}
// If the given type is an object or union type with a single signature, and if that signature has at
// least as many parameters as the given function, return the signature. Otherwise return undefined.
function getContextualCallSignature(type: Type, node: SignatureDeclaration): Signature | undefined {
const signatures = getSignaturesOfType(type, SignatureKind.Call);
if (signatures.length === 1) {
const signature = signatures[0];
if (!isAritySmaller(signature, node)) {
return signature;
}
}
}
/** If the contextual signature has fewer parameters than the function expression, do not use it */
function isAritySmaller(signature: Signature, target: SignatureDeclaration) {
let targetParameterCount = 0;
for (; targetParameterCount < target.parameters.length; targetParameterCount++) {
const param = target.parameters[targetParameterCount];
if (param.initializer || param.questionToken || param.dotDotDotToken || isJSDocOptionalParameter(param)) {
break;
}
}
if (target.parameters.length && parameterIsThisKeyword(target.parameters[0])) {
targetParameterCount--;
}
return !hasEffectiveRestParameter(signature) && getParameterCount(signature) < targetParameterCount;
}
function isFunctionExpressionOrArrowFunction(node: Node): node is FunctionExpression | ArrowFunction {
return node.kind === SyntaxKind.FunctionExpression || node.kind === SyntaxKind.ArrowFunction;
}
function getContextualSignatureForFunctionLikeDeclaration(node: FunctionLikeDeclaration): Signature | undefined {
// Only function expressions, arrow functions, and object literal methods are contextually typed.
return isFunctionExpressionOrArrowFunction(node) || isObjectLiteralMethod(node)
? getContextualSignature(<FunctionExpression>node)
: undefined;
}
function getContextualTypeForFunctionLikeDeclaration(node: FunctionExpression | ArrowFunction | MethodDeclaration) {
return isObjectLiteralMethod(node) ?
getContextualTypeForObjectLiteralMethod(node) :
getApparentTypeOfContextualType(node);
}
// Return the contextual signature for a given expression node. A contextual type provides a
// contextual signature if it has a single call signature and if that call signature is non-generic.
// If the contextual type is a union type, get the signature from each type possible and if they are
// all identical ignoring their return type, the result is same signature but with return type as
// union type of return types from these signatures
function getContextualSignature(node: FunctionExpression | ArrowFunction | MethodDeclaration): Signature | undefined {
Debug.assert(node.kind !== SyntaxKind.MethodDeclaration || isObjectLiteralMethod(node));
const typeTagSignature = getSignatureOfTypeTag(node);
if (typeTagSignature) {
return typeTagSignature;
}
const type = getContextualTypeForFunctionLikeDeclaration(node);
if (!type) {
return undefined;
}
if (!(type.flags & TypeFlags.Union)) {
return getContextualCallSignature(type, node);
}
let signatureList: Signature[] | undefined;
const types = (<UnionType>type).types;
for (const current of types) {
const signature = getContextualCallSignature(current, node);
if (signature) {
if (!signatureList) {
// This signature will contribute to contextual union signature
signatureList = [signature];
}
else if (!compareSignaturesIdentical(signatureList[0], signature, /*partialMatch*/ false, /*ignoreThisTypes*/ true, /*ignoreReturnTypes*/ true, compareTypesIdentical)) {
// Signatures aren't identical, do not use
return undefined;
}
else {
// Use this signature for contextual union signature
signatureList.push(signature);
}
}
}
// Result is union of signatures collected (return type is union of return types of this signature set)
let result: Signature | undefined;
if (signatureList) {
result = cloneSignature(signatureList[0]);
result.unionSignatures = signatureList;
}
return result;
}
function checkSpreadExpression(node: SpreadElement, checkMode?: CheckMode): Type {
if (languageVersion < ScriptTarget.ES2015 && compilerOptions.downlevelIteration) {
checkExternalEmitHelpers(node, ExternalEmitHelpers.SpreadIncludes);
}
const arrayOrIterableType = checkExpression(node.expression, checkMode);
return checkIteratedTypeOrElementType(arrayOrIterableType, node.expression, /*allowStringInput*/ false, /*allowAsyncIterables*/ false);
}
function hasDefaultValue(node: BindingElement | Expression): boolean {
return (node.kind === SyntaxKind.BindingElement && !!(<BindingElement>node).initializer) ||
(node.kind === SyntaxKind.BinaryExpression && (<BinaryExpression>node).operatorToken.kind === SyntaxKind.EqualsToken);
}
function checkArrayLiteral(node: ArrayLiteralExpression, checkMode: CheckMode | undefined, forceTuple: boolean | undefined): Type {
const elements = node.elements;
const elementCount = elements.length;
let hasNonEndingSpreadElement = false;
const elementTypes: Type[] = [];
const inDestructuringPattern = isAssignmentTarget(node);
const contextualType = getApparentTypeOfContextualType(node);
const inConstContext = isConstContext(node);
for (let index = 0; index < elementCount; index++) {
const e = elements[index];
if (inDestructuringPattern && e.kind === SyntaxKind.SpreadElement) {
// Given the following situation:
// var c: {};
// [...c] = ["", 0];
//
// c is represented in the tree as a spread element in an array literal.
// But c really functions as a rest element, and its purpose is to provide
// a contextual type for the right hand side of the assignment. Therefore,
// instead of calling checkExpression on "...c", which will give an error
// if c is not iterable/array-like, we need to act as if we are trying to
// get the contextual element type from it. So we do something similar to
// getContextualTypeForElementExpression, which will crucially not error
// if there is no index type / iterated type.
const restArrayType = checkExpression((<SpreadElement>e).expression, checkMode, forceTuple);
const restElementType = getIndexTypeOfType(restArrayType, IndexKind.Number) ||
getIteratedTypeOrElementType(restArrayType, /*errorNode*/ undefined, /*allowStringInput*/ false, /*allowAsyncIterables*/ false, /*checkAssignability*/ false);
if (restElementType) {
elementTypes.push(restElementType);
}
}
else {
const elementContextualType = getContextualTypeForElementExpression(contextualType, index);
const type = checkExpressionForMutableLocation(e, checkMode, elementContextualType, forceTuple);
elementTypes.push(type);
}
if (index < elementCount - 1 && e.kind === SyntaxKind.SpreadElement) {
hasNonEndingSpreadElement = true;
}
}
if (!hasNonEndingSpreadElement) {
const hasRestElement = elementCount > 0 && elements[elementCount - 1].kind === SyntaxKind.SpreadElement;
const minLength = elementCount - (hasRestElement ? 1 : 0);
// If array literal is actually a destructuring pattern, mark it as an implied type. We do this such
// that we get the same behavior for "var [x, y] = []" and "[x, y] = []".
let tupleResult: Type | undefined;
if (inDestructuringPattern && minLength > 0) {
const type = cloneTypeReference(<TypeReference>createTupleType(elementTypes, minLength, hasRestElement));
type.pattern = node;
return type;
}
else if (tupleResult = getArrayLiteralTupleTypeIfApplicable(elementTypes, contextualType, hasRestElement, elementCount, inConstContext)) {
return tupleResult;
}
else if (forceTuple) {
return createTupleType(elementTypes, minLength, hasRestElement);
}
}
return createArrayType(elementTypes.length ?
getUnionType(elementTypes, UnionReduction.Subtype) :
strictNullChecks ? implicitNeverType : undefinedWideningType, inConstContext);
}
function getArrayLiteralTupleTypeIfApplicable(elementTypes: Type[], contextualType: Type | undefined, hasRestElement: boolean, elementCount = elementTypes.length, readonly = false) {
// Infer a tuple type when the contextual type is or contains a tuple-like type
if (readonly || (contextualType && forEachType(contextualType, isTupleLikeType))) {
const minLength = elementCount - (hasRestElement ? 1 : 0);
const pattern = contextualType && contextualType.pattern;
// If array literal is contextually typed by a binding pattern or an assignment pattern, pad the resulting
// tuple type with the corresponding binding or assignment element types to make the lengths equal.
if (!hasRestElement && pattern && (pattern.kind === SyntaxKind.ArrayBindingPattern || pattern.kind === SyntaxKind.ArrayLiteralExpression)) {
const patternElements = (<BindingPattern | ArrayLiteralExpression>pattern).elements;
for (let i = elementCount; i < patternElements.length; i++) {
const e = patternElements[i];
if (hasDefaultValue(e)) {
elementTypes.push((<TypeReference>contextualType).typeArguments![i]);
}
else if (i < patternElements.length - 1 || !(e.kind === SyntaxKind.BindingElement && (<BindingElement>e).dotDotDotToken || e.kind === SyntaxKind.SpreadElement)) {
if (e.kind !== SyntaxKind.OmittedExpression) {
error(e, Diagnostics.Initializer_provides_no_value_for_this_binding_element_and_the_binding_element_has_no_default_value);
}
elementTypes.push(strictNullChecks ? implicitNeverType : undefinedWideningType);
}
}
}
return createTupleType(elementTypes, minLength, hasRestElement, readonly);
}
}
function isNumericName(name: DeclarationName): boolean {
switch (name.kind) {
case SyntaxKind.ComputedPropertyName:
return isNumericComputedName(name);
case SyntaxKind.Identifier:
return isNumericLiteralName(name.escapedText);
case SyntaxKind.NumericLiteral:
case SyntaxKind.StringLiteral:
return isNumericLiteralName(name.text);
default:
return false;
}
}
function isNumericComputedName(name: ComputedPropertyName): boolean {
// It seems odd to consider an expression of type Any to result in a numeric name,
// but this behavior is consistent with checkIndexedAccess
return isTypeAssignableToKind(checkComputedPropertyName(name), TypeFlags.NumberLike);
}
function isInfinityOrNaNString(name: string | __String): boolean {
return name === "Infinity" || name === "-Infinity" || name === "NaN";
}
function isNumericLiteralName(name: string | __String) {
// The intent of numeric names is that
// - they are names with text in a numeric form, and that
// - setting properties/indexing with them is always equivalent to doing so with the numeric literal 'numLit',
// acquired by applying the abstract 'ToNumber' operation on the name's text.
//
// The subtlety is in the latter portion, as we cannot reliably say that anything that looks like a numeric literal is a numeric name.
// In fact, it is the case that the text of the name must be equal to 'ToString(numLit)' for this to hold.
//
// Consider the property name '"0xF00D"'. When one indexes with '0xF00D', they are actually indexing with the value of 'ToString(0xF00D)'
// according to the ECMAScript specification, so it is actually as if the user indexed with the string '"61453"'.
// Thus, the text of all numeric literals equivalent to '61543' such as '0xF00D', '0xf00D', '0170015', etc. are not valid numeric names
// because their 'ToString' representation is not equal to their original text.
// This is motivated by ECMA-262 sections 9.3.1, 9.8.1, 11.1.5, and 11.2.1.
//
// Here, we test whether 'ToString(ToNumber(name))' is exactly equal to 'name'.
// The '+' prefix operator is equivalent here to applying the abstract ToNumber operation.
// Applying the 'toString()' method on a number gives us the abstract ToString operation on a number.
//
// Note that this accepts the values 'Infinity', '-Infinity', and 'NaN', and that this is intentional.
// This is desired behavior, because when indexing with them as numeric entities, you are indexing
// with the strings '"Infinity"', '"-Infinity"', and '"NaN"' respectively.
return (+name).toString() === name;
}
function checkComputedPropertyName(node: ComputedPropertyName): Type {
const links = getNodeLinks(node.expression);
if (!links.resolvedType) {
links.resolvedType = checkExpression(node.expression);
// This will allow types number, string, symbol or any. It will also allow enums, the unknown
// type, and any union of these types (like string | number).
if (links.resolvedType.flags & TypeFlags.Nullable ||
!isTypeAssignableToKind(links.resolvedType, TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.ESSymbolLike) &&
!isTypeAssignableTo(links.resolvedType, stringNumberSymbolType)) {
error(node, Diagnostics.A_computed_property_name_must_be_of_type_string_number_symbol_or_any);
}
else {
checkThatExpressionIsProperSymbolReference(node.expression, links.resolvedType, /*reportError*/ true);
}
}
return links.resolvedType;
}
function getObjectLiteralIndexInfo(node: ObjectLiteralExpression, offset: number, properties: Symbol[], kind: IndexKind): IndexInfo {
const propTypes: Type[] = [];
for (let i = 0; i < properties.length; i++) {
if (kind === IndexKind.String || isNumericName(node.properties[i + offset].name!)) {
propTypes.push(getTypeOfSymbol(properties[i]));
}
}
const unionType = propTypes.length ? getUnionType(propTypes, UnionReduction.Subtype) : undefinedType;
return createIndexInfo(unionType, isConstContext(node));
}
function getImmediateAliasedSymbol(symbol: Symbol): Symbol | undefined {
Debug.assert((symbol.flags & SymbolFlags.Alias) !== 0, "Should only get Alias here.");
const links = getSymbolLinks(symbol);
if (!links.immediateTarget) {
const node = getDeclarationOfAliasSymbol(symbol);
if (!node) return Debug.fail();
links.immediateTarget = getTargetOfAliasDeclaration(node, /*dontRecursivelyResolve*/ true);
}
return links.immediateTarget;
}
function checkObjectLiteral(node: ObjectLiteralExpression, checkMode?: CheckMode): Type {
const inDestructuringPattern = isAssignmentTarget(node);
// Grammar checking
checkGrammarObjectLiteralExpression(node, inDestructuringPattern);
let propertiesTable: SymbolTable;
let propertiesArray: Symbol[] = [];
let spread: Type = emptyObjectType;
const contextualType = getApparentTypeOfContextualType(node);
const contextualTypeHasPattern = contextualType && contextualType.pattern &&
(contextualType.pattern.kind === SyntaxKind.ObjectBindingPattern || contextualType.pattern.kind === SyntaxKind.ObjectLiteralExpression);
const inConstContext = isConstContext(node);
const checkFlags = inConstContext ? CheckFlags.Readonly : 0;
const isInJavascript = isInJSFile(node) && !isInJsonFile(node);
const enumTag = getJSDocEnumTag(node);
const isJSObjectLiteral = !contextualType && isInJavascript && !enumTag;
let objectFlags: ObjectFlags = freshObjectLiteralFlag;
let patternWithComputedProperties = false;
let hasComputedStringProperty = false;
let hasComputedNumberProperty = false;
propertiesTable = createSymbolTable();
let offset = 0;
for (let i = 0; i < node.properties.length; i++) {
const memberDecl = node.properties[i];
let member = getSymbolOfNode(memberDecl);
const computedNameType = memberDecl.name && memberDecl.name.kind === SyntaxKind.ComputedPropertyName && !isWellKnownSymbolSyntactically(memberDecl.name.expression) ?
checkComputedPropertyName(memberDecl.name) : undefined;
if (memberDecl.kind === SyntaxKind.PropertyAssignment ||
memberDecl.kind === SyntaxKind.ShorthandPropertyAssignment ||
isObjectLiteralMethod(memberDecl)) {
let type = memberDecl.kind === SyntaxKind.PropertyAssignment ? checkPropertyAssignment(memberDecl, checkMode) :
memberDecl.kind === SyntaxKind.ShorthandPropertyAssignment ? checkExpressionForMutableLocation(memberDecl.name, checkMode) :
checkObjectLiteralMethod(memberDecl, checkMode);
if (isInJavascript) {
const jsDocType = getTypeForDeclarationFromJSDocComment(memberDecl);
if (jsDocType) {
checkTypeAssignableTo(type, jsDocType, memberDecl);
type = jsDocType;
}
else if (enumTag && enumTag.typeExpression) {
checkTypeAssignableTo(type, getTypeFromTypeNode(enumTag.typeExpression), memberDecl);
}
}
objectFlags |= getObjectFlags(type) & ObjectFlags.PropagatingFlags;
const nameType = computedNameType && isTypeUsableAsPropertyName(computedNameType) ? computedNameType : undefined;
const prop = nameType ?
createSymbol(SymbolFlags.Property | member.flags, getPropertyNameFromType(nameType), checkFlags | CheckFlags.Late) :
createSymbol(SymbolFlags.Property | member.flags, member.escapedName, checkFlags);
if (nameType) {
prop.nameType = nameType;
}
if (inDestructuringPattern) {
// If object literal is an assignment pattern and if the assignment pattern specifies a default value
// for the property, make the property optional.
const isOptional =
(memberDecl.kind === SyntaxKind.PropertyAssignment && hasDefaultValue(memberDecl.initializer)) ||
(memberDecl.kind === SyntaxKind.ShorthandPropertyAssignment && memberDecl.objectAssignmentInitializer);
if (isOptional) {
prop.flags |= SymbolFlags.Optional;
}
}
else if (contextualTypeHasPattern && !(getObjectFlags(contextualType!) & ObjectFlags.ObjectLiteralPatternWithComputedProperties)) {
// If object literal is contextually typed by the implied type of a binding pattern, and if the
// binding pattern specifies a default value for the property, make the property optional.
const impliedProp = getPropertyOfType(contextualType!, member.escapedName);
if (impliedProp) {
prop.flags |= impliedProp.flags & SymbolFlags.Optional;
}
else if (!compilerOptions.suppressExcessPropertyErrors && !getIndexInfoOfType(contextualType!, IndexKind.String)) {
error(memberDecl.name, Diagnostics.Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1,
symbolToString(member), typeToString(contextualType!));
}
}
prop.declarations = member.declarations;
prop.parent = member.parent;
if (member.valueDeclaration) {
prop.valueDeclaration = member.valueDeclaration;
}
prop.type = type;
prop.target = member;
member = prop;
}
else if (memberDecl.kind === SyntaxKind.SpreadAssignment) {
if (languageVersion < ScriptTarget.ES2015) {
checkExternalEmitHelpers(memberDecl, ExternalEmitHelpers.Assign);
}
if (propertiesArray.length > 0) {
spread = getSpreadType(spread, createObjectLiteralType(), node.symbol, objectFlags, inConstContext);
propertiesArray = [];
propertiesTable = createSymbolTable();
hasComputedStringProperty = false;
hasComputedNumberProperty = false;
}
const type = checkExpression(memberDecl.expression);
if (!isValidSpreadType(type)) {
error(memberDecl, Diagnostics.Spread_types_may_only_be_created_from_object_types);
return errorType;
}
spread = getSpreadType(spread, type, node.symbol, objectFlags, inConstContext);
offset = i + 1;
continue;
}
else {
// TypeScript 1.0 spec (April 2014)
// A get accessor declaration is processed in the same manner as
// an ordinary function declaration(section 6.1) with no parameters.
// A set accessor declaration is processed in the same manner
// as an ordinary function declaration with a single parameter and a Void return type.
Debug.assert(memberDecl.kind === SyntaxKind.GetAccessor || memberDecl.kind === SyntaxKind.SetAccessor);
checkNodeDeferred(memberDecl);
}
if (computedNameType && !(computedNameType.flags & TypeFlags.StringOrNumberLiteralOrUnique)) {
if (isTypeAssignableTo(computedNameType, stringNumberSymbolType)) {
if (isTypeAssignableTo(computedNameType, numberType)) {
hasComputedNumberProperty = true;
}
else {
hasComputedStringProperty = true;
}
if (inDestructuringPattern) {
patternWithComputedProperties = true;
}
}
}
else {
propertiesTable.set(member.escapedName, member);
}
propertiesArray.push(member);
}
// If object literal is contextually typed by the implied type of a binding pattern, augment the result
// type with those properties for which the binding pattern specifies a default value.
if (contextualTypeHasPattern) {
for (const prop of getPropertiesOfType(contextualType!)) {
if (!propertiesTable.get(prop.escapedName) && !(spread && getPropertyOfType(spread, prop.escapedName))) {
if (!(prop.flags & SymbolFlags.Optional)) {
error(prop.valueDeclaration || (<TransientSymbol>prop).bindingElement,
Diagnostics.Initializer_provides_no_value_for_this_binding_element_and_the_binding_element_has_no_default_value);
}
propertiesTable.set(prop.escapedName, prop);
propertiesArray.push(prop);
}
}
}
if (spread !== emptyObjectType) {
if (propertiesArray.length > 0) {
spread = getSpreadType(spread, createObjectLiteralType(), node.symbol, objectFlags, inConstContext);
}
return spread;
}
return createObjectLiteralType();
function createObjectLiteralType() {
const stringIndexInfo = hasComputedStringProperty ? getObjectLiteralIndexInfo(node, offset, propertiesArray, IndexKind.String) : undefined;
const numberIndexInfo = hasComputedNumberProperty ? getObjectLiteralIndexInfo(node, offset, propertiesArray, IndexKind.Number) : undefined;
const result = createAnonymousType(node.symbol, propertiesTable, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
result.objectFlags |= objectFlags | ObjectFlags.ObjectLiteral | ObjectFlags.ContainsObjectLiteral;
if (isJSObjectLiteral) {
result.objectFlags |= ObjectFlags.JSLiteral;
}
if (patternWithComputedProperties) {
result.objectFlags |= ObjectFlags.ObjectLiteralPatternWithComputedProperties;
}
if (inDestructuringPattern) {
result.pattern = node;
}
return result;
}
}
function isValidSpreadType(type: Type): boolean {
return !!(type.flags & (TypeFlags.AnyOrUnknown | TypeFlags.NonPrimitive | TypeFlags.Object | TypeFlags.InstantiableNonPrimitive) ||
getFalsyFlags(type) & TypeFlags.DefinitelyFalsy && isValidSpreadType(removeDefinitelyFalsyTypes(type)) ||
type.flags & TypeFlags.UnionOrIntersection && every((<UnionOrIntersectionType>type).types, isValidSpreadType));
}
function checkJsxSelfClosingElementDeferred(node: JsxSelfClosingElement) {
checkJsxOpeningLikeElementOrOpeningFragment(node);
}
function checkJsxSelfClosingElement(node: JsxSelfClosingElement, _checkMode: CheckMode | undefined): Type {
checkNodeDeferred(node);
return getJsxElementTypeAt(node) || anyType;
}
function checkJsxElementDeferred(node: JsxElement) {
// Check attributes
checkJsxOpeningLikeElementOrOpeningFragment(node.openingElement);
// Perform resolution on the closing tag so that rename/go to definition/etc work
if (isJsxIntrinsicIdentifier(node.closingElement.tagName)) {
getIntrinsicTagSymbol(node.closingElement);
}
else {
checkExpression(node.closingElement.tagName);
}
checkJsxChildren(node);
}
function checkJsxElement(node: JsxElement, _checkMode: CheckMode | undefined): Type {
checkNodeDeferred(node);
return getJsxElementTypeAt(node) || anyType;
}
function checkJsxFragment(node: JsxFragment): Type {
checkJsxOpeningLikeElementOrOpeningFragment(node.openingFragment);
if (compilerOptions.jsx === JsxEmit.React && (compilerOptions.jsxFactory || getSourceFileOfNode(node).pragmas.has("jsx"))) {
error(node, compilerOptions.jsxFactory
? Diagnostics.JSX_fragment_is_not_supported_when_using_jsxFactory
: Diagnostics.JSX_fragment_is_not_supported_when_using_an_inline_JSX_factory_pragma);
}
checkJsxChildren(node);
return getJsxElementTypeAt(node) || anyType;
}
/**
* Returns true iff the JSX element name would be a valid JS identifier, ignoring restrictions about keywords not being identifiers
*/
function isUnhyphenatedJsxName(name: string | __String) {
// - is the only character supported in JSX attribute names that isn't valid in JavaScript identifiers
return !stringContains(name as string, "-");
}
/**
* Returns true iff React would emit this tag name as a string rather than an identifier or qualified name
*/
function isJsxIntrinsicIdentifier(tagName: JsxTagNameExpression): boolean {
return tagName.kind === SyntaxKind.Identifier && isIntrinsicJsxName(tagName.escapedText);
}
function checkJsxAttribute(node: JsxAttribute, checkMode?: CheckMode) {
return node.initializer
? checkExpressionForMutableLocation(node.initializer, checkMode)
: trueType; // <Elem attr /> is sugar for <Elem attr={true} />
}
/**
* Get attributes type of the JSX opening-like element. The result is from resolving "attributes" property of the opening-like element.
*
* @param openingLikeElement a JSX opening-like element
* @param filter a function to remove attributes that will not participate in checking whether attributes are assignable
* @return an anonymous type (similar to the one returned by checkObjectLiteral) in which its properties are attributes property.
* @remarks Because this function calls getSpreadType, it needs to use the same checks as checkObjectLiteral,
* which also calls getSpreadType.
*/
function createJsxAttributesTypeFromAttributesProperty(openingLikeElement: JsxOpeningLikeElement, checkMode: CheckMode | undefined) {
const attributes = openingLikeElement.attributes;
let attributesTable = createSymbolTable();
let spread: Type = emptyJsxObjectType;
let hasSpreadAnyType = false;
let typeToIntersect: Type | undefined;
let explicitlySpecifyChildrenAttribute = false;
let objectFlags: ObjectFlags = ObjectFlags.JsxAttributes;
const jsxChildrenPropertyName = getJsxElementChildrenPropertyName(getJsxNamespaceAt(openingLikeElement));
for (const attributeDecl of attributes.properties) {
const member = attributeDecl.symbol;
if (isJsxAttribute(attributeDecl)) {
const exprType = checkJsxAttribute(attributeDecl, checkMode);
objectFlags |= getObjectFlags(exprType) & ObjectFlags.PropagatingFlags;
const attributeSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Transient | member.flags, member.escapedName);
attributeSymbol.declarations = member.declarations;
attributeSymbol.parent = member.parent;
if (member.valueDeclaration) {
attributeSymbol.valueDeclaration = member.valueDeclaration;
}
attributeSymbol.type = exprType;
attributeSymbol.target = member;
attributesTable.set(attributeSymbol.escapedName, attributeSymbol);
if (attributeDecl.name.escapedText === jsxChildrenPropertyName) {
explicitlySpecifyChildrenAttribute = true;
}
}
else {
Debug.assert(attributeDecl.kind === SyntaxKind.JsxSpreadAttribute);
if (attributesTable.size > 0) {
spread = getSpreadType(spread, createJsxAttributesType(), attributes.symbol, objectFlags, /*readonly*/ false);
attributesTable = createSymbolTable();
}
const exprType = checkExpressionCached(attributeDecl.expression, checkMode);
if (isTypeAny(exprType)) {
hasSpreadAnyType = true;
}
if (isValidSpreadType(exprType)) {
spread = getSpreadType(spread, exprType, attributes.symbol, objectFlags, /*readonly*/ false);
}
else {
typeToIntersect = typeToIntersect ? getIntersectionType([typeToIntersect, exprType]) : exprType;
}
}
}
if (!hasSpreadAnyType) {
if (attributesTable.size > 0) {
spread = getSpreadType(spread, createJsxAttributesType(), attributes.symbol, objectFlags, /*readonly*/ false);
}
}
// Handle children attribute
const parent = openingLikeElement.parent.kind === SyntaxKind.JsxElement ? openingLikeElement.parent as JsxElement : undefined;
// We have to check that openingElement of the parent is the one we are visiting as this may not be true for selfClosingElement
if (parent && parent.openingElement === openingLikeElement && parent.children.length > 0) {
const childrenTypes: Type[] = checkJsxChildren(parent, checkMode);
if (!hasSpreadAnyType && jsxChildrenPropertyName && jsxChildrenPropertyName !== "") {
// Error if there is a attribute named "children" explicitly specified and children element.
// This is because children element will overwrite the value from attributes.
// Note: we will not warn "children" attribute overwritten if "children" attribute is specified in object spread.
if (explicitlySpecifyChildrenAttribute) {
error(attributes, Diagnostics._0_are_specified_twice_The_attribute_named_0_will_be_overwritten, unescapeLeadingUnderscores(jsxChildrenPropertyName));
}
const contextualType = getApparentTypeOfContextualType(openingLikeElement.attributes);
const childrenContextualType = contextualType && getTypeOfPropertyOfContextualType(contextualType, jsxChildrenPropertyName);
// If there are children in the body of JSX element, create dummy attribute "children" with the union of children types so that it will pass the attribute checking process
const childrenPropSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Transient, jsxChildrenPropertyName);
childrenPropSymbol.type = childrenTypes.length === 1 ?
childrenTypes[0] :
(getArrayLiteralTupleTypeIfApplicable(childrenTypes, childrenContextualType, /*hasRestElement*/ false) || createArrayType(getUnionType(childrenTypes)));
// Fake up a property declaration for the children
childrenPropSymbol.valueDeclaration = createPropertySignature(/*modifiers*/ undefined, unescapeLeadingUnderscores(jsxChildrenPropertyName), /*questionToken*/ undefined, /*type*/ undefined, /*initializer*/ undefined);
childrenPropSymbol.valueDeclaration.parent = attributes;
childrenPropSymbol.valueDeclaration.symbol = childrenPropSymbol;
const childPropMap = createSymbolTable();
childPropMap.set(jsxChildrenPropertyName, childrenPropSymbol);
spread = getSpreadType(spread, createAnonymousType(attributes.symbol, childPropMap, emptyArray, emptyArray, /*stringIndexInfo*/ undefined, /*numberIndexInfo*/ undefined),
attributes.symbol, objectFlags, /*readonly*/ false);
}
}
if (hasSpreadAnyType) {
return anyType;
}
if (typeToIntersect && spread !== emptyJsxObjectType) {
return getIntersectionType([typeToIntersect, spread]);
}
return typeToIntersect || (spread === emptyJsxObjectType ? createJsxAttributesType() : spread);
/**
* Create anonymous type from given attributes symbol table.
* @param symbol a symbol of JsxAttributes containing attributes corresponding to attributesTable
* @param attributesTable a symbol table of attributes property
*/
function createJsxAttributesType() {
objectFlags |= freshObjectLiteralFlag;
const result = createAnonymousType(attributes.symbol, attributesTable, emptyArray, emptyArray, /*stringIndexInfo*/ undefined, /*numberIndexInfo*/ undefined);
result.objectFlags |= objectFlags | ObjectFlags.ObjectLiteral | ObjectFlags.ContainsObjectLiteral;
return result;
}
}
function checkJsxChildren(node: JsxElement | JsxFragment, checkMode?: CheckMode) {
const childrenTypes: Type[] = [];
for (const child of node.children) {
// In React, JSX text that contains only whitespaces will be ignored so we don't want to type-check that
// because then type of children property will have constituent of string type.
if (child.kind === SyntaxKind.JsxText) {
if (!child.containsOnlyWhiteSpaces) {
childrenTypes.push(stringType);
}
}
else {
childrenTypes.push(checkExpressionForMutableLocation(child, checkMode));
}
}
return childrenTypes;
}
/**
* Check attributes property of opening-like element. This function is called during chooseOverload to get call signature of a JSX opening-like element.
* (See "checkApplicableSignatureForJsxOpeningLikeElement" for how the function is used)
* @param node a JSXAttributes to be resolved of its type
*/
function checkJsxAttributes(node: JsxAttributes, checkMode: CheckMode | undefined) {
return createJsxAttributesTypeFromAttributesProperty(node.parent, checkMode);
}
function getJsxType(name: __String, location: Node | undefined) {
const namespace = getJsxNamespaceAt(location);
const exports = namespace && getExportsOfSymbol(namespace);
const typeSymbol = exports && getSymbol(exports, name, SymbolFlags.Type);
return typeSymbol ? getDeclaredTypeOfSymbol(typeSymbol) : errorType;
}
/**
* Looks up an intrinsic tag name and returns a symbol that either points to an intrinsic
* property (in which case nodeLinks.jsxFlags will be IntrinsicNamedElement) or an intrinsic
* string index signature (in which case nodeLinks.jsxFlags will be IntrinsicIndexedElement).
* May also return unknownSymbol if both of these lookups fail.
*/
function getIntrinsicTagSymbol(node: JsxOpeningLikeElement | JsxClosingElement): Symbol {
const links = getNodeLinks(node);
if (!links.resolvedSymbol) {
const intrinsicElementsType = getJsxType(JsxNames.IntrinsicElements, node);
if (intrinsicElementsType !== errorType) {
// Property case
if (!isIdentifier(node.tagName)) return Debug.fail();
const intrinsicProp = getPropertyOfType(intrinsicElementsType, node.tagName.escapedText);
if (intrinsicProp) {
links.jsxFlags |= JsxFlags.IntrinsicNamedElement;
return links.resolvedSymbol = intrinsicProp;
}
// Intrinsic string indexer case
const indexSignatureType = getIndexTypeOfType(intrinsicElementsType, IndexKind.String);
if (indexSignatureType) {
links.jsxFlags |= JsxFlags.IntrinsicIndexedElement;
return links.resolvedSymbol = intrinsicElementsType.symbol;
}
// Wasn't found
error(node, Diagnostics.Property_0_does_not_exist_on_type_1, idText(node.tagName), "JSX." + JsxNames.IntrinsicElements);
return links.resolvedSymbol = unknownSymbol;
}
else {
if (noImplicitAny) {
error(node, Diagnostics.JSX_element_implicitly_has_type_any_because_no_interface_JSX_0_exists, unescapeLeadingUnderscores(JsxNames.IntrinsicElements));
}
return links.resolvedSymbol = unknownSymbol;
}
}
return links.resolvedSymbol;
}
function getJsxNamespaceAt(location: Node | undefined): Symbol {
const links = location && getNodeLinks(location);
if (links && links.jsxNamespace) {
return links.jsxNamespace;
}
if (!links || links.jsxNamespace !== false) {
const namespaceName = getJsxNamespace(location);
const resolvedNamespace = resolveName(location, namespaceName, SymbolFlags.Namespace, /*diagnosticMessage*/ undefined, namespaceName, /*isUse*/ false);
if (resolvedNamespace) {
const candidate = resolveSymbol(getSymbol(getExportsOfSymbol(resolveSymbol(resolvedNamespace)), JsxNames.JSX, SymbolFlags.Namespace));
if (candidate) {
if (links) {
links.jsxNamespace = candidate;
}
return candidate;
}
if (links) {
links.jsxNamespace = false;
}
}
}
// JSX global fallback
return getGlobalSymbol(JsxNames.JSX, SymbolFlags.Namespace, /*diagnosticMessage*/ undefined)!; // TODO: GH#18217
}
/**
* Look into JSX namespace and then look for container with matching name as nameOfAttribPropContainer.
* Get a single property from that container if existed. Report an error if there are more than one property.
*
* @param nameOfAttribPropContainer a string of value JsxNames.ElementAttributesPropertyNameContainer or JsxNames.ElementChildrenAttributeNameContainer
* if other string is given or the container doesn't exist, return undefined.
*/
function getNameFromJsxElementAttributesContainer(nameOfAttribPropContainer: __String, jsxNamespace: Symbol): __String | undefined {
// JSX.ElementAttributesProperty | JSX.ElementChildrenAttribute [symbol]
const jsxElementAttribPropInterfaceSym = jsxNamespace && getSymbol(jsxNamespace.exports!, nameOfAttribPropContainer, SymbolFlags.Type);
// JSX.ElementAttributesProperty | JSX.ElementChildrenAttribute [type]
const jsxElementAttribPropInterfaceType = jsxElementAttribPropInterfaceSym && getDeclaredTypeOfSymbol(jsxElementAttribPropInterfaceSym);
// The properties of JSX.ElementAttributesProperty | JSX.ElementChildrenAttribute
const propertiesOfJsxElementAttribPropInterface = jsxElementAttribPropInterfaceType && getPropertiesOfType(jsxElementAttribPropInterfaceType);
if (propertiesOfJsxElementAttribPropInterface) {
// Element Attributes has zero properties, so the element attributes type will be the class instance type
if (propertiesOfJsxElementAttribPropInterface.length === 0) {
return "" as __String;
}
// Element Attributes has one property, so the element attributes type will be the type of the corresponding
// property of the class instance type
else if (propertiesOfJsxElementAttribPropInterface.length === 1) {
return propertiesOfJsxElementAttribPropInterface[0].escapedName;
}
else if (propertiesOfJsxElementAttribPropInterface.length > 1) {
// More than one property on ElementAttributesProperty is an error
error(jsxElementAttribPropInterfaceSym!.declarations[0], Diagnostics.The_global_type_JSX_0_may_not_have_more_than_one_property, unescapeLeadingUnderscores(nameOfAttribPropContainer));
}
}
return undefined;
}
function getJsxLibraryManagedAttributes(jsxNamespace: Symbol) {
// JSX.LibraryManagedAttributes [symbol]
return jsxNamespace && getSymbol(jsxNamespace.exports!, JsxNames.LibraryManagedAttributes, SymbolFlags.Type);
}
/// e.g. "props" for React.d.ts,
/// or 'undefined' if ElementAttributesProperty doesn't exist (which means all
/// non-intrinsic elements' attributes type is 'any'),
/// or '' if it has 0 properties (which means every
/// non-intrinsic elements' attributes type is the element instance type)
function getJsxElementPropertiesName(jsxNamespace: Symbol) {
return getNameFromJsxElementAttributesContainer(JsxNames.ElementAttributesPropertyNameContainer, jsxNamespace);
}
function getJsxElementChildrenPropertyName(jsxNamespace: Symbol): __String | undefined {
return getNameFromJsxElementAttributesContainer(JsxNames.ElementChildrenAttributeNameContainer, jsxNamespace);
}
function getUninstantiatedJsxSignaturesOfType(elementType: Type, caller: JsxOpeningLikeElement): ReadonlyArray<Signature> {
if (elementType.flags & TypeFlags.String) {
return [anySignature];
}
else if (elementType.flags & TypeFlags.StringLiteral) {
const intrinsicType = getIntrinsicAttributesTypeFromStringLiteralType(elementType as StringLiteralType, caller);
if (!intrinsicType) {
error(caller, Diagnostics.Property_0_does_not_exist_on_type_1, (elementType as StringLiteralType).value, "JSX." + JsxNames.IntrinsicElements);
return emptyArray;
}
else {
const fakeSignature = createSignatureForJSXIntrinsic(caller, intrinsicType);
return [fakeSignature];
}
}
const apparentElemType = getApparentType(elementType);
// Resolve the signatures, preferring constructor
let signatures = getSignaturesOfType(apparentElemType, SignatureKind.Construct);
if (signatures.length === 0) {
// No construct signatures, try call signatures
signatures = getSignaturesOfType(apparentElemType, SignatureKind.Call);
}
if (signatures.length === 0 && apparentElemType.flags & TypeFlags.Union) {
// If each member has some combination of new/call signatures; make a union signature list for those
signatures = getUnionSignatures(map((apparentElemType as UnionType).types, t => getUninstantiatedJsxSignaturesOfType(t, caller)));
}
return signatures;
}
function getIntrinsicAttributesTypeFromStringLiteralType(type: StringLiteralType, location: Node): Type | undefined {
// If the elemType is a stringLiteral type, we can then provide a check to make sure that the string literal type is one of the Jsx intrinsic element type
// For example:
// var CustomTag: "h1" = "h1";
// <CustomTag> Hello World </CustomTag>
const intrinsicElementsType = getJsxType(JsxNames.IntrinsicElements, location);
if (intrinsicElementsType !== errorType) {
const stringLiteralTypeName = type.value;
const intrinsicProp = getPropertyOfType(intrinsicElementsType, escapeLeadingUnderscores(stringLiteralTypeName));
if (intrinsicProp) {
return getTypeOfSymbol(intrinsicProp);
}
const indexSignatureType = getIndexTypeOfType(intrinsicElementsType, IndexKind.String);
if (indexSignatureType) {
return indexSignatureType;
}
return undefined;
}
// If we need to report an error, we already done so here. So just return any to prevent any more error downstream
return anyType;
}
function checkJsxReturnAssignableToAppropriateBound(refKind: JsxReferenceKind, elemInstanceType: Type, openingLikeElement: Node) {
if (refKind === JsxReferenceKind.Function) {
const sfcReturnConstraint = getJsxStatelessElementTypeAt(openingLikeElement);
if (sfcReturnConstraint) {
checkTypeRelatedTo(elemInstanceType, sfcReturnConstraint, assignableRelation, openingLikeElement, Diagnostics.JSX_element_type_0_is_not_a_constructor_function_for_JSX_elements);
}
}
else if (refKind === JsxReferenceKind.Component) {
const classConstraint = getJsxElementClassTypeAt(openingLikeElement);
if (classConstraint) {
// Issue an error if this return type isn't assignable to JSX.ElementClass or JSX.Element, failing that
checkTypeRelatedTo(elemInstanceType, classConstraint, assignableRelation, openingLikeElement, Diagnostics.JSX_element_type_0_is_not_a_constructor_function_for_JSX_elements);
}
}
else { // Mixed
const sfcReturnConstraint = getJsxStatelessElementTypeAt(openingLikeElement);
const classConstraint = getJsxElementClassTypeAt(openingLikeElement);
if (!sfcReturnConstraint || !classConstraint) {
return;
}
const combined = getUnionType([sfcReturnConstraint, classConstraint]);
checkTypeRelatedTo(elemInstanceType, combined, assignableRelation, openingLikeElement, Diagnostics.JSX_element_type_0_is_not_a_constructor_function_for_JSX_elements);
}
}
/**
* Get attributes type of the given intrinsic opening-like Jsx element by resolving the tag name.
* The function is intended to be called from a function which has checked that the opening element is an intrinsic element.
* @param node an intrinsic JSX opening-like element
*/
function getIntrinsicAttributesTypeFromJsxOpeningLikeElement(node: JsxOpeningLikeElement): Type {
Debug.assert(isJsxIntrinsicIdentifier(node.tagName));
const links = getNodeLinks(node);
if (!links.resolvedJsxElementAttributesType) {
const symbol = getIntrinsicTagSymbol(node);
if (links.jsxFlags & JsxFlags.IntrinsicNamedElement) {
return links.resolvedJsxElementAttributesType = getTypeOfSymbol(symbol);
}
else if (links.jsxFlags & JsxFlags.IntrinsicIndexedElement) {
return links.resolvedJsxElementAttributesType = getIndexInfoOfSymbol(symbol, IndexKind.String)!.type;
}
else {
return links.resolvedJsxElementAttributesType = errorType;
}
}
return links.resolvedJsxElementAttributesType;
}
function getJsxElementClassTypeAt(location: Node): Type | undefined {
const type = getJsxType(JsxNames.ElementClass, location);
if (type === errorType) return undefined;
return type;
}
function getJsxElementTypeAt(location: Node): Type {
return getJsxType(JsxNames.Element, location);
}
function getJsxStatelessElementTypeAt(location: Node): Type | undefined {
const jsxElementType = getJsxElementTypeAt(location);
if (jsxElementType) {
return getUnionType([jsxElementType, nullType]);
}
}
/**
* Returns all the properties of the Jsx.IntrinsicElements interface
*/
function getJsxIntrinsicTagNamesAt(location: Node): Symbol[] {
const intrinsics = getJsxType(JsxNames.IntrinsicElements, location);
return intrinsics ? getPropertiesOfType(intrinsics) : emptyArray;
}
function checkJsxPreconditions(errorNode: Node) {
// Preconditions for using JSX
if ((compilerOptions.jsx || JsxEmit.None) === JsxEmit.None) {
error(errorNode, Diagnostics.Cannot_use_JSX_unless_the_jsx_flag_is_provided);
}
if (getJsxElementTypeAt(errorNode) === undefined) {
if (noImplicitAny) {
error(errorNode, Diagnostics.JSX_element_implicitly_has_type_any_because_the_global_type_JSX_Element_does_not_exist);
}
}
}
function checkJsxOpeningLikeElementOrOpeningFragment(node: JsxOpeningLikeElement | JsxOpeningFragment) {
const isNodeOpeningLikeElement = isJsxOpeningLikeElement(node);
if (isNodeOpeningLikeElement) {
checkGrammarJsxElement(<JsxOpeningLikeElement>node);
}
checkJsxPreconditions(node);
// The reactNamespace/jsxFactory's root symbol should be marked as 'used' so we don't incorrectly elide its import.
// And if there is no reactNamespace/jsxFactory's symbol in scope when targeting React emit, we should issue an error.
const reactRefErr = diagnostics && compilerOptions.jsx === JsxEmit.React ? Diagnostics.Cannot_find_name_0 : undefined;
const reactNamespace = getJsxNamespace(node);
const reactLocation = isNodeOpeningLikeElement ? (<JsxOpeningLikeElement>node).tagName : node;
const reactSym = resolveName(reactLocation, reactNamespace, SymbolFlags.Value, reactRefErr, reactNamespace, /*isUse*/ true);
if (reactSym) {
// Mark local symbol as referenced here because it might not have been marked
// if jsx emit was not react as there wont be error being emitted
reactSym.isReferenced = SymbolFlags.All;
// If react symbol is alias, mark it as referenced
if (reactSym.flags & SymbolFlags.Alias && !isConstEnumOrConstEnumOnlyModule(resolveAlias(reactSym))) {
markAliasSymbolAsReferenced(reactSym);
}
}
if (isNodeOpeningLikeElement) {
const sig = getResolvedSignature(node as JsxOpeningLikeElement);
checkJsxReturnAssignableToAppropriateBound(getJsxReferenceKind(node as JsxOpeningLikeElement), getReturnTypeOfSignature(sig), node);
}
}
/**
* Check if a property with the given name is known anywhere in the given type. In an object type, a property
* is considered known if
* 1. the object type is empty and the check is for assignability, or
* 2. if the object type has index signatures, or
* 3. if the property is actually declared in the object type
* (this means that 'toString', for example, is not usually a known property).
* 4. In a union or intersection type,
* a property is considered known if it is known in any constituent type.
* @param targetType a type to search a given name in
* @param name a property name to search
* @param isComparingJsxAttributes a boolean flag indicating whether we are searching in JsxAttributesType
*/
function isKnownProperty(targetType: Type, name: __String, isComparingJsxAttributes: boolean): boolean {
if (targetType.flags & TypeFlags.Object) {
const resolved = resolveStructuredTypeMembers(targetType as ObjectType);
if (resolved.stringIndexInfo ||
resolved.numberIndexInfo && isNumericLiteralName(name) ||
getPropertyOfObjectType(targetType, name) ||
isComparingJsxAttributes && !isUnhyphenatedJsxName(name)) {
// For JSXAttributes, if the attribute has a hyphenated name, consider that the attribute to be known.
return true;
}
}
else if (targetType.flags & TypeFlags.UnionOrIntersection && isExcessPropertyCheckTarget(targetType)) {
for (const t of (targetType as UnionOrIntersectionType).types) {
if (isKnownProperty(t, name, isComparingJsxAttributes)) {
return true;
}
}
}
return false;
}
function isExcessPropertyCheckTarget(type: Type): boolean {
return !!(type.flags & TypeFlags.Object && !(getObjectFlags(type) & ObjectFlags.ObjectLiteralPatternWithComputedProperties) ||
type.flags & TypeFlags.NonPrimitive ||
type.flags & TypeFlags.Union && some((<UnionType>type).types, isExcessPropertyCheckTarget) ||
type.flags & TypeFlags.Intersection && every((<IntersectionType>type).types, isExcessPropertyCheckTarget));
}
function checkJsxExpression(node: JsxExpression, checkMode?: CheckMode) {
if (node.expression) {
const type = checkExpression(node.expression, checkMode);
if (node.dotDotDotToken && type !== anyType && !isArrayType(type)) {
error(node, Diagnostics.JSX_spread_child_must_be_an_array_type);
}
return type;
}
else {
return errorType;
}
}
function getDeclarationNodeFlagsFromSymbol(s: Symbol): NodeFlags {
return s.valueDeclaration ? getCombinedNodeFlags(s.valueDeclaration) : 0;
}
/**
* Return whether this symbol is a member of a prototype somewhere
* Note that this is not tracked well within the compiler, so the answer may be incorrect.
*/
function isPrototypeProperty(symbol: Symbol) {
if (symbol.flags & SymbolFlags.Method || getCheckFlags(symbol) & CheckFlags.SyntheticMethod) {
return true;
}
if (isInJSFile(symbol.valueDeclaration)) {
const parent = symbol.valueDeclaration.parent;
return parent && isBinaryExpression(parent) &&
getAssignmentDeclarationKind(parent) === AssignmentDeclarationKind.PrototypeProperty;
}
}
/**
* Check whether the requested property access is valid.
* Returns true if node is a valid property access, and false otherwise.
* @param node The node to be checked.
* @param isSuper True if the access is from `super.`.
* @param type The type of the object whose property is being accessed. (Not the type of the property.)
* @param prop The symbol for the property being accessed.
*/
function checkPropertyAccessibility(
node: PropertyAccessExpression | QualifiedName | PropertyAccessExpression | VariableDeclaration | ParameterDeclaration | ImportTypeNode | PropertyAssignment | ShorthandPropertyAssignment | BindingElement,
isSuper: boolean, type: Type, prop: Symbol): boolean {
const flags = getDeclarationModifierFlagsFromSymbol(prop);
const errorNode = node.kind === SyntaxKind.QualifiedName ? node.right : node.kind === SyntaxKind.ImportType ? node : node.name;
if (getCheckFlags(prop) & CheckFlags.ContainsPrivate) {
// Synthetic property with private constituent property
error(errorNode, Diagnostics.Property_0_has_conflicting_declarations_and_is_inaccessible_in_type_1, symbolToString(prop), typeToString(type));
return false;
}
if (isSuper) {
// TS 1.0 spec (April 2014): 4.8.2
// - In a constructor, instance member function, instance member accessor, or
// instance member variable initializer where this references a derived class instance,
// a super property access is permitted and must specify a public instance member function of the base class.
// - In a static member function or static member accessor
// where this references the constructor function object of a derived class,
// a super property access is permitted and must specify a public static member function of the base class.
if (languageVersion < ScriptTarget.ES2015) {
if (symbolHasNonMethodDeclaration(prop)) {
error(errorNode, Diagnostics.Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword);
return false;
}
}
if (flags & ModifierFlags.Abstract) {
// A method cannot be accessed in a super property access if the method is abstract.
// This error could mask a private property access error. But, a member
// cannot simultaneously be private and abstract, so this will trigger an
// additional error elsewhere.
error(errorNode, Diagnostics.Abstract_method_0_in_class_1_cannot_be_accessed_via_super_expression, symbolToString(prop), typeToString(getDeclaringClass(prop)!));
return false;
}
}
// Referencing abstract properties within their own constructors is not allowed
if ((flags & ModifierFlags.Abstract) && isThisProperty(node) && symbolHasNonMethodDeclaration(prop)) {
const declaringClassDeclaration = getClassLikeDeclarationOfSymbol(getParentOfSymbol(prop)!);
if (declaringClassDeclaration && isNodeUsedDuringClassInitialization(node)) {
error(errorNode, Diagnostics.Abstract_property_0_in_class_1_cannot_be_accessed_in_the_constructor, symbolToString(prop), getTextOfIdentifierOrLiteral(declaringClassDeclaration.name!)); // TODO: GH#18217
return false;
}
}
// Public properties are otherwise accessible.
if (!(flags & ModifierFlags.NonPublicAccessibilityModifier)) {
return true;
}
// Property is known to be private or protected at this point
// Private property is accessible if the property is within the declaring class
if (flags & ModifierFlags.Private) {
const declaringClassDeclaration = getClassLikeDeclarationOfSymbol(getParentOfSymbol(prop)!)!;
if (!isNodeWithinClass(node, declaringClassDeclaration)) {
error(errorNode, Diagnostics.Property_0_is_private_and_only_accessible_within_class_1, symbolToString(prop), typeToString(getDeclaringClass(prop)!));
return false;
}
return true;
}
// Property is known to be protected at this point
// All protected properties of a supertype are accessible in a super access
if (isSuper) {
return true;
}
// Find the first enclosing class that has the declaring classes of the protected constituents
// of the property as base classes
let enclosingClass = forEachEnclosingClass(node, enclosingDeclaration => {
const enclosingClass = <InterfaceType>getDeclaredTypeOfSymbol(getSymbolOfNode(enclosingDeclaration)!);
return isClassDerivedFromDeclaringClasses(enclosingClass, prop) ? enclosingClass : undefined;
});
// A protected property is accessible if the property is within the declaring class or classes derived from it
if (!enclosingClass) {
// allow PropertyAccessibility if context is in function with this parameter
// static member access is disallow
let thisParameter: ParameterDeclaration | undefined;
if (flags & ModifierFlags.Static || !(thisParameter = getThisParameterFromNodeContext(node)) || !thisParameter.type) {
error(errorNode, Diagnostics.Property_0_is_protected_and_only_accessible_within_class_1_and_its_subclasses, symbolToString(prop), typeToString(getDeclaringClass(prop) || type));
return false;
}
const thisType = getTypeFromTypeNode(thisParameter.type);
enclosingClass = ((thisType.flags & TypeFlags.TypeParameter) ? getConstraintOfTypeParameter(<TypeParameter>thisType) : thisType) as InterfaceType;
}
// No further restrictions for static properties
if (flags & ModifierFlags.Static) {
return true;
}
if (type.flags & TypeFlags.TypeParameter) {
// get the original type -- represented as the type constraint of the 'this' type
type = (type as TypeParameter).isThisType ? getConstraintOfTypeParameter(<TypeParameter>type)! : getBaseConstraintOfType(<TypeParameter>type)!; // TODO: GH#18217 Use a different variable that's allowed to be undefined
}
if (!type || !hasBaseType(type, enclosingClass)) {
error(errorNode, Diagnostics.Property_0_is_protected_and_only_accessible_through_an_instance_of_class_1, symbolToString(prop), typeToString(enclosingClass));
return false;
}
return true;
}
function getThisParameterFromNodeContext (node: Node) {
const thisContainer = getThisContainer(node, /* includeArrowFunctions */ false);
return thisContainer && isFunctionLike(thisContainer) ? getThisParameter(thisContainer) : undefined;
}
function symbolHasNonMethodDeclaration(symbol: Symbol) {
return !!forEachProperty(symbol, prop => !(prop.flags & SymbolFlags.Method));
}
function checkNonNullExpression(
node: Expression | QualifiedName,
nullDiagnostic?: DiagnosticMessage,
undefinedDiagnostic?: DiagnosticMessage,
nullOrUndefinedDiagnostic?: DiagnosticMessage,
) {
return checkNonNullType(
checkExpression(node),
node,
nullDiagnostic,
undefinedDiagnostic,
nullOrUndefinedDiagnostic
);
}
function getNonNullableTypeIfNeeded(type: Type) {
const kind = (strictNullChecks ? getFalsyFlags(type) : type.flags) & TypeFlags.Nullable;
if (kind) {
return getNonNullableType(type);
}
return type;
}
function checkNonNullType(
type: Type,
node: Node,
nullDiagnostic?: DiagnosticMessage,
undefinedDiagnostic?: DiagnosticMessage,
nullOrUndefinedDiagnostic?: DiagnosticMessage
): Type {
if (type.flags & TypeFlags.Unknown) {
error(node, Diagnostics.Object_is_of_type_unknown);
return errorType;
}
const kind = (strictNullChecks ? getFalsyFlags(type) : type.flags) & TypeFlags.Nullable;
if (kind) {
error(node, kind & TypeFlags.Undefined ? kind & TypeFlags.Null ?
(nullOrUndefinedDiagnostic || Diagnostics.Object_is_possibly_null_or_undefined) :
(undefinedDiagnostic || Diagnostics.Object_is_possibly_undefined) :
(nullDiagnostic || Diagnostics.Object_is_possibly_null)
);
const t = getNonNullableType(type);
return t.flags & (TypeFlags.Nullable | TypeFlags.Never) ? errorType : t;
}
return type;
}
function checkPropertyAccessExpression(node: PropertyAccessExpression) {
return checkPropertyAccessExpressionOrQualifiedName(node, node.expression, node.name);
}
function checkQualifiedName(node: QualifiedName) {
return checkPropertyAccessExpressionOrQualifiedName(node, node.left, node.right);
}
function checkPropertyAccessExpressionOrQualifiedName(node: PropertyAccessExpression | QualifiedName, left: Expression | QualifiedName, right: Identifier) {
let propType: Type;
const leftType = checkNonNullExpression(left);
const parentSymbol = getNodeLinks(left).resolvedSymbol;
const apparentType = getApparentType(getWidenedType(leftType));
if (isTypeAny(apparentType) || apparentType === silentNeverType) {
if (isIdentifier(left) && parentSymbol) {
markAliasReferenced(parentSymbol, node);
}
return apparentType;
}
const assignmentKind = getAssignmentTargetKind(node);
const prop = getPropertyOfType(apparentType, right.escapedText);
if (isIdentifier(left) && parentSymbol && !(prop && isConstEnumOrConstEnumOnlyModule(prop))) {
markAliasReferenced(parentSymbol, node);
}
if (!prop) {
const indexInfo = getIndexInfoOfType(apparentType, IndexKind.String);
if (!(indexInfo && indexInfo.type)) {
if (isJSLiteralType(leftType)) {
return anyType;
}
if (leftType.symbol === globalThisSymbol) {
if (noImplicitAny) {
error(right, Diagnostics.Element_implicitly_has_an_any_type_because_type_0_has_no_index_signature, typeToString(leftType));
}
return anyType;
}
if (right.escapedText && !checkAndReportErrorForExtendingInterface(node)) {
reportNonexistentProperty(right, leftType.flags & TypeFlags.TypeParameter && (leftType as TypeParameter).isThisType ? apparentType : leftType);
}
return errorType;
}
if (indexInfo.isReadonly && (isAssignmentTarget(node) || isDeleteTarget(node))) {
error(node, Diagnostics.Index_signature_in_type_0_only_permits_reading, typeToString(apparentType));
}
propType = indexInfo.type;
}
else {
checkPropertyNotUsedBeforeDeclaration(prop, node, right);
markPropertyAsReferenced(prop, node, left.kind === SyntaxKind.ThisKeyword);
getNodeLinks(node).resolvedSymbol = prop;
checkPropertyAccessibility(node, left.kind === SyntaxKind.SuperKeyword, apparentType, prop);
if (assignmentKind) {
if (isReferenceToReadonlyEntity(<Expression>node, prop) || isReferenceThroughNamespaceImport(<Expression>node)) {
error(right, Diagnostics.Cannot_assign_to_0_because_it_is_a_read_only_property, idText(right));
return errorType;
}
}
propType = getConstraintForLocation(getTypeOfSymbol(prop), node);
}
// Only compute control flow type if this is a property access expression that isn't an
// assignment target, and the referenced property was declared as a variable, property,
// accessor, or optional method.
if (node.kind !== SyntaxKind.PropertyAccessExpression ||
assignmentKind === AssignmentKind.Definite ||
prop && !(prop.flags & (SymbolFlags.Variable | SymbolFlags.Property | SymbolFlags.Accessor)) && !(prop.flags & SymbolFlags.Method && propType.flags & TypeFlags.Union)) {
return propType;
}
// If strict null checks and strict property initialization checks are enabled, if we have
// a this.xxx property access, if the property is an instance property without an initializer,
// and if we are in a constructor of the same class as the property declaration, assume that
// the property is uninitialized at the top of the control flow.
let assumeUninitialized = false;
if (strictNullChecks && strictPropertyInitialization && left.kind === SyntaxKind.ThisKeyword) {
const declaration = prop && prop.valueDeclaration;
if (declaration && isInstancePropertyWithoutInitializer(declaration)) {
const flowContainer = getControlFlowContainer(node);
if (flowContainer.kind === SyntaxKind.Constructor && flowContainer.parent === declaration.parent) {
assumeUninitialized = true;
}
}
}
else if (strictNullChecks && prop && prop.valueDeclaration &&
isPropertyAccessExpression(prop.valueDeclaration) &&
getAssignmentDeclarationPropertyAccessKind(prop.valueDeclaration) &&
getControlFlowContainer(node) === getControlFlowContainer(prop.valueDeclaration)) {
assumeUninitialized = true;
}
const flowType = getFlowTypeOfReference(node, propType, assumeUninitialized ? getOptionalType(propType) : propType);
if (assumeUninitialized && !(getFalsyFlags(propType) & TypeFlags.Undefined) && getFalsyFlags(flowType) & TypeFlags.Undefined) {
error(right, Diagnostics.Property_0_is_used_before_being_assigned, symbolToString(prop!)); // TODO: GH#18217
// Return the declared type to reduce follow-on errors
return propType;
}
return assignmentKind ? getBaseTypeOfLiteralType(flowType) : flowType;
}
function checkPropertyNotUsedBeforeDeclaration(prop: Symbol, node: PropertyAccessExpression | QualifiedName, right: Identifier): void {
const { valueDeclaration } = prop;
if (!valueDeclaration) {
return;
}
let diagnosticMessage;
const declarationName = idText(right);
if (isInPropertyInitializer(node) &&
!isBlockScopedNameDeclaredBeforeUse(valueDeclaration, right)
&& !isPropertyDeclaredInAncestorClass(prop)) {
diagnosticMessage = error(right, Diagnostics.Property_0_is_used_before_its_initialization, declarationName);
}
else if (valueDeclaration.kind === SyntaxKind.ClassDeclaration &&
node.parent.kind !== SyntaxKind.TypeReference &&
!(valueDeclaration.flags & NodeFlags.Ambient) &&
!isBlockScopedNameDeclaredBeforeUse(valueDeclaration, right)) {
diagnosticMessage = error(right, Diagnostics.Class_0_used_before_its_declaration, declarationName);
}
if (diagnosticMessage) {
addRelatedInfo(diagnosticMessage,
createDiagnosticForNode(valueDeclaration, Diagnostics._0_is_declared_here, declarationName)
);
}
}
function isInPropertyInitializer(node: Node): boolean {
return !!findAncestor(node, node => {
switch (node.kind) {
case SyntaxKind.PropertyDeclaration:
return true;
case SyntaxKind.PropertyAssignment:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
case SyntaxKind.SpreadAssignment:
case SyntaxKind.ComputedPropertyName:
case SyntaxKind.TemplateSpan:
case SyntaxKind.JsxExpression:
case SyntaxKind.JsxAttribute:
case SyntaxKind.JsxAttributes:
case SyntaxKind.JsxSpreadAttribute:
case SyntaxKind.JsxOpeningElement:
case SyntaxKind.ExpressionWithTypeArguments:
case SyntaxKind.HeritageClause:
return false;
default:
return isExpressionNode(node) ? false : "quit";
}
});
}
/**
* It's possible that "prop.valueDeclaration" is a local declaration, but the property was also declared in a superclass.
* In that case we won't consider it used before its declaration, because it gets its value from the superclass' declaration.
*/
function isPropertyDeclaredInAncestorClass(prop: Symbol): boolean {
if (!(prop.parent!.flags & SymbolFlags.Class)) {
return false;
}
let classType: InterfaceType | undefined = getTypeOfSymbol(prop.parent!) as InterfaceType;
while (true) {
classType = classType.symbol && getSuperClass(classType) as InterfaceType | undefined;
if (!classType) {
return false;
}
const superProperty = getPropertyOfType(classType, prop.escapedName);
if (superProperty && superProperty.valueDeclaration) {
return true;
}
}
}
function getSuperClass(classType: InterfaceType): Type | undefined {
const x = getBaseTypes(classType);
if (x.length === 0) {
return undefined;
}
return getIntersectionType(x);
}
function reportNonexistentProperty(propNode: Identifier, containingType: Type) {
let errorInfo: DiagnosticMessageChain | undefined;
let relatedInfo: Diagnostic | undefined;
if (containingType.flags & TypeFlags.Union && !(containingType.flags & TypeFlags.Primitive)) {
for (const subtype of (containingType as UnionType).types) {
if (!getPropertyOfType(subtype, propNode.escapedText)) {
errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1, declarationNameToString(propNode), typeToString(subtype));
break;
}
}
}
if (typeHasStaticProperty(propNode.escapedText, containingType)) {
errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_is_a_static_member_of_type_1, declarationNameToString(propNode), typeToString(containingType));
}
else {
const promisedType = getPromisedTypeOfPromise(containingType);
if (promisedType && getPropertyOfType(promisedType, propNode.escapedText)) {
errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_forget_to_use_await, declarationNameToString(propNode), typeToString(containingType));
}
else {
const suggestion = getSuggestedSymbolForNonexistentProperty(propNode, containingType);
if (suggestion !== undefined) {
const suggestedName = symbolName(suggestion);
errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_mean_2, declarationNameToString(propNode), typeToString(containingType), suggestedName);
relatedInfo = suggestion.valueDeclaration && createDiagnosticForNode(suggestion.valueDeclaration, Diagnostics._0_is_declared_here, suggestedName);
}
else {
errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1, declarationNameToString(propNode), typeToString(containingType));
}
}
}
const resultDiagnostic = createDiagnosticForNodeFromMessageChain(propNode, errorInfo);
if (relatedInfo) {
addRelatedInfo(resultDiagnostic, relatedInfo);
}
diagnostics.add(resultDiagnostic);
}
function typeHasStaticProperty(propName: __String, containingType: Type): boolean {
const prop = containingType.symbol && getPropertyOfType(getTypeOfSymbol(containingType.symbol), propName);
return prop !== undefined && prop.valueDeclaration && hasModifier(prop.valueDeclaration, ModifierFlags.Static);
}
function getSuggestedSymbolForNonexistentProperty(name: Identifier | string, containingType: Type): Symbol | undefined {
return getSpellingSuggestionForName(isString(name) ? name : idText(name), getPropertiesOfType(containingType), SymbolFlags.Value);
}
function getSuggestionForNonexistentProperty(name: Identifier | string, containingType: Type): string | undefined {
const suggestion = getSuggestedSymbolForNonexistentProperty(name, containingType);
return suggestion && symbolName(suggestion);
}
function getSuggestedSymbolForNonexistentSymbol(location: Node | undefined, outerName: __String, meaning: SymbolFlags): Symbol | undefined {
Debug.assert(outerName !== undefined, "outername should always be defined");
const result = resolveNameHelper(location, outerName, meaning, /*nameNotFoundMessage*/ undefined, outerName, /*isUse*/ false, /*excludeGlobals*/ false, (symbols, name, meaning) => {
Debug.assertEqual(outerName, name, "name should equal outerName");
const symbol = getSymbol(symbols, name, meaning);
// Sometimes the symbol is found when location is a return type of a function: `typeof x` and `x` is declared in the body of the function
// So the table *contains* `x` but `x` isn't actually in scope.
// However, resolveNameHelper will continue and call this callback again, so we'll eventually get a correct suggestion.
return symbol || getSpellingSuggestionForName(unescapeLeadingUnderscores(name), arrayFrom(symbols.values()), meaning);
});
return result;
}
function getSuggestionForNonexistentSymbol(location: Node | undefined, outerName: __String, meaning: SymbolFlags): string | undefined {
const symbolResult = getSuggestedSymbolForNonexistentSymbol(location, outerName, meaning);
return symbolResult && symbolName(symbolResult);
}
function getSuggestedSymbolForNonexistentModule(name: Identifier, targetModule: Symbol): Symbol | undefined {
return targetModule.exports && getSpellingSuggestionForName(idText(name), getExportsOfModuleAsArray(targetModule), SymbolFlags.ModuleMember);
}
function getSuggestionForNonexistentExport(name: Identifier, targetModule: Symbol): string | undefined {
const suggestion = getSuggestedSymbolForNonexistentModule(name, targetModule);
return suggestion && symbolName(suggestion);
}
/**
* Given a name and a list of symbols whose names are *not* equal to the name, return a spelling suggestion if there is one that is close enough.
* Names less than length 3 only check for case-insensitive equality, not levenshtein distance.
*
* If there is a candidate that's the same except for case, return that.
* If there is a candidate that's within one edit of the name, return that.
* Otherwise, return the candidate with the smallest Levenshtein distance,
* except for candidates:
* * With no name
* * Whose meaning doesn't match the `meaning` parameter.
* * Whose length differs from the target name by more than 0.34 of the length of the name.
* * Whose levenshtein distance is more than 0.4 of the length of the name
* (0.4 allows 1 substitution/transposition for every 5 characters,
* and 1 insertion/deletion at 3 characters)
*/
function getSpellingSuggestionForName(name: string, symbols: Symbol[], meaning: SymbolFlags): Symbol | undefined {
return getSpellingSuggestion(name, symbols, getCandidateName);
function getCandidateName(candidate: Symbol) {
const candidateName = symbolName(candidate);
return !startsWith(candidateName, "\"") && candidate.flags & meaning ? candidateName : undefined;
}
}
function markPropertyAsReferenced(prop: Symbol, nodeForCheckWriteOnly: Node | undefined, isThisAccess: boolean) {
if (!prop || !(prop.flags & SymbolFlags.ClassMember) || !prop.valueDeclaration || !hasModifier(prop.valueDeclaration, ModifierFlags.Private)) {
return;
}
if (nodeForCheckWriteOnly && isWriteOnlyAccess(nodeForCheckWriteOnly) && !(prop.flags & SymbolFlags.SetAccessor && !(prop.flags & SymbolFlags.GetAccessor))) {
return;
}
if (isThisAccess) {
// Find any FunctionLikeDeclaration because those create a new 'this' binding. But this should only matter for methods (or getters/setters).
const containingMethod = findAncestor(nodeForCheckWriteOnly, isFunctionLikeDeclaration);
if (containingMethod && containingMethod.symbol === prop) {
return;
}
}
(getCheckFlags(prop) & CheckFlags.Instantiated ? getSymbolLinks(prop).target : prop)!.isReferenced = SymbolFlags.All;
}
function isValidPropertyAccess(node: PropertyAccessExpression | QualifiedName | ImportTypeNode, propertyName: __String): boolean {
switch (node.kind) {
case SyntaxKind.PropertyAccessExpression:
return isValidPropertyAccessWithType(node, node.expression.kind === SyntaxKind.SuperKeyword, propertyName, getWidenedType(checkExpression(node.expression)));
case SyntaxKind.QualifiedName:
return isValidPropertyAccessWithType(node, /*isSuper*/ false, propertyName, getWidenedType(checkExpression(node.left)));
case SyntaxKind.ImportType:
return isValidPropertyAccessWithType(node, /*isSuper*/ false, propertyName, getTypeFromTypeNode(node));
}
}
function isValidPropertyAccessForCompletions(node: PropertyAccessExpression | ImportTypeNode | QualifiedName, type: Type, property: Symbol): boolean {
return isValidPropertyAccessWithType(node, node.kind === SyntaxKind.PropertyAccessExpression && node.expression.kind === SyntaxKind.SuperKeyword, property.escapedName, type)
&& (!(property.flags & SymbolFlags.Method) || isValidMethodAccess(property, type));
}
function isValidMethodAccess(method: Symbol, actualThisType: Type): boolean {
const propType = getTypeOfPropertyOfType(actualThisType, method.escapedName)!;
const signatures = getSignaturesOfType(getNonNullableType(propType), SignatureKind.Call);
Debug.assert(signatures.length !== 0);
return signatures.some(sig => {
const signatureThisType = getThisTypeOfSignature(sig);
return !signatureThisType || isTypeAssignableTo(actualThisType, getInstantiatedSignatureThisType(sig, signatureThisType, actualThisType));
});
}
function getInstantiatedSignatureThisType(sig: Signature, signatureThisType: Type, actualThisType: Type): Type {
if (!sig.typeParameters) {
return signatureThisType;
}
const context = createInferenceContext(sig.typeParameters, sig, InferenceFlags.None);
inferTypes(context.inferences, actualThisType, signatureThisType);
return instantiateType(signatureThisType, createSignatureTypeMapper(sig, getInferredTypes(context)));
}
function isValidPropertyAccessWithType(
node: PropertyAccessExpression | QualifiedName | ImportTypeNode,
isSuper: boolean,
propertyName: __String,
type: Type): boolean {
if (type === errorType || isTypeAny(type)) {
return true;
}
const prop = getPropertyOfType(type, propertyName);
return prop ? checkPropertyAccessibility(node, isSuper, type, prop)
// In js files properties of unions are allowed in completion
: isInJSFile(node) && (type.flags & TypeFlags.Union) !== 0 && (<UnionType>type).types.some(elementType => isValidPropertyAccessWithType(node, isSuper, propertyName, elementType));
}
/**
* Return the symbol of the for-in variable declared or referenced by the given for-in statement.
*/
function getForInVariableSymbol(node: ForInStatement): Symbol | undefined {
const initializer = node.initializer;
if (initializer.kind === SyntaxKind.VariableDeclarationList) {
const variable = (<VariableDeclarationList>initializer).declarations[0];
if (variable && !isBindingPattern(variable.name)) {
return getSymbolOfNode(variable);
}
}
else if (initializer.kind === SyntaxKind.Identifier) {
return getResolvedSymbol(<Identifier>initializer);
}
return undefined;
}
/**
* Return true if the given type is considered to have numeric property names.
*/
function hasNumericPropertyNames(type: Type) {
return getIndexTypeOfType(type, IndexKind.Number) && !getIndexTypeOfType(type, IndexKind.String);
}
/**
* Return true if given node is an expression consisting of an identifier (possibly parenthesized)
* that references a for-in variable for an object with numeric property names.
*/
function isForInVariableForNumericPropertyNames(expr: Expression) {
const e = skipParentheses(expr);
if (e.kind === SyntaxKind.Identifier) {
const symbol = getResolvedSymbol(<Identifier>e);
if (symbol.flags & SymbolFlags.Variable) {
let child: Node = expr;
let node = expr.parent;
while (node) {
if (node.kind === SyntaxKind.ForInStatement &&
child === (<ForInStatement>node).statement &&
getForInVariableSymbol(<ForInStatement>node) === symbol &&
hasNumericPropertyNames(getTypeOfExpression((<ForInStatement>node).expression))) {
return true;
}
child = node;
node = node.parent;
}
}
}
return false;
}
function checkIndexedAccess(node: ElementAccessExpression): Type {
const objectType = checkNonNullExpression(node.expression);
const indexExpression = node.argumentExpression;
if (!indexExpression) {
const sourceFile = getSourceFileOfNode(node);
if (node.parent.kind === SyntaxKind.NewExpression && (<NewExpression>node.parent).expression === node) {
const start = skipTrivia(sourceFile.text, node.expression.end);
const end = node.end;
grammarErrorAtPos(sourceFile, start, end - start, Diagnostics.new_T_cannot_be_used_to_create_an_array_Use_new_Array_T_instead);
}
else {
const start = node.end - "]".length;
const end = node.end;
grammarErrorAtPos(sourceFile, start, end - start, Diagnostics.Expression_expected);
}
return errorType;
}
const indexType = checkExpression(indexExpression);
if (objectType === errorType || objectType === silentNeverType) {
return objectType;
}
if (isConstEnumObjectType(objectType) && indexExpression.kind !== SyntaxKind.StringLiteral) {
error(indexExpression, Diagnostics.A_const_enum_member_can_only_be_accessed_using_a_string_literal);
return errorType;
}
return checkIndexedAccessIndexType(getIndexedAccessType(objectType, isForInVariableForNumericPropertyNames(indexExpression) ? numberType : indexType, node), node);
}
function checkThatExpressionIsProperSymbolReference(expression: Expression, expressionType: Type, reportError: boolean): boolean {
if (expressionType === errorType) {
// There is already an error, so no need to report one.
return false;
}
if (!isWellKnownSymbolSyntactically(expression)) {
return false;
}
// Make sure the property type is the primitive symbol type
if ((expressionType.flags & TypeFlags.ESSymbolLike) === 0) {
if (reportError) {
error(expression, Diagnostics.A_computed_property_name_of_the_form_0_must_be_of_type_symbol, getTextOfNode(expression));
}
return false;
}
// The name is Symbol.<someName>, so make sure Symbol actually resolves to the
// global Symbol object
const leftHandSide = <Identifier>(<PropertyAccessExpression>expression).expression;
const leftHandSideSymbol = getResolvedSymbol(leftHandSide);
if (!leftHandSideSymbol) {
return false;
}
const globalESSymbol = getGlobalESSymbolConstructorSymbol(/*reportErrors*/ true);
if (!globalESSymbol) {
// Already errored when we tried to look up the symbol
return false;
}
if (leftHandSideSymbol !== globalESSymbol) {
if (reportError) {
error(leftHandSide, Diagnostics.Symbol_reference_does_not_refer_to_the_global_Symbol_constructor_object);
}
return false;
}
return true;
}
function callLikeExpressionMayHaveTypeArguments(node: CallLikeExpression): node is CallExpression | NewExpression | TaggedTemplateExpression | JsxOpeningElement {
return isCallOrNewExpression(node) || isTaggedTemplateExpression(node) || isJsxOpeningLikeElement(node);
}
function resolveUntypedCall(node: CallLikeExpression): Signature {
if (callLikeExpressionMayHaveTypeArguments(node)) {
// Check type arguments even though we will give an error that untyped calls may not accept type arguments.
// This gets us diagnostics for the type arguments and marks them as referenced.
forEach(node.typeArguments, checkSourceElement);
}
if (node.kind === SyntaxKind.TaggedTemplateExpression) {
checkExpression(node.template);
}
else if (isJsxOpeningLikeElement(node)) {
checkExpression(node.attributes);
}
else if (node.kind !== SyntaxKind.Decorator) {
forEach((<CallExpression>node).arguments, argument => {
checkExpression(argument);
});
}
return anySignature;
}
function resolveErrorCall(node: CallLikeExpression): Signature {
resolveUntypedCall(node);
return unknownSignature;
}
// Re-order candidate signatures into the result array. Assumes the result array to be empty.
// The candidate list orders groups in reverse, but within a group signatures are kept in declaration order
// A nit here is that we reorder only signatures that belong to the same symbol,
// so order how inherited signatures are processed is still preserved.
// interface A { (x: string): void }
// interface B extends A { (x: 'foo'): string }
// const b: B;
// b('foo') // <- here overloads should be processed as [(x:'foo'): string, (x: string): void]
function reorderCandidates(signatures: ReadonlyArray<Signature>, result: Signature[]): void {
let lastParent: Node | undefined;
let lastSymbol: Symbol | undefined;
let cutoffIndex = 0;
let index: number | undefined;
let specializedIndex = -1;
let spliceIndex: number;
Debug.assert(!result.length);
for (const signature of signatures) {
const symbol = signature.declaration && getSymbolOfNode(signature.declaration);
const parent = signature.declaration && signature.declaration.parent;
if (!lastSymbol || symbol === lastSymbol) {
if (lastParent && parent === lastParent) {
index = index! + 1;
}
else {
lastParent = parent;
index = cutoffIndex;
}
}
else {
// current declaration belongs to a different symbol
// set cutoffIndex so re-orderings in the future won't change result set from 0 to cutoffIndex
index = cutoffIndex = result.length;
lastParent = parent;
}
lastSymbol = symbol;
// specialized signatures always need to be placed before non-specialized signatures regardless
// of the cutoff position; see GH#1133
if (signature.hasLiteralTypes) {
specializedIndex++;
spliceIndex = specializedIndex;
// The cutoff index always needs to be greater than or equal to the specialized signature index
// in order to prevent non-specialized signatures from being added before a specialized
// signature.
cutoffIndex++;
}
else {
spliceIndex = index;
}
result.splice(spliceIndex, 0, signature);
}
}
function isSpreadArgument(arg: Expression | undefined): arg is Expression {
return !!arg && (arg.kind === SyntaxKind.SpreadElement || arg.kind === SyntaxKind.SyntheticExpression && (<SyntheticExpression>arg).isSpread);
}
function getSpreadArgumentIndex(args: ReadonlyArray<Expression>): number {
return findIndex(args, isSpreadArgument);
}
function acceptsVoid(t: Type): boolean {
return !!(t.flags & TypeFlags.Void);
}
function hasCorrectArity(node: CallLikeExpression, args: ReadonlyArray<Expression>, signature: Signature, signatureHelpTrailingComma = false) {
let argCount: number;
let callIsIncomplete = false; // In incomplete call we want to be lenient when we have too few arguments
let effectiveParameterCount = getParameterCount(signature);
let effectiveMinimumArguments = getMinArgumentCount(signature);
if (node.kind === SyntaxKind.TaggedTemplateExpression) {
argCount = args.length;
if (node.template.kind === SyntaxKind.TemplateExpression) {
// If a tagged template expression lacks a tail literal, the call is incomplete.
// Specifically, a template only can end in a TemplateTail or a Missing literal.
const lastSpan = last(node.template.templateSpans); // we should always have at least one span.
callIsIncomplete = nodeIsMissing(lastSpan.literal) || !!lastSpan.literal.isUnterminated;
}
else {
// If the template didn't end in a backtick, or its beginning occurred right prior to EOF,
// then this might actually turn out to be a TemplateHead in the future;
// so we consider the call to be incomplete.
const templateLiteral = <LiteralExpression>node.template;
Debug.assert(templateLiteral.kind === SyntaxKind.NoSubstitutionTemplateLiteral);
callIsIncomplete = !!templateLiteral.isUnterminated;
}
}
else if (node.kind === SyntaxKind.Decorator) {
argCount = getDecoratorArgumentCount(node, signature);
}
else if (isJsxOpeningLikeElement(node)) {
callIsIncomplete = node.attributes.end === node.end;
if (callIsIncomplete) {
return true;
}
argCount = effectiveMinimumArguments === 0 ? args.length : 1;
effectiveParameterCount = args.length === 0 ? effectiveParameterCount : 1; // class may have argumentless ctor functions - still resolve ctor and compare vs props member type
effectiveMinimumArguments = Math.min(effectiveMinimumArguments, 1); // sfc may specify context argument - handled by framework and not typechecked
}
else {
if (!node.arguments) {
// This only happens when we have something of the form: 'new C'
Debug.assert(node.kind === SyntaxKind.NewExpression);
return getMinArgumentCount(signature) === 0;
}
argCount = signatureHelpTrailingComma ? args.length + 1 : args.length;
// If we are missing the close parenthesis, the call is incomplete.
callIsIncomplete = node.arguments.end === node.end;
// If a spread argument is present, check that it corresponds to a rest parameter or at least that it's in the valid range.
const spreadArgIndex = getSpreadArgumentIndex(args);
if (spreadArgIndex >= 0) {
return spreadArgIndex >= getMinArgumentCount(signature) && (hasEffectiveRestParameter(signature) || spreadArgIndex < getParameterCount(signature));
}
}
// Too many arguments implies incorrect arity.
if (!hasEffectiveRestParameter(signature) && argCount > effectiveParameterCount) {
return false;
}
// If the call is incomplete, we should skip the lower bound check.
// JSX signatures can have extra parameters provided by the library which we don't check
if (callIsIncomplete || argCount >= effectiveMinimumArguments) {
return true;
}
for (let i = argCount; i < effectiveMinimumArguments; i++) {
const type = getTypeAtPosition(signature, i);
if (filterType(type, acceptsVoid).flags & TypeFlags.Never) {
return false;
}
}
return true;
}
function hasCorrectTypeArgumentArity(signature: Signature, typeArguments: NodeArray<TypeNode> | undefined) {
// If the user supplied type arguments, but the number of type arguments does not match
// the declared number of type parameters, the call has an incorrect arity.
const numTypeParameters = length(signature.typeParameters);
const minTypeArgumentCount = getMinTypeArgumentCount(signature.typeParameters);
return !typeArguments ||
(typeArguments.length >= minTypeArgumentCount && typeArguments.length <= numTypeParameters);
}
// If type has a single call signature and no other members, return that signature. Otherwise, return undefined.
function getSingleCallSignature(type: Type): Signature | undefined {
if (type.flags & TypeFlags.Object) {
const resolved = resolveStructuredTypeMembers(<ObjectType>type);
if (resolved.callSignatures.length === 1 && resolved.constructSignatures.length === 0 &&
resolved.properties.length === 0 && !resolved.stringIndexInfo && !resolved.numberIndexInfo) {
return resolved.callSignatures[0];
}
}
return undefined;
}
// Instantiate a generic signature in the context of a non-generic signature (section 3.8.5 in TypeScript spec)
function instantiateSignatureInContextOf(signature: Signature, contextualSignature: Signature, contextualMapper?: TypeMapper, compareTypes?: TypeComparer): Signature {
const context = createInferenceContext(signature.typeParameters!, signature, InferenceFlags.None, compareTypes);
// We clone the contextualMapper to avoid fixing. For example, when the source signature is <T>(x: T) => T[] and
// the contextual signature is (...args: A) => B, we want to infer the element type of A's constraint (say 'any')
// for T but leave it possible to later infer '[any]' back to A.
const restType = getEffectiveRestType(contextualSignature);
const mapper = contextualMapper && restType && restType.flags & TypeFlags.TypeParameter ? cloneTypeMapper(contextualMapper) : contextualMapper;
const sourceSignature = mapper ? instantiateSignature(contextualSignature, mapper) : contextualSignature;
forEachMatchingParameterType(sourceSignature, signature, (source, target) => {
// Type parameters from outer context referenced by source type are fixed by instantiation of the source type
inferTypes(context.inferences, source, target);
});
if (!contextualMapper) {
inferTypes(context.inferences, getReturnTypeOfSignature(contextualSignature), getReturnTypeOfSignature(signature), InferencePriority.ReturnType);
}
return getSignatureInstantiation(signature, getInferredTypes(context), isInJSFile(contextualSignature.declaration));
}
function inferJsxTypeArguments(node: JsxOpeningLikeElement, signature: Signature, checkMode: CheckMode, context: InferenceContext): Type[] {
const paramType = getEffectiveFirstArgumentForJsxSignature(signature, node);
const checkAttrType = checkExpressionWithContextualType(node.attributes, paramType, context, checkMode);
inferTypes(context.inferences, checkAttrType, paramType);
return getInferredTypes(context);
}
function inferTypeArguments(node: CallLikeExpression, signature: Signature, args: ReadonlyArray<Expression>, checkMode: CheckMode, context: InferenceContext): Type[] {
// Clear out all the inference results from the last time inferTypeArguments was called on this context
for (const inference of context.inferences) {
// As an optimization, we don't have to clear (and later recompute) inferred types
// for type parameters that have already been fixed on the previous call to inferTypeArguments.
// It would be just as correct to reset all of them. But then we'd be repeating the same work
// for the type parameters that were fixed, namely the work done by getInferredType.
if (!inference.isFixed) {
inference.inferredType = undefined;
}
}
if (isJsxOpeningLikeElement(node)) {
return inferJsxTypeArguments(node, signature, checkMode, context);
}
// If a contextual type is available, infer from that type to the return type of the call expression. For
// example, given a 'function wrap<T, U>(cb: (x: T) => U): (x: T) => U' and a call expression
// 'let f: (x: string) => number = wrap(s => s.length)', we infer from the declared type of 'f' to the
// return type of 'wrap'.
if (node.kind !== SyntaxKind.Decorator) {
const contextualType = getContextualType(node);
if (contextualType) {
// We clone the contextual mapper to avoid disturbing a resolution in progress for an
// outer call expression. Effectively we just want a snapshot of whatever has been
// inferred for any outer call expression so far.
const instantiatedType = instantiateType(contextualType, cloneTypeMapper(getContextualMapper(node), InferenceFlags.NoDefault));
// If the contextual type is a generic function type with a single call signature, we
// instantiate the type with its own type parameters and type arguments. This ensures that
// the type parameters are not erased to type any during type inference such that they can
// be inferred as actual types from the contextual type. For example:
// declare function arrayMap<T, U>(f: (x: T) => U): (a: T[]) => U[];
// const boxElements: <A>(a: A[]) => { value: A }[] = arrayMap(value => ({ value }));
// Above, the type of the 'value' parameter is inferred to be 'A'.
const contextualSignature = getSingleCallSignature(instantiatedType);
const inferenceSourceType = contextualSignature && contextualSignature.typeParameters ?
getOrCreateTypeFromSignature(getSignatureInstantiationWithoutFillingInTypeArguments(contextualSignature, contextualSignature.typeParameters)) :
instantiatedType;
const inferenceTargetType = getReturnTypeOfSignature(signature);
// Inferences made from return types have lower priority than all other inferences.
inferTypes(context.inferences, inferenceSourceType, inferenceTargetType, InferencePriority.ReturnType);
// Create a type mapper for instantiating generic contextual types using the inferences made
// from the return type.
context.returnMapper = cloneInferredPartOfContext(context);
}
}
const thisType = getThisTypeOfSignature(signature);
if (thisType) {
const thisArgumentNode = getThisArgumentOfCall(node);
const thisArgumentType = thisArgumentNode ? checkExpression(thisArgumentNode) : voidType;
inferTypes(context.inferences, thisArgumentType, thisType);
}
const restType = getNonArrayRestType(signature);
const argCount = restType ? Math.min(getParameterCount(signature) - 1, args.length) : args.length;
for (let i = 0; i < argCount; i++) {
const arg = args[i];
if (arg.kind !== SyntaxKind.OmittedExpression) {
const paramType = getTypeAtPosition(signature, i);
const argType = checkExpressionWithContextualType(arg, paramType, context, checkMode);
inferTypes(context.inferences, argType, paramType);
}
}
if (restType) {
const spreadType = getSpreadArgumentType(args, argCount, args.length, restType, context);
inferTypes(context.inferences, spreadType, restType);
}
return getInferredTypes(context);
}
function getArrayifiedType(type: Type) {
if (forEachType(type, t => !(t.flags & (TypeFlags.Any | TypeFlags.Instantiable) || isArrayType(t) || isTupleType(t)))) {
return createArrayType(getIndexTypeOfType(type, IndexKind.Number) || errorType);
}
return type;
}
function getSpreadArgumentType(args: ReadonlyArray<Expression>, index: number, argCount: number, restType: TypeParameter, context: InferenceContext | undefined) {
if (index >= argCount - 1) {
const arg = args[argCount - 1];
if (isSpreadArgument(arg)) {
// We are inferring from a spread expression in the last argument position, i.e. both the parameter
// and the argument are ...x forms.
return arg.kind === SyntaxKind.SyntheticExpression ?
createArrayType((<SyntheticExpression>arg).type) :
getArrayifiedType(checkExpressionWithContextualType((<SpreadElement>arg).expression, restType, context, CheckMode.Normal));
}
}
const contextualType = getIndexTypeOfType(restType, IndexKind.Number) || anyType;
const hasPrimitiveContextualType = maybeTypeOfKind(contextualType, TypeFlags.Primitive | TypeFlags.Index);
const types = [];
let spreadIndex = -1;
for (let i = index; i < argCount; i++) {
const argType = checkExpressionWithContextualType(args[i], contextualType, context, CheckMode.Normal);
if (spreadIndex < 0 && isSpreadArgument(args[i])) {
spreadIndex = i - index;
}
types.push(hasPrimitiveContextualType ? getRegularTypeOfLiteralType(argType) : getWidenedLiteralType(argType));
}
return spreadIndex < 0 ?
createTupleType(types) :
createTupleType(append(types.slice(0, spreadIndex), getUnionType(types.slice(spreadIndex))), spreadIndex, /*hasRestElement*/ true);
}
function checkTypeArguments(signature: Signature, typeArgumentNodes: ReadonlyArray<TypeNode>, reportErrors: boolean, headMessage?: DiagnosticMessage): Type[] | undefined {
const isJavascript = isInJSFile(signature.declaration);
const typeParameters = signature.typeParameters!;
const typeArgumentTypes = fillMissingTypeArguments(map(typeArgumentNodes, getTypeFromTypeNode), typeParameters, getMinTypeArgumentCount(typeParameters), isJavascript);
let mapper: TypeMapper | undefined;
for (let i = 0; i < typeArgumentNodes.length; i++) {
Debug.assert(typeParameters[i] !== undefined, "Should not call checkTypeArguments with too many type arguments");
const constraint = getConstraintOfTypeParameter(typeParameters[i]);
if (constraint) {
const errorInfo = reportErrors && headMessage ? (() => chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Type_0_does_not_satisfy_the_constraint_1)) : undefined;
const typeArgumentHeadMessage = headMessage || Diagnostics.Type_0_does_not_satisfy_the_constraint_1;
if (!mapper) {
mapper = createTypeMapper(typeParameters, typeArgumentTypes);
}
const typeArgument = typeArgumentTypes[i];
if (!checkTypeAssignableTo(
typeArgument,
getTypeWithThisArgument(instantiateType(constraint, mapper), typeArgument),
reportErrors ? typeArgumentNodes[i] : undefined,
typeArgumentHeadMessage,
errorInfo)) {
return undefined;
}
}
}
return typeArgumentTypes;
}
function getJsxReferenceKind(node: JsxOpeningLikeElement): JsxReferenceKind {
if (isJsxIntrinsicIdentifier(node.tagName)) {
return JsxReferenceKind.Mixed;
}
const tagType = getApparentType(checkExpression(node.tagName));
if (length(getSignaturesOfType(tagType, SignatureKind.Construct))) {
return JsxReferenceKind.Component;
}
if (length(getSignaturesOfType(tagType, SignatureKind.Call))) {
return JsxReferenceKind.Function;
}
return JsxReferenceKind.Mixed;
}
/**
* Check if the given signature can possibly be a signature called by the JSX opening-like element.
* @param node a JSX opening-like element we are trying to figure its call signature
* @param signature a candidate signature we are trying whether it is a call signature
* @param relation a relationship to check parameter and argument type
*/
function checkApplicableSignatureForJsxOpeningLikeElement(node: JsxOpeningLikeElement, signature: Signature, relation: Map<RelationComparisonResult>, checkMode: CheckMode, reportErrors: boolean) {
// Stateless function components can have maximum of three arguments: "props", "context", and "updater".
// However "context" and "updater" are implicit and can't be specify by users. Only the first parameter, props,
// can be specified by users through attributes property.
const paramType = getEffectiveFirstArgumentForJsxSignature(signature, node);
const attributesType = checkExpressionWithContextualType(node.attributes, paramType, /*contextualMapper*/ undefined, checkMode);
return checkTypeRelatedToAndOptionallyElaborate(attributesType, paramType, relation, reportErrors ? node.tagName : undefined, node.attributes);
}
function checkApplicableSignature(
node: CallLikeExpression,
args: ReadonlyArray<Expression>,
signature: Signature,
relation: Map<RelationComparisonResult>,
checkMode: CheckMode,
reportErrors: boolean) {
if (isJsxOpeningLikeElement(node)) {
return checkApplicableSignatureForJsxOpeningLikeElement(node, signature, relation, checkMode, reportErrors);
}
const thisType = getThisTypeOfSignature(signature);
if (thisType && thisType !== voidType && node.kind !== SyntaxKind.NewExpression) {
// If the called expression is not of the form `x.f` or `x["f"]`, then sourceType = voidType
// If the signature's 'this' type is voidType, then the check is skipped -- anything is compatible.
// If the expression is a new expression, then the check is skipped.
const thisArgumentNode = getThisArgumentOfCall(node);
const thisArgumentType = thisArgumentNode ? checkExpression(thisArgumentNode) : voidType;
const errorNode = reportErrors ? (thisArgumentNode || node) : undefined;
const headMessage = Diagnostics.The_this_context_of_type_0_is_not_assignable_to_method_s_this_of_type_1;
if (!checkTypeRelatedTo(thisArgumentType, thisType, relation, errorNode, headMessage)) {
return false;
}
}
const headMessage = Diagnostics.Argument_of_type_0_is_not_assignable_to_parameter_of_type_1;
const restType = getNonArrayRestType(signature);
const argCount = restType ? Math.min(getParameterCount(signature) - 1, args.length) : args.length;
for (let i = 0; i < argCount; i++) {
const arg = args[i];
if (arg.kind !== SyntaxKind.OmittedExpression) {
const paramType = getTypeAtPosition(signature, i);
const argType = checkExpressionWithContextualType(arg, paramType, /*contextualMapper*/ undefined, checkMode);
// If one or more arguments are still excluded (as indicated by CheckMode.SkipContextSensitive),
// we obtain the regular type of any object literal arguments because we may not have inferred complete
// parameter types yet and therefore excess property checks may yield false positives (see #17041).
const checkArgType = checkMode & CheckMode.SkipContextSensitive ? getRegularTypeOfObjectLiteral(argType) : argType;
if (!checkTypeRelatedToAndOptionallyElaborate(checkArgType, paramType, relation, reportErrors ? arg : undefined, arg, headMessage)) {
return false;
}
}
}
if (restType) {
const spreadType = getSpreadArgumentType(args, argCount, args.length, restType, /*context*/ undefined);
const errorNode = reportErrors ? argCount < args.length ? args[argCount] : node : undefined;
return checkTypeRelatedTo(spreadType, restType, relation, errorNode, headMessage);
}
return true;
}
/**
* Returns the this argument in calls like x.f(...) and x[f](...). Undefined otherwise.
*/
function getThisArgumentOfCall(node: CallLikeExpression): LeftHandSideExpression | undefined {
if (node.kind === SyntaxKind.CallExpression) {
const callee = skipOuterExpressions(node.expression);
if (callee.kind === SyntaxKind.PropertyAccessExpression || callee.kind === SyntaxKind.ElementAccessExpression) {
return (callee as AccessExpression).expression;
}
}
}
function createSyntheticExpression(parent: Node, type: Type, isSpread?: boolean) {
const result = <SyntheticExpression>createNode(SyntaxKind.SyntheticExpression, parent.pos, parent.end);
result.parent = parent;
result.type = type;
result.isSpread = isSpread || false;
return result;
}
/**
* Returns the effective arguments for an expression that works like a function invocation.
*/
function getEffectiveCallArguments(node: CallLikeExpression): ReadonlyArray<Expression> {
if (node.kind === SyntaxKind.TaggedTemplateExpression) {
const template = node.template;
const args: Expression[] = [createSyntheticExpression(template, getGlobalTemplateStringsArrayType())];
if (template.kind === SyntaxKind.TemplateExpression) {
forEach(template.templateSpans, span => {
args.push(span.expression);
});
}
return args;
}
if (node.kind === SyntaxKind.Decorator) {
return getEffectiveDecoratorArguments(node);
}
if (isJsxOpeningLikeElement(node)) {
return node.attributes.properties.length > 0 || (isJsxOpeningElement(node) && node.parent.children.length > 0) ? [node.attributes] : emptyArray;
}
const args = node.arguments || emptyArray;
const length = args.length;
if (length && isSpreadArgument(args[length - 1]) && getSpreadArgumentIndex(args) === length - 1) {
// We have a spread argument in the last position and no other spread arguments. If the type
// of the argument is a tuple type, spread the tuple elements into the argument list. We can
// call checkExpressionCached because spread expressions never have a contextual type.
const spreadArgument = <SpreadElement>args[length - 1];
const type = checkExpressionCached(spreadArgument.expression);
if (isTupleType(type)) {
const typeArguments = (<TypeReference>type).typeArguments || emptyArray;
const restIndex = type.target.hasRestElement ? typeArguments.length - 1 : -1;
const syntheticArgs = map(typeArguments, (t, i) => createSyntheticExpression(spreadArgument, t, /*isSpread*/ i === restIndex));
return concatenate(args.slice(0, length - 1), syntheticArgs);
}
}
return args;
}
/**
* Returns the synthetic argument list for a decorator invocation.
*/
function getEffectiveDecoratorArguments(node: Decorator): ReadonlyArray<Expression> {
const parent = node.parent;
const expr = node.expression;
switch (parent.kind) {
case SyntaxKind.ClassDeclaration:
case SyntaxKind.ClassExpression:
// For a class decorator, the `target` is the type of the class (e.g. the
// "static" or "constructor" side of the class).
return [
createSyntheticExpression(expr, getTypeOfSymbol(getSymbolOfNode(parent)))
];
case SyntaxKind.Parameter:
// A parameter declaration decorator will have three arguments (see
// `ParameterDecorator` in core.d.ts).
const func = <FunctionLikeDeclaration>parent.parent;
return [
createSyntheticExpression(expr, parent.parent.kind === SyntaxKind.Constructor ? getTypeOfSymbol(getSymbolOfNode(func)) : errorType),
createSyntheticExpression(expr, anyType),
createSyntheticExpression(expr, numberType)
];
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
// A method or accessor declaration decorator will have two or three arguments (see
// `PropertyDecorator` and `MethodDecorator` in core.d.ts). If we are emitting decorators
// for ES3, we will only pass two arguments.
const hasPropDesc = parent.kind !== SyntaxKind.PropertyDeclaration && languageVersion !== ScriptTarget.ES3;
return [
createSyntheticExpression(expr, getParentTypeOfClassElement(<ClassElement>parent)),
createSyntheticExpression(expr, getClassElementPropertyKeyType(<ClassElement>parent)),
createSyntheticExpression(expr, hasPropDesc ? createTypedPropertyDescriptorType(getTypeOfNode(parent)) : anyType)
];
}
return Debug.fail();
}
/**
* Returns the argument count for a decorator node that works like a function invocation.
*/
function getDecoratorArgumentCount(node: Decorator, signature: Signature) {
switch (node.parent.kind) {
case SyntaxKind.ClassDeclaration:
case SyntaxKind.ClassExpression:
return 1;
case SyntaxKind.PropertyDeclaration:
return 2;
case SyntaxKind.MethodDeclaration:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
// For ES3 or decorators with only two parameters we supply only two arguments
return languageVersion === ScriptTarget.ES3 || signature.parameters.length <= 2 ? 2 : 3;
case SyntaxKind.Parameter:
return 3;
default:
return Debug.fail();
}
}
function getArgumentArityError(node: Node, signatures: ReadonlyArray<Signature>, args: ReadonlyArray<Expression>) {
let min = Number.POSITIVE_INFINITY;
let max = Number.NEGATIVE_INFINITY;
let belowArgCount = Number.NEGATIVE_INFINITY;
let aboveArgCount = Number.POSITIVE_INFINITY;
let argCount = args.length;
let closestSignature: Signature | undefined;
for (const sig of signatures) {
const minCount = getMinArgumentCount(sig);
const maxCount = getParameterCount(sig);
if (minCount < argCount && minCount > belowArgCount) belowArgCount = minCount;
if (argCount < maxCount && maxCount < aboveArgCount) aboveArgCount = maxCount;
if (minCount < min) {
min = minCount;
closestSignature = sig;
}
max = Math.max(max, maxCount);
}
const hasRestParameter = some(signatures, hasEffectiveRestParameter);
const paramRange = hasRestParameter ? min :
min < max ? min + "-" + max :
min;
const hasSpreadArgument = getSpreadArgumentIndex(args) > -1;
if (argCount <= max && hasSpreadArgument) {
argCount--;
}
let related: DiagnosticWithLocation | undefined;
if (closestSignature && getMinArgumentCount(closestSignature) > argCount && closestSignature.declaration) {
const paramDecl = closestSignature.declaration.parameters[closestSignature.thisParameter ? argCount + 1 : argCount];
if (paramDecl) {
related = createDiagnosticForNode(
paramDecl,
isBindingPattern(paramDecl.name) ? Diagnostics.An_argument_matching_this_binding_pattern_was_not_provided : Diagnostics.An_argument_for_0_was_not_provided,
!paramDecl.name ? argCount : !isBindingPattern(paramDecl.name) ? idText(getFirstIdentifier(paramDecl.name)) : undefined
);
}
}
if (hasRestParameter || hasSpreadArgument) {
const error = hasRestParameter && hasSpreadArgument ? Diagnostics.Expected_at_least_0_arguments_but_got_1_or_more :
hasRestParameter ? Diagnostics.Expected_at_least_0_arguments_but_got_1 :
Diagnostics.Expected_0_arguments_but_got_1_or_more;
const diagnostic = createDiagnosticForNode(node, error, paramRange, argCount);
return related ? addRelatedInfo(diagnostic, related) : diagnostic;
}
if (min < argCount && argCount < max) {
return createDiagnosticForNode(node, Diagnostics.No_overload_expects_0_arguments_but_overloads_do_exist_that_expect_either_1_or_2_arguments, argCount, belowArgCount, aboveArgCount);
}
const diagnostic = createDiagnosticForNode(node, Diagnostics.Expected_0_arguments_but_got_1, paramRange, argCount);
return related ? addRelatedInfo(diagnostic, related) : diagnostic;
}
function getTypeArgumentArityError(node: Node, signatures: ReadonlyArray<Signature>, typeArguments: NodeArray<TypeNode>) {
const argCount = typeArguments.length;
// No overloads exist
if (signatures.length === 1) {
const sig = signatures[0];
const min = getMinTypeArgumentCount(sig.typeParameters);
const max = length(sig.typeParameters);
return createDiagnosticForNodeArray(getSourceFileOfNode(node), typeArguments, Diagnostics.Expected_0_type_arguments_but_got_1, min < max ? min + "-" + max : min , argCount);
}
// Overloads exist
let belowArgCount = -Infinity;
let aboveArgCount = Infinity;
for (const sig of signatures) {
const min = getMinTypeArgumentCount(sig.typeParameters);
const max = length(sig.typeParameters);
if (min > argCount) {
aboveArgCount = Math.min(aboveArgCount, min);
}
else if (max < argCount) {
belowArgCount = Math.max(belowArgCount, max);
}
}
if (belowArgCount !== -Infinity && aboveArgCount !== Infinity) {
return createDiagnosticForNodeArray(getSourceFileOfNode(node), typeArguments, Diagnostics.No_overload_expects_0_type_arguments_but_overloads_do_exist_that_expect_either_1_or_2_type_arguments, argCount, belowArgCount, aboveArgCount);
}
return createDiagnosticForNodeArray(getSourceFileOfNode(node), typeArguments, Diagnostics.Expected_0_type_arguments_but_got_1, belowArgCount === -Infinity ? aboveArgCount : belowArgCount, argCount);
}
function resolveCall(node: CallLikeExpression, signatures: ReadonlyArray<Signature>, candidatesOutArray: Signature[] | undefined, checkMode: CheckMode, fallbackError?: DiagnosticMessage): Signature {
const isTaggedTemplate = node.kind === SyntaxKind.TaggedTemplateExpression;
const isDecorator = node.kind === SyntaxKind.Decorator;
const isJsxOpeningOrSelfClosingElement = isJsxOpeningLikeElement(node);
const reportErrors = !candidatesOutArray;
let typeArguments: NodeArray<TypeNode> | undefined;
if (!isDecorator) {
typeArguments = (<CallExpression>node).typeArguments;
// We already perform checking on the type arguments on the class declaration itself.
if (isTaggedTemplate || isJsxOpeningOrSelfClosingElement || (<CallExpression>node).expression.kind !== SyntaxKind.SuperKeyword) {
forEach(typeArguments, checkSourceElement);
}
}
const candidates = candidatesOutArray || [];
// reorderCandidates fills up the candidates array directly
reorderCandidates(signatures, candidates);
if (!candidates.length) {
if (reportErrors) {
diagnostics.add(createDiagnosticForNode(node, Diagnostics.Call_target_does_not_contain_any_signatures));
}
return resolveErrorCall(node);
}
const args = getEffectiveCallArguments(node);
// The excludeArgument array contains true for each context sensitive argument (an argument
// is context sensitive it is susceptible to a one-time permanent contextual typing).
//
// The idea is that we will perform type argument inference & assignability checking once
// without using the susceptible parameters that are functions, and once more for those
// parameters, contextually typing each as we go along.
//
// For a tagged template, then the first argument be 'undefined' if necessary because it
// represents a TemplateStringsArray.
//
// For a decorator, no arguments are susceptible to contextual typing due to the fact
// decorators are applied to a declaration by the emitter, and not to an expression.
const isSingleNonGenericCandidate = candidates.length === 1 && !candidates[0].typeParameters;
let argCheckMode = !isDecorator && !isSingleNonGenericCandidate && some(args, isContextSensitive) ? CheckMode.SkipContextSensitive : CheckMode.Normal;
// The following variables are captured and modified by calls to chooseOverload.
// If overload resolution or type argument inference fails, we want to report the
// best error possible. The best error is one which says that an argument was not
// assignable to a parameter. This implies that everything else about the overload
// was fine. So if there is any overload that is only incorrect because of an
// argument, we will report an error on that one.
//
// function foo(s: string): void;
// function foo(n: number): void; // Report argument error on this overload
// function foo(): void;
// foo(true);
//
// If none of the overloads even made it that far, there are two possibilities.
// There was a problem with type arguments for some overload, in which case
// report an error on that. Or none of the overloads even had correct arity,
// in which case give an arity error.
//
// function foo<T extends string>(x: T): void; // Report type argument error
// function foo(): void;
// foo<number>(0);
//
let candidateForArgumentError: Signature | undefined;
let candidateForArgumentArityError: Signature | undefined;
let candidateForTypeArgumentError: Signature | undefined;
let result: Signature | undefined;
// If we are in signature help, a trailing comma indicates that we intend to provide another argument,
// so we will only accept overloads with arity at least 1 higher than the current number of provided arguments.
const signatureHelpTrailingComma =
!!(checkMode & CheckMode.IsForSignatureHelp) && node.kind === SyntaxKind.CallExpression && node.arguments.hasTrailingComma;
// Section 4.12.1:
// if the candidate list contains one or more signatures for which the type of each argument
// expression is a subtype of each corresponding parameter type, the return type of the first
// of those signatures becomes the return type of the function call.
// Otherwise, the return type of the first signature in the candidate list becomes the return
// type of the function call.
//
// Whether the call is an error is determined by assignability of the arguments. The subtype pass
// is just important for choosing the best signature. So in the case where there is only one
// signature, the subtype pass is useless. So skipping it is an optimization.
if (candidates.length > 1) {
result = chooseOverload(candidates, subtypeRelation, signatureHelpTrailingComma);
}
if (!result) {
result = chooseOverload(candidates, assignableRelation, signatureHelpTrailingComma);
}
if (result) {
return result;
}
// No signatures were applicable. Now report errors based on the last applicable signature with
// no arguments excluded from assignability checks.
// If candidate is undefined, it means that no candidates had a suitable arity. In that case,
// skip the checkApplicableSignature check.
if (reportErrors) {
if (candidateForArgumentError) {
checkApplicableSignature(node, args, candidateForArgumentError, assignableRelation, CheckMode.Normal, /*reportErrors*/ true);
}
else if (candidateForArgumentArityError) {
diagnostics.add(getArgumentArityError(node, [candidateForArgumentArityError], args));
}
else if (candidateForTypeArgumentError) {
checkTypeArguments(candidateForTypeArgumentError, (node as CallExpression | TaggedTemplateExpression | JsxOpeningLikeElement).typeArguments!, /*reportErrors*/ true, fallbackError);
}
else {
const signaturesWithCorrectTypeArgumentArity = filter(signatures, s => hasCorrectTypeArgumentArity(s, typeArguments));
if (signaturesWithCorrectTypeArgumentArity.length === 0) {
diagnostics.add(getTypeArgumentArityError(node, signatures, typeArguments!));
}
else if (!isDecorator) {
diagnostics.add(getArgumentArityError(node, signaturesWithCorrectTypeArgumentArity, args));
}
else if (fallbackError) {
diagnostics.add(createDiagnosticForNode(node, fallbackError));
}
}
}
return produceDiagnostics || !args ? resolveErrorCall(node) : getCandidateForOverloadFailure(node, candidates, args, !!candidatesOutArray);
function chooseOverload(candidates: Signature[], relation: Map<RelationComparisonResult>, signatureHelpTrailingComma = false) {
candidateForArgumentError = undefined;
candidateForArgumentArityError = undefined;
candidateForTypeArgumentError = undefined;
if (isSingleNonGenericCandidate) {
const candidate = candidates[0];
if (typeArguments || !hasCorrectArity(node, args, candidate, signatureHelpTrailingComma)) {
return undefined;
}
if (!checkApplicableSignature(node, args, candidate, relation, CheckMode.Normal, /*reportErrors*/ false)) {
candidateForArgumentError = candidate;
return undefined;
}
return candidate;
}
for (let candidateIndex = 0; candidateIndex < candidates.length; candidateIndex++) {
const candidate = candidates[candidateIndex];
if (!hasCorrectTypeArgumentArity(candidate, typeArguments) || !hasCorrectArity(node, args, candidate, signatureHelpTrailingComma)) {
continue;
}
let checkCandidate: Signature;
let inferenceContext: InferenceContext | undefined;
if (candidate.typeParameters) {
let typeArgumentTypes: Type[] | undefined;
if (typeArguments) {
typeArgumentTypes = checkTypeArguments(candidate, typeArguments, /*reportErrors*/ false);
if (!typeArgumentTypes) {
candidateForTypeArgumentError = candidate;
continue;
}
}
else {
inferenceContext = createInferenceContext(candidate.typeParameters, candidate, /*flags*/ isInJSFile(node) ? InferenceFlags.AnyDefault : InferenceFlags.None);
typeArgumentTypes = inferTypeArguments(node, candidate, args, argCheckMode | CheckMode.SkipGenericFunctions, inferenceContext);
argCheckMode |= inferenceContext.flags & InferenceFlags.SkippedGenericFunction ? CheckMode.SkipGenericFunctions : CheckMode.Normal;
}
checkCandidate = getSignatureInstantiation(candidate, typeArgumentTypes, isInJSFile(candidate.declaration), inferenceContext && inferenceContext.inferredTypeParameters);
// If the original signature has a generic rest type, instantiation may produce a
// signature with different arity and we need to perform another arity check.
if (getNonArrayRestType(candidate) && !hasCorrectArity(node, args, checkCandidate, signatureHelpTrailingComma)) {
candidateForArgumentArityError = checkCandidate;
continue;
}
}
else {
checkCandidate = candidate;
}
if (!checkApplicableSignature(node, args, checkCandidate, relation, argCheckMode, /*reportErrors*/ false)) {
// Give preference to error candidates that have no rest parameters (as they are more specific)
if (!candidateForArgumentError || getEffectiveRestType(candidateForArgumentError) || !getEffectiveRestType(checkCandidate)) {
candidateForArgumentError = checkCandidate;
}
continue;
}
if (argCheckMode) {
// If one or more context sensitive arguments were excluded, we start including
// them now (and keeping do so for any subsequent candidates) and perform a second
// round of type inference and applicability checking for this particular candidate.
argCheckMode = CheckMode.Normal;
if (inferenceContext) {
const typeArgumentTypes = inferTypeArguments(node, candidate, args, argCheckMode, inferenceContext);
checkCandidate = getSignatureInstantiation(candidate, typeArgumentTypes, isInJSFile(candidate.declaration), inferenceContext && inferenceContext.inferredTypeParameters);
// If the original signature has a generic rest type, instantiation may produce a
// signature with different arity and we need to perform another arity check.
if (getNonArrayRestType(candidate) && !hasCorrectArity(node, args, checkCandidate, signatureHelpTrailingComma)) {
candidateForArgumentArityError = checkCandidate;
continue;
}
}
if (!checkApplicableSignature(node, args, checkCandidate, relation, argCheckMode, /*reportErrors*/ false)) {
// Give preference to error candidates that have no rest parameters (as they are more specific)
if (!candidateForArgumentError || getEffectiveRestType(candidateForArgumentError) || !getEffectiveRestType(checkCandidate)) {
candidateForArgumentError = checkCandidate;
}
continue;
}
}
candidates[candidateIndex] = checkCandidate;
return checkCandidate;
}
return undefined;
}
}
// No signature was applicable. We have already reported the errors for the invalid signature.
// If this is a type resolution session, e.g. Language Service, try to get better information than anySignature.
function getCandidateForOverloadFailure(
node: CallLikeExpression,
candidates: Signature[],
args: ReadonlyArray<Expression>,
hasCandidatesOutArray: boolean,
): Signature {
Debug.assert(candidates.length > 0); // Else should not have called this.
// Normally we will combine overloads. Skip this if they have type parameters since that's hard to combine.
// Don't do this if there is a `candidatesOutArray`,
// because then we want the chosen best candidate to be one of the overloads, not a combination.
return hasCandidatesOutArray || candidates.length === 1 || candidates.some(c => !!c.typeParameters)
? pickLongestCandidateSignature(node, candidates, args)
: createUnionOfSignaturesForOverloadFailure(candidates);
}
function createUnionOfSignaturesForOverloadFailure(candidates: ReadonlyArray<Signature>): Signature {
const thisParameters = mapDefined(candidates, c => c.thisParameter);
let thisParameter: Symbol | undefined;
if (thisParameters.length) {
thisParameter = createCombinedSymbolFromTypes(thisParameters, thisParameters.map(getTypeOfParameter));
}
const { min: minArgumentCount, max: maxNonRestParam } = minAndMax(candidates, getNumNonRestParameters);
const parameters: Symbol[] = [];
for (let i = 0; i < maxNonRestParam; i++) {
const symbols = mapDefined(candidates, ({ parameters, hasRestParameter }) => hasRestParameter ?
i < parameters.length - 1 ? parameters[i] : last(parameters) :
i < parameters.length ? parameters[i] : undefined);
Debug.assert(symbols.length !== 0);
parameters.push(createCombinedSymbolFromTypes(symbols, mapDefined(candidates, candidate => tryGetTypeAtPosition(candidate, i))));
}
const restParameterSymbols = mapDefined(candidates, c => c.hasRestParameter ? last(c.parameters) : undefined);
const hasRestParameter = restParameterSymbols.length !== 0;
if (hasRestParameter) {
const type = createArrayType(getUnionType(mapDefined(candidates, tryGetRestTypeOfSignature), UnionReduction.Subtype));
parameters.push(createCombinedSymbolForOverloadFailure(restParameterSymbols, type));
}
return createSignature(
candidates[0].declaration,
/*typeParameters*/ undefined, // Before calling this we tested for `!candidates.some(c => !!c.typeParameters)`.
thisParameter,
parameters,
/*resolvedReturnType*/ getIntersectionType(candidates.map(getReturnTypeOfSignature)),
/*typePredicate*/ undefined,
minArgumentCount,
hasRestParameter,
/*hasLiteralTypes*/ candidates.some(c => c.hasLiteralTypes));
}
function getNumNonRestParameters(signature: Signature): number {
const numParams = signature.parameters.length;
return signature.hasRestParameter ? numParams - 1 : numParams;
}
function createCombinedSymbolFromTypes(sources: ReadonlyArray<Symbol>, types: Type[]): Symbol {
return createCombinedSymbolForOverloadFailure(sources, getUnionType(types, UnionReduction.Subtype));
}
function createCombinedSymbolForOverloadFailure(sources: ReadonlyArray<Symbol>, type: Type): Symbol {
// This function is currently only used for erroneous overloads, so it's good enough to just use the first source.
return createSymbolWithType(first(sources), type);
}
function pickLongestCandidateSignature(node: CallLikeExpression, candidates: Signature[], args: ReadonlyArray<Expression>): Signature {
// Pick the longest signature. This way we can get a contextual type for cases like:
// declare function f(a: { xa: number; xb: number; }, b: number);
// f({ |
// Also, use explicitly-supplied type arguments if they are provided, so we can get a contextual signature in cases like:
// declare function f<T>(k: keyof T);
// f<Foo>("
const bestIndex = getLongestCandidateIndex(candidates, apparentArgumentCount === undefined ? args.length : apparentArgumentCount);
const candidate = candidates[bestIndex];
const { typeParameters } = candidate;
if (!typeParameters) {
return candidate;
}
const typeArgumentNodes: ReadonlyArray<TypeNode> | undefined = callLikeExpressionMayHaveTypeArguments(node) ? node.typeArguments : undefined;
const instantiated = typeArgumentNodes
? createSignatureInstantiation(candidate, getTypeArgumentsFromNodes(typeArgumentNodes, typeParameters, isInJSFile(node)))
: inferSignatureInstantiationForOverloadFailure(node, typeParameters, candidate, args);
candidates[bestIndex] = instantiated;
return instantiated;
}
function getTypeArgumentsFromNodes(typeArgumentNodes: ReadonlyArray<TypeNode>, typeParameters: ReadonlyArray<TypeParameter>, isJs: boolean): ReadonlyArray<Type> {
const typeArguments = typeArgumentNodes.map(getTypeOfNode);
while (typeArguments.length > typeParameters.length) {
typeArguments.pop();
}
while (typeArguments.length < typeParameters.length) {
typeArguments.push(getConstraintOfTypeParameter(typeParameters[typeArguments.length]) || getDefaultTypeArgumentType(isJs));
}
return typeArguments;
}
function inferSignatureInstantiationForOverloadFailure(node: CallLikeExpression, typeParameters: ReadonlyArray<TypeParameter>, candidate: Signature, args: ReadonlyArray<Expression>): Signature {
const inferenceContext = createInferenceContext(typeParameters, candidate, /*flags*/ isInJSFile(node) ? InferenceFlags.AnyDefault : InferenceFlags.None);
const typeArgumentTypes = inferTypeArguments(node, candidate, args, CheckMode.SkipContextSensitive | CheckMode.SkipGenericFunctions, inferenceContext);
return createSignatureInstantiation(candidate, typeArgumentTypes);
}
function getLongestCandidateIndex(candidates: Signature[], argsCount: number): number {
let maxParamsIndex = -1;
let maxParams = -1;
for (let i = 0; i < candidates.length; i++) {
const candidate = candidates[i];
const paramCount = getParameterCount(candidate);
if (hasEffectiveRestParameter(candidate) || paramCount >= argsCount) {
return i;
}
if (paramCount > maxParams) {
maxParams = paramCount;
maxParamsIndex = i;
}
}
return maxParamsIndex;
}
function resolveCallExpression(node: CallExpression, candidatesOutArray: Signature[] | undefined, checkMode: CheckMode): Signature {
if (node.expression.kind === SyntaxKind.SuperKeyword) {
const superType = checkSuperExpression(node.expression);
if (isTypeAny(superType)) {
for (const arg of node.arguments) {
checkExpression(arg); // Still visit arguments so they get marked for visibility, etc
}
return anySignature;
}
if (superType !== errorType) {
// In super call, the candidate signatures are the matching arity signatures of the base constructor function instantiated
// with the type arguments specified in the extends clause.
const baseTypeNode = getEffectiveBaseTypeNode(getContainingClass(node)!);
if (baseTypeNode) {
const baseConstructors = getInstantiatedConstructorsForTypeArguments(superType, baseTypeNode.typeArguments, baseTypeNode);
return resolveCall(node, baseConstructors, candidatesOutArray, checkMode);
}
}
return resolveUntypedCall(node);
}
const funcType = checkNonNullExpression(
node.expression,
Diagnostics.Cannot_invoke_an_object_which_is_possibly_null,
Diagnostics.Cannot_invoke_an_object_which_is_possibly_undefined,
Diagnostics.Cannot_invoke_an_object_which_is_possibly_null_or_undefined
);
if (funcType === silentNeverType) {
return silentNeverSignature;
}
const apparentType = getApparentType(funcType);
if (apparentType === errorType) {
// Another error has already been reported
return resolveErrorCall(node);
}
// Technically, this signatures list may be incomplete. We are taking the apparent type,
// but we are not including call signatures that may have been added to the Object or
// Function interface, since they have none by default. This is a bit of a leap of faith
// that the user will not add any.
const callSignatures = getSignaturesOfType(apparentType, SignatureKind.Call);
const numConstructSignatures = getSignaturesOfType(apparentType, SignatureKind.Construct).length;
// TS 1.0 Spec: 4.12
// In an untyped function call no TypeArgs are permitted, Args can be any argument list, no contextual
// types are provided for the argument expressions, and the result is always of type Any.
if (isUntypedFunctionCall(funcType, apparentType, callSignatures.length, numConstructSignatures)) {
// The unknownType indicates that an error already occurred (and was reported). No
// need to report another error in this case.
if (funcType !== errorType && node.typeArguments) {
error(node, Diagnostics.Untyped_function_calls_may_not_accept_type_arguments);
}
return resolveUntypedCall(node);
}
// If FuncExpr's apparent type(section 3.8.1) is a function type, the call is a typed function call.
// TypeScript employs overload resolution in typed function calls in order to support functions
// with multiple call signatures.
if (!callSignatures.length) {
if (numConstructSignatures) {
error(node, Diagnostics.Value_of_type_0_is_not_callable_Did_you_mean_to_include_new, typeToString(funcType));
}
else {
let relatedInformation: DiagnosticRelatedInformation | undefined;
if (node.arguments.length === 1) {
const text = getSourceFileOfNode(node).text;
if (isLineBreak(text.charCodeAt(skipTrivia(text, node.expression.end, /* stopAfterLineBreak */ true) - 1))) {
relatedInformation = createDiagnosticForNode(node.expression, Diagnostics.It_is_highly_likely_that_you_are_missing_a_semicolon);
}
}
invocationError(node, apparentType, SignatureKind.Call, relatedInformation);
}
return resolveErrorCall(node);
}
// When a call to a generic function is an argument to an outer call to a generic function for which
// inference is in process, we have a choice to make. If the inner call relies on inferences made from
// its contextual type to its return type, deferring the inner call processing allows the best possible
// contextual type to accumulate. But if the outer call relies on inferences made from the return type of
// the inner call, the inner call should be processed early. There's no sure way to know which choice is
// right (only a full unification algorithm can determine that), so we resort to the following heuristic:
// If no type arguments are specified in the inner call and at least one call signature is generic and
// returns a function type, we choose to defer processing. This narrowly permits function composition
// operators to flow inferences through return types, but otherwise processes calls right away. We
// use the resolvingSignature singleton to indicate that we deferred processing. This result will be
// propagated out and eventually turned into silentNeverType (a type that is assignable to anything and
// from which we never make inferences).
if (checkMode & CheckMode.SkipGenericFunctions && !node.typeArguments && callSignatures.some(isGenericFunctionReturningFunction)) {
skippedGenericFunction(node, checkMode);
return resolvingSignature;
}
// If the function is explicitly marked with `@class`, then it must be constructed.
if (callSignatures.some(sig => isInJSFile(sig.declaration) && !!getJSDocClassTag(sig.declaration!))) {
error(node, Diagnostics.Value_of_type_0_is_not_callable_Did_you_mean_to_include_new, typeToString(funcType));
return resolveErrorCall(node);
}
return resolveCall(node, callSignatures, candidatesOutArray, checkMode);
}
function isGenericFunctionReturningFunction(signature: Signature) {
return !!(signature.typeParameters && isFunctionType(getReturnTypeOfSignature(signature)));
}
/**
* TS 1.0 spec: 4.12
* If FuncExpr is of type Any, or of an object type that has no call or construct signatures
* but is a subtype of the Function interface, the call is an untyped function call.
*/
function isUntypedFunctionCall(funcType: Type, apparentFuncType: Type, numCallSignatures: number, numConstructSignatures: number): boolean {
// We exclude union types because we may have a union of function types that happen to have no common signatures.
return isTypeAny(funcType) || isTypeAny(apparentFuncType) && !!(funcType.flags & TypeFlags.TypeParameter) ||
!numCallSignatures && !numConstructSignatures && !(apparentFuncType.flags & (TypeFlags.Union | TypeFlags.Never)) && isTypeAssignableTo(funcType, globalFunctionType);
}
function resolveNewExpression(node: NewExpression, candidatesOutArray: Signature[] | undefined, checkMode: CheckMode): Signature {
if (node.arguments && languageVersion < ScriptTarget.ES5) {
const spreadIndex = getSpreadArgumentIndex(node.arguments);
if (spreadIndex >= 0) {
error(node.arguments[spreadIndex], Diagnostics.Spread_operator_in_new_expressions_is_only_available_when_targeting_ECMAScript_5_and_higher);
}
}
let expressionType = checkNonNullExpression(node.expression);
if (expressionType === silentNeverType) {
return silentNeverSignature;
}
// If expressionType's apparent type(section 3.8.1) is an object type with one or
// more construct signatures, the expression is processed in the same manner as a
// function call, but using the construct signatures as the initial set of candidate
// signatures for overload resolution. The result type of the function call becomes
// the result type of the operation.
expressionType = getApparentType(expressionType);
if (expressionType === errorType) {
// Another error has already been reported
return resolveErrorCall(node);
}
// TS 1.0 spec: 4.11
// If expressionType is of type Any, Args can be any argument
// list and the result of the operation is of type Any.
if (isTypeAny(expressionType)) {
if (node.typeArguments) {
error(node, Diagnostics.Untyped_function_calls_may_not_accept_type_arguments);
}
return resolveUntypedCall(node);
}
// Technically, this signatures list may be incomplete. We are taking the apparent type,
// but we are not including construct signatures that may have been added to the Object or
// Function interface, since they have none by default. This is a bit of a leap of faith
// that the user will not add any.
const constructSignatures = getSignaturesOfType(expressionType, SignatureKind.Construct);
if (constructSignatures.length) {
if (!isConstructorAccessible(node, constructSignatures[0])) {
return resolveErrorCall(node);
}
// If the expression is a class of abstract type, then it cannot be instantiated.
// Note, only class declarations can be declared abstract.
// In the case of a merged class-module or class-interface declaration,
// only the class declaration node will have the Abstract flag set.
const valueDecl = expressionType.symbol && getClassLikeDeclarationOfSymbol(expressionType.symbol);
if (valueDecl && hasModifier(valueDecl, ModifierFlags.Abstract)) {
error(node, Diagnostics.Cannot_create_an_instance_of_an_abstract_class);
return resolveErrorCall(node);
}
return resolveCall(node, constructSignatures, candidatesOutArray, checkMode);
}
// If expressionType's apparent type is an object type with no construct signatures but
// one or more call signatures, the expression is processed as a function call. A compile-time
// error occurs if the result of the function call is not Void. The type of the result of the
// operation is Any. It is an error to have a Void this type.
const callSignatures = getSignaturesOfType(expressionType, SignatureKind.Call);
if (callSignatures.length) {
const signature = resolveCall(node, callSignatures, candidatesOutArray, checkMode);
if (!noImplicitAny) {
if (signature.declaration && !isJSConstructor(signature.declaration) && getReturnTypeOfSignature(signature) !== voidType) {
error(node, Diagnostics.Only_a_void_function_can_be_called_with_the_new_keyword);
}
if (getThisTypeOfSignature(signature) === voidType) {
error(node, Diagnostics.A_function_that_is_called_with_the_new_keyword_cannot_have_a_this_type_that_is_void);
}
}
return signature;
}
invocationError(node, expressionType, SignatureKind.Construct);
return resolveErrorCall(node);
}
function typeHasProtectedAccessibleBase(target: Symbol, type: InterfaceType): boolean {
const baseTypes = getBaseTypes(type);
if (!length(baseTypes)) {
return false;
}
const firstBase = baseTypes[0];
if (firstBase.flags & TypeFlags.Intersection) {
const types = (firstBase as IntersectionType).types;
const mixinCount = countWhere(types, isMixinConstructorType);
let i = 0;
for (const intersectionMember of (firstBase as IntersectionType).types) {
i++;
// We want to ignore mixin ctors
if (mixinCount === 0 || mixinCount === types.length && i === 0 || !isMixinConstructorType(intersectionMember)) {
if (getObjectFlags(intersectionMember) & (ObjectFlags.Class | ObjectFlags.Interface)) {
if (intersectionMember.symbol === target) {
return true;
}
if (typeHasProtectedAccessibleBase(target, intersectionMember as InterfaceType)) {
return true;
}
}
}
}
return false;
}
if (firstBase.symbol === target) {
return true;
}
return typeHasProtectedAccessibleBase(target, firstBase as InterfaceType);
}
function isConstructorAccessible(node: NewExpression, signature: Signature) {
if (!signature || !signature.declaration) {
return true;
}
const declaration = signature.declaration;
const modifiers = getSelectedModifierFlags(declaration, ModifierFlags.NonPublicAccessibilityModifier);
// Public constructor is accessible.
if (!modifiers) {
return true;
}
const declaringClassDeclaration = getClassLikeDeclarationOfSymbol(declaration.parent.symbol)!;
const declaringClass = <InterfaceType>getDeclaredTypeOfSymbol(declaration.parent.symbol);
// A private or protected constructor can only be instantiated within its own class (or a subclass, for protected)
if (!isNodeWithinClass(node, declaringClassDeclaration)) {
const containingClass = getContainingClass(node);
if (containingClass && modifiers & ModifierFlags.Protected) {
const containingType = getTypeOfNode(containingClass);
if (typeHasProtectedAccessibleBase(declaration.parent.symbol, containingType as InterfaceType)) {
return true;
}
}
if (modifiers & ModifierFlags.Private) {
error(node, Diagnostics.Constructor_of_class_0_is_private_and_only_accessible_within_the_class_declaration, typeToString(declaringClass));
}
if (modifiers & ModifierFlags.Protected) {
error(node, Diagnostics.Constructor_of_class_0_is_protected_and_only_accessible_within_the_class_declaration, typeToString(declaringClass));
}
return false;
}
return true;
}
function invocationError(node: Node, apparentType: Type, kind: SignatureKind, relatedInformation?: DiagnosticRelatedInformation) {
const diagnostic = error(node, (kind === SignatureKind.Call ?
Diagnostics.Cannot_invoke_an_expression_whose_type_lacks_a_call_signature_Type_0_has_no_compatible_call_signatures :
Diagnostics.Cannot_use_new_with_an_expression_whose_type_lacks_a_call_or_construct_signature
), typeToString(apparentType));
invocationErrorRecovery(apparentType, kind, relatedInformation ? addRelatedInfo(diagnostic, relatedInformation) : diagnostic);
}
function invocationErrorRecovery(apparentType: Type, kind: SignatureKind, diagnostic: Diagnostic) {
if (!apparentType.symbol) {
return;
}
const importNode = getSymbolLinks(apparentType.symbol).originatingImport;
// Create a diagnostic on the originating import if possible onto which we can attach a quickfix
// An import call expression cannot be rewritten into another form to correct the error - the only solution is to use `.default` at the use-site
if (importNode && !isImportCall(importNode)) {
const sigs = getSignaturesOfType(getTypeOfSymbol(getSymbolLinks(apparentType.symbol).target!), kind);
if (!sigs || !sigs.length) return;
addRelatedInfo(diagnostic,
createDiagnosticForNode(importNode, Diagnostics.Type_originates_at_this_import_A_namespace_style_import_cannot_be_called_or_constructed_and_will_cause_a_failure_at_runtime_Consider_using_a_default_import_or_import_require_here_instead)
);
}
}
function resolveTaggedTemplateExpression(node: TaggedTemplateExpression, candidatesOutArray: Signature[] | undefined, checkMode: CheckMode): Signature {
const tagType = checkExpression(node.tag);
const apparentType = getApparentType(tagType);
if (apparentType === errorType) {
// Another error has already been reported
return resolveErrorCall(node);
}
const callSignatures = getSignaturesOfType(apparentType, SignatureKind.Call);
const numConstructSignatures = getSignaturesOfType(apparentType, SignatureKind.Construct).length;
if (isUntypedFunctionCall(tagType, apparentType, callSignatures.length, numConstructSignatures)) {
return resolveUntypedCall(node);
}
if (!callSignatures.length) {
invocationError(node, apparentType, SignatureKind.Call);
return resolveErrorCall(node);
}
return resolveCall(node, callSignatures, candidatesOutArray, checkMode);
}
/**
* Gets the localized diagnostic head message to use for errors when resolving a decorator as a call expression.
*/
function getDiagnosticHeadMessageForDecoratorResolution(node: Decorator) {
switch (node.parent.kind) {
case SyntaxKind.ClassDeclaration:
case SyntaxKind.ClassExpression:
return Diagnostics.Unable_to_resolve_signature_of_class_decorator_when_called_as_an_expression;
case SyntaxKind.Parameter:
return Diagnostics.Unable_to_resolve_signature_of_parameter_decorator_when_called_as_an_expression;
case SyntaxKind.PropertyDeclaration:
return Diagnostics.Unable_to_resolve_signature_of_property_decorator_when_called_as_an_expression;
case SyntaxKind.MethodDeclaration:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
return Diagnostics.Unable_to_resolve_signature_of_method_decorator_when_called_as_an_expression;
default:
return Debug.fail();
}
}
/**
* Resolves a decorator as if it were a call expression.
*/
function resolveDecorator(node: Decorator, candidatesOutArray: Signature[] | undefined, checkMode: CheckMode): Signature {
const funcType = checkExpression(node.expression);
const apparentType = getApparentType(funcType);
if (apparentType === errorType) {
return resolveErrorCall(node);
}
const callSignatures = getSignaturesOfType(apparentType, SignatureKind.Call);
const numConstructSignatures = getSignaturesOfType(apparentType, SignatureKind.Construct).length;
if (isUntypedFunctionCall(funcType, apparentType, callSignatures.length, numConstructSignatures)) {
return resolveUntypedCall(node);
}
if (isPotentiallyUncalledDecorator(node, callSignatures)) {
const nodeStr = getTextOfNode(node.expression, /*includeTrivia*/ false);
error(node, Diagnostics._0_accepts_too_few_arguments_to_be_used_as_a_decorator_here_Did_you_mean_to_call_it_first_and_write_0, nodeStr);
return resolveErrorCall(node);
}
const headMessage = getDiagnosticHeadMessageForDecoratorResolution(node);
if (!callSignatures.length) {
let errorInfo = chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Cannot_invoke_an_expression_whose_type_lacks_a_call_signature_Type_0_has_no_compatible_call_signatures, typeToString(apparentType));
errorInfo = chainDiagnosticMessages(errorInfo, headMessage);
const diag = createDiagnosticForNodeFromMessageChain(node, errorInfo);
diagnostics.add(diag);
invocationErrorRecovery(apparentType, SignatureKind.Call, diag);
return resolveErrorCall(node);
}
return resolveCall(node, callSignatures, candidatesOutArray, checkMode, headMessage);
}
function createSignatureForJSXIntrinsic(node: JsxOpeningLikeElement, result: Type): Signature {
const namespace = getJsxNamespaceAt(node);
const exports = namespace && getExportsOfSymbol(namespace);
// We fake up a SFC signature for each intrinsic, however a more specific per-element signature drawn from the JSX declaration
// file would probably be preferable.
const typeSymbol = exports && getSymbol(exports, JsxNames.Element, SymbolFlags.Type);
const returnNode = typeSymbol && nodeBuilder.symbolToEntityName(typeSymbol, SymbolFlags.Type, node);
const declaration = createFunctionTypeNode(/*typeParameters*/ undefined,
[createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotdotdot*/ undefined, "props", /*questionMark*/ undefined, nodeBuilder.typeToTypeNode(result, node))],
returnNode ? createTypeReferenceNode(returnNode, /*typeArguments*/ undefined) : createKeywordTypeNode(SyntaxKind.AnyKeyword)
);
const parameterSymbol = createSymbol(SymbolFlags.FunctionScopedVariable, "props" as __String);
parameterSymbol.type = result;
return createSignature(
declaration,
/*typeParameters*/ undefined,
/*thisParameter*/ undefined,
[parameterSymbol],
typeSymbol ? getDeclaredTypeOfSymbol(typeSymbol) : errorType,
/*returnTypePredicate*/ undefined,
1,
/*hasRestparameter*/ false,
/*hasLiteralTypes*/ false
);
}
function resolveJsxOpeningLikeElement(node: JsxOpeningLikeElement, candidatesOutArray: Signature[] | undefined, checkMode: CheckMode): Signature {
if (isJsxIntrinsicIdentifier(node.tagName)) {
const result = getIntrinsicAttributesTypeFromJsxOpeningLikeElement(node);
const fakeSignature = createSignatureForJSXIntrinsic(node, result);
checkTypeAssignableToAndOptionallyElaborate(checkExpressionWithContextualType(node.attributes, getEffectiveFirstArgumentForJsxSignature(fakeSignature, node), /*mapper*/ undefined, CheckMode.Normal), result, node.tagName, node.attributes);
return fakeSignature;
}
const exprTypes = checkExpression(node.tagName);
const apparentType = getApparentType(exprTypes);
if (apparentType === errorType) {
return resolveErrorCall(node);
}
const signatures = getUninstantiatedJsxSignaturesOfType(exprTypes, node);
if (isUntypedFunctionCall(exprTypes, apparentType, signatures.length, /*constructSignatures*/ 0)) {
return resolveUntypedCall(node);
}
if (signatures.length === 0) {
// We found no signatures at all, which is an error
error(node.tagName, Diagnostics.JSX_element_type_0_does_not_have_any_construct_or_call_signatures, getTextOfNode(node.tagName));
return resolveErrorCall(node);
}
return resolveCall(node, signatures, candidatesOutArray, checkMode);
}
/**
* Sometimes, we have a decorator that could accept zero arguments,
* but is receiving too many arguments as part of the decorator invocation.
* In those cases, a user may have meant to *call* the expression before using it as a decorator.
*/
function isPotentiallyUncalledDecorator(decorator: Decorator, signatures: ReadonlyArray<Signature>) {
return signatures.length && every(signatures, signature =>
signature.minArgumentCount === 0 &&
!signature.hasRestParameter &&
signature.parameters.length < getDecoratorArgumentCount(decorator, signature));
}
function resolveSignature(node: CallLikeExpression, candidatesOutArray: Signature[] | undefined, checkMode: CheckMode): Signature {
switch (node.kind) {
case SyntaxKind.CallExpression:
return resolveCallExpression(node, candidatesOutArray, checkMode);
case SyntaxKind.NewExpression:
return resolveNewExpression(node, candidatesOutArray, checkMode);
case SyntaxKind.TaggedTemplateExpression:
return resolveTaggedTemplateExpression(node, candidatesOutArray, checkMode);
case SyntaxKind.Decorator:
return resolveDecorator(node, candidatesOutArray, checkMode);
case SyntaxKind.JsxOpeningElement:
case SyntaxKind.JsxSelfClosingElement:
return resolveJsxOpeningLikeElement(node, candidatesOutArray, checkMode);
}
throw Debug.assertNever(node, "Branch in 'resolveSignature' should be unreachable.");
}
/**
* Resolve a signature of a given call-like expression.
* @param node a call-like expression to try resolve a signature for
* @param candidatesOutArray an array of signature to be filled in by the function. It is passed by signature help in the language service;
* the function will fill it up with appropriate candidate signatures
* @return a signature of the call-like expression or undefined if one can't be found
*/
function getResolvedSignature(node: CallLikeExpression, candidatesOutArray?: Signature[] | undefined, checkMode?: CheckMode): Signature {
const links = getNodeLinks(node);
// If getResolvedSignature has already been called, we will have cached the resolvedSignature.
// However, it is possible that either candidatesOutArray was not passed in the first time,
// or that a different candidatesOutArray was passed in. Therefore, we need to redo the work
// to correctly fill the candidatesOutArray.
const cached = links.resolvedSignature;
if (cached && cached !== resolvingSignature && !candidatesOutArray) {
return cached;
}
links.resolvedSignature = resolvingSignature;
const result = resolveSignature(node, candidatesOutArray, checkMode || CheckMode.Normal);
// When CheckMode.SkipGenericFunctions is set we use resolvingSignature to indicate that call
// resolution should be deferred.
if (result !== resolvingSignature) {
// If signature resolution originated in control flow type analysis (for example to compute the
// assigned type in a flow assignment) we don't cache the result as it may be based on temporary
// types from the control flow analysis.
links.resolvedSignature = flowLoopStart === flowLoopCount ? result : cached;
}
return result;
}
/**
* Indicates whether a declaration can be treated as a constructor in a JavaScript
* file.
*/
function isJSConstructor(node: Declaration | undefined): boolean {
if (!node || !isInJSFile(node)) {
return false;
}
const func = isFunctionDeclaration(node) || isFunctionExpression(node) ? node :
isVariableDeclaration(node) && node.initializer && isFunctionExpression(node.initializer) ? node.initializer :
undefined;
if (func) {
// If the node has a @class tag, treat it like a constructor.
if (getJSDocClassTag(node)) return true;
// If the symbol of the node has members, treat it like a constructor.
const symbol = getSymbolOfNode(func);
return !!symbol && (symbol.members !== undefined || symbol.exports !== undefined && symbol.exports.get("prototype" as __String) !== undefined);
}
return false;
}
function isJSConstructorType(type: Type) {
if (type.flags & TypeFlags.Object) {
const resolved = resolveStructuredTypeMembers(<ObjectType>type);
return resolved.callSignatures.length === 1 && isJSConstructor(resolved.callSignatures[0].declaration);
}
return false;
}
function getJSClassType(symbol: Symbol): Type | undefined {
let inferred: Type | undefined;
if (isJSConstructor(symbol.valueDeclaration)) {
inferred = getInferredClassType(symbol);
}
const assigned = getAssignedClassType(symbol);
return assigned && inferred ?
getIntersectionType([inferred, assigned]) :
assigned || inferred;
}
function getAssignedClassType(symbol: Symbol): Type | undefined {
const decl = symbol.valueDeclaration;
const assignmentSymbol = decl && decl.parent &&
(isFunctionDeclaration(decl) && getSymbolOfNode(decl) ||
isBinaryExpression(decl.parent) && getSymbolOfNode(decl.parent.left) ||
isVariableDeclaration(decl.parent) && getSymbolOfNode(decl.parent));
const prototype = assignmentSymbol && assignmentSymbol.exports && assignmentSymbol.exports.get("prototype" as __String);
const init = prototype && prototype.valueDeclaration && getAssignedJSPrototype(prototype.valueDeclaration);
return init ? checkExpression(init) : undefined;
}
function getAssignedJSPrototype(node: Node) {
if (!node.parent) {
return false;
}
let parent: Node = node.parent;
while (parent && parent.kind === SyntaxKind.PropertyAccessExpression) {
parent = parent.parent;
}
if (parent && isBinaryExpression(parent) && isPrototypeAccess(parent.left) && parent.operatorToken.kind === SyntaxKind.EqualsToken) {
const right = getInitializerOfBinaryExpression(parent);
return isObjectLiteralExpression(right) && right;
}
}
function getInferredClassType(symbol: Symbol) {
const links = getSymbolLinks(symbol);
if (!links.inferredClassType) {
links.inferredClassType = createAnonymousType(symbol, getMembersOfSymbol(symbol) || emptySymbols, emptyArray, emptyArray, /*stringIndexType*/ undefined, /*numberIndexType*/ undefined);
}
return links.inferredClassType;
}
/**
* Syntactically and semantically checks a call or new expression.
* @param node The call/new expression to be checked.
* @returns On success, the expression's signature's return type. On failure, anyType.
*/
function checkCallExpression(node: CallExpression | NewExpression, checkMode?: CheckMode): Type {
if (!checkGrammarTypeArguments(node, node.typeArguments)) checkGrammarArguments(node.arguments);
const signature = getResolvedSignature(node, /*candidatesOutArray*/ undefined, checkMode);
if (signature === resolvingSignature) {
// CheckMode.SkipGenericFunctions is enabled and this is a call to a generic function that
// returns a function type. We defer checking and return anyFunctionType.
return silentNeverType;
}
if (node.expression.kind === SyntaxKind.SuperKeyword) {
return voidType;
}
if (node.kind === SyntaxKind.NewExpression) {
const declaration = signature.declaration;
if (declaration &&
declaration.kind !== SyntaxKind.Constructor &&
declaration.kind !== SyntaxKind.ConstructSignature &&
declaration.kind !== SyntaxKind.ConstructorType &&
!isJSDocConstructSignature(declaration) &&
!isJSConstructor(declaration)) {
// When resolved signature is a call signature (and not a construct signature) the result type is any
if (noImplicitAny) {
error(node, Diagnostics.new_expression_whose_target_lacks_a_construct_signature_implicitly_has_an_any_type);
}
return anyType;
}
}
// In JavaScript files, calls to any identifier 'require' are treated as external module imports
if (isInJSFile(node) && isCommonJsRequire(node)) {
return resolveExternalModuleTypeByLiteral(node.arguments![0] as StringLiteral);
}
const returnType = getReturnTypeOfSignature(signature);
// Treat any call to the global 'Symbol' function that is part of a const variable or readonly property
// as a fresh unique symbol literal type.
if (returnType.flags & TypeFlags.ESSymbolLike && isSymbolOrSymbolForCall(node)) {
return getESSymbolLikeTypeForNode(walkUpParenthesizedExpressions(node.parent));
}
let jsAssignmentType: Type | undefined;
if (isInJSFile(node)) {
const decl = getDeclarationOfExpando(node);
if (decl) {
const jsSymbol = getSymbolOfNode(decl);
if (jsSymbol && hasEntries(jsSymbol.exports)) {
jsAssignmentType = createAnonymousType(jsSymbol, jsSymbol.exports, emptyArray, emptyArray, undefined, undefined);
(jsAssignmentType as ObjectType).objectFlags |= ObjectFlags.JSLiteral;
}
}
}
return jsAssignmentType ? getIntersectionType([returnType, jsAssignmentType]) : returnType;
}
function isSymbolOrSymbolForCall(node: Node) {
if (!isCallExpression(node)) return false;
let left = node.expression;
if (isPropertyAccessExpression(left) && left.name.escapedText === "for") {
left = left.expression;
}
if (!isIdentifier(left) || left.escapedText !== "Symbol") {
return false;
}
// make sure `Symbol` is the global symbol
const globalESSymbol = getGlobalESSymbolConstructorSymbol(/*reportErrors*/ false);
if (!globalESSymbol) {
return false;
}
return globalESSymbol === resolveName(left, "Symbol" as __String, SymbolFlags.Value, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ false);
}
function checkImportCallExpression(node: ImportCall): Type {
// Check grammar of dynamic import
if (!checkGrammarArguments(node.arguments)) checkGrammarImportCallExpression(node);
if (node.arguments.length === 0) {
return createPromiseReturnType(node, anyType);
}
const specifier = node.arguments[0];
const specifierType = checkExpressionCached(specifier);
// Even though multiple arguments is grammatically incorrect, type-check extra arguments for completion
for (let i = 1; i < node.arguments.length; ++i) {
checkExpressionCached(node.arguments[i]);
}
if (specifierType.flags & TypeFlags.Undefined || specifierType.flags & TypeFlags.Null || !isTypeAssignableTo(specifierType, stringType)) {
error(specifier, Diagnostics.Dynamic_import_s_specifier_must_be_of_type_string_but_here_has_type_0, typeToString(specifierType));
}
// resolveExternalModuleName will return undefined if the moduleReferenceExpression is not a string literal
const moduleSymbol = resolveExternalModuleName(node, specifier);
if (moduleSymbol) {
const esModuleSymbol = resolveESModuleSymbol(moduleSymbol, specifier, /*dontRecursivelyResolve*/ true);
if (esModuleSymbol) {
return createPromiseReturnType(node, getTypeWithSyntheticDefaultImportType(getTypeOfSymbol(esModuleSymbol), esModuleSymbol, moduleSymbol));
}
}
return createPromiseReturnType(node, anyType);
}
function getTypeWithSyntheticDefaultImportType(type: Type, symbol: Symbol, originalSymbol: Symbol): Type {
if (allowSyntheticDefaultImports && type && type !== errorType) {
const synthType = type as SyntheticDefaultModuleType;
if (!synthType.syntheticType) {
const file = find(originalSymbol.declarations, isSourceFile);
const hasSyntheticDefault = canHaveSyntheticDefault(file, originalSymbol, /*dontResolveAlias*/ false);
if (hasSyntheticDefault) {
const memberTable = createSymbolTable();
const newSymbol = createSymbol(SymbolFlags.Alias, InternalSymbolName.Default);
newSymbol.nameType = getLiteralType("default");
newSymbol.target = resolveSymbol(symbol);
memberTable.set(InternalSymbolName.Default, newSymbol);
const anonymousSymbol = createSymbol(SymbolFlags.TypeLiteral, InternalSymbolName.Type);
const defaultContainingObject = createAnonymousType(anonymousSymbol, memberTable, emptyArray, emptyArray, /*stringIndexInfo*/ undefined, /*numberIndexInfo*/ undefined);
anonymousSymbol.type = defaultContainingObject;
synthType.syntheticType = isValidSpreadType(type) ? getSpreadType(type, defaultContainingObject, anonymousSymbol, /*objectFlags*/ 0, /*readonly*/ false) : defaultContainingObject;
}
else {
synthType.syntheticType = type;
}
}
return synthType.syntheticType;
}
return type;
}
function isCommonJsRequire(node: Node): boolean {
if (!isRequireCall(node, /*checkArgumentIsStringLiteralLike*/ true)) {
return false;
}
// Make sure require is not a local function
if (!isIdentifier(node.expression)) return Debug.fail();
const resolvedRequire = resolveName(node.expression, node.expression.escapedText, SymbolFlags.Value, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ true)!; // TODO: GH#18217
if (resolvedRequire === requireSymbol) {
return true;
}
// project includes symbol named 'require' - make sure that it is ambient and local non-alias
if (resolvedRequire.flags & SymbolFlags.Alias) {
return false;
}
const targetDeclarationKind = resolvedRequire.flags & SymbolFlags.Function
? SyntaxKind.FunctionDeclaration
: resolvedRequire.flags & SymbolFlags.Variable
? SyntaxKind.VariableDeclaration
: SyntaxKind.Unknown;
if (targetDeclarationKind !== SyntaxKind.Unknown) {
const decl = getDeclarationOfKind(resolvedRequire, targetDeclarationKind)!;
// function/variable declaration should be ambient
return !!decl && !!(decl.flags & NodeFlags.Ambient);
}
return false;
}
function checkTaggedTemplateExpression(node: TaggedTemplateExpression): Type {
checkGrammarTypeArguments(node, node.typeArguments);
if (languageVersion < ScriptTarget.ES2015) {
checkExternalEmitHelpers(node, ExternalEmitHelpers.MakeTemplateObject);
}
return getReturnTypeOfSignature(getResolvedSignature(node));
}
function checkAssertion(node: AssertionExpression) {
return checkAssertionWorker(node, node.type, node.expression);
}
function isValidConstAssertionArgument(node: Node): boolean {
switch (node.kind) {
case SyntaxKind.StringLiteral:
case SyntaxKind.NoSubstitutionTemplateLiteral:
case SyntaxKind.NumericLiteral:
case SyntaxKind.BigIntLiteral:
case SyntaxKind.TrueKeyword:
case SyntaxKind.FalseKeyword:
case SyntaxKind.ArrayLiteralExpression:
case SyntaxKind.ObjectLiteralExpression:
return true;
case SyntaxKind.ParenthesizedExpression:
return isValidConstAssertionArgument((<ParenthesizedExpression>node).expression);
case SyntaxKind.PrefixUnaryExpression:
const op = (<PrefixUnaryExpression>node).operator;
const arg = (<PrefixUnaryExpression>node).operand;
return op === SyntaxKind.MinusToken && (arg.kind === SyntaxKind.NumericLiteral || arg.kind === SyntaxKind.BigIntLiteral) ||
op === SyntaxKind.PlusToken && arg.kind === SyntaxKind.NumericLiteral;
}
return false;
}
function checkAssertionWorker(errNode: Node, type: TypeNode, expression: UnaryExpression | Expression, checkMode?: CheckMode) {
let exprType = checkExpression(expression, checkMode);
if (isConstTypeReference(type)) {
if (!isValidConstAssertionArgument(expression)) {
error(expression, Diagnostics.A_const_assertion_can_only_be_applied_to_a_string_number_boolean_array_or_object_literal);
}
return getRegularTypeOfLiteralType(exprType);
}
checkSourceElement(type);
exprType = getRegularTypeOfObjectLiteral(getBaseTypeOfLiteralType(exprType));
const targetType = getTypeFromTypeNode(type);
if (produceDiagnostics && targetType !== errorType) {
const widenedType = getWidenedType(exprType);
if (!isTypeComparableTo(targetType, widenedType)) {
checkTypeComparableTo(exprType, targetType, errNode,
Diagnostics.Conversion_of_type_0_to_type_1_may_be_a_mistake_because_neither_type_sufficiently_overlaps_with_the_other_If_this_was_intentional_convert_the_expression_to_unknown_first);
}
}
return targetType;
}
function checkNonNullAssertion(node: NonNullExpression) {
return getNonNullableType(checkExpression(node.expression));
}
function checkMetaProperty(node: MetaProperty): Type {
checkGrammarMetaProperty(node);
if (node.keywordToken === SyntaxKind.NewKeyword) {
return checkNewTargetMetaProperty(node);
}
if (node.keywordToken === SyntaxKind.ImportKeyword) {
return checkImportMetaProperty(node);
}
return Debug.assertNever(node.keywordToken);
}
function checkNewTargetMetaProperty(node: MetaProperty) {
const container = getNewTargetContainer(node);
if (!container) {
error(node, Diagnostics.Meta_property_0_is_only_allowed_in_the_body_of_a_function_declaration_function_expression_or_constructor, "new.target");
return errorType;
}
else if (container.kind === SyntaxKind.Constructor) {
const symbol = getSymbolOfNode(container.parent as ClassLikeDeclaration);
return getTypeOfSymbol(symbol);
}
else {
const symbol = getSymbolOfNode(container)!;
return getTypeOfSymbol(symbol);
}
}
function checkImportMetaProperty(node: MetaProperty) {
if (languageVersion < ScriptTarget.ESNext || moduleKind < ModuleKind.ESNext) {
error(node, Diagnostics.The_import_meta_meta_property_is_only_allowed_using_ESNext_for_the_target_and_module_compiler_options);
}
const file = getSourceFileOfNode(node);
Debug.assert(!!(file.flags & NodeFlags.PossiblyContainsImportMeta), "Containing file is missing import meta node flag.");
Debug.assert(!!file.externalModuleIndicator, "Containing file should be a module.");
return node.name.escapedText === "meta" ? getGlobalImportMetaType() : errorType;
}
function getTypeOfParameter(symbol: Symbol) {
const type = getTypeOfSymbol(symbol);
if (strictNullChecks) {
const declaration = symbol.valueDeclaration;
if (declaration && hasInitializer(declaration)) {
return getOptionalType(type);
}
}
return type;
}
function getParameterNameAtPosition(signature: Signature, pos: number) {
const paramCount = signature.parameters.length - (signature.hasRestParameter ? 1 : 0);
if (pos < paramCount) {
return signature.parameters[pos].escapedName;
}
const restParameter = signature.parameters[paramCount] || unknownSymbol;
const restType = getTypeOfSymbol(restParameter);
if (isTupleType(restType)) {
const associatedNames = (<TupleType>(<TypeReference>restType).target).associatedNames;
const index = pos - paramCount;
return associatedNames ? associatedNames[index] : restParameter.escapedName + "_" + index as __String;
}
return restParameter.escapedName;
}
function getTypeAtPosition(signature: Signature, pos: number): Type {
return tryGetTypeAtPosition(signature, pos) || anyType;
}
function tryGetTypeAtPosition(signature: Signature, pos: number): Type | undefined {
const paramCount = signature.parameters.length - (signature.hasRestParameter ? 1 : 0);
if (pos < paramCount) {
return getTypeOfParameter(signature.parameters[pos]);
}
if (signature.hasRestParameter) {
const restType = getTypeOfSymbol(signature.parameters[paramCount]);
const indexType = getLiteralType(pos - paramCount);
return getIndexedAccessType(restType, indexType);
}
return undefined;
}
function getRestTypeAtPosition(source: Signature, pos: number): Type {
const paramCount = getParameterCount(source);
const restType = getEffectiveRestType(source);
const nonRestCount = paramCount - (restType ? 1 : 0);
if (restType && pos === nonRestCount) {
return restType;
}
const types = [];
const names = [];
for (let i = pos; i < nonRestCount; i++) {
types.push(getTypeAtPosition(source, i));
names.push(getParameterNameAtPosition(source, i));
}
if (restType) {
types.push(getIndexedAccessType(restType, numberType));
names.push(getParameterNameAtPosition(source, nonRestCount));
}
const minArgumentCount = getMinArgumentCount(source);
const minLength = minArgumentCount < pos ? 0 : minArgumentCount - pos;
return createTupleType(types, minLength, !!restType, /*readonly*/ false, names);
}
function getParameterCount(signature: Signature) {
const length = signature.parameters.length;
if (signature.hasRestParameter) {
const restType = getTypeOfSymbol(signature.parameters[length - 1]);
if (isTupleType(restType)) {
return length + (restType.typeArguments || emptyArray).length - 1;
}
}
return length;
}
function getMinArgumentCount(signature: Signature) {
if (signature.hasRestParameter) {
const restType = getTypeOfSymbol(signature.parameters[signature.parameters.length - 1]);
if (isTupleType(restType)) {
const minLength = restType.target.minLength;
if (minLength > 0) {
return signature.parameters.length - 1 + minLength;
}
}
}
return signature.minArgumentCount;
}
function hasEffectiveRestParameter(signature: Signature) {
if (signature.hasRestParameter) {
const restType = getTypeOfSymbol(signature.parameters[signature.parameters.length - 1]);
return !isTupleType(restType) || restType.target.hasRestElement;
}
return false;
}
function getEffectiveRestType(signature: Signature) {
if (signature.hasRestParameter) {
const restType = getTypeOfSymbol(signature.parameters[signature.parameters.length - 1]);
return isTupleType(restType) ? getRestArrayTypeOfTupleType(restType) : restType;
}
return undefined;
}
function getNonArrayRestType(signature: Signature) {
const restType = getEffectiveRestType(signature);
return restType && !isArrayType(restType) && !isTypeAny(restType) ? restType : undefined;
}
function getTypeOfFirstParameterOfSignature(signature: Signature) {
return getTypeOfFirstParameterOfSignatureWithFallback(signature, neverType);
}
function getTypeOfFirstParameterOfSignatureWithFallback(signature: Signature, fallbackType: Type) {
return signature.parameters.length > 0 ? getTypeAtPosition(signature, 0) : fallbackType;
}
function inferFromAnnotatedParameters(signature: Signature, context: Signature, mapper: TypeMapper) {
const len = signature.parameters.length - (signature.hasRestParameter ? 1 : 0);
for (let i = 0; i < len; i++) {
const declaration = <ParameterDeclaration>signature.parameters[i].valueDeclaration;
if (declaration.type) {
const typeNode = getEffectiveTypeAnnotationNode(declaration);
if (typeNode) {
inferTypes((<InferenceContext>mapper).inferences, getTypeFromTypeNode(typeNode), getTypeAtPosition(context, i));
}
}
}
const restType = getEffectiveRestType(context);
if (restType && restType.flags & TypeFlags.TypeParameter) {
// The contextual signature has a generic rest parameter. We first instantiate the contextual
// signature (without fixing type parameters) and assign types to contextually typed parameters.
const instantiatedContext = instantiateSignature(context, cloneTypeMapper(mapper));
assignContextualParameterTypes(signature, instantiatedContext);
// We then infer from a tuple type representing the parameters that correspond to the contextual
// rest parameter.
const restPos = getParameterCount(context) - 1;
inferTypes((<InferenceContext>mapper).inferences, getRestTypeAtPosition(signature, restPos), restType);
}
}
function assignContextualParameterTypes(signature: Signature, context: Signature) {
signature.typeParameters = context.typeParameters;
if (context.thisParameter) {
const parameter = signature.thisParameter;
if (!parameter || parameter.valueDeclaration && !(<ParameterDeclaration>parameter.valueDeclaration).type) {
if (!parameter) {
signature.thisParameter = createSymbolWithType(context.thisParameter, /*type*/ undefined);
}
assignTypeToParameterAndFixTypeParameters(signature.thisParameter!, getTypeOfSymbol(context.thisParameter));
}
}
const len = signature.parameters.length - (signature.hasRestParameter ? 1 : 0);
for (let i = 0; i < len; i++) {
const parameter = signature.parameters[i];
if (!getEffectiveTypeAnnotationNode(<ParameterDeclaration>parameter.valueDeclaration)) {
const contextualParameterType = getTypeAtPosition(context, i);
assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType);
}
}
if (signature.hasRestParameter) {
// parameter might be a transient symbol generated by use of `arguments` in the function body.
const parameter = last(signature.parameters);
if (isTransientSymbol(parameter) || !getEffectiveTypeAnnotationNode(<ParameterDeclaration>parameter.valueDeclaration)) {
const contextualParameterType = getRestTypeAtPosition(context, len);
assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType);
}
}
}
// When contextual typing assigns a type to a parameter that contains a binding pattern, we also need to push
// the destructured type into the contained binding elements.
function assignBindingElementTypes(pattern: BindingPattern) {
for (const element of pattern.elements) {
if (!isOmittedExpression(element)) {
if (element.name.kind === SyntaxKind.Identifier) {
getSymbolLinks(getSymbolOfNode(element)).type = getTypeForBindingElement(element);
}
else {
assignBindingElementTypes(element.name);
}
}
}
}
function assignTypeToParameterAndFixTypeParameters(parameter: Symbol, contextualType: Type) {
const links = getSymbolLinks(parameter);
if (!links.type) {
links.type = contextualType;
const decl = parameter.valueDeclaration as ParameterDeclaration;
if (decl.name.kind !== SyntaxKind.Identifier) {
// if inference didn't come up with anything but {}, fall back to the binding pattern if present.
if (links.type === emptyObjectType) {
links.type = getTypeFromBindingPattern(decl.name);
}
assignBindingElementTypes(decl.name);
}
}
}
function createPromiseType(promisedType: Type): Type {
// creates a `Promise<T>` type where `T` is the promisedType argument
const globalPromiseType = getGlobalPromiseType(/*reportErrors*/ true);
if (globalPromiseType !== emptyGenericType) {
// if the promised type is itself a promise, get the underlying type; otherwise, fallback to the promised type
promisedType = getAwaitedType(promisedType) || emptyObjectType;
return createTypeReference(globalPromiseType, [promisedType]);
}
return emptyObjectType;
}
function createPromiseLikeType(promisedType: Type): Type {
// creates a `PromiseLike<T>` type where `T` is the promisedType argument
const globalPromiseLikeType = getGlobalPromiseLikeType(/*reportErrors*/ true);
if (globalPromiseLikeType !== emptyGenericType) {
// if the promised type is itself a promise, get the underlying type; otherwise, fallback to the promised type
promisedType = getAwaitedType(promisedType) || emptyObjectType;
return createTypeReference(globalPromiseLikeType, [promisedType]);
}
return emptyObjectType;
}
function createPromiseReturnType(func: FunctionLikeDeclaration | ImportCall, promisedType: Type) {
const promiseType = createPromiseType(promisedType);
if (promiseType === emptyObjectType) {
error(func, isImportCall(func) ?
Diagnostics.A_dynamic_import_call_returns_a_Promise_Make_sure_you_have_a_declaration_for_Promise_or_include_ES2015_in_your_lib_option :
Diagnostics.An_async_function_or_method_must_return_a_Promise_Make_sure_you_have_a_declaration_for_Promise_or_include_ES2015_in_your_lib_option);
return errorType;
}
else if (!getGlobalPromiseConstructorSymbol(/*reportErrors*/ true)) {
error(func, isImportCall(func) ?
Diagnostics.A_dynamic_import_call_in_ES5_SlashES3_requires_the_Promise_constructor_Make_sure_you_have_a_declaration_for_the_Promise_constructor_or_include_ES2015_in_your_lib_option :
Diagnostics.An_async_function_or_method_in_ES5_SlashES3_requires_the_Promise_constructor_Make_sure_you_have_a_declaration_for_the_Promise_constructor_or_include_ES2015_in_your_lib_option);
}
return promiseType;
}
function getReturnTypeFromBody(func: FunctionLikeDeclaration, checkMode?: CheckMode): Type {
if (!func.body) {
return errorType;
}
const functionFlags = getFunctionFlags(func);
let type: Type;
if (func.body.kind !== SyntaxKind.Block) {
type = checkExpressionCached(func.body, checkMode && checkMode & ~CheckMode.SkipGenericFunctions);
if (functionFlags & FunctionFlags.Async) {
// From within an async function you can return either a non-promise value or a promise. Any
// Promise/A+ compatible implementation will always assimilate any foreign promise, so the
// return type of the body should be unwrapped to its awaited type, which we will wrap in
// the native Promise<T> type later in this function.
type = checkAwaitedType(type, /*errorNode*/ func, Diagnostics.The_return_type_of_an_async_function_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);
}
}
else {
let types = checkAndAggregateReturnExpressionTypes(func, checkMode);
if (functionFlags & FunctionFlags.Generator) { // Generator or AsyncGenerator function
types = concatenate(checkAndAggregateYieldOperandTypes(func, checkMode), types);
if (!types || types.length === 0) {
const iterableIteratorAny = functionFlags & FunctionFlags.Async
? createAsyncIterableIteratorType(anyType) // AsyncGenerator function
: createIterableIteratorType(anyType); // Generator function
if (noImplicitAny) {
error(func.asteriskToken,
Diagnostics.Generator_implicitly_has_type_0_because_it_does_not_yield_any_values_Consider_supplying_a_return_type, typeToString(iterableIteratorAny));
}
return iterableIteratorAny;
}
}
else {
if (!types) {
// For an async function, the return type will not be never, but rather a Promise for never.
return functionFlags & FunctionFlags.Async
? createPromiseReturnType(func, neverType) // Async function
: neverType; // Normal function
}
if (types.length === 0) {
// For an async function, the return type will not be void, but rather a Promise for void.
return functionFlags & FunctionFlags.Async
? createPromiseReturnType(func, voidType) // Async function
: voidType; // Normal function
}
}
// Return a union of the return expression types.
type = getUnionType(types, UnionReduction.Subtype);
}
const contextualSignature = getContextualSignatureForFunctionLikeDeclaration(func);
if (!contextualSignature) {
reportErrorsFromWidening(func, type);
}
if (isUnitType(type)) {
let contextualType = !contextualSignature ? undefined :
contextualSignature === getSignatureFromDeclaration(func) ? type :
getReturnTypeOfSignature(contextualSignature);
if (contextualType) {
switch (functionFlags & FunctionFlags.AsyncGenerator) {
case FunctionFlags.AsyncGenerator:
contextualType = getIteratedTypeOfGenerator(contextualType, /*isAsyncGenerator*/ true);
break;
case FunctionFlags.Generator:
contextualType = getIteratedTypeOfGenerator(contextualType, /*isAsyncGenerator*/ false);
break;
case FunctionFlags.Async:
contextualType = getPromisedTypeOfPromise(contextualType);
break;
}
}
type = getWidenedLiteralLikeTypeForContextualType(type, contextualType);
}
const widenedType = getWidenedType(type);
switch (functionFlags & FunctionFlags.AsyncGenerator) {
case FunctionFlags.AsyncGenerator:
return createAsyncIterableIteratorType(widenedType);
case FunctionFlags.Generator:
return createIterableIteratorType(widenedType);
case FunctionFlags.Async:
// From within an async function you can return either a non-promise value or a promise. Any
// Promise/A+ compatible implementation will always assimilate any foreign promise, so the
// return type of the body is awaited type of the body, wrapped in a native Promise<T> type.
return createPromiseType(widenedType);
default:
return widenedType;
}
}
function checkAndAggregateYieldOperandTypes(func: FunctionLikeDeclaration, checkMode: CheckMode | undefined): Type[] {
const aggregatedTypes: Type[] = [];
const isAsync = (getFunctionFlags(func) & FunctionFlags.Async) !== 0;
forEachYieldExpression(<Block>func.body, yieldExpression => {
pushIfUnique(aggregatedTypes, getYieldedTypeOfYieldExpression(yieldExpression, isAsync, checkMode));
});
return aggregatedTypes;
}
function getYieldedTypeOfYieldExpression(node: YieldExpression, isAsync: boolean, checkMode?: CheckMode): Type | undefined {
const errorNode = node.expression || node;
const expressionType = node.expression ? checkExpression(node.expression, checkMode) : undefinedWideningType;
// A `yield*` expression effectively yields everything that its operand yields
const yieldedType = node.asteriskToken ? checkIteratedTypeOrElementType(expressionType, errorNode, /*allowStringInput*/ false, isAsync) : expressionType;
return !isAsync ? yieldedType : getAwaitedType(yieldedType, errorNode, node.asteriskToken
? Diagnostics.Type_of_iterated_elements_of_a_yield_Asterisk_operand_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member
: Diagnostics.Type_of_yield_operand_in_an_async_generator_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);
}
/**
* Collect the TypeFacts learned from a typeof switch with
* total clauses `witnesses`, and the active clause ranging
* from `start` to `end`. Parameter `hasDefault` denotes
* whether the active clause contains a default clause.
*/
function getFactsFromTypeofSwitch(start: number, end: number, witnesses: string[], hasDefault: boolean): TypeFacts {
let facts: TypeFacts = TypeFacts.None;
// When in the default we only collect inequality facts
// because default is 'in theory' a set of infinite
// equalities.
if (hasDefault) {
// Value is not equal to any types after the active clause.
for (let i = end; i < witnesses.length; i++) {
facts |= typeofNEFacts.get(witnesses[i]) || TypeFacts.TypeofNEHostObject;
}
// Remove inequalities for types that appear in the
// active clause because they appear before other
// types collected so far.
for (let i = start; i < end; i++) {
facts &= ~(typeofNEFacts.get(witnesses[i]) || 0);
}
// Add inequalities for types before the active clause unconditionally.
for (let i = 0; i < start; i++) {
facts |= typeofNEFacts.get(witnesses[i]) || TypeFacts.TypeofNEHostObject;
}
}
// When in an active clause without default the set of
// equalities is finite.
else {
// Add equalities for all types in the active clause.
for (let i = start; i < end; i++) {
facts |= typeofEQFacts.get(witnesses[i]) || TypeFacts.TypeofEQHostObject;
}
// Remove equalities for types that appear before the
// active clause.
for (let i = 0; i < start; i++) {
facts &= ~(typeofEQFacts.get(witnesses[i]) || 0);
}
}
return facts;
}
function isExhaustiveSwitchStatement(node: SwitchStatement): boolean {
if (!node.possiblyExhaustive) {
return false;
}
if (node.expression.kind === SyntaxKind.TypeOfExpression) {
const operandType = getTypeOfExpression((node.expression as TypeOfExpression).expression);
// This cast is safe because the switch is possibly exhaustive and does not contain a default case, so there can be no undefined.
const witnesses = <string[]>getSwitchClauseTypeOfWitnesses(node);
// notEqualFacts states that the type of the switched value is not equal to every type in the switch.
const notEqualFacts = getFactsFromTypeofSwitch(0, 0, witnesses, /*hasDefault*/ true);
const type = getBaseConstraintOfType(operandType) || operandType;
return !!(filterType(type, t => (getTypeFacts(t) & notEqualFacts) === notEqualFacts).flags & TypeFlags.Never);
}
const type = getTypeOfExpression(node.expression);
if (!isLiteralType(type)) {
return false;
}
const switchTypes = getSwitchClauseTypes(node);
if (!switchTypes.length || some(switchTypes, isNeitherUnitTypeNorNever)) {
return false;
}
return eachTypeContainedIn(mapType(type, getRegularTypeOfLiteralType), switchTypes);
}
function functionHasImplicitReturn(func: FunctionLikeDeclaration) {
if (!(func.flags & NodeFlags.HasImplicitReturn)) {
return false;
}
if (some((<Block>func.body).statements, statement => statement.kind === SyntaxKind.SwitchStatement && isExhaustiveSwitchStatement(<SwitchStatement>statement))) {
return false;
}
return true;
}
/** NOTE: Return value of `[]` means a different thing than `undefined`. `[]` means func returns `void`, `undefined` means it returns `never`. */
function checkAndAggregateReturnExpressionTypes(func: FunctionLikeDeclaration, checkMode: CheckMode | undefined): Type[] | undefined {
const functionFlags = getFunctionFlags(func);
const aggregatedTypes: Type[] = [];
let hasReturnWithNoExpression = functionHasImplicitReturn(func);
let hasReturnOfTypeNever = false;
forEachReturnStatement(<Block>func.body, returnStatement => {
const expr = returnStatement.expression;
if (expr) {
let type = checkExpressionCached(expr, checkMode && checkMode & ~CheckMode.SkipGenericFunctions);
if (functionFlags & FunctionFlags.Async) {
// From within an async function you can return either a non-promise value or a promise. Any
// Promise/A+ compatible implementation will always assimilate any foreign promise, so the
// return type of the body should be unwrapped to its awaited type, which should be wrapped in
// the native Promise<T> type by the caller.
type = checkAwaitedType(type, func, Diagnostics.The_return_type_of_an_async_function_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);
}
if (type.flags & TypeFlags.Never) {
hasReturnOfTypeNever = true;
}
pushIfUnique(aggregatedTypes, type);
}
else {
hasReturnWithNoExpression = true;
}
});
if (aggregatedTypes.length === 0 && !hasReturnWithNoExpression && (hasReturnOfTypeNever || mayReturnNever(func))) {
return undefined;
}
if (strictNullChecks && aggregatedTypes.length && hasReturnWithNoExpression &&
!(isJSConstructor(func) && aggregatedTypes.some(t => t.symbol === func.symbol))) {
// Javascript "callable constructors", containing eg `if (!(this instanceof A)) return new A()` should not add undefined
pushIfUnique(aggregatedTypes, undefinedType);
}
return aggregatedTypes;
}
function mayReturnNever(func: FunctionLikeDeclaration): boolean {
switch (func.kind) {
case SyntaxKind.FunctionExpression:
case SyntaxKind.ArrowFunction:
return true;
case SyntaxKind.MethodDeclaration:
return func.parent.kind === SyntaxKind.ObjectLiteralExpression;
default:
return false;
}
}
/**
* TypeScript Specification 1.0 (6.3) - July 2014
* An explicitly typed function whose return type isn't the Void type,
* the Any type, or a union type containing the Void or Any type as a constituent
* must have at least one return statement somewhere in its body.
* An exception to this rule is if the function implementation consists of a single 'throw' statement.
*
* @param returnType - return type of the function, can be undefined if return type is not explicitly specified
*/
function checkAllCodePathsInNonVoidFunctionReturnOrThrow(func: FunctionLikeDeclaration | MethodSignature, returnType: Type | undefined): void {
if (!produceDiagnostics) {
return;
}
// Functions with with an explicitly specified 'void' or 'any' return type don't need any return expressions.
if (returnType && maybeTypeOfKind(returnType, TypeFlags.Any | TypeFlags.Void)) {
return;
}
// If all we have is a function signature, or an arrow function with an expression body, then there is nothing to check.
// also if HasImplicitReturn flag is not set this means that all codepaths in function body end with return or throw
if (func.kind === SyntaxKind.MethodSignature || nodeIsMissing(func.body) || func.body!.kind !== SyntaxKind.Block || !functionHasImplicitReturn(func)) {
return;
}
const hasExplicitReturn = func.flags & NodeFlags.HasExplicitReturn;
if (returnType && returnType.flags & TypeFlags.Never) {
error(getEffectiveReturnTypeNode(func), Diagnostics.A_function_returning_never_cannot_have_a_reachable_end_point);
}
else if (returnType && !hasExplicitReturn) {
// minimal check: function has syntactic return type annotation and no explicit return statements in the body
// this function does not conform to the specification.
// NOTE: having returnType !== undefined is a precondition for entering this branch so func.type will always be present
error(getEffectiveReturnTypeNode(func), Diagnostics.A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value);
}
else if (returnType && strictNullChecks && !isTypeAssignableTo(undefinedType, returnType)) {
error(getEffectiveReturnTypeNode(func), Diagnostics.Function_lacks_ending_return_statement_and_return_type_does_not_include_undefined);
}
else if (compilerOptions.noImplicitReturns) {
if (!returnType) {
// If return type annotation is omitted check if function has any explicit return statements.
// If it does not have any - its inferred return type is void - don't do any checks.
// Otherwise get inferred return type from function body and report error only if it is not void / anytype
if (!hasExplicitReturn) {
return;
}
const inferredReturnType = getReturnTypeOfSignature(getSignatureFromDeclaration(func));
if (isUnwrappedReturnTypeVoidOrAny(func, inferredReturnType)) {
return;
}
}
error(getEffectiveReturnTypeNode(func) || func, Diagnostics.Not_all_code_paths_return_a_value);
}
}
function checkFunctionExpressionOrObjectLiteralMethod(node: FunctionExpression | MethodDeclaration, checkMode?: CheckMode): Type {
Debug.assert(node.kind !== SyntaxKind.MethodDeclaration || isObjectLiteralMethod(node));
checkNodeDeferred(node);
// The identityMapper object is used to indicate that function expressions are wildcards
if (checkMode && checkMode & CheckMode.SkipContextSensitive && isContextSensitive(node)) {
// Skip parameters, return signature with return type that retains noncontextual parts so inferences can still be drawn in an early stage
if (!getEffectiveReturnTypeNode(node) && hasContextSensitiveReturnExpression(node)) {
const links = getNodeLinks(node);
if (links.contextFreeType) {
return links.contextFreeType;
}
const returnType = getReturnTypeFromBody(node, checkMode);
const returnOnlySignature = createSignature(undefined, undefined, undefined, emptyArray, returnType, /*resolvedTypePredicate*/ undefined, 0, /*hasRestParameter*/ false, /*hasLiteralTypes*/ false);
const returnOnlyType = createAnonymousType(node.symbol, emptySymbols, [returnOnlySignature], emptyArray, undefined, undefined);
returnOnlyType.objectFlags |= ObjectFlags.ContainsAnyFunctionType;
return links.contextFreeType = returnOnlyType;
}
return anyFunctionType;
}
// Grammar checking
const hasGrammarError = checkGrammarFunctionLikeDeclaration(node);
if (!hasGrammarError && node.kind === SyntaxKind.FunctionExpression) {
checkGrammarForGenerator(node);
}
const links = getNodeLinks(node);
const type = getTypeOfSymbol(getMergedSymbol(node.symbol));
if (isTypeAny(type)) {
return type;
}
// Check if function expression is contextually typed and assign parameter types if so.
if (!(links.flags & NodeCheckFlags.ContextChecked)) {
const contextualSignature = getContextualSignature(node);
// If a type check is started at a function expression that is an argument of a function call, obtaining the
// contextual type may recursively get back to here during overload resolution of the call. If so, we will have
// already assigned contextual types.
if (!(links.flags & NodeCheckFlags.ContextChecked)) {
links.flags |= NodeCheckFlags.ContextChecked;
if (contextualSignature) {
const signature = getSignaturesOfType(type, SignatureKind.Call)[0];
if (isContextSensitive(node)) {
const contextualMapper = getContextualMapper(node);
if (checkMode && checkMode & CheckMode.Inferential) {
inferFromAnnotatedParameters(signature, contextualSignature, contextualMapper);
}
const instantiatedContextualSignature = contextualMapper === identityMapper ?
contextualSignature : instantiateSignature(contextualSignature, contextualMapper);
assignContextualParameterTypes(signature, instantiatedContextualSignature);
}
if (!getReturnTypeFromAnnotation(node) && !signature.resolvedReturnType) {
const returnType = getReturnTypeFromBody(node, checkMode);
if (!signature.resolvedReturnType) {
signature.resolvedReturnType = returnType;
}
}
}
checkSignatureDeclaration(node);
}
}
return type;
}
function getReturnOrPromisedType(node: FunctionLikeDeclaration | MethodSignature, functionFlags: FunctionFlags) {
const type = getReturnTypeFromAnnotation(node);
return type && ((functionFlags & FunctionFlags.AsyncGenerator) === FunctionFlags.Async) ?
getAwaitedType(type) || errorType : type;
}
function checkFunctionExpressionOrObjectLiteralMethodDeferred(node: ArrowFunction | FunctionExpression | MethodDeclaration) {
Debug.assert(node.kind !== SyntaxKind.MethodDeclaration || isObjectLiteralMethod(node));
const functionFlags = getFunctionFlags(node);
const returnOrPromisedType = getReturnOrPromisedType(node, functionFlags);
if ((functionFlags & FunctionFlags.Generator) === 0) { // Async function or normal function
// return is not necessary in the body of generators
checkAllCodePathsInNonVoidFunctionReturnOrThrow(node, returnOrPromisedType);
}
if (node.body) {
if (!getEffectiveReturnTypeNode(node)) {
// There are some checks that are only performed in getReturnTypeFromBody, that may produce errors
// we need. An example is the noImplicitAny errors resulting from widening the return expression
// of a function. Because checking of function expression bodies is deferred, there was never an
// appropriate time to do this during the main walk of the file (see the comment at the top of
// checkFunctionExpressionBodies). So it must be done now.
getReturnTypeOfSignature(getSignatureFromDeclaration(node));
}
if (node.body.kind === SyntaxKind.Block) {
checkSourceElement(node.body);
}
else {
// From within an async function you can return either a non-promise value or a promise. Any
// Promise/A+ compatible implementation will always assimilate any foreign promise, so we
// should not be checking assignability of a promise to the return type. Instead, we need to
// check assignability of the awaited type of the expression body against the promised type of
// its return type annotation.
const exprType = checkExpression(node.body);
if (returnOrPromisedType) {
if ((functionFlags & FunctionFlags.AsyncGenerator) === FunctionFlags.Async) { // Async function
const awaitedType = checkAwaitedType(exprType, node.body, Diagnostics.The_return_type_of_an_async_function_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);
checkTypeAssignableToAndOptionallyElaborate(awaitedType, returnOrPromisedType, node.body, node.body);
}
else { // Normal function
checkTypeAssignableToAndOptionallyElaborate(exprType, returnOrPromisedType, node.body, node.body);
}
}
}
}
}
function checkArithmeticOperandType(operand: Node, type: Type, diagnostic: DiagnosticMessage): boolean {
if (!isTypeAssignableTo(type, numberOrBigIntType)) {
error(operand, diagnostic);
return false;
}
return true;
}
function isReadonlyAssignmentDeclaration(d: Declaration) {
if (!isCallExpression(d)) {
return false;
}
if (!isBindableObjectDefinePropertyCall(d)) {
return false;
}
const objectLitType = checkExpressionCached(d.arguments[2]);
const valueType = getTypeOfPropertyOfType(objectLitType, "value" as __String);
if (valueType) {
const writableProp = getPropertyOfType(objectLitType, "writable" as __String);
const writableType = writableProp && getTypeOfSymbol(writableProp);
if (!writableType || writableType === falseType || writableType === regularFalseType) {
return true;
}
// We include this definition whereupon we walk back and check the type at the declaration because
// The usual definition of `Object.defineProperty` will _not_ cause literal types to be preserved in the
// argument types, should the type be contextualized by the call itself.
if (writableProp && writableProp.valueDeclaration && isPropertyAssignment(writableProp.valueDeclaration)) {
const initializer = writableProp.valueDeclaration.initializer;
const rawOriginalType = checkExpression(initializer);
if (rawOriginalType === falseType || rawOriginalType === regularFalseType) {
return true;
}
}
return false;
}
const setProp = getPropertyOfType(objectLitType, "set" as __String);
return !setProp;
}
function isReadonlySymbol(symbol: Symbol): boolean {
// The following symbols are considered read-only:
// Properties with a 'readonly' modifier
// Variables declared with 'const'
// Get accessors without matching set accessors
// Enum members
// Object.defineProperty assignments with writable false or no setter
// Unions and intersections of the above (unions and intersections eagerly set isReadonly on creation)
return !!(getCheckFlags(symbol) & CheckFlags.Readonly ||
symbol.flags & SymbolFlags.Property && getDeclarationModifierFlagsFromSymbol(symbol) & ModifierFlags.Readonly ||
symbol.flags & SymbolFlags.Variable && getDeclarationNodeFlagsFromSymbol(symbol) & NodeFlags.Const ||
symbol.flags & SymbolFlags.Accessor && !(symbol.flags & SymbolFlags.SetAccessor) ||
symbol.flags & SymbolFlags.EnumMember ||
some(symbol.declarations, isReadonlyAssignmentDeclaration)
);
}
function isReferenceToReadonlyEntity(expr: Expression, symbol: Symbol): boolean {
if (isReadonlySymbol(symbol)) {
// Allow assignments to readonly properties within constructors of the same class declaration.
if (symbol.flags & SymbolFlags.Property &&
(expr.kind === SyntaxKind.PropertyAccessExpression || expr.kind === SyntaxKind.ElementAccessExpression) &&
(expr as AccessExpression).expression.kind === SyntaxKind.ThisKeyword) {
// Look for if this is the constructor for the class that `symbol` is a property of.
const func = getContainingFunction(expr);
if (!(func && func.kind === SyntaxKind.Constructor)) {
return true;
}
// If func.parent is a class and symbol is a (readonly) property of that class, or
// if func is a constructor and symbol is a (readonly) parameter property declared in it,
// then symbol is writeable here.
return !symbol.valueDeclaration || !(func.parent === symbol.valueDeclaration.parent || func === symbol.valueDeclaration.parent);
}
return true;
}
return false;
}
function isReferenceThroughNamespaceImport(expr: Expression): boolean {
if (expr.kind === SyntaxKind.PropertyAccessExpression || expr.kind === SyntaxKind.ElementAccessExpression) {
const node = skipParentheses((expr as AccessExpression).expression);
if (node.kind === SyntaxKind.Identifier) {
const symbol = getNodeLinks(node).resolvedSymbol!;
if (symbol.flags & SymbolFlags.Alias) {
const declaration = getDeclarationOfAliasSymbol(symbol);
return !!declaration && declaration.kind === SyntaxKind.NamespaceImport;
}
}
}
return false;
}
function checkReferenceExpression(expr: Expression, invalidReferenceMessage: DiagnosticMessage): boolean {
// References are combinations of identifiers, parentheses, and property accesses.
const node = skipOuterExpressions(expr, OuterExpressionKinds.Assertions | OuterExpressionKinds.Parentheses);
if (node.kind !== SyntaxKind.Identifier && node.kind !== SyntaxKind.PropertyAccessExpression && node.kind !== SyntaxKind.ElementAccessExpression) {
error(expr, invalidReferenceMessage);
return false;
}
return true;
}
function checkDeleteExpression(node: DeleteExpression): Type {
checkExpression(node.expression);
const expr = skipParentheses(node.expression);
if (expr.kind !== SyntaxKind.PropertyAccessExpression && expr.kind !== SyntaxKind.ElementAccessExpression) {
error(expr, Diagnostics.The_operand_of_a_delete_operator_must_be_a_property_reference);
return booleanType;
}
const links = getNodeLinks(expr);
const symbol = getExportSymbolOfValueSymbolIfExported(links.resolvedSymbol);
if (symbol && isReadonlySymbol(symbol)) {
error(expr, Diagnostics.The_operand_of_a_delete_operator_cannot_be_a_read_only_property);
}
return booleanType;
}
function checkTypeOfExpression(node: TypeOfExpression): Type {
checkExpression(node.expression);
return typeofType;
}
function checkVoidExpression(node: VoidExpression): Type {
checkExpression(node.expression);
return undefinedWideningType;
}
function checkAwaitExpression(node: AwaitExpression): Type {
// Grammar checking
if (produceDiagnostics) {
if (!(node.flags & NodeFlags.AwaitContext)) {
grammarErrorOnFirstToken(node, Diagnostics.await_expression_is_only_allowed_within_an_async_function);
}
if (isInParameterInitializerBeforeContainingFunction(node)) {
error(node, Diagnostics.await_expressions_cannot_be_used_in_a_parameter_initializer);
}
}
const operandType = checkExpression(node.expression);
return checkAwaitedType(operandType, node, Diagnostics.Type_of_await_operand_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);
}
function checkPrefixUnaryExpression(node: PrefixUnaryExpression): Type {
const operandType = checkExpression(node.operand);
if (operandType === silentNeverType) {
return silentNeverType;
}
switch (node.operand.kind) {
case SyntaxKind.NumericLiteral:
switch (node.operator) {
case SyntaxKind.MinusToken:
return getFreshTypeOfLiteralType(getLiteralType(-(node.operand as NumericLiteral).text));
case SyntaxKind.PlusToken:
return getFreshTypeOfLiteralType(getLiteralType(+(node.operand as NumericLiteral).text));
}
break;
case SyntaxKind.BigIntLiteral:
if (node.operator === SyntaxKind.MinusToken) {
return getFreshTypeOfLiteralType(getLiteralType({
negative: true,
base10Value: parsePseudoBigInt((node.operand as BigIntLiteral).text)
}));
}
}
switch (node.operator) {
case SyntaxKind.PlusToken:
case SyntaxKind.MinusToken:
case SyntaxKind.TildeToken:
checkNonNullType(operandType, node.operand);
if (maybeTypeOfKind(operandType, TypeFlags.ESSymbolLike)) {
error(node.operand, Diagnostics.The_0_operator_cannot_be_applied_to_type_symbol, tokenToString(node.operator));
}
if (node.operator === SyntaxKind.PlusToken) {
if (maybeTypeOfKind(operandType, TypeFlags.BigIntLike)) {
error(node.operand, Diagnostics.Operator_0_cannot_be_applied_to_type_1, tokenToString(node.operator), typeToString(operandType));
}
return numberType;
}
return getUnaryResultType(operandType);
case SyntaxKind.ExclamationToken:
checkTruthinessExpression(node.operand);
const facts = getTypeFacts(operandType) & (TypeFacts.Truthy | TypeFacts.Falsy);
return facts === TypeFacts.Truthy ? falseType :
facts === TypeFacts.Falsy ? trueType :
booleanType;
case SyntaxKind.PlusPlusToken:
case SyntaxKind.MinusMinusToken:
const ok = checkArithmeticOperandType(node.operand, checkNonNullType(operandType, node.operand),
Diagnostics.An_arithmetic_operand_must_be_of_type_any_number_bigint_or_an_enum_type);
if (ok) {
// run check only if former checks succeeded to avoid reporting cascading errors
checkReferenceExpression(node.operand, Diagnostics.The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access);
}
return getUnaryResultType(operandType);
}
return errorType;
}
function checkPostfixUnaryExpression(node: PostfixUnaryExpression): Type {
const operandType = checkExpression(node.operand);
if (operandType === silentNeverType) {
return silentNeverType;
}
const ok = checkArithmeticOperandType(
node.operand,
checkNonNullType(operandType, node.operand),
Diagnostics.An_arithmetic_operand_must_be_of_type_any_number_bigint_or_an_enum_type);
if (ok) {
// run check only if former checks succeeded to avoid reporting cascading errors
checkReferenceExpression(node.operand, Diagnostics.The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access);
}
return getUnaryResultType(operandType);
}
function getUnaryResultType(operandType: Type): Type {
if (maybeTypeOfKind(operandType, TypeFlags.BigIntLike)) {
return isTypeAssignableToKind(operandType, TypeFlags.AnyOrUnknown) || maybeTypeOfKind(operandType, TypeFlags.NumberLike)
? numberOrBigIntType
: bigintType;
}
// If it's not a bigint type, implicit coercion will result in a number
return numberType;
}
// Return true if type might be of the given kind. A union or intersection type might be of a given
// kind if at least one constituent type is of the given kind.
function maybeTypeOfKind(type: Type, kind: TypeFlags): boolean {
if (type.flags & kind & ~TypeFlags.GenericMappedType || kind & TypeFlags.GenericMappedType && isGenericMappedType(type)) {
return true;
}
if (type.flags & TypeFlags.UnionOrIntersection) {
const types = (<UnionOrIntersectionType>type).types;
for (const t of types) {
if (maybeTypeOfKind(t, kind)) {
return true;
}
}
}
return false;
}
function isTypeAssignableToKind(source: Type, kind: TypeFlags, strict?: boolean): boolean {
if (source.flags & kind) {
return true;
}
if (strict && source.flags & (TypeFlags.AnyOrUnknown | TypeFlags.Void | TypeFlags.Undefined | TypeFlags.Null)) {
return false;
}
return !!(kind & TypeFlags.NumberLike) && isTypeAssignableTo(source, numberType) ||
!!(kind & TypeFlags.BigIntLike) && isTypeAssignableTo(source, bigintType) ||
!!(kind & TypeFlags.StringLike) && isTypeAssignableTo(source, stringType) ||
!!(kind & TypeFlags.BooleanLike) && isTypeAssignableTo(source, booleanType) ||
!!(kind & TypeFlags.Void) && isTypeAssignableTo(source, voidType) ||
!!(kind & TypeFlags.Never) && isTypeAssignableTo(source, neverType) ||
!!(kind & TypeFlags.Null) && isTypeAssignableTo(source, nullType) ||
!!(kind & TypeFlags.Undefined) && isTypeAssignableTo(source, undefinedType) ||
!!(kind & TypeFlags.ESSymbol) && isTypeAssignableTo(source, esSymbolType) ||
!!(kind & TypeFlags.NonPrimitive) && isTypeAssignableTo(source, nonPrimitiveType);
}
function allTypesAssignableToKind(source: Type, kind: TypeFlags, strict?: boolean): boolean {
return source.flags & TypeFlags.Union ?
every((source as UnionType).types, subType => allTypesAssignableToKind(subType, kind, strict)) :
isTypeAssignableToKind(source, kind, strict);
}
function isConstEnumObjectType(type: Type): boolean {
return !!(getObjectFlags(type) & ObjectFlags.Anonymous) && !!type.symbol && isConstEnumSymbol(type.symbol);
}
function isConstEnumSymbol(symbol: Symbol): boolean {
return (symbol.flags & SymbolFlags.ConstEnum) !== 0;
}
function checkInstanceOfExpression(left: Expression, right: Expression, leftType: Type, rightType: Type): Type {
if (leftType === silentNeverType || rightType === silentNeverType) {
return silentNeverType;
}
// TypeScript 1.0 spec (April 2014): 4.15.4
// The instanceof operator requires the left operand to be of type Any, an object type, or a type parameter type,
// and the right operand to be of type Any, a subtype of the 'Function' interface type, or have a call or construct signature.
// The result is always of the Boolean primitive type.
// NOTE: do not raise error if leftType is unknown as related error was already reported
if (!isTypeAny(leftType) &&
allTypesAssignableToKind(leftType, TypeFlags.Primitive)) {
error(left, Diagnostics.The_left_hand_side_of_an_instanceof_expression_must_be_of_type_any_an_object_type_or_a_type_parameter);
}
// NOTE: do not raise error if right is unknown as related error was already reported
if (!(isTypeAny(rightType) || typeHasCallOrConstructSignatures(rightType) || isTypeSubtypeOf(rightType, globalFunctionType))) {
error(right, Diagnostics.The_right_hand_side_of_an_instanceof_expression_must_be_of_type_any_or_of_a_type_assignable_to_the_Function_interface_type);
}
return booleanType;
}
function checkInExpression(left: Expression, right: Expression, leftType: Type, rightType: Type): Type {
if (leftType === silentNeverType || rightType === silentNeverType) {
return silentNeverType;
}
leftType = checkNonNullType(leftType, left);
rightType = checkNonNullType(rightType, right);
// TypeScript 1.0 spec (April 2014): 4.15.5
// The in operator requires the left operand to be of type Any, the String primitive type, or the Number primitive type,
// and the right operand to be of type Any, an object type, or a type parameter type.
// The result is always of the Boolean primitive type.
if (!(isTypeComparableTo(leftType, stringType) || isTypeAssignableToKind(leftType, TypeFlags.NumberLike | TypeFlags.ESSymbolLike))) {
error(left, Diagnostics.The_left_hand_side_of_an_in_expression_must_be_of_type_any_string_number_or_symbol);
}
if (!allTypesAssignableToKind(rightType, TypeFlags.NonPrimitive | TypeFlags.InstantiableNonPrimitive)) {
error(right, Diagnostics.The_right_hand_side_of_an_in_expression_must_be_of_type_any_an_object_type_or_a_type_parameter);
}
return booleanType;
}
function checkObjectLiteralAssignment(node: ObjectLiteralExpression, sourceType: Type, rightIsThis?: boolean): Type {
const properties = node.properties;
if (strictNullChecks && properties.length === 0) {
return checkNonNullType(sourceType, node);
}
for (const p of properties) {
checkObjectLiteralDestructuringPropertyAssignment(sourceType, p, properties, rightIsThis);
}
return sourceType;
}
/** Note: If property cannot be a SpreadAssignment, then allProperties does not need to be provided */
function checkObjectLiteralDestructuringPropertyAssignment(objectLiteralType: Type, property: ObjectLiteralElementLike, allProperties?: NodeArray<ObjectLiteralElementLike>, rightIsThis = false) {
if (property.kind === SyntaxKind.PropertyAssignment || property.kind === SyntaxKind.ShorthandPropertyAssignment) {
const name = property.name;
const exprType = getLiteralTypeFromPropertyName(name);
if (isTypeUsableAsPropertyName(exprType)) {
const text = getPropertyNameFromType(exprType);
const prop = getPropertyOfType(objectLiteralType, text);
if (prop) {
markPropertyAsReferenced(prop, property, rightIsThis);
checkPropertyAccessibility(property, /*isSuper*/ false, objectLiteralType, prop);
}
}
const elementType = getIndexedAccessType(objectLiteralType, exprType, name);
const type = getFlowTypeOfDestructuring(property, elementType);
return checkDestructuringAssignment(property.kind === SyntaxKind.ShorthandPropertyAssignment ? property : property.initializer, type);
}
else if (property.kind === SyntaxKind.SpreadAssignment) {
if (languageVersion < ScriptTarget.ESNext) {
checkExternalEmitHelpers(property, ExternalEmitHelpers.Rest);
}
const nonRestNames: PropertyName[] = [];
if (allProperties) {
for (let i = 0; i < allProperties.length - 1; i++) {
nonRestNames.push(allProperties[i].name!);
}
}
const type = getRestType(objectLiteralType, nonRestNames, objectLiteralType.symbol);
checkGrammarForDisallowedTrailingComma(allProperties, Diagnostics.A_rest_parameter_or_binding_pattern_may_not_have_a_trailing_comma);
return checkDestructuringAssignment(property.expression, type);
}
else {
error(property, Diagnostics.Property_assignment_expected);
}
}
function checkArrayLiteralAssignment(node: ArrayLiteralExpression, sourceType: Type, checkMode?: CheckMode): Type {
const elements = node.elements;
if (languageVersion < ScriptTarget.ES2015 && compilerOptions.downlevelIteration) {
checkExternalEmitHelpers(node, ExternalEmitHelpers.Read);
}
// This elementType will be used if the specific property corresponding to this index is not
// present (aka the tuple element property). This call also checks that the parentType is in
// fact an iterable or array (depending on target language).
const elementType = checkIteratedTypeOrElementType(sourceType, node, /*allowStringInput*/ false, /*allowAsyncIterables*/ false) || errorType;
for (let i = 0; i < elements.length; i++) {
checkArrayLiteralDestructuringElementAssignment(node, sourceType, i, elementType, checkMode);
}
return sourceType;
}
function checkArrayLiteralDestructuringElementAssignment(node: ArrayLiteralExpression, sourceType: Type,
elementIndex: number, elementType: Type, checkMode?: CheckMode) {
const elements = node.elements;
const element = elements[elementIndex];
if (element.kind !== SyntaxKind.OmittedExpression) {
if (element.kind !== SyntaxKind.SpreadElement) {
const indexType = getLiteralType(elementIndex);
if (isArrayLikeType(sourceType)) {
// We create a synthetic expression so that getIndexedAccessType doesn't get confused
// when the element is a SyntaxKind.ElementAccessExpression.
const elementType = getIndexedAccessType(sourceType, indexType, createSyntheticExpression(element, indexType));
const type = getFlowTypeOfDestructuring(element, elementType);
return checkDestructuringAssignment(element, type, checkMode);
}
return checkDestructuringAssignment(element, elementType, checkMode);
}
if (elementIndex < elements.length - 1) {
error(element, Diagnostics.A_rest_element_must_be_last_in_a_destructuring_pattern);
}
else {
const restExpression = (<SpreadElement>element).expression;
if (restExpression.kind === SyntaxKind.BinaryExpression && (<BinaryExpression>restExpression).operatorToken.kind === SyntaxKind.EqualsToken) {
error((<BinaryExpression>restExpression).operatorToken, Diagnostics.A_rest_element_cannot_have_an_initializer);
}
else {
checkGrammarForDisallowedTrailingComma(node.elements, Diagnostics.A_rest_parameter_or_binding_pattern_may_not_have_a_trailing_comma);
const type = everyType(sourceType, isTupleType) ?
mapType(sourceType, t => sliceTupleType(<TupleTypeReference>t, elementIndex)) :
createArrayType(elementType);
return checkDestructuringAssignment(restExpression, type, checkMode);
}
}
}
return undefined;
}
function checkDestructuringAssignment(exprOrAssignment: Expression | ShorthandPropertyAssignment, sourceType: Type, checkMode?: CheckMode, rightIsThis?: boolean): Type {
let target: Expression;
if (exprOrAssignment.kind === SyntaxKind.ShorthandPropertyAssignment) {
const prop = <ShorthandPropertyAssignment>exprOrAssignment;
if (prop.objectAssignmentInitializer) {
// In strict null checking mode, if a default value of a non-undefined type is specified, remove
// undefined from the final type.
if (strictNullChecks &&
!(getFalsyFlags(checkExpression(prop.objectAssignmentInitializer)) & TypeFlags.Undefined)) {
sourceType = getTypeWithFacts(sourceType, TypeFacts.NEUndefined);
}
checkBinaryLikeExpression(prop.name, prop.equalsToken!, prop.objectAssignmentInitializer, checkMode);
}
target = (<ShorthandPropertyAssignment>exprOrAssignment).name;
}
else {
target = exprOrAssignment;
}
if (target.kind === SyntaxKind.BinaryExpression && (<BinaryExpression>target).operatorToken.kind === SyntaxKind.EqualsToken) {
checkBinaryExpression(<BinaryExpression>target, checkMode);
target = (<BinaryExpression>target).left;
}
if (target.kind === SyntaxKind.ObjectLiteralExpression) {
return checkObjectLiteralAssignment(<ObjectLiteralExpression>target, sourceType, rightIsThis);
}
if (target.kind === SyntaxKind.ArrayLiteralExpression) {
return checkArrayLiteralAssignment(<ArrayLiteralExpression>target, sourceType, checkMode);
}
return checkReferenceAssignment(target, sourceType, checkMode);
}
function checkReferenceAssignment(target: Expression, sourceType: Type, checkMode?: CheckMode): Type {
const targetType = checkExpression(target, checkMode);
const error = target.parent.kind === SyntaxKind.SpreadAssignment ?
Diagnostics.The_target_of_an_object_rest_assignment_must_be_a_variable_or_a_property_access :
Diagnostics.The_left_hand_side_of_an_assignment_expression_must_be_a_variable_or_a_property_access;
if (checkReferenceExpression(target, error)) {
checkTypeAssignableToAndOptionallyElaborate(sourceType, targetType, target, target);
}
return sourceType;
}
/**
* This is a *shallow* check: An expression is side-effect-free if the
* evaluation of the expression *itself* cannot produce side effects.
* For example, x++ / 3 is side-effect free because the / operator
* does not have side effects.
* The intent is to "smell test" an expression for correctness in positions where
* its value is discarded (e.g. the left side of the comma operator).
*/
function isSideEffectFree(node: Node): boolean {
node = skipParentheses(node);
switch (node.kind) {
case SyntaxKind.Identifier:
case SyntaxKind.StringLiteral:
case SyntaxKind.RegularExpressionLiteral:
case SyntaxKind.TaggedTemplateExpression:
case SyntaxKind.TemplateExpression:
case SyntaxKind.NoSubstitutionTemplateLiteral:
case SyntaxKind.NumericLiteral:
case SyntaxKind.BigIntLiteral:
case SyntaxKind.TrueKeyword:
case SyntaxKind.FalseKeyword:
case SyntaxKind.NullKeyword:
case SyntaxKind.UndefinedKeyword:
case SyntaxKind.FunctionExpression:
case SyntaxKind.ClassExpression:
case SyntaxKind.ArrowFunction:
case SyntaxKind.ArrayLiteralExpression:
case SyntaxKind.ObjectLiteralExpression:
case SyntaxKind.TypeOfExpression:
case SyntaxKind.NonNullExpression:
case SyntaxKind.JsxSelfClosingElement:
case SyntaxKind.JsxElement:
return true;
case SyntaxKind.ConditionalExpression:
return isSideEffectFree((node as ConditionalExpression).whenTrue) &&
isSideEffectFree((node as ConditionalExpression).whenFalse);
case SyntaxKind.BinaryExpression:
if (isAssignmentOperator((node as BinaryExpression).operatorToken.kind)) {
return false;
}
return isSideEffectFree((node as BinaryExpression).left) &&
isSideEffectFree((node as BinaryExpression).right);
case SyntaxKind.PrefixUnaryExpression:
case SyntaxKind.PostfixUnaryExpression:
// Unary operators ~, !, +, and - have no side effects.
// The rest do.
switch ((node as PrefixUnaryExpression).operator) {
case SyntaxKind.ExclamationToken:
case SyntaxKind.PlusToken:
case SyntaxKind.MinusToken:
case SyntaxKind.TildeToken:
return true;
}
return false;
// Some forms listed here for clarity
case SyntaxKind.VoidExpression: // Explicit opt-out
case SyntaxKind.TypeAssertionExpression: // Not SEF, but can produce useful type warnings
case SyntaxKind.AsExpression: // Not SEF, but can produce useful type warnings
default:
return false;
}
}
function isTypeEqualityComparableTo(source: Type, target: Type) {
return (target.flags & TypeFlags.Nullable) !== 0 || isTypeComparableTo(source, target);
}
function checkBinaryExpression(node: BinaryExpression, checkMode?: CheckMode) {
if (isInJSFile(node) && getAssignedExpandoInitializer(node)) {
return checkExpression(node.right, checkMode);
}
return checkBinaryLikeExpression(node.left, node.operatorToken, node.right, checkMode, node);
}
function checkBinaryLikeExpression(left: Expression, operatorToken: Node, right: Expression, checkMode?: CheckMode, errorNode?: Node): Type {
const operator = operatorToken.kind;
if (operator === SyntaxKind.EqualsToken && (left.kind === SyntaxKind.ObjectLiteralExpression || left.kind === SyntaxKind.ArrayLiteralExpression)) {
return checkDestructuringAssignment(left, checkExpression(right, checkMode), checkMode, right.kind === SyntaxKind.ThisKeyword);
}
let leftType: Type;
if (operator === SyntaxKind.AmpersandAmpersandToken || operator === SyntaxKind.BarBarToken) {
leftType = checkTruthinessExpression(left, checkMode);
}
else {
leftType = checkExpression(left, checkMode);
}
let rightType = checkExpression(right, checkMode);
switch (operator) {
case SyntaxKind.AsteriskToken:
case SyntaxKind.AsteriskAsteriskToken:
case SyntaxKind.AsteriskEqualsToken:
case SyntaxKind.AsteriskAsteriskEqualsToken:
case SyntaxKind.SlashToken:
case SyntaxKind.SlashEqualsToken:
case SyntaxKind.PercentToken:
case SyntaxKind.PercentEqualsToken:
case SyntaxKind.MinusToken:
case SyntaxKind.MinusEqualsToken:
case SyntaxKind.LessThanLessThanToken:
case SyntaxKind.LessThanLessThanEqualsToken:
case SyntaxKind.GreaterThanGreaterThanToken:
case SyntaxKind.GreaterThanGreaterThanEqualsToken:
case SyntaxKind.GreaterThanGreaterThanGreaterThanToken:
case SyntaxKind.GreaterThanGreaterThanGreaterThanEqualsToken:
case SyntaxKind.BarToken:
case SyntaxKind.BarEqualsToken:
case SyntaxKind.CaretToken:
case SyntaxKind.CaretEqualsToken:
case SyntaxKind.AmpersandToken:
case SyntaxKind.AmpersandEqualsToken:
if (leftType === silentNeverType || rightType === silentNeverType) {
return silentNeverType;
}
leftType = checkNonNullType(leftType, left);
rightType = checkNonNullType(rightType, right);
let suggestedOperator: SyntaxKind | undefined;
// if a user tries to apply a bitwise operator to 2 boolean operands
// try and return them a helpful suggestion
if ((leftType.flags & TypeFlags.BooleanLike) &&
(rightType.flags & TypeFlags.BooleanLike) &&
(suggestedOperator = getSuggestedBooleanOperator(operatorToken.kind)) !== undefined) {
error(errorNode || operatorToken, Diagnostics.The_0_operator_is_not_allowed_for_boolean_types_Consider_using_1_instead, tokenToString(operatorToken.kind), tokenToString(suggestedOperator));
return numberType;
}
else {
// otherwise just check each operand separately and report errors as normal
const leftOk = checkArithmeticOperandType(left, leftType, Diagnostics.The_left_hand_side_of_an_arithmetic_operation_must_be_of_type_any_number_bigint_or_an_enum_type);
const rightOk = checkArithmeticOperandType(right, rightType, Diagnostics.The_right_hand_side_of_an_arithmetic_operation_must_be_of_type_any_number_bigint_or_an_enum_type);
let resultType: Type;
// If both are any or unknown, allow operation; assume it will resolve to number
if ((isTypeAssignableToKind(leftType, TypeFlags.AnyOrUnknown) && isTypeAssignableToKind(rightType, TypeFlags.AnyOrUnknown)) ||
// Or, if neither could be bigint, implicit coercion results in a number result
!(maybeTypeOfKind(leftType, TypeFlags.BigIntLike) || maybeTypeOfKind(rightType, TypeFlags.BigIntLike))
) {
resultType = numberType;
}
// At least one is assignable to bigint, so both should be only assignable to bigint
else if (isTypeAssignableToKind(leftType, TypeFlags.BigIntLike) && isTypeAssignableToKind(rightType, TypeFlags.BigIntLike)) {
switch (operator) {
case SyntaxKind.GreaterThanGreaterThanGreaterThanToken:
case SyntaxKind.GreaterThanGreaterThanGreaterThanEqualsToken:
reportOperatorError();
}
resultType = bigintType;
}
else {
reportOperatorError();
resultType = errorType;
}
if (leftOk && rightOk) {
checkAssignmentOperator(resultType);
}
return resultType;
}
case SyntaxKind.PlusToken:
case SyntaxKind.PlusEqualsToken:
if (leftType === silentNeverType || rightType === silentNeverType) {
return silentNeverType;
}
if (!isTypeAssignableToKind(leftType, TypeFlags.StringLike) && !isTypeAssignableToKind(rightType, TypeFlags.StringLike)) {
leftType = checkNonNullType(leftType, left);
rightType = checkNonNullType(rightType, right);
}
let resultType: Type | undefined;
if (isTypeAssignableToKind(leftType, TypeFlags.NumberLike, /*strict*/ true) && isTypeAssignableToKind(rightType, TypeFlags.NumberLike, /*strict*/ true)) {
// Operands of an enum type are treated as having the primitive type Number.
// If both operands are of the Number primitive type, the result is of the Number primitive type.
resultType = numberType;
}
else if (isTypeAssignableToKind(leftType, TypeFlags.BigIntLike, /*strict*/ true) && isTypeAssignableToKind(rightType, TypeFlags.BigIntLike, /*strict*/ true)) {
// If both operands are of the BigInt primitive type, the result is of the BigInt primitive type.
resultType = bigintType;
}
else if (isTypeAssignableToKind(leftType, TypeFlags.StringLike, /*strict*/ true) || isTypeAssignableToKind(rightType, TypeFlags.StringLike, /*strict*/ true)) {
// If one or both operands are of the String primitive type, the result is of the String primitive type.
resultType = stringType;
}
else if (isTypeAny(leftType) || isTypeAny(rightType)) {
// Otherwise, the result is of type Any.
// NOTE: unknown type here denotes error type. Old compiler treated this case as any type so do we.
resultType = leftType === errorType || rightType === errorType ? errorType : anyType;
}
// Symbols are not allowed at all in arithmetic expressions
if (resultType && !checkForDisallowedESSymbolOperand(operator)) {
return resultType;
}
if (!resultType) {
reportOperatorError();
return anyType;
}
if (operator === SyntaxKind.PlusEqualsToken) {
checkAssignmentOperator(resultType);
}
return resultType;
case SyntaxKind.LessThanToken:
case SyntaxKind.GreaterThanToken:
case SyntaxKind.LessThanEqualsToken:
case SyntaxKind.GreaterThanEqualsToken:
if (checkForDisallowedESSymbolOperand(operator)) {
leftType = getBaseTypeOfLiteralType(checkNonNullType(leftType, left));
rightType = getBaseTypeOfLiteralType(checkNonNullType(rightType, right));
if (!(isTypeComparableTo(leftType, rightType) || isTypeComparableTo(rightType, leftType) ||
(isTypeAssignableTo(leftType, numberOrBigIntType) && isTypeAssignableTo(rightType, numberOrBigIntType))
)) {
reportOperatorError();
}
}
return booleanType;
case SyntaxKind.EqualsEqualsToken:
case SyntaxKind.ExclamationEqualsToken:
case SyntaxKind.EqualsEqualsEqualsToken:
case SyntaxKind.ExclamationEqualsEqualsToken:
const leftIsLiteral = isLiteralType(leftType);
const rightIsLiteral = isLiteralType(rightType);
if (!leftIsLiteral || !rightIsLiteral) {
leftType = leftIsLiteral ? getBaseTypeOfLiteralType(leftType) : leftType;
rightType = rightIsLiteral ? getBaseTypeOfLiteralType(rightType) : rightType;
}
if (!isTypeEqualityComparableTo(leftType, rightType) && !isTypeEqualityComparableTo(rightType, leftType)) {
reportOperatorError();
}
return booleanType;
case SyntaxKind.InstanceOfKeyword:
return checkInstanceOfExpression(left, right, leftType, rightType);
case SyntaxKind.InKeyword:
return checkInExpression(left, right, leftType, rightType);
case SyntaxKind.AmpersandAmpersandToken:
return getTypeFacts(leftType) & TypeFacts.Truthy ?
getUnionType([extractDefinitelyFalsyTypes(strictNullChecks ? leftType : getBaseTypeOfLiteralType(rightType)), rightType]) :
leftType;
case SyntaxKind.BarBarToken:
return getTypeFacts(leftType) & TypeFacts.Falsy ?
getUnionType([removeDefinitelyFalsyTypes(leftType), rightType], UnionReduction.Subtype) :
leftType;
case SyntaxKind.EqualsToken:
const declKind = isBinaryExpression(left.parent) ? getAssignmentDeclarationKind(left.parent) : AssignmentDeclarationKind.None;
checkAssignmentDeclaration(declKind, rightType);
if (isAssignmentDeclaration(declKind)) {
if (!(rightType.flags & TypeFlags.Object) ||
declKind !== AssignmentDeclarationKind.ModuleExports &&
declKind !== AssignmentDeclarationKind.Prototype &&
!isEmptyObjectType(rightType) &&
!isFunctionObjectType(rightType as ObjectType) &&
!(getObjectFlags(rightType) & ObjectFlags.Class)) {
// don't check assignability of module.exports=, C.prototype=, or expando types because they will necessarily be incomplete
checkAssignmentOperator(rightType);
}
return leftType;
}
else {
checkAssignmentOperator(rightType);
return getRegularTypeOfObjectLiteral(rightType);
}
case SyntaxKind.CommaToken:
if (!compilerOptions.allowUnreachableCode && isSideEffectFree(left) && !isEvalNode(right)) {
error(left, Diagnostics.Left_side_of_comma_operator_is_unused_and_has_no_side_effects);
}
return rightType;
default:
return Debug.fail();
}
function checkAssignmentDeclaration(kind: AssignmentDeclarationKind, rightType: Type) {
if (kind === AssignmentDeclarationKind.ModuleExports) {
for (const prop of getPropertiesOfObjectType(rightType)) {
const propType = getTypeOfSymbol(prop);
if (propType.symbol && propType.symbol.flags & SymbolFlags.Class) {
const name = prop.escapedName;
const symbol = resolveName(prop.valueDeclaration, name, SymbolFlags.Type, undefined, name, /*isUse*/ false);
if (symbol && symbol.declarations.some(isJSDocTypedefTag)) {
grammarErrorOnNode(symbol.declarations[0], Diagnostics.Duplicate_identifier_0, unescapeLeadingUnderscores(name));
return grammarErrorOnNode(prop.valueDeclaration, Diagnostics.Duplicate_identifier_0, unescapeLeadingUnderscores(name));
}
}
}
}
}
function isEvalNode(node: Expression) {
return node.kind === SyntaxKind.Identifier && (node as Identifier).escapedText === "eval";
}
// Return true if there was no error, false if there was an error.
function checkForDisallowedESSymbolOperand(operator: SyntaxKind): boolean {
const offendingSymbolOperand =
maybeTypeOfKind(leftType, TypeFlags.ESSymbolLike) ? left :
maybeTypeOfKind(rightType, TypeFlags.ESSymbolLike) ? right :
undefined;
if (offendingSymbolOperand) {
error(offendingSymbolOperand, Diagnostics.The_0_operator_cannot_be_applied_to_type_symbol, tokenToString(operator));
return false;
}
return true;
}
function getSuggestedBooleanOperator(operator: SyntaxKind): SyntaxKind | undefined {
switch (operator) {
case SyntaxKind.BarToken:
case SyntaxKind.BarEqualsToken:
return SyntaxKind.BarBarToken;
case SyntaxKind.CaretToken:
case SyntaxKind.CaretEqualsToken:
return SyntaxKind.ExclamationEqualsEqualsToken;
case SyntaxKind.AmpersandToken:
case SyntaxKind.AmpersandEqualsToken:
return SyntaxKind.AmpersandAmpersandToken;
default:
return undefined;
}
}
function checkAssignmentOperator(valueType: Type): void {
if (produceDiagnostics && isAssignmentOperator(operator)) {
// TypeScript 1.0 spec (April 2014): 4.17
// An assignment of the form
// VarExpr = ValueExpr
// requires VarExpr to be classified as a reference
// A compound assignment furthermore requires VarExpr to be classified as a reference (section 4.1)
// and the type of the non-compound operation to be assignable to the type of VarExpr.
if (checkReferenceExpression(left, Diagnostics.The_left_hand_side_of_an_assignment_expression_must_be_a_variable_or_a_property_access)
&& (!isIdentifier(left) || unescapeLeadingUnderscores(left.escapedText) !== "exports")) {
// to avoid cascading errors check assignability only if 'isReference' check succeeded and no errors were reported
checkTypeAssignableToAndOptionallyElaborate(valueType, leftType, left, right);
}
}
}
function isAssignmentDeclaration(kind: AssignmentDeclarationKind) {
switch (kind) {
case AssignmentDeclarationKind.ModuleExports:
return true;
case AssignmentDeclarationKind.ExportsProperty:
case AssignmentDeclarationKind.Property:
case AssignmentDeclarationKind.Prototype:
case AssignmentDeclarationKind.PrototypeProperty:
case AssignmentDeclarationKind.ThisProperty:
const symbol = getSymbolOfNode(left);
const init = getAssignedExpandoInitializer(right);
return init && isObjectLiteralExpression(init) &&
symbol && hasEntries(symbol.exports);
default:
return false;
}
}
function reportOperatorError() {
const leftStr = typeToString(leftType);
const rightStr = typeToString(rightType);
const errNode = errorNode || operatorToken;
if (!tryGiveBetterPrimaryError(errNode, leftStr, rightStr)) {
error(
errNode,
Diagnostics.Operator_0_cannot_be_applied_to_types_1_and_2,
tokenToString(operatorToken.kind),
leftStr,
rightStr,
);
}
}
function tryGiveBetterPrimaryError(errNode: Node, leftStr: string, rightStr: string) {
switch (operatorToken.kind) {
case SyntaxKind.EqualsEqualsEqualsToken:
case SyntaxKind.EqualsEqualsToken:
return error(errNode, Diagnostics.This_condition_will_always_return_0_since_the_types_1_and_2_have_no_overlap, "false", leftStr, rightStr);
case SyntaxKind.ExclamationEqualsEqualsToken:
case SyntaxKind.ExclamationEqualsToken:
return error(errNode, Diagnostics.This_condition_will_always_return_0_since_the_types_1_and_2_have_no_overlap, "true", leftStr, rightStr);
}
return undefined;
}
}
function isYieldExpressionInClass(node: YieldExpression): boolean {
let current: Node = node;
let parent = node.parent;
while (parent) {
if (isFunctionLike(parent) && current === (<FunctionLikeDeclaration>parent).body) {
return false;
}
else if (isClassLike(current)) {
return true;
}
current = parent;
parent = parent.parent;
}
return false;
}
function checkYieldExpression(node: YieldExpression): Type {
// Grammar checking
if (produceDiagnostics) {
if (!(node.flags & NodeFlags.YieldContext) || isYieldExpressionInClass(node)) {
grammarErrorOnFirstToken(node, Diagnostics.A_yield_expression_is_only_allowed_in_a_generator_body);
}
if (isInParameterInitializerBeforeContainingFunction(node)) {
error(node, Diagnostics.yield_expressions_cannot_be_used_in_a_parameter_initializer);
}
}
const func = getContainingFunction(node);
if (!func) return anyType;
const functionFlags = getFunctionFlags(func);
if (!(functionFlags & FunctionFlags.Generator)) {
// If the user's code is syntactically correct, the func should always have a star. After all, we are in a yield context.
return anyType;
}
if (node.asteriskToken) {
// Async generator functions prior to ESNext require the __await, __asyncDelegator,
// and __asyncValues helpers
if ((functionFlags & FunctionFlags.AsyncGenerator) === FunctionFlags.AsyncGenerator &&
languageVersion < ScriptTarget.ESNext) {
checkExternalEmitHelpers(node, ExternalEmitHelpers.AsyncDelegatorIncludes);
}
// Generator functions prior to ES2015 require the __values helper
if ((functionFlags & FunctionFlags.AsyncGenerator) === FunctionFlags.Generator &&
languageVersion < ScriptTarget.ES2015 && compilerOptions.downlevelIteration) {
checkExternalEmitHelpers(node, ExternalEmitHelpers.Values);
}
}
const isAsync = (functionFlags & FunctionFlags.Async) !== 0;
const yieldedType = getYieldedTypeOfYieldExpression(node, isAsync)!; // TODO: GH#18217
// There is no point in doing an assignability check if the function
// has no explicit return type because the return type is directly computed
// from the yield expressions.
const returnType = getReturnTypeFromAnnotation(func);
if (returnType) {
const signatureElementType = getIteratedTypeOfGenerator(returnType, isAsync) || anyType;
checkTypeAssignableToAndOptionallyElaborate(yieldedType, signatureElementType, node.expression || node, node.expression);
}
// Both yield and yield* expressions have type 'any'
return anyType;
}
function checkConditionalExpression(node: ConditionalExpression, checkMode?: CheckMode): Type {
checkTruthinessExpression(node.condition);
const type1 = checkExpression(node.whenTrue, checkMode);
const type2 = checkExpression(node.whenFalse, checkMode);
return getUnionType([type1, type2], UnionReduction.Subtype);
}
function checkTemplateExpression(node: TemplateExpression): Type {
// We just want to check each expressions, but we are unconcerned with
// the type of each expression, as any value may be coerced into a string.
// It is worth asking whether this is what we really want though.
// A place where we actually *are* concerned with the expressions' types are
// in tagged templates.
forEach(node.templateSpans, templateSpan => {
if (maybeTypeOfKind(checkExpression(templateSpan.expression), TypeFlags.ESSymbolLike)) {
error(templateSpan.expression, Diagnostics.Implicit_conversion_of_a_symbol_to_a_string_will_fail_at_runtime_Consider_wrapping_this_expression_in_String);
}
});
return stringType;
}
function getContextNode(node: Expression): Node {
if (node.kind === SyntaxKind.JsxAttributes && !isJsxSelfClosingElement(node.parent)) {
return node.parent.parent; // Needs to be the root JsxElement, so it encompasses the attributes _and_ the children (which are essentially part of the attributes)
}
return node;
}
function checkExpressionWithContextualType(node: Expression, contextualType: Type, contextualMapper: TypeMapper | undefined, checkMode: CheckMode): Type {
const context = getContextNode(node);
const saveContextualType = context.contextualType;
const saveContextualMapper = context.contextualMapper;
context.contextualType = contextualType;
context.contextualMapper = contextualMapper;
const type = checkExpression(node, checkMode | CheckMode.Contextual | (contextualMapper ? CheckMode.Inferential : 0));
// We strip literal freshness when an appropriate contextual type is present such that contextually typed
// literals always preserve their literal types (otherwise they might widen during type inference). An alternative
// here would be to not mark contextually typed literals as fresh in the first place.
const result = maybeTypeOfKind(type, TypeFlags.Literal) && isLiteralOfContextualType(type, instantiateContextualType(contextualType, node)) ?
getRegularTypeOfLiteralType(type) : type;
context.contextualType = saveContextualType;
context.contextualMapper = saveContextualMapper;
return result;
}
function checkExpressionCached(node: Expression, checkMode?: CheckMode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
if (checkMode && checkMode !== CheckMode.Normal) {
return checkExpression(node, checkMode);
}
// When computing a type that we're going to cache, we need to ignore any ongoing control flow
// analysis because variables may have transient types in indeterminable states. Moving flowLoopStart
// to the top of the stack ensures all transient types are computed from a known point.
const saveFlowLoopStart = flowLoopStart;
flowLoopStart = flowLoopCount;
links.resolvedType = checkExpression(node, checkMode);
flowLoopStart = saveFlowLoopStart;
}
return links.resolvedType;
}
function isTypeAssertion(node: Expression) {
node = skipParentheses(node);
return node.kind === SyntaxKind.TypeAssertionExpression || node.kind === SyntaxKind.AsExpression;
}
function checkDeclarationInitializer(declaration: HasExpressionInitializer) {
const initializer = getEffectiveInitializer(declaration)!;
const type = getTypeOfExpression(initializer, /*cache*/ true);
const widened = getCombinedNodeFlags(declaration) & NodeFlags.Const ||
isDeclarationReadonly(declaration) ||
isTypeAssertion(initializer) ||
isLiteralOfContextualType(type, getContextualType(initializer)) ? type : getWidenedLiteralType(type);
if (isInJSFile(declaration)) {
if (widened.flags & TypeFlags.Nullable) {
reportImplicitAny(declaration, anyType);
return anyType;
}
else if (isEmptyArrayLiteralType(widened)) {
reportImplicitAny(declaration, anyArrayType);
return anyArrayType;
}
}
return widened;
}
function isLiteralOfContextualType(candidateType: Type, contextualType: Type | undefined): boolean {
if (contextualType) {
if (contextualType.flags & TypeFlags.UnionOrIntersection) {
const types = (<UnionType>contextualType).types;
return some(types, t => isLiteralOfContextualType(candidateType, t));
}
if (contextualType.flags & TypeFlags.InstantiableNonPrimitive) {
// If the contextual type is a type variable constrained to a primitive type, consider
// this a literal context for literals of that primitive type. For example, given a
// type parameter 'T extends string', infer string literal types for T.
const constraint = getBaseConstraintOfType(contextualType) || emptyObjectType;
return maybeTypeOfKind(constraint, TypeFlags.String) && maybeTypeOfKind(candidateType, TypeFlags.StringLiteral) ||
maybeTypeOfKind(constraint, TypeFlags.Number) && maybeTypeOfKind(candidateType, TypeFlags.NumberLiteral) ||
maybeTypeOfKind(constraint, TypeFlags.BigInt) && maybeTypeOfKind(candidateType, TypeFlags.BigIntLiteral) ||
maybeTypeOfKind(constraint, TypeFlags.ESSymbol) && maybeTypeOfKind(candidateType, TypeFlags.UniqueESSymbol) ||
isLiteralOfContextualType(candidateType, constraint);
}
// If the contextual type is a literal of a particular primitive type, we consider this a
// literal context for all literals of that primitive type.
return !!(contextualType.flags & (TypeFlags.StringLiteral | TypeFlags.Index) && maybeTypeOfKind(candidateType, TypeFlags.StringLiteral) ||
contextualType.flags & TypeFlags.NumberLiteral && maybeTypeOfKind(candidateType, TypeFlags.NumberLiteral) ||
contextualType.flags & TypeFlags.BigIntLiteral && maybeTypeOfKind(candidateType, TypeFlags.BigIntLiteral) ||
contextualType.flags & TypeFlags.BooleanLiteral && maybeTypeOfKind(candidateType, TypeFlags.BooleanLiteral) ||
contextualType.flags & TypeFlags.UniqueESSymbol && maybeTypeOfKind(candidateType, TypeFlags.UniqueESSymbol));
}
return false;
}
function isConstContext(node: Expression): boolean {
const parent = node.parent;
return isAssertionExpression(parent) && isConstTypeReference(parent.type) ||
(isParenthesizedExpression(parent) || isArrayLiteralExpression(parent) || isSpreadElement(parent)) && isConstContext(parent) ||
(isPropertyAssignment(parent) || isShorthandPropertyAssignment(parent)) && isConstContext(parent.parent);
}
function checkExpressionForMutableLocation(node: Expression, checkMode: CheckMode | undefined, contextualType?: Type, forceTuple?: boolean): Type {
const type = checkExpression(node, checkMode, forceTuple);
return isConstContext(node) ? getRegularTypeOfLiteralType(type) :
isTypeAssertion(node) ? type :
getWidenedLiteralLikeTypeForContextualType(type, instantiateContextualType(arguments.length === 2 ? getContextualType(node) : contextualType, node));
}
function checkPropertyAssignment(node: PropertyAssignment, checkMode?: CheckMode): Type {
// Do not use hasDynamicName here, because that returns false for well known symbols.
// We want to perform checkComputedPropertyName for all computed properties, including
// well known symbols.
if (node.name.kind === SyntaxKind.ComputedPropertyName) {
checkComputedPropertyName(node.name);
}
return checkExpressionForMutableLocation(node.initializer, checkMode);
}
function checkObjectLiteralMethod(node: MethodDeclaration, checkMode?: CheckMode): Type {
// Grammar checking
checkGrammarMethod(node);
// Do not use hasDynamicName here, because that returns false for well known symbols.
// We want to perform checkComputedPropertyName for all computed properties, including
// well known symbols.
if (node.name.kind === SyntaxKind.ComputedPropertyName) {
checkComputedPropertyName(node.name);
}
const uninstantiatedType = checkFunctionExpressionOrObjectLiteralMethod(node, checkMode);
return instantiateTypeWithSingleGenericCallSignature(node, uninstantiatedType, checkMode);
}
function instantiateTypeWithSingleGenericCallSignature(node: Expression | MethodDeclaration | QualifiedName, type: Type, checkMode?: CheckMode) {
if (checkMode && checkMode & (CheckMode.Inferential | CheckMode.SkipGenericFunctions)) {
const signature = getSingleCallSignature(type);
if (signature && signature.typeParameters) {
if (checkMode & CheckMode.SkipGenericFunctions) {
skippedGenericFunction(node, checkMode);
return anyFunctionType;
}
const contextualType = getApparentTypeOfContextualType(<Expression>node);
if (contextualType) {
const contextualSignature = getSingleCallSignature(getNonNullableType(contextualType));
if (contextualSignature && !contextualSignature.typeParameters) {
const context = <InferenceContext>getContextualMapper(node);
// We have an expression that is an argument of a generic function for which we are performing
// type argument inference. The expression is of a function type with a single generic call
// signature and a contextual function type with a single non-generic call signature. Now check
// if the outer function returns a function type with a single non-generic call signature and
// if some of the outer function type parameters have no inferences so far. If so, we can
// potentially add inferred type parameters to the outer function return type.
const returnSignature = context.signature && getSingleCallSignature(getReturnTypeOfSignature(context.signature));
if (returnSignature && !returnSignature.typeParameters && !every(context.inferences, hasInferenceCandidates)) {
// Instantiate the expression type with its own type parameters as type arguments. This
// ensures that the type parameters are not erased to type any during type inference such
// that they can be inferred as actual types.
const uniqueTypeParameters = getUniqueTypeParameters(context, signature.typeParameters);
const strippedType = getOrCreateTypeFromSignature(getSignatureInstantiationWithoutFillingInTypeArguments(signature, uniqueTypeParameters));
// Infer from the stripped expression type to the contextual type starting with an empty
// set of inference candidates.
const inferences = map(context.typeParameters, createInferenceInfo);
inferTypes(inferences, strippedType, contextualType);
// If we produced some inference candidates and if the type parameters for which we produced
// candidates do not already have existing inferences, we adopt the new inference candidates and
// add the type parameters of the expression type to the set of inferred type parameters for
// the outer function return type.
if (some(inferences, hasInferenceCandidates) && !hasOverlappingInferences(context.inferences, inferences)) {
mergeInferences(context.inferences, inferences);
context.inferredTypeParameters = concatenate(context.inferredTypeParameters, uniqueTypeParameters);
return strippedType;
}
}
return getOrCreateTypeFromSignature(instantiateSignatureInContextOf(signature, contextualSignature, context));
}
}
}
}
return type;
}
function skippedGenericFunction(node: Node, checkMode: CheckMode) {
if (checkMode & CheckMode.Inferential) {
// We have skipped a generic function during inferential typing. Obtain the inference context and
// indicate this has occurred such that we know a second pass of inference is be needed.
const context = <InferenceContext>getContextualMapper(node);
context.flags |= InferenceFlags.SkippedGenericFunction;
}
}
function hasInferenceCandidates(info: InferenceInfo) {
return !!(info.candidates || info.contraCandidates);
}
function hasOverlappingInferences(a: InferenceInfo[], b: InferenceInfo[]) {
for (let i = 0; i < a.length; i++) {
if (hasInferenceCandidates(a[i]) && hasInferenceCandidates(b[i])) {
return true;
}
}
return false;
}
function mergeInferences(target: InferenceInfo[], source: InferenceInfo[]) {
for (let i = 0; i < target.length; i++) {
if (!hasInferenceCandidates(target[i]) && hasInferenceCandidates(source[i])) {
target[i] = source[i];
}
}
}
function getUniqueTypeParameters(context: InferenceContext, typeParameters: ReadonlyArray<TypeParameter>): ReadonlyArray<TypeParameter> {
const result: TypeParameter[] = [];
let oldTypeParameters: TypeParameter[] | undefined;
let newTypeParameters: TypeParameter[] | undefined;
for (const tp of typeParameters) {
const name = tp.symbol.escapedName;
if (hasTypeParameterByName(context.inferredTypeParameters, name) || hasTypeParameterByName(result, name)) {
const newName = getUniqueTypeParameterName(concatenate(context.inferredTypeParameters, result), name);
const symbol = createSymbol(SymbolFlags.TypeParameter, newName);
const newTypeParameter = createTypeParameter(symbol);
newTypeParameter.target = tp;
oldTypeParameters = append(oldTypeParameters, tp);
newTypeParameters = append(newTypeParameters, newTypeParameter);
result.push(newTypeParameter);
}
else {
result.push(tp);
}
}
if (newTypeParameters) {
const mapper = createTypeMapper(oldTypeParameters!, newTypeParameters);
for (const tp of newTypeParameters) {
tp.mapper = mapper;
}
}
return result;
}
function hasTypeParameterByName(typeParameters: ReadonlyArray<TypeParameter> | undefined, name: __String) {
return some(typeParameters, tp => tp.symbol.escapedName === name);
}
function getUniqueTypeParameterName(typeParameters: ReadonlyArray<TypeParameter>, baseName: __String) {
let len = (<string>baseName).length;
while (len > 1 && (<string>baseName).charCodeAt(len - 1) >= CharacterCodes._0 && (<string>baseName).charCodeAt(len - 1) <= CharacterCodes._9) len--;
const s = (<string>baseName).slice(0, len);
for (let index = 1; true; index++) {
const augmentedName = <__String>(s + index);
if (!hasTypeParameterByName(typeParameters, augmentedName)) {
return augmentedName;
}
}
}
/**
* Returns the type of an expression. Unlike checkExpression, this function is simply concerned
* with computing the type and may not fully check all contained sub-expressions for errors.
* A cache argument of true indicates that if the function performs a full type check, it is ok
* to cache the result.
*/
function getTypeOfExpression(node: Expression, cache?: boolean) {
const expr = skipParentheses(node);
// Optimize for the common case of a call to a function with a single non-generic call
// signature where we can just fetch the return type without checking the arguments.
if (expr.kind === SyntaxKind.CallExpression && (<CallExpression>expr).expression.kind !== SyntaxKind.SuperKeyword && !isRequireCall(expr, /*checkArgumentIsStringLiteralLike*/ true) && !isSymbolOrSymbolForCall(expr)) {
const funcType = checkNonNullExpression((<CallExpression>expr).expression);
const signature = getSingleCallSignature(funcType);
if (signature && !signature.typeParameters) {
return getReturnTypeOfSignature(signature);
}
}
else if (isAssertionExpression(expr) && !isConstTypeReference(expr.type)) {
return getTypeFromTypeNode((<TypeAssertion>expr).type);
}
// Otherwise simply call checkExpression. Ideally, the entire family of checkXXX functions
// should have a parameter that indicates whether full error checking is required such that
// we can perform the optimizations locally.
return cache ? checkExpressionCached(node) : checkExpression(node);
}
/**
* Returns the type of an expression. Unlike checkExpression, this function is simply concerned
* with computing the type and may not fully check all contained sub-expressions for errors.
* It is intended for uses where you know there is no contextual type,
* and requesting the contextual type might cause a circularity or other bad behaviour.
* It sets the contextual type of the node to any before calling getTypeOfExpression.
*/
function getContextFreeTypeOfExpression(node: Expression) {
const links = getNodeLinks(node);
if (links.contextFreeType) {
return links.contextFreeType;
}
const saveContextualType = node.contextualType;
node.contextualType = anyType;
const type = links.contextFreeType = checkExpression(node, CheckMode.SkipContextSensitive);
node.contextualType = saveContextualType;
return type;
}
// Checks an expression and returns its type. The contextualMapper parameter serves two purposes: When
// contextualMapper is not undefined and not equal to the identityMapper function object it indicates that the
// expression is being inferentially typed (section 4.15.2 in spec) and provides the type mapper to use in
// conjunction with the generic contextual type. When contextualMapper is equal to the identityMapper function
// object, it serves as an indicator that all contained function and arrow expressions should be considered to
// have the wildcard function type; this form of type check is used during overload resolution to exclude
// contextually typed function and arrow expressions in the initial phase.
function checkExpression(node: Expression | QualifiedName, checkMode?: CheckMode, forceTuple?: boolean): Type {
const saveCurrentNode = currentNode;
currentNode = node;
const uninstantiatedType = checkExpressionWorker(node, checkMode, forceTuple);
const type = instantiateTypeWithSingleGenericCallSignature(node, uninstantiatedType, checkMode);
if (isConstEnumObjectType(type)) {
checkConstEnumAccess(node, type);
}
currentNode = saveCurrentNode;
return type;
}
function checkConstEnumAccess(node: Expression | QualifiedName, type: Type) {
// enum object type for const enums are only permitted in:
// - 'left' in property access
// - 'object' in indexed access
// - target in rhs of import statement
const ok =
(node.parent.kind === SyntaxKind.PropertyAccessExpression && (<PropertyAccessExpression>node.parent).expression === node) ||
(node.parent.kind === SyntaxKind.ElementAccessExpression && (<ElementAccessExpression>node.parent).expression === node) ||
((node.kind === SyntaxKind.Identifier || node.kind === SyntaxKind.QualifiedName) && isInRightSideOfImportOrExportAssignment(<Identifier>node) ||
(node.parent.kind === SyntaxKind.TypeQuery && (<TypeQueryNode>node.parent).exprName === node));
if (!ok) {
error(node, Diagnostics.const_enums_can_only_be_used_in_property_or_index_access_expressions_or_the_right_hand_side_of_an_import_declaration_or_export_assignment_or_type_query);
}
if (compilerOptions.isolatedModules) {
Debug.assert(!!(type.symbol.flags & SymbolFlags.ConstEnum));
const constEnumDeclaration = type.symbol.valueDeclaration as EnumDeclaration;
if (constEnumDeclaration.flags & NodeFlags.Ambient) {
error(node, Diagnostics.Cannot_access_ambient_const_enums_when_the_isolatedModules_flag_is_provided);
}
}
}
function checkParenthesizedExpression(node: ParenthesizedExpression, checkMode?: CheckMode): Type {
const tag = isInJSFile(node) ? getJSDocTypeTag(node) : undefined;
if (tag) {
return checkAssertionWorker(tag, tag.typeExpression!.type, node.expression, checkMode);
}
return checkExpression(node.expression, checkMode);
}
function checkExpressionWorker(node: Expression | QualifiedName, checkMode: CheckMode | undefined, forceTuple?: boolean): Type {
switch (node.kind) {
case SyntaxKind.Identifier:
return checkIdentifier(<Identifier>node);
case SyntaxKind.ThisKeyword:
return checkThisExpression(node);
case SyntaxKind.SuperKeyword:
return checkSuperExpression(node);
case SyntaxKind.NullKeyword:
return nullWideningType;
case SyntaxKind.NoSubstitutionTemplateLiteral:
case SyntaxKind.StringLiteral:
return getFreshTypeOfLiteralType(getLiteralType((node as StringLiteralLike).text));
case SyntaxKind.NumericLiteral:
checkGrammarNumericLiteral(node as NumericLiteral);
return getFreshTypeOfLiteralType(getLiteralType(+(node as NumericLiteral).text));
case SyntaxKind.BigIntLiteral:
checkGrammarBigIntLiteral(node as BigIntLiteral);
return getFreshTypeOfLiteralType(getBigIntLiteralType(node as BigIntLiteral));
case SyntaxKind.TrueKeyword:
return trueType;
case SyntaxKind.FalseKeyword:
return falseType;
case SyntaxKind.TemplateExpression:
return checkTemplateExpression(<TemplateExpression>node);
case SyntaxKind.RegularExpressionLiteral:
return globalRegExpType;
case SyntaxKind.ArrayLiteralExpression:
return checkArrayLiteral(<ArrayLiteralExpression>node, checkMode, forceTuple);
case SyntaxKind.ObjectLiteralExpression:
return checkObjectLiteral(<ObjectLiteralExpression>node, checkMode);
case SyntaxKind.PropertyAccessExpression:
return checkPropertyAccessExpression(<PropertyAccessExpression>node);
case SyntaxKind.QualifiedName:
return checkQualifiedName(<QualifiedName>node);
case SyntaxKind.ElementAccessExpression:
return checkIndexedAccess(<ElementAccessExpression>node);
case SyntaxKind.CallExpression:
if ((<CallExpression>node).expression.kind === SyntaxKind.ImportKeyword) {
return checkImportCallExpression(<ImportCall>node);
}
/* falls through */
case SyntaxKind.NewExpression:
return checkCallExpression(<CallExpression>node, checkMode);
case SyntaxKind.TaggedTemplateExpression:
return checkTaggedTemplateExpression(<TaggedTemplateExpression>node);
case SyntaxKind.ParenthesizedExpression:
return checkParenthesizedExpression(<ParenthesizedExpression>node, checkMode);
case SyntaxKind.ClassExpression:
return checkClassExpression(<ClassExpression>node);
case SyntaxKind.FunctionExpression:
case SyntaxKind.ArrowFunction:
return checkFunctionExpressionOrObjectLiteralMethod(<FunctionExpression>node, checkMode);
case SyntaxKind.TypeOfExpression:
return checkTypeOfExpression(<TypeOfExpression>node);
case SyntaxKind.TypeAssertionExpression:
case SyntaxKind.AsExpression:
return checkAssertion(<AssertionExpression>node);
case SyntaxKind.NonNullExpression:
return checkNonNullAssertion(<NonNullExpression>node);
case SyntaxKind.MetaProperty:
return checkMetaProperty(<MetaProperty>node);
case SyntaxKind.DeleteExpression:
return checkDeleteExpression(<DeleteExpression>node);
case SyntaxKind.VoidExpression:
return checkVoidExpression(<VoidExpression>node);
case SyntaxKind.AwaitExpression:
return checkAwaitExpression(<AwaitExpression>node);
case SyntaxKind.PrefixUnaryExpression:
return checkPrefixUnaryExpression(<PrefixUnaryExpression>node);
case SyntaxKind.PostfixUnaryExpression:
return checkPostfixUnaryExpression(<PostfixUnaryExpression>node);
case SyntaxKind.BinaryExpression:
return checkBinaryExpression(<BinaryExpression>node, checkMode);
case SyntaxKind.ConditionalExpression:
return checkConditionalExpression(<ConditionalExpression>node, checkMode);
case SyntaxKind.SpreadElement:
return checkSpreadExpression(<SpreadElement>node, checkMode);
case SyntaxKind.OmittedExpression:
return undefinedWideningType;
case SyntaxKind.YieldExpression:
return checkYieldExpression(<YieldExpression>node);
case SyntaxKind.SyntheticExpression:
return (<SyntheticExpression>node).type;
case SyntaxKind.JsxExpression:
return checkJsxExpression(<JsxExpression>node, checkMode);
case SyntaxKind.JsxElement:
return checkJsxElement(<JsxElement>node, checkMode);
case SyntaxKind.JsxSelfClosingElement:
return checkJsxSelfClosingElement(<JsxSelfClosingElement>node, checkMode);
case SyntaxKind.JsxFragment:
return checkJsxFragment(<JsxFragment>node);
case SyntaxKind.JsxAttributes:
return checkJsxAttributes(<JsxAttributes>node, checkMode);
case SyntaxKind.JsxOpeningElement:
Debug.fail("Shouldn't ever directly check a JsxOpeningElement");
}
return errorType;
}
// DECLARATION AND STATEMENT TYPE CHECKING
function checkTypeParameter(node: TypeParameterDeclaration) {
// Grammar Checking
if (node.expression) {
grammarErrorOnFirstToken(node.expression, Diagnostics.Type_expected);
}
checkSourceElement(node.constraint);
checkSourceElement(node.default);
const typeParameter = getDeclaredTypeOfTypeParameter(getSymbolOfNode(node));
// Resolve base constraint to reveal circularity errors
getBaseConstraintOfType(typeParameter);
if (!hasNonCircularTypeParameterDefault(typeParameter)) {
error(node.default, Diagnostics.Type_parameter_0_has_a_circular_default, typeToString(typeParameter));
}
const constraintType = getConstraintOfTypeParameter(typeParameter);
const defaultType = getDefaultFromTypeParameter(typeParameter);
if (constraintType && defaultType) {
checkTypeAssignableTo(defaultType, getTypeWithThisArgument(constraintType, defaultType), node.default, Diagnostics.Type_0_does_not_satisfy_the_constraint_1);
}
if (produceDiagnostics) {
checkTypeNameIsReserved(node.name, Diagnostics.Type_parameter_name_cannot_be_0);
}
}
function checkParameter(node: ParameterDeclaration) {
// Grammar checking
// It is a SyntaxError if the Identifier "eval" or the Identifier "arguments" occurs as the
// Identifier in a PropertySetParameterList of a PropertyAssignment that is contained in strict code
// or if its FunctionBody is strict code(11.1.5).
checkGrammarDecoratorsAndModifiers(node);
checkVariableLikeDeclaration(node);
const func = getContainingFunction(node)!;
if (hasModifier(node, ModifierFlags.ParameterPropertyModifier)) {
if (!(func.kind === SyntaxKind.Constructor && nodeIsPresent(func.body))) {
error(node, Diagnostics.A_parameter_property_is_only_allowed_in_a_constructor_implementation);
}
}
if (node.questionToken && isBindingPattern(node.name) && (func as FunctionLikeDeclaration).body) {
error(node, Diagnostics.A_binding_pattern_parameter_cannot_be_optional_in_an_implementation_signature);
}
if (node.name && isIdentifier(node.name) && (node.name.escapedText === "this" || node.name.escapedText === "new")) {
if (func.parameters.indexOf(node) !== 0) {
error(node, Diagnostics.A_0_parameter_must_be_the_first_parameter, node.name.escapedText as string);
}
if (func.kind === SyntaxKind.Constructor || func.kind === SyntaxKind.ConstructSignature || func.kind === SyntaxKind.ConstructorType) {
error(node, Diagnostics.A_constructor_cannot_have_a_this_parameter);
}
if (func.kind === SyntaxKind.ArrowFunction) {
error(node, Diagnostics.An_arrow_function_cannot_have_a_this_parameter);
}
}
// Only check rest parameter type if it's not a binding pattern. Since binding patterns are
// not allowed in a rest parameter, we already have an error from checkGrammarParameterList.
if (node.dotDotDotToken && !isBindingPattern(node.name) && !isTypeAssignableTo(getTypeOfSymbol(node.symbol), anyReadonlyArrayType)) {
error(node, Diagnostics.A_rest_parameter_must_be_of_an_array_type);
}
}
function checkTypePredicate(node: TypePredicateNode): void {
const parent = getTypePredicateParent(node);
if (!parent) {
// The parent must not be valid.
error(node, Diagnostics.A_type_predicate_is_only_allowed_in_return_type_position_for_functions_and_methods);
return;
}
const typePredicate = getTypePredicateOfSignature(getSignatureFromDeclaration(parent));
if (!typePredicate) {
return;
}
checkSourceElement(node.type);
const { parameterName } = node;
if (isThisTypePredicate(typePredicate)) {
getTypeFromThisTypeNode(parameterName as ThisTypeNode);
}
else {
if (typePredicate.parameterIndex >= 0) {
if (parent.parameters[typePredicate.parameterIndex].dotDotDotToken) {
error(parameterName,
Diagnostics.A_type_predicate_cannot_reference_a_rest_parameter);
}
else {
const leadingError = () => chainDiagnosticMessages(/*details*/ undefined, Diagnostics.A_type_predicate_s_type_must_be_assignable_to_its_parameter_s_type);
checkTypeAssignableTo(typePredicate.type,
getTypeOfNode(parent.parameters[typePredicate.parameterIndex]),
node.type,
/*headMessage*/ undefined,
leadingError);
}
}
else if (parameterName) {
let hasReportedError = false;
for (const { name } of parent.parameters) {
if (isBindingPattern(name) &&
checkIfTypePredicateVariableIsDeclaredInBindingPattern(name, parameterName, typePredicate.parameterName)) {
hasReportedError = true;
break;
}
}
if (!hasReportedError) {
error(node.parameterName, Diagnostics.Cannot_find_parameter_0, typePredicate.parameterName);
}
}
}
}
function getTypePredicateParent(node: Node): SignatureDeclaration | undefined {
switch (node.parent.kind) {
case SyntaxKind.ArrowFunction:
case SyntaxKind.CallSignature:
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.FunctionExpression:
case SyntaxKind.FunctionType:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.MethodSignature:
const parent = <SignatureDeclaration>node.parent;
if (node === parent.type) {
return parent;
}
}
}
function checkIfTypePredicateVariableIsDeclaredInBindingPattern(
pattern: BindingPattern,
predicateVariableNode: Node,
predicateVariableName: string) {
for (const element of pattern.elements) {
if (isOmittedExpression(element)) {
continue;
}
const name = element.name;
if (name.kind === SyntaxKind.Identifier && name.escapedText === predicateVariableName) {
error(predicateVariableNode,
Diagnostics.A_type_predicate_cannot_reference_element_0_in_a_binding_pattern,
predicateVariableName);
return true;
}
else if (name.kind === SyntaxKind.ArrayBindingPattern || name.kind === SyntaxKind.ObjectBindingPattern) {
if (checkIfTypePredicateVariableIsDeclaredInBindingPattern(
name,
predicateVariableNode,
predicateVariableName)) {
return true;
}
}
}
}
function checkSignatureDeclaration(node: SignatureDeclaration) {
// Grammar checking
if (node.kind === SyntaxKind.IndexSignature) {
checkGrammarIndexSignature(<SignatureDeclaration>node);
}
// TODO (yuisu): Remove this check in else-if when SyntaxKind.Construct is moved and ambient context is handled
else if (node.kind === SyntaxKind.FunctionType || node.kind === SyntaxKind.FunctionDeclaration || node.kind === SyntaxKind.ConstructorType ||
node.kind === SyntaxKind.CallSignature || node.kind === SyntaxKind.Constructor ||
node.kind === SyntaxKind.ConstructSignature) {
checkGrammarFunctionLikeDeclaration(<FunctionLikeDeclaration>node);
}
const functionFlags = getFunctionFlags(<FunctionLikeDeclaration>node);
if (!(functionFlags & FunctionFlags.Invalid)) {
// Async generators prior to ESNext require the __await and __asyncGenerator helpers
if ((functionFlags & FunctionFlags.AsyncGenerator) === FunctionFlags.AsyncGenerator && languageVersion < ScriptTarget.ESNext) {
checkExternalEmitHelpers(node, ExternalEmitHelpers.AsyncGeneratorIncludes);
}
// Async functions prior to ES2017 require the __awaiter helper
if ((functionFlags & FunctionFlags.AsyncGenerator) === FunctionFlags.Async && languageVersion < ScriptTarget.ES2017) {
checkExternalEmitHelpers(node, ExternalEmitHelpers.Awaiter);
}
// Generator functions, Async functions, and Async Generator functions prior to
// ES2015 require the __generator helper
if ((functionFlags & FunctionFlags.AsyncGenerator) !== FunctionFlags.Normal && languageVersion < ScriptTarget.ES2015) {
checkExternalEmitHelpers(node, ExternalEmitHelpers.Generator);
}
}
checkTypeParameters(node.typeParameters);
forEach(node.parameters, checkParameter);
// TODO(rbuckton): Should we start checking JSDoc types?
if (node.type) {
checkSourceElement(node.type);
}
if (produceDiagnostics) {
checkCollisionWithArgumentsInGeneratedCode(node);
const returnTypeNode = getEffectiveReturnTypeNode(node);
if (noImplicitAny && !returnTypeNode) {
switch (node.kind) {
case SyntaxKind.ConstructSignature:
error(node, Diagnostics.Construct_signature_which_lacks_return_type_annotation_implicitly_has_an_any_return_type);
break;
case SyntaxKind.CallSignature:
error(node, Diagnostics.Call_signature_which_lacks_return_type_annotation_implicitly_has_an_any_return_type);
break;
}
}
if (returnTypeNode) {
const functionFlags = getFunctionFlags(<FunctionDeclaration>node);
if ((functionFlags & (FunctionFlags.Invalid | FunctionFlags.Generator)) === FunctionFlags.Generator) {
const returnType = getTypeFromTypeNode(returnTypeNode);
if (returnType === voidType) {
error(returnTypeNode, Diagnostics.A_generator_cannot_have_a_void_type_annotation);
}
else {
const generatorElementType = getIteratedTypeOfGenerator(returnType, (functionFlags & FunctionFlags.Async) !== 0) || anyType;
const iterableIteratorInstantiation = functionFlags & FunctionFlags.Async
? createAsyncIterableIteratorType(generatorElementType) // AsyncGenerator function
: createIterableIteratorType(generatorElementType); // Generator function
// Naively, one could check that IterableIterator<any> is assignable to the return type annotation.
// However, that would not catch the error in the following case.
//
// interface BadGenerator extends Iterable<number>, Iterator<string> { }
// function* g(): BadGenerator { } // Iterable and Iterator have different types!
//
checkTypeAssignableTo(iterableIteratorInstantiation, returnType, returnTypeNode);
}
}
else if ((functionFlags & FunctionFlags.AsyncGenerator) === FunctionFlags.Async) {
checkAsyncFunctionReturnType(<FunctionLikeDeclaration>node, returnTypeNode);
}
}
if (node.kind !== SyntaxKind.IndexSignature && node.kind !== SyntaxKind.JSDocFunctionType) {
registerForUnusedIdentifiersCheck(node);
}
}
}
function checkClassForDuplicateDeclarations(node: ClassLikeDeclaration) {
const enum Declaration {
Getter = 1,
Setter = 2,
Method = 4,
Property = Getter | Setter
}
const instanceNames = createUnderscoreEscapedMap<Declaration>();
const staticNames = createUnderscoreEscapedMap<Declaration>();
for (const member of node.members) {
if (member.kind === SyntaxKind.Constructor) {
for (const param of (member as ConstructorDeclaration).parameters) {
if (isParameterPropertyDeclaration(param) && !isBindingPattern(param.name)) {
addName(instanceNames, param.name, param.name.escapedText, Declaration.Property);
}
}
}
else {
const isStatic = hasModifier(member, ModifierFlags.Static);
const names = isStatic ? staticNames : instanceNames;
const name = member.name;
const memberName = name && getPropertyNameForPropertyNameNode(name);
if (name && memberName) {
switch (member.kind) {
case SyntaxKind.GetAccessor:
addName(names, name, memberName, Declaration.Getter);
break;
case SyntaxKind.SetAccessor:
addName(names, name, memberName, Declaration.Setter);
break;
case SyntaxKind.PropertyDeclaration:
addName(names, name, memberName, Declaration.Property);
break;
case SyntaxKind.MethodDeclaration:
addName(names, name, memberName, Declaration.Method);
break;
}
}
}
}
function addName(names: UnderscoreEscapedMap<Declaration>, location: Node, name: __String, meaning: Declaration) {
const prev = names.get(name);
if (prev) {
if (prev & Declaration.Method) {
if (meaning !== Declaration.Method) {
error(location, Diagnostics.Duplicate_identifier_0, getTextOfNode(location));
}
}
else if (prev & meaning) {
error(location, Diagnostics.Duplicate_identifier_0, getTextOfNode(location));
}
else {
names.set(name, prev | meaning);
}
}
else {
names.set(name, meaning);
}
}
}
/**
* Static members being set on a constructor function may conflict with built-in properties
* of Function. Esp. in ECMAScript 5 there are non-configurable and non-writable
* built-in properties. This check issues a transpile error when a class has a static
* member with the same name as a non-writable built-in property.
*
* @see http://www.ecma-international.org/ecma-262/5.1/#sec-15.3.3
* @see http://www.ecma-international.org/ecma-262/5.1/#sec-15.3.5
* @see http://www.ecma-international.org/ecma-262/6.0/#sec-properties-of-the-function-constructor
* @see http://www.ecma-international.org/ecma-262/6.0/#sec-function-instances
*/
function checkClassForStaticPropertyNameConflicts(node: ClassLikeDeclaration) {
for (const member of node.members) {
const memberNameNode = member.name;
const isStatic = hasModifier(member, ModifierFlags.Static);
if (isStatic && memberNameNode) {
const memberName = getPropertyNameForPropertyNameNode(memberNameNode);
switch (memberName) {
case "name":
case "length":
case "caller":
case "arguments":
case "prototype":
const message = Diagnostics.Static_property_0_conflicts_with_built_in_property_Function_0_of_constructor_function_1;
const className = getNameOfSymbolAsWritten(getSymbolOfNode(node));
error(memberNameNode, message, memberName, className);
break;
}
}
}
}
function checkObjectTypeForDuplicateDeclarations(node: TypeLiteralNode | InterfaceDeclaration) {
const names = createMap<boolean>();
for (const member of node.members) {
if (member.kind === SyntaxKind.PropertySignature) {
let memberName: string;
const name = member.name!;
switch (name.kind) {
case SyntaxKind.StringLiteral:
case SyntaxKind.NumericLiteral:
memberName = name.text;
break;
case SyntaxKind.Identifier:
memberName = idText(name);
break;
default:
continue;
}
if (names.get(memberName)) {
error(getNameOfDeclaration(member.symbol.valueDeclaration), Diagnostics.Duplicate_identifier_0, memberName);
error(member.name, Diagnostics.Duplicate_identifier_0, memberName);
}
else {
names.set(memberName, true);
}
}
}
}
function checkTypeForDuplicateIndexSignatures(node: Node) {
if (node.kind === SyntaxKind.InterfaceDeclaration) {
const nodeSymbol = getSymbolOfNode(node as InterfaceDeclaration);
// in case of merging interface declaration it is possible that we'll enter this check procedure several times for every declaration
// to prevent this run check only for the first declaration of a given kind
if (nodeSymbol.declarations.length > 0 && nodeSymbol.declarations[0] !== node) {
return;
}
}
// TypeScript 1.0 spec (April 2014)
// 3.7.4: An object type can contain at most one string index signature and one numeric index signature.
// 8.5: A class declaration can have at most one string index member declaration and one numeric index member declaration
const indexSymbol = getIndexSymbol(getSymbolOfNode(node)!);
if (indexSymbol) {
let seenNumericIndexer = false;
let seenStringIndexer = false;
for (const decl of indexSymbol.declarations) {
const declaration = <SignatureDeclaration>decl;
if (declaration.parameters.length === 1 && declaration.parameters[0].type) {
switch (declaration.parameters[0].type.kind) {
case SyntaxKind.StringKeyword:
if (!seenStringIndexer) {
seenStringIndexer = true;
}
else {
error(declaration, Diagnostics.Duplicate_string_index_signature);
}
break;
case SyntaxKind.NumberKeyword:
if (!seenNumericIndexer) {
seenNumericIndexer = true;
}
else {
error(declaration, Diagnostics.Duplicate_number_index_signature);
}
break;
}
}
}
}
}
function checkPropertyDeclaration(node: PropertyDeclaration | PropertySignature) {
// Grammar checking
if (!checkGrammarDecoratorsAndModifiers(node) && !checkGrammarProperty(node)) checkGrammarComputedPropertyName(node.name);
checkVariableLikeDeclaration(node);
}
function checkMethodDeclaration(node: MethodDeclaration | MethodSignature) {
// Grammar checking
if (!checkGrammarMethod(node)) checkGrammarComputedPropertyName(node.name);
// Grammar checking for modifiers is done inside the function checkGrammarFunctionLikeDeclaration
checkFunctionOrMethodDeclaration(node);
// Abstract methods cannot have an implementation.
// Extra checks are to avoid reporting multiple errors relating to the "abstractness" of the node.
if (hasModifier(node, ModifierFlags.Abstract) && node.kind === SyntaxKind.MethodDeclaration && node.body) {
error(node, Diagnostics.Method_0_cannot_have_an_implementation_because_it_is_marked_abstract, declarationNameToString(node.name));
}
}
function checkConstructorDeclaration(node: ConstructorDeclaration) {
// Grammar check on signature of constructor and modifier of the constructor is done in checkSignatureDeclaration function.
checkSignatureDeclaration(node);
// Grammar check for checking only related to constructorDeclaration
if (!checkGrammarConstructorTypeParameters(node)) checkGrammarConstructorTypeAnnotation(node);
checkSourceElement(node.body);
const symbol = getSymbolOfNode(node);
const firstDeclaration = getDeclarationOfKind(symbol, node.kind);
// Only type check the symbol once
if (node === firstDeclaration) {
checkFunctionOrConstructorSymbol(symbol);
}
// exit early in the case of signature - super checks are not relevant to them
if (nodeIsMissing(node.body)) {
return;
}
if (!produceDiagnostics) {
return;
}
function isInstancePropertyWithInitializer(n: Node): boolean {
return n.kind === SyntaxKind.PropertyDeclaration &&
!hasModifier(n, ModifierFlags.Static) &&
!!(<PropertyDeclaration>n).initializer;
}
// TS 1.0 spec (April 2014): 8.3.2
// Constructors of classes with no extends clause may not contain super calls, whereas
// constructors of derived classes must contain at least one super call somewhere in their function body.
const containingClassDecl = <ClassDeclaration>node.parent;
if (getClassExtendsHeritageElement(containingClassDecl)) {
captureLexicalThis(node.parent, containingClassDecl);
const classExtendsNull = classDeclarationExtendsNull(containingClassDecl);
const superCall = getSuperCallInConstructor(node);
if (superCall) {
if (classExtendsNull) {
error(superCall, Diagnostics.A_constructor_cannot_contain_a_super_call_when_its_class_extends_null);
}
// The first statement in the body of a constructor (excluding prologue directives) must be a super call
// if both of the following are true:
// - The containing class is a derived class.
// - The constructor declares parameter properties
// or the containing class declares instance member variables with initializers.
const superCallShouldBeFirst =
some((<ClassDeclaration>node.parent).members, isInstancePropertyWithInitializer) ||
some(node.parameters, p => hasModifier(p, ModifierFlags.ParameterPropertyModifier));
// Skip past any prologue directives to find the first statement
// to ensure that it was a super call.
if (superCallShouldBeFirst) {
const statements = node.body!.statements;
let superCallStatement: ExpressionStatement | undefined;
for (const statement of statements) {
if (statement.kind === SyntaxKind.ExpressionStatement && isSuperCall((<ExpressionStatement>statement).expression)) {
superCallStatement = <ExpressionStatement>statement;
break;
}
if (!isPrologueDirective(statement)) {
break;
}
}
if (!superCallStatement) {
error(node, Diagnostics.A_super_call_must_be_the_first_statement_in_the_constructor_when_a_class_contains_initialized_properties_or_has_parameter_properties);
}
}
}
else if (!classExtendsNull) {
error(node, Diagnostics.Constructors_for_derived_classes_must_contain_a_super_call);
}
}
}
function checkAccessorDeclaration(node: AccessorDeclaration) {
if (produceDiagnostics) {
// Grammar checking accessors
if (!checkGrammarFunctionLikeDeclaration(node) && !checkGrammarAccessor(node)) checkGrammarComputedPropertyName(node.name);
checkDecorators(node);
checkSignatureDeclaration(node);
if (node.kind === SyntaxKind.GetAccessor) {
if (!(node.flags & NodeFlags.Ambient) && nodeIsPresent(node.body) && (node.flags & NodeFlags.HasImplicitReturn)) {
if (!(node.flags & NodeFlags.HasExplicitReturn)) {
error(node.name, Diagnostics.A_get_accessor_must_return_a_value);
}
}
}
// Do not use hasDynamicName here, because that returns false for well known symbols.
// We want to perform checkComputedPropertyName for all computed properties, including
// well known symbols.
if (node.name.kind === SyntaxKind.ComputedPropertyName) {
checkComputedPropertyName(node.name);
}
if (!hasNonBindableDynamicName(node)) {
// TypeScript 1.0 spec (April 2014): 8.4.3
// Accessors for the same member name must specify the same accessibility.
const otherKind = node.kind === SyntaxKind.GetAccessor ? SyntaxKind.SetAccessor : SyntaxKind.GetAccessor;
const otherAccessor = getDeclarationOfKind<AccessorDeclaration>(getSymbolOfNode(node), otherKind);
if (otherAccessor) {
const nodeFlags = getModifierFlags(node);
const otherFlags = getModifierFlags(otherAccessor);
if ((nodeFlags & ModifierFlags.AccessibilityModifier) !== (otherFlags & ModifierFlags.AccessibilityModifier)) {
error(node.name, Diagnostics.Getter_and_setter_accessors_do_not_agree_in_visibility);
}
if ((nodeFlags & ModifierFlags.Abstract) !== (otherFlags & ModifierFlags.Abstract)) {
error(node.name, Diagnostics.Accessors_must_both_be_abstract_or_non_abstract);
}
// TypeScript 1.0 spec (April 2014): 4.5
// If both accessors include type annotations, the specified types must be identical.
checkAccessorDeclarationTypesIdentical(node, otherAccessor, getAnnotatedAccessorType, Diagnostics.get_and_set_accessor_must_have_the_same_type);
checkAccessorDeclarationTypesIdentical(node, otherAccessor, getThisTypeOfDeclaration, Diagnostics.get_and_set_accessor_must_have_the_same_this_type);
}
}
const returnType = getTypeOfAccessors(getSymbolOfNode(node));
if (node.kind === SyntaxKind.GetAccessor) {
checkAllCodePathsInNonVoidFunctionReturnOrThrow(node, returnType);
}
}
checkSourceElement(node.body);
}
function checkAccessorDeclarationTypesIdentical(first: AccessorDeclaration, second: AccessorDeclaration, getAnnotatedType: (a: AccessorDeclaration) => Type | undefined, message: DiagnosticMessage) {
const firstType = getAnnotatedType(first);
const secondType = getAnnotatedType(second);
if (firstType && secondType && !isTypeIdenticalTo(firstType, secondType)) {
error(first, message);
}
}
function checkMissingDeclaration(node: Node) {
checkDecorators(node);
}
function getEffectiveTypeArguments(node: TypeReferenceNode | ExpressionWithTypeArguments, typeParameters: ReadonlyArray<TypeParameter>): Type[] {
return fillMissingTypeArguments(map(node.typeArguments!, getTypeFromTypeNode), typeParameters,
getMinTypeArgumentCount(typeParameters), isInJSFile(node));
}
function checkTypeArgumentConstraints(node: TypeReferenceNode | ExpressionWithTypeArguments, typeParameters: ReadonlyArray<TypeParameter>): boolean {
let typeArguments: Type[] | undefined;
let mapper: TypeMapper | undefined;
let result = true;
for (let i = 0; i < typeParameters.length; i++) {
const constraint = getConstraintOfTypeParameter(typeParameters[i]);
if (constraint) {
if (!typeArguments) {
typeArguments = getEffectiveTypeArguments(node, typeParameters);
mapper = createTypeMapper(typeParameters, typeArguments);
}
result = result && checkTypeAssignableTo(
typeArguments[i],
instantiateType(constraint, mapper!),
node.typeArguments![i],
Diagnostics.Type_0_does_not_satisfy_the_constraint_1);
}
}
return result;
}
function getTypeParametersForTypeReference(node: TypeReferenceNode | ExpressionWithTypeArguments) {
const type = getTypeFromTypeReference(node);
if (type !== errorType) {
const symbol = getNodeLinks(node).resolvedSymbol;
if (symbol) {
return symbol.flags & SymbolFlags.TypeAlias && getSymbolLinks(symbol).typeParameters ||
(getObjectFlags(type) & ObjectFlags.Reference ? (<TypeReference>type).target.localTypeParameters : undefined);
}
}
return undefined;
}
function checkTypeReferenceNode(node: TypeReferenceNode | ExpressionWithTypeArguments) {
checkGrammarTypeArguments(node, node.typeArguments);
if (node.kind === SyntaxKind.TypeReference && node.typeName.jsdocDotPos !== undefined && !isInJSFile(node) && !isInJSDoc(node)) {
grammarErrorAtPos(node, node.typeName.jsdocDotPos, 1, Diagnostics.JSDoc_types_can_only_be_used_inside_documentation_comments);
}
const type = getTypeFromTypeReference(node);
if (type !== errorType) {
if (node.typeArguments) {
// Do type argument local checks only if referenced type is successfully resolved
forEach(node.typeArguments, checkSourceElement);
if (produceDiagnostics) {
const typeParameters = getTypeParametersForTypeReference(node);
if (typeParameters) {
checkTypeArgumentConstraints(node, typeParameters);
}
}
}
if (type.flags & TypeFlags.Enum && getNodeLinks(node).resolvedSymbol!.flags & SymbolFlags.EnumMember) {
error(node, Diagnostics.Enum_type_0_has_members_with_initializers_that_are_not_literals, typeToString(type));
}
}
}
function getTypeArgumentConstraint(node: TypeNode): Type | undefined {
const typeReferenceNode = tryCast(node.parent, isTypeReferenceType);
if (!typeReferenceNode) return undefined;
const typeParameters = getTypeParametersForTypeReference(typeReferenceNode)!; // TODO: GH#18217
const constraint = getConstraintOfTypeParameter(typeParameters[typeReferenceNode.typeArguments!.indexOf(node)]);
return constraint && instantiateType(constraint, createTypeMapper(typeParameters, getEffectiveTypeArguments(typeReferenceNode, typeParameters)));
}
function checkTypeQuery(node: TypeQueryNode) {
getTypeFromTypeQueryNode(node);
}
function checkTypeLiteral(node: TypeLiteralNode) {
forEach(node.members, checkSourceElement);
if (produceDiagnostics) {
const type = getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node);
checkIndexConstraints(type);
checkTypeForDuplicateIndexSignatures(node);
checkObjectTypeForDuplicateDeclarations(node);
}
}
function checkArrayType(node: ArrayTypeNode) {
checkSourceElement(node.elementType);
}
function checkTupleType(node: TupleTypeNode) {
const elementTypes = node.elementTypes;
let seenOptionalElement = false;
for (let i = 0; i < elementTypes.length; i++) {
const e = elementTypes[i];
if (e.kind === SyntaxKind.RestType) {
if (i !== elementTypes.length - 1) {
grammarErrorOnNode(e, Diagnostics.A_rest_element_must_be_last_in_a_tuple_type);
break;
}
if (!isArrayType(getTypeFromTypeNode(e))) {
error(e, Diagnostics.A_rest_element_type_must_be_an_array_type);
}
}
else if (e.kind === SyntaxKind.OptionalType) {
seenOptionalElement = true;
}
else if (seenOptionalElement) {
grammarErrorOnNode(e, Diagnostics.A_required_element_cannot_follow_an_optional_element);
break;
}
}
forEach(node.elementTypes, checkSourceElement);
}
function checkUnionOrIntersectionType(node: UnionOrIntersectionTypeNode) {
forEach(node.types, checkSourceElement);
}
function checkIndexedAccessIndexType(type: Type, accessNode: Node) {
if (!(type.flags & TypeFlags.IndexedAccess)) {
return type;
}
// Check if the index type is assignable to 'keyof T' for the object type.
const objectType = (<IndexedAccessType>type).objectType;
const indexType = (<IndexedAccessType>type).indexType;
if (isTypeAssignableTo(indexType, getIndexType(objectType, /*stringsOnly*/ false))) {
if (accessNode.kind === SyntaxKind.ElementAccessExpression && isAssignmentTarget(accessNode) &&
getObjectFlags(objectType) & ObjectFlags.Mapped && getMappedTypeModifiers(<MappedType>objectType) & MappedTypeModifiers.IncludeReadonly) {
error(accessNode, Diagnostics.Index_signature_in_type_0_only_permits_reading, typeToString(objectType));
}
return type;
}
// Check if we're indexing with a numeric type and if either object or index types
// is a generic type with a constraint that has a numeric index signature.
if (getIndexInfoOfType(getApparentType(objectType), IndexKind.Number) && isTypeAssignableToKind(indexType, TypeFlags.NumberLike)) {
return type;
}
error(accessNode, Diagnostics.Type_0_cannot_be_used_to_index_type_1, typeToString(indexType), typeToString(objectType));
return type;
}
function checkIndexedAccessType(node: IndexedAccessTypeNode) {
checkSourceElement(node.objectType);
checkSourceElement(node.indexType);
checkIndexedAccessIndexType(getTypeFromIndexedAccessTypeNode(node), node);
}
function checkMappedType(node: MappedTypeNode) {
checkSourceElement(node.typeParameter);
checkSourceElement(node.type);
if (!node.type) {
reportImplicitAny(node, anyType);
}
const type = <MappedType>getTypeFromMappedTypeNode(node);
const constraintType = getConstraintTypeFromMappedType(type);
checkTypeAssignableTo(constraintType, keyofConstraintType, getEffectiveConstraintOfTypeParameter(node.typeParameter));
}
function checkThisType(node: ThisTypeNode) {
getTypeFromThisTypeNode(node);
}
function checkTypeOperator(node: TypeOperatorNode) {
checkGrammarTypeOperatorNode(node);
checkSourceElement(node.type);
}
function checkConditionalType(node: ConditionalTypeNode) {
forEachChild(node, checkSourceElement);
}
function checkInferType(node: InferTypeNode) {
if (!findAncestor(node, n => n.parent && n.parent.kind === SyntaxKind.ConditionalType && (<ConditionalTypeNode>n.parent).extendsType === n)) {
grammarErrorOnNode(node, Diagnostics.infer_declarations_are_only_permitted_in_the_extends_clause_of_a_conditional_type);
}
checkSourceElement(node.typeParameter);
registerForUnusedIdentifiersCheck(node);
}
function checkImportType(node: ImportTypeNode) {
checkSourceElement(node.argument);
getTypeFromTypeNode(node);
}
function isPrivateWithinAmbient(node: Node): boolean {
return hasModifier(node, ModifierFlags.Private) && !!(node.flags & NodeFlags.Ambient);
}
function getEffectiveDeclarationFlags(n: Declaration, flagsToCheck: ModifierFlags): ModifierFlags {
let flags = getCombinedModifierFlags(n);
// children of classes (even ambient classes) should not be marked as ambient or export
// because those flags have no useful semantics there.
if (n.parent.kind !== SyntaxKind.InterfaceDeclaration &&
n.parent.kind !== SyntaxKind.ClassDeclaration &&
n.parent.kind !== SyntaxKind.ClassExpression &&
n.flags & NodeFlags.Ambient) {
if (!(flags & ModifierFlags.Ambient) && !(isModuleBlock(n.parent) && isModuleDeclaration(n.parent.parent) && isGlobalScopeAugmentation(n.parent.parent))) {
// It is nested in an ambient context, which means it is automatically exported
flags |= ModifierFlags.Export;
}
flags |= ModifierFlags.Ambient;
}
return flags & flagsToCheck;
}
function checkFunctionOrConstructorSymbol(symbol: Symbol): void {
if (!produceDiagnostics) {
return;
}
function getCanonicalOverload(overloads: Declaration[], implementation: FunctionLikeDeclaration | undefined): Declaration {
// Consider the canonical set of flags to be the flags of the bodyDeclaration or the first declaration
// Error on all deviations from this canonical set of flags
// The caveat is that if some overloads are defined in lib.d.ts, we don't want to
// report the errors on those. To achieve this, we will say that the implementation is
// the canonical signature only if it is in the same container as the first overload
const implementationSharesContainerWithFirstOverload = implementation !== undefined && implementation.parent === overloads[0].parent;
return implementationSharesContainerWithFirstOverload ? implementation! : overloads[0];
}
function checkFlagAgreementBetweenOverloads(overloads: Declaration[], implementation: FunctionLikeDeclaration | undefined, flagsToCheck: ModifierFlags, someOverloadFlags: ModifierFlags, allOverloadFlags: ModifierFlags): void {
// Error if some overloads have a flag that is not shared by all overloads. To find the
// deviations, we XOR someOverloadFlags with allOverloadFlags
const someButNotAllOverloadFlags = someOverloadFlags ^ allOverloadFlags;
if (someButNotAllOverloadFlags !== 0) {
const canonicalFlags = getEffectiveDeclarationFlags(getCanonicalOverload(overloads, implementation), flagsToCheck);
forEach(overloads, o => {
const deviation = getEffectiveDeclarationFlags(o, flagsToCheck) ^ canonicalFlags;
if (deviation & ModifierFlags.Export) {
error(getNameOfDeclaration(o), Diagnostics.Overload_signatures_must_all_be_exported_or_non_exported);
}
else if (deviation & ModifierFlags.Ambient) {
error(getNameOfDeclaration(o), Diagnostics.Overload_signatures_must_all_be_ambient_or_non_ambient);
}
else if (deviation & (ModifierFlags.Private | ModifierFlags.Protected)) {
error(getNameOfDeclaration(o) || o, Diagnostics.Overload_signatures_must_all_be_public_private_or_protected);
}
else if (deviation & ModifierFlags.Abstract) {
error(getNameOfDeclaration(o), Diagnostics.Overload_signatures_must_all_be_abstract_or_non_abstract);
}
});
}
}
function checkQuestionTokenAgreementBetweenOverloads(overloads: Declaration[], implementation: FunctionLikeDeclaration | undefined, someHaveQuestionToken: boolean, allHaveQuestionToken: boolean): void {
if (someHaveQuestionToken !== allHaveQuestionToken) {
const canonicalHasQuestionToken = hasQuestionToken(getCanonicalOverload(overloads, implementation));
forEach(overloads, o => {
const deviation = hasQuestionToken(o) !== canonicalHasQuestionToken;
if (deviation) {
error(getNameOfDeclaration(o), Diagnostics.Overload_signatures_must_all_be_optional_or_required);
}
});
}
}
const flagsToCheck: ModifierFlags = ModifierFlags.Export | ModifierFlags.Ambient | ModifierFlags.Private | ModifierFlags.Protected | ModifierFlags.Abstract;
let someNodeFlags: ModifierFlags = ModifierFlags.None;
let allNodeFlags = flagsToCheck;
let someHaveQuestionToken = false;
let allHaveQuestionToken = true;
let hasOverloads = false;
let bodyDeclaration: FunctionLikeDeclaration | undefined;
let lastSeenNonAmbientDeclaration: FunctionLikeDeclaration | undefined;
let previousDeclaration: SignatureDeclaration | undefined;
const declarations = symbol.declarations;
const isConstructor = (symbol.flags & SymbolFlags.Constructor) !== 0;
function reportImplementationExpectedError(node: SignatureDeclaration): void {
if (node.name && nodeIsMissing(node.name)) {
return;
}
let seen = false;
const subsequentNode = forEachChild(node.parent, c => {
if (seen) {
return c;
}
else {
seen = c === node;
}
});
// We may be here because of some extra nodes between overloads that could not be parsed into a valid node.
// In this case the subsequent node is not really consecutive (.pos !== node.end), and we must ignore it here.
if (subsequentNode && subsequentNode.pos === node.end) {
if (subsequentNode.kind === node.kind) {
const errorNode: Node = (<FunctionLikeDeclaration>subsequentNode).name || subsequentNode;
// TODO: GH#17345: These are methods, so handle computed name case. (`Always allowing computed property names is *not* the correct behavior!)
const subsequentName = (<FunctionLikeDeclaration>subsequentNode).name;
if (node.name && subsequentName &&
(isComputedPropertyName(node.name) && isComputedPropertyName(subsequentName) ||
!isComputedPropertyName(node.name) && !isComputedPropertyName(subsequentName) && getEscapedTextOfIdentifierOrLiteral(node.name) === getEscapedTextOfIdentifierOrLiteral(subsequentName))) {
const reportError =
(node.kind === SyntaxKind.MethodDeclaration || node.kind === SyntaxKind.MethodSignature) &&
hasModifier(node, ModifierFlags.Static) !== hasModifier(subsequentNode, ModifierFlags.Static);
// we can get here in two cases
// 1. mixed static and instance class members
// 2. something with the same name was defined before the set of overloads that prevents them from merging
// here we'll report error only for the first case since for second we should already report error in binder
if (reportError) {
const diagnostic = hasModifier(node, ModifierFlags.Static) ? Diagnostics.Function_overload_must_be_static : Diagnostics.Function_overload_must_not_be_static;
error(errorNode, diagnostic);
}
return;
}
else if (nodeIsPresent((<FunctionLikeDeclaration>subsequentNode).body)) {
error(errorNode, Diagnostics.Function_implementation_name_must_be_0, declarationNameToString(node.name!));
return;
}
}
}
const errorNode: Node = node.name || node;
if (isConstructor) {
error(errorNode, Diagnostics.Constructor_implementation_is_missing);
}
else {
// Report different errors regarding non-consecutive blocks of declarations depending on whether
// the node in question is abstract.
if (hasModifier(node, ModifierFlags.Abstract)) {
error(errorNode, Diagnostics.All_declarations_of_an_abstract_method_must_be_consecutive);
}
else {
error(errorNode, Diagnostics.Function_implementation_is_missing_or_not_immediately_following_the_declaration);
}
}
}
let duplicateFunctionDeclaration = false;
let multipleConstructorImplementation = false;
for (const current of declarations) {
const node = <SignatureDeclaration>current;
const inAmbientContext = node.flags & NodeFlags.Ambient;
const inAmbientContextOrInterface = node.parent.kind === SyntaxKind.InterfaceDeclaration || node.parent.kind === SyntaxKind.TypeLiteral || inAmbientContext;
if (inAmbientContextOrInterface) {
// check if declarations are consecutive only if they are non-ambient
// 1. ambient declarations can be interleaved
// i.e. this is legal
// declare function foo();
// declare function bar();
// declare function foo();
// 2. mixing ambient and non-ambient declarations is a separate error that will be reported - do not want to report an extra one
previousDeclaration = undefined;
}
if (node.kind === SyntaxKind.FunctionDeclaration || node.kind === SyntaxKind.MethodDeclaration || node.kind === SyntaxKind.MethodSignature || node.kind === SyntaxKind.Constructor) {
const currentNodeFlags = getEffectiveDeclarationFlags(node, flagsToCheck);
someNodeFlags |= currentNodeFlags;
allNodeFlags &= currentNodeFlags;
someHaveQuestionToken = someHaveQuestionToken || hasQuestionToken(node);
allHaveQuestionToken = allHaveQuestionToken && hasQuestionToken(node);
if (nodeIsPresent((node as FunctionLikeDeclaration).body) && bodyDeclaration) {
if (isConstructor) {
multipleConstructorImplementation = true;
}
else {
duplicateFunctionDeclaration = true;
}
}
else if (previousDeclaration && previousDeclaration.parent === node.parent && previousDeclaration.end !== node.pos) {
reportImplementationExpectedError(previousDeclaration);
}
if (nodeIsPresent((node as FunctionLikeDeclaration).body)) {
if (!bodyDeclaration) {
bodyDeclaration = node as FunctionLikeDeclaration;
}
}
else {
hasOverloads = true;
}
previousDeclaration = node;
if (!inAmbientContextOrInterface) {
lastSeenNonAmbientDeclaration = node as FunctionLikeDeclaration;
}
}
}
if (multipleConstructorImplementation) {
forEach(declarations, declaration => {
error(declaration, Diagnostics.Multiple_constructor_implementations_are_not_allowed);
});
}
if (duplicateFunctionDeclaration) {
forEach(declarations, declaration => {
error(getNameOfDeclaration(declaration), Diagnostics.Duplicate_function_implementation);
});
}
// Abstract methods can't have an implementation -- in particular, they don't need one.
if (lastSeenNonAmbientDeclaration && !lastSeenNonAmbientDeclaration.body &&
!hasModifier(lastSeenNonAmbientDeclaration, ModifierFlags.Abstract) && !lastSeenNonAmbientDeclaration.questionToken) {
reportImplementationExpectedError(lastSeenNonAmbientDeclaration);
}
if (hasOverloads) {
checkFlagAgreementBetweenOverloads(declarations, bodyDeclaration, flagsToCheck, someNodeFlags, allNodeFlags);
checkQuestionTokenAgreementBetweenOverloads(declarations, bodyDeclaration, someHaveQuestionToken, allHaveQuestionToken);
if (bodyDeclaration) {
const signatures = getSignaturesOfSymbol(symbol);
const bodySignature = getSignatureFromDeclaration(bodyDeclaration);
for (const signature of signatures) {
if (!isImplementationCompatibleWithOverload(bodySignature, signature)) {
addRelatedInfo(
error(signature.declaration, Diagnostics.This_overload_signature_is_not_compatible_with_its_implementation_signature),
createDiagnosticForNode(bodyDeclaration, Diagnostics.The_implementation_signature_is_declared_here)
);
break;
}
}
}
}
}
const enum DeclarationSpaces {
None = 0,
ExportValue = 1 << 0,
ExportType = 1 << 1,
ExportNamespace = 1 << 2,
}
function checkExportsOnMergedDeclarations(node: Node): void {
if (!produceDiagnostics) {
return;
}
// if localSymbol is defined on node then node itself is exported - check is required
let symbol = node.localSymbol;
if (!symbol) {
// local symbol is undefined => this declaration is non-exported.
// however symbol might contain other declarations that are exported
symbol = getSymbolOfNode(node)!;
if (!symbol.exportSymbol) {
// this is a pure local symbol (all declarations are non-exported) - no need to check anything
return;
}
}
// run the check only for the first declaration in the list
if (getDeclarationOfKind(symbol, node.kind) !== node) {
return;
}
let exportedDeclarationSpaces = DeclarationSpaces.None;
let nonExportedDeclarationSpaces = DeclarationSpaces.None;
let defaultExportedDeclarationSpaces = DeclarationSpaces.None;
for (const d of symbol.declarations) {
const declarationSpaces = getDeclarationSpaces(d);
const effectiveDeclarationFlags = getEffectiveDeclarationFlags(d, ModifierFlags.Export | ModifierFlags.Default);
if (effectiveDeclarationFlags & ModifierFlags.Export) {
if (effectiveDeclarationFlags & ModifierFlags.Default) {
defaultExportedDeclarationSpaces |= declarationSpaces;
}
else {
exportedDeclarationSpaces |= declarationSpaces;
}
}
else {
nonExportedDeclarationSpaces |= declarationSpaces;
}
}
// Spaces for anything not declared a 'default export'.
const nonDefaultExportedDeclarationSpaces = exportedDeclarationSpaces | nonExportedDeclarationSpaces;
const commonDeclarationSpacesForExportsAndLocals = exportedDeclarationSpaces & nonExportedDeclarationSpaces;
const commonDeclarationSpacesForDefaultAndNonDefault = defaultExportedDeclarationSpaces & nonDefaultExportedDeclarationSpaces;
if (commonDeclarationSpacesForExportsAndLocals || commonDeclarationSpacesForDefaultAndNonDefault) {
// declaration spaces for exported and non-exported declarations intersect
for (const d of symbol.declarations) {
const declarationSpaces = getDeclarationSpaces(d);
const name = getNameOfDeclaration(d);
// Only error on the declarations that contributed to the intersecting spaces.
if (declarationSpaces & commonDeclarationSpacesForDefaultAndNonDefault) {
error(name, Diagnostics.Merged_declaration_0_cannot_include_a_default_export_declaration_Consider_adding_a_separate_export_default_0_declaration_instead, declarationNameToString(name));
}
else if (declarationSpaces & commonDeclarationSpacesForExportsAndLocals) {
error(name, Diagnostics.Individual_declarations_in_merged_declaration_0_must_be_all_exported_or_all_local, declarationNameToString(name));
}
}
}
function getDeclarationSpaces(decl: Declaration): DeclarationSpaces {
let d = decl as Node;
switch (d.kind) {
case SyntaxKind.InterfaceDeclaration:
case SyntaxKind.TypeAliasDeclaration:
// A jsdoc typedef and callback are, by definition, type aliases
case SyntaxKind.JSDocTypedefTag:
case SyntaxKind.JSDocCallbackTag:
return DeclarationSpaces.ExportType;
case SyntaxKind.ModuleDeclaration:
return isAmbientModule(d as ModuleDeclaration) || getModuleInstanceState(d as ModuleDeclaration) !== ModuleInstanceState.NonInstantiated
? DeclarationSpaces.ExportNamespace | DeclarationSpaces.ExportValue
: DeclarationSpaces.ExportNamespace;
case SyntaxKind.ClassDeclaration:
case SyntaxKind.EnumDeclaration:
return DeclarationSpaces.ExportType | DeclarationSpaces.ExportValue;
case SyntaxKind.SourceFile:
return DeclarationSpaces.ExportType | DeclarationSpaces.ExportValue | DeclarationSpaces.ExportNamespace;
case SyntaxKind.ExportAssignment:
// Export assigned entity name expressions act as aliases and should fall through, otherwise they export values
if (!isEntityNameExpression((d as ExportAssignment).expression)) {
return DeclarationSpaces.ExportValue;
}
d = (d as ExportAssignment).expression;
/* falls through */
// The below options all declare an Alias, which is allowed to merge with other values within the importing module
case SyntaxKind.ImportEqualsDeclaration:
case SyntaxKind.NamespaceImport:
case SyntaxKind.ImportClause:
let result = DeclarationSpaces.None;
const target = resolveAlias(getSymbolOfNode(d)!);
forEach(target.declarations, d => { result |= getDeclarationSpaces(d); });
return result;
case SyntaxKind.VariableDeclaration:
case SyntaxKind.BindingElement:
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.ImportSpecifier: // https://github.com/Microsoft/TypeScript/pull/7591
return DeclarationSpaces.ExportValue;
default:
return Debug.fail(Debug.showSyntaxKind(d));
}
}
}
function getAwaitedTypeOfPromise(type: Type, errorNode?: Node, diagnosticMessage?: DiagnosticMessage): Type | undefined {
const promisedType = getPromisedTypeOfPromise(type, errorNode);
return promisedType && getAwaitedType(promisedType, errorNode, diagnosticMessage);
}
/**
* Gets the "promised type" of a promise.
* @param type The type of the promise.
* @remarks The "promised type" of a type is the type of the "value" parameter of the "onfulfilled" callback.
*/
function getPromisedTypeOfPromise(promise: Type, errorNode?: Node): Type | undefined {
//
// { // promise
// then( // thenFunction
// onfulfilled: ( // onfulfilledParameterType
// value: T // valueParameterType
// ) => any
// ): any;
// }
//
if (isTypeAny(promise)) {
return undefined;
}
const typeAsPromise = <PromiseOrAwaitableType>promise;
if (typeAsPromise.promisedTypeOfPromise) {
return typeAsPromise.promisedTypeOfPromise;
}
if (isReferenceToType(promise, getGlobalPromiseType(/*reportErrors*/ false))) {
return typeAsPromise.promisedTypeOfPromise = (<GenericType>promise).typeArguments![0];
}
const thenFunction = getTypeOfPropertyOfType(promise, "then" as __String)!; // TODO: GH#18217
if (isTypeAny(thenFunction)) {
return undefined;
}
const thenSignatures = thenFunction ? getSignaturesOfType(thenFunction, SignatureKind.Call) : emptyArray;
if (thenSignatures.length === 0) {
if (errorNode) {
error(errorNode, Diagnostics.A_promise_must_have_a_then_method);
}
return undefined;
}
const onfulfilledParameterType = getTypeWithFacts(getUnionType(map(thenSignatures, getTypeOfFirstParameterOfSignature)), TypeFacts.NEUndefinedOrNull);
if (isTypeAny(onfulfilledParameterType)) {
return undefined;
}
const onfulfilledParameterSignatures = getSignaturesOfType(onfulfilledParameterType, SignatureKind.Call);
if (onfulfilledParameterSignatures.length === 0) {
if (errorNode) {
error(errorNode, Diagnostics.The_first_parameter_of_the_then_method_of_a_promise_must_be_a_callback);
}
return undefined;
}
return typeAsPromise.promisedTypeOfPromise = getUnionType(map(onfulfilledParameterSignatures, getTypeOfFirstParameterOfSignature), UnionReduction.Subtype);
}
/**
* Gets the "awaited type" of a type.
* @param type The type to await.
* @remarks The "awaited type" of an expression is its "promised type" if the expression is a
* Promise-like type; otherwise, it is the type of the expression. This is used to reflect
* The runtime behavior of the `await` keyword.
*/
function checkAwaitedType(type: Type, errorNode: Node, diagnosticMessage: DiagnosticMessage): Type {
return getAwaitedType(type, errorNode, diagnosticMessage) || errorType;
}
function getAwaitedType(type: Type, errorNode?: Node, diagnosticMessage?: DiagnosticMessage): Type | undefined {
const typeAsAwaitable = <PromiseOrAwaitableType>type;
if (typeAsAwaitable.awaitedTypeOfType) {
return typeAsAwaitable.awaitedTypeOfType;
}
if (isTypeAny(type)) {
return typeAsAwaitable.awaitedTypeOfType = type;
}
if (type.flags & TypeFlags.Union) {
let types: Type[] | undefined;
for (const constituentType of (<UnionType>type).types) {
types = append<Type>(types, getAwaitedType(constituentType, errorNode, diagnosticMessage));
}
if (!types) {
return undefined;
}
return typeAsAwaitable.awaitedTypeOfType = getUnionType(types);
}
const promisedType = getPromisedTypeOfPromise(type);
if (promisedType) {
if (type.id === promisedType.id || awaitedTypeStack.indexOf(promisedType.id) >= 0) {
// Verify that we don't have a bad actor in the form of a promise whose
// promised type is the same as the promise type, or a mutually recursive
// promise. If so, we return undefined as we cannot guess the shape. If this
// were the actual case in the JavaScript, this Promise would never resolve.
//
// An example of a bad actor with a singly-recursive promise type might
// be:
//
// interface BadPromise {
// then(
// onfulfilled: (value: BadPromise) => any,
// onrejected: (error: any) => any): BadPromise;
// }
// The above interface will pass the PromiseLike check, and return a
// promised type of `BadPromise`. Since this is a self reference, we
// don't want to keep recursing ad infinitum.
//
// An example of a bad actor in the form of a mutually-recursive
// promise type might be:
//
// interface BadPromiseA {
// then(
// onfulfilled: (value: BadPromiseB) => any,
// onrejected: (error: any) => any): BadPromiseB;
// }
//
// interface BadPromiseB {
// then(
// onfulfilled: (value: BadPromiseA) => any,
// onrejected: (error: any) => any): BadPromiseA;
// }
//
if (errorNode) {
error(errorNode, Diagnostics.Type_is_referenced_directly_or_indirectly_in_the_fulfillment_callback_of_its_own_then_method);
}
return undefined;
}
// Keep track of the type we're about to unwrap to avoid bad recursive promise types.
// See the comments above for more information.
awaitedTypeStack.push(type.id);
const awaitedType = getAwaitedType(promisedType, errorNode, diagnosticMessage);
awaitedTypeStack.pop();
if (!awaitedType) {
return undefined;
}
return typeAsAwaitable.awaitedTypeOfType = awaitedType;
}
// The type was not a promise, so it could not be unwrapped any further.
// As long as the type does not have a callable "then" property, it is
// safe to return the type; otherwise, an error will be reported in
// the call to getNonThenableType and we will return undefined.
//
// An example of a non-promise "thenable" might be:
//
// await { then(): void {} }
//
// The "thenable" does not match the minimal definition for a promise. When
// a Promise/A+-compatible or ES6 promise tries to adopt this value, the promise
// will never settle. We treat this as an error to help flag an early indicator
// of a runtime problem. If the user wants to return this value from an async
// function, they would need to wrap it in some other value. If they want it to
// be treated as a promise, they can cast to <any>.
const thenFunction = getTypeOfPropertyOfType(type, "then" as __String);
if (thenFunction && getSignaturesOfType(thenFunction, SignatureKind.Call).length > 0) {
if (errorNode) {
if (!diagnosticMessage) return Debug.fail();
error(errorNode, diagnosticMessage);
}
return undefined;
}
return typeAsAwaitable.awaitedTypeOfType = type;
}
/**
* Checks the return type of an async function to ensure it is a compatible
* Promise implementation.
*
* This checks that an async function has a valid Promise-compatible return type.
* An async function has a valid Promise-compatible return type if the resolved value
* of the return type has a construct signature that takes in an `initializer` function
* that in turn supplies a `resolve` function as one of its arguments and results in an
* object with a callable `then` signature.
*
* @param node The signature to check
*/
function checkAsyncFunctionReturnType(node: FunctionLikeDeclaration | MethodSignature, returnTypeNode: TypeNode) {
// As part of our emit for an async function, we will need to emit the entity name of
// the return type annotation as an expression. To meet the necessary runtime semantics
// for __awaiter, we must also check that the type of the declaration (e.g. the static
// side or "constructor" of the promise type) is compatible `PromiseConstructorLike`.
//
// An example might be (from lib.es6.d.ts):
//
// interface Promise<T> { ... }
// interface PromiseConstructor {
// new <T>(...): Promise<T>;
// }
// declare var Promise: PromiseConstructor;
//
// When an async function declares a return type annotation of `Promise<T>`, we
// need to get the type of the `Promise` variable declaration above, which would
// be `PromiseConstructor`.
//
// The same case applies to a class:
//
// declare class Promise<T> {
// constructor(...);
// then<U>(...): Promise<U>;
// }
//
const returnType = getTypeFromTypeNode(returnTypeNode);
if (languageVersion >= ScriptTarget.ES2015) {
if (returnType === errorType) {
return;
}
const globalPromiseType = getGlobalPromiseType(/*reportErrors*/ true);
if (globalPromiseType !== emptyGenericType && !isReferenceToType(returnType, globalPromiseType)) {
// The promise type was not a valid type reference to the global promise type, so we
// report an error and return the unknown type.
error(returnTypeNode, Diagnostics.The_return_type_of_an_async_function_or_method_must_be_the_global_Promise_T_type);
return;
}
}
else {
// Always mark the type node as referenced if it points to a value
markTypeNodeAsReferenced(returnTypeNode);
if (returnType === errorType) {
return;
}
const promiseConstructorName = getEntityNameFromTypeNode(returnTypeNode);
if (promiseConstructorName === undefined) {
error(returnTypeNode, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, typeToString(returnType));
return;
}
const promiseConstructorSymbol = resolveEntityName(promiseConstructorName, SymbolFlags.Value, /*ignoreErrors*/ true);
const promiseConstructorType = promiseConstructorSymbol ? getTypeOfSymbol(promiseConstructorSymbol) : errorType;
if (promiseConstructorType === errorType) {
if (promiseConstructorName.kind === SyntaxKind.Identifier && promiseConstructorName.escapedText === "Promise" && getTargetType(returnType) === getGlobalPromiseType(/*reportErrors*/ false)) {
error(returnTypeNode, Diagnostics.An_async_function_or_method_in_ES5_SlashES3_requires_the_Promise_constructor_Make_sure_you_have_a_declaration_for_the_Promise_constructor_or_include_ES2015_in_your_lib_option);
}
else {
error(returnTypeNode, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, entityNameToString(promiseConstructorName));
}
return;
}
const globalPromiseConstructorLikeType = getGlobalPromiseConstructorLikeType(/*reportErrors*/ true);
if (globalPromiseConstructorLikeType === emptyObjectType) {
// If we couldn't resolve the global PromiseConstructorLike type we cannot verify
// compatibility with __awaiter.
error(returnTypeNode, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, entityNameToString(promiseConstructorName));
return;
}
if (!checkTypeAssignableTo(promiseConstructorType, globalPromiseConstructorLikeType, returnTypeNode,
Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value)) {
return;
}
// Verify there is no local declaration that could collide with the promise constructor.
const rootName = promiseConstructorName && getFirstIdentifier(promiseConstructorName);
const collidingSymbol = getSymbol(node.locals!, rootName.escapedText, SymbolFlags.Value);
if (collidingSymbol) {
error(collidingSymbol.valueDeclaration, Diagnostics.Duplicate_identifier_0_Compiler_uses_declaration_1_to_support_async_functions,
idText(rootName),
entityNameToString(promiseConstructorName));
return;
}
}
checkAwaitedType(returnType, node, Diagnostics.The_return_type_of_an_async_function_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);
}
/** Check a decorator */
function checkDecorator(node: Decorator): void {
const signature = getResolvedSignature(node);
const returnType = getReturnTypeOfSignature(signature);
if (returnType.flags & TypeFlags.Any) {
return;
}
let expectedReturnType: Type;
const headMessage = getDiagnosticHeadMessageForDecoratorResolution(node);
let errorInfo: DiagnosticMessageChain | undefined;
switch (node.parent.kind) {
case SyntaxKind.ClassDeclaration:
const classSymbol = getSymbolOfNode(node.parent);
const classConstructorType = getTypeOfSymbol(classSymbol);
expectedReturnType = getUnionType([classConstructorType, voidType]);
break;
case SyntaxKind.Parameter:
expectedReturnType = voidType;
errorInfo = chainDiagnosticMessages(
/*details*/ undefined,
Diagnostics.The_return_type_of_a_parameter_decorator_function_must_be_either_void_or_any);
break;
case SyntaxKind.PropertyDeclaration:
expectedReturnType = voidType;
errorInfo = chainDiagnosticMessages(
/*details*/ undefined,
Diagnostics.The_return_type_of_a_property_decorator_function_must_be_either_void_or_any);
break;
case SyntaxKind.MethodDeclaration:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
const methodType = getTypeOfNode(node.parent);
const descriptorType = createTypedPropertyDescriptorType(methodType);
expectedReturnType = getUnionType([descriptorType, voidType]);
break;
default:
return Debug.fail();
}
checkTypeAssignableTo(
returnType,
expectedReturnType,
node,
headMessage,
() => errorInfo);
}
/**
* If a TypeNode can be resolved to a value symbol imported from an external module, it is
* marked as referenced to prevent import elision.
*/
function markTypeNodeAsReferenced(node: TypeNode) {
markEntityNameOrEntityExpressionAsReference(node && getEntityNameFromTypeNode(node));
}
function markEntityNameOrEntityExpressionAsReference(typeName: EntityNameOrEntityNameExpression | undefined) {
if (!typeName) return;
const rootName = getFirstIdentifier(typeName);
const meaning = (typeName.kind === SyntaxKind.Identifier ? SymbolFlags.Type : SymbolFlags.Namespace) | SymbolFlags.Alias;
const rootSymbol = resolveName(rootName, rootName.escapedText, meaning, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isRefernce*/ true);
if (rootSymbol
&& rootSymbol.flags & SymbolFlags.Alias
&& symbolIsValue(rootSymbol)
&& !isConstEnumOrConstEnumOnlyModule(resolveAlias(rootSymbol))) {
markAliasSymbolAsReferenced(rootSymbol);
}
}
/**
* This function marks the type used for metadata decorator as referenced if it is import
* from external module.
* This is different from markTypeNodeAsReferenced because it tries to simplify type nodes in
* union and intersection type
* @param node
*/
function markDecoratorMedataDataTypeNodeAsReferenced(node: TypeNode | undefined): void {
const entityName = getEntityNameForDecoratorMetadata(node);
if (entityName && isEntityName(entityName)) {
markEntityNameOrEntityExpressionAsReference(entityName);
}
}
function getEntityNameForDecoratorMetadata(node: TypeNode | undefined): EntityName | undefined {
if (node) {
switch (node.kind) {
case SyntaxKind.IntersectionType:
case SyntaxKind.UnionType:
return getEntityNameForDecoratorMetadataFromTypeList((<UnionOrIntersectionTypeNode>node).types);
case SyntaxKind.ConditionalType:
return getEntityNameForDecoratorMetadataFromTypeList([(<ConditionalTypeNode>node).trueType, (<ConditionalTypeNode>node).falseType]);
case SyntaxKind.ParenthesizedType:
return getEntityNameForDecoratorMetadata((<ParenthesizedTypeNode>node).type);
case SyntaxKind.TypeReference:
return (<TypeReferenceNode>node).typeName;
}
}
}
function getEntityNameForDecoratorMetadataFromTypeList(types: ReadonlyArray<TypeNode>): EntityName | undefined {
let commonEntityName: EntityName | undefined;
for (let typeNode of types) {
while (typeNode.kind === SyntaxKind.ParenthesizedType) {
typeNode = (typeNode as ParenthesizedTypeNode).type; // Skip parens if need be
}
if (typeNode.kind === SyntaxKind.NeverKeyword) {
continue; // Always elide `never` from the union/intersection if possible
}
if (!strictNullChecks && (typeNode.kind === SyntaxKind.NullKeyword || typeNode.kind === SyntaxKind.UndefinedKeyword)) {
continue; // Elide null and undefined from unions for metadata, just like what we did prior to the implementation of strict null checks
}
const individualEntityName = getEntityNameForDecoratorMetadata(typeNode);
if (!individualEntityName) {
// Individual is something like string number
// So it would be serialized to either that type or object
// Safe to return here
return undefined;
}
if (commonEntityName) {
// Note this is in sync with the transformation that happens for type node.
// Keep this in sync with serializeUnionOrIntersectionType
// Verify if they refer to same entity and is identifier
// return undefined if they dont match because we would emit object
if (!isIdentifier(commonEntityName) ||
!isIdentifier(individualEntityName) ||
commonEntityName.escapedText !== individualEntityName.escapedText) {
return undefined;
}
}
else {
commonEntityName = individualEntityName;
}
}
return commonEntityName;
}
function getParameterTypeNodeForDecoratorCheck(node: ParameterDeclaration): TypeNode | undefined {
const typeNode = getEffectiveTypeAnnotationNode(node);
return isRestParameter(node) ? getRestParameterElementType(typeNode) : typeNode;
}
/** Check the decorators of a node */
function checkDecorators(node: Node): void {
if (!node.decorators) {
return;
}
// skip this check for nodes that cannot have decorators. These should have already had an error reported by
// checkGrammarDecorators.
if (!nodeCanBeDecorated(node, node.parent, node.parent.parent)) {
return;
}
if (!compilerOptions.experimentalDecorators) {
error(node, Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning);
}
const firstDecorator = node.decorators[0];
checkExternalEmitHelpers(firstDecorator, ExternalEmitHelpers.Decorate);
if (node.kind === SyntaxKind.Parameter) {
checkExternalEmitHelpers(firstDecorator, ExternalEmitHelpers.Param);
}
if (compilerOptions.emitDecoratorMetadata) {
checkExternalEmitHelpers(firstDecorator, ExternalEmitHelpers.Metadata);
// we only need to perform these checks if we are emitting serialized type metadata for the target of a decorator.
switch (node.kind) {
case SyntaxKind.ClassDeclaration:
const constructor = getFirstConstructorWithBody(<ClassDeclaration>node);
if (constructor) {
for (const parameter of constructor.parameters) {
markDecoratorMedataDataTypeNodeAsReferenced(getParameterTypeNodeForDecoratorCheck(parameter));
}
}
break;
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
const otherKind = node.kind === SyntaxKind.GetAccessor ? SyntaxKind.SetAccessor : SyntaxKind.GetAccessor;
const otherAccessor = getDeclarationOfKind<AccessorDeclaration>(getSymbolOfNode(node as AccessorDeclaration), otherKind);
markDecoratorMedataDataTypeNodeAsReferenced(getAnnotatedAccessorTypeNode(node as AccessorDeclaration) || otherAccessor && getAnnotatedAccessorTypeNode(otherAccessor));
break;
case SyntaxKind.MethodDeclaration:
for (const parameter of (<FunctionLikeDeclaration>node).parameters) {
markDecoratorMedataDataTypeNodeAsReferenced(getParameterTypeNodeForDecoratorCheck(parameter));
}
markDecoratorMedataDataTypeNodeAsReferenced(getEffectiveReturnTypeNode(<FunctionLikeDeclaration>node));
break;
case SyntaxKind.PropertyDeclaration:
markDecoratorMedataDataTypeNodeAsReferenced(getEffectiveTypeAnnotationNode(<ParameterDeclaration>node));
break;
case SyntaxKind.Parameter:
markDecoratorMedataDataTypeNodeAsReferenced(getParameterTypeNodeForDecoratorCheck(<ParameterDeclaration>node));
const containingSignature = (node as ParameterDeclaration).parent;
for (const parameter of containingSignature.parameters) {
markDecoratorMedataDataTypeNodeAsReferenced(getParameterTypeNodeForDecoratorCheck(parameter));
}
break;
}
}
forEach(node.decorators, checkDecorator);
}
function checkFunctionDeclaration(node: FunctionDeclaration): void {
if (produceDiagnostics) {
checkFunctionOrMethodDeclaration(node);
checkGrammarForGenerator(node);
checkCollisionWithRequireExportsInGeneratedCode(node, node.name!);
checkCollisionWithGlobalPromiseInGeneratedCode(node, node.name!);
}
}
function checkJSDocTypeAliasTag(node: JSDocTypedefTag | JSDocCallbackTag) {
if (!node.typeExpression) {
// If the node had `@property` tags, `typeExpression` would have been set to the first property tag.
error(node.name, Diagnostics.JSDoc_typedef_tag_should_either_have_a_type_annotation_or_be_followed_by_property_or_member_tags);
}
if (node.name) {
checkTypeNameIsReserved(node.name, Diagnostics.Type_alias_name_cannot_be_0);
}
checkSourceElement(node.typeExpression);
}
function checkJSDocTemplateTag(node: JSDocTemplateTag): void {
checkSourceElement(node.constraint);
for (const tp of node.typeParameters) {
checkSourceElement(tp);
}
}
function checkJSDocTypeTag(node: JSDocTypeTag) {
checkSourceElement(node.typeExpression);
}
function checkJSDocParameterTag(node: JSDocParameterTag) {
checkSourceElement(node.typeExpression);
if (!getParameterSymbolFromJSDoc(node)) {
const decl = getHostSignatureFromJSDoc(node);
// don't issue an error for invalid hosts -- just functions --
// and give a better error message when the host function mentions `arguments`
// but the tag doesn't have an array type
if (decl) {
const i = getJSDocTags(decl).filter(isJSDocParameterTag).indexOf(node);
if (i > -1 && i < decl.parameters.length && isBindingPattern(decl.parameters[i].name)) {
return;
}
if (!containsArgumentsReference(decl)) {
if (isQualifiedName(node.name)) {
error(node.name,
Diagnostics.Qualified_name_0_is_not_allowed_without_a_leading_param_object_1,
entityNameToString(node.name),
entityNameToString(node.name.left));
}
else {
error(node.name,
Diagnostics.JSDoc_param_tag_has_name_0_but_there_is_no_parameter_with_that_name,
idText(node.name));
}
}
else if (findLast(getJSDocTags(decl), isJSDocParameterTag) === node &&
node.typeExpression && node.typeExpression.type &&
!isArrayType(getTypeFromTypeNode(node.typeExpression.type))) {
error(node.name,
Diagnostics.JSDoc_param_tag_has_name_0_but_there_is_no_parameter_with_that_name_It_would_match_arguments_if_it_had_an_array_type,
idText(node.name.kind === SyntaxKind.QualifiedName ? node.name.right : node.name));
}
}
}
}
function checkJSDocFunctionType(node: JSDocFunctionType): void {
if (produceDiagnostics && !node.type && !isJSDocConstructSignature(node)) {
reportImplicitAny(node, anyType);
}
checkSignatureDeclaration(node);
}
function checkJSDocAugmentsTag(node: JSDocAugmentsTag): void {
const classLike = getJSDocHost(node);
if (!isClassDeclaration(classLike) && !isClassExpression(classLike)) {
error(classLike, Diagnostics.JSDoc_0_is_not_attached_to_a_class, idText(node.tagName));
return;
}
const augmentsTags = getJSDocTags(classLike).filter(isJSDocAugmentsTag);
Debug.assert(augmentsTags.length > 0);
if (augmentsTags.length > 1) {
error(augmentsTags[1], Diagnostics.Class_declarations_cannot_have_more_than_one_augments_or_extends_tag);
}
const name = getIdentifierFromEntityNameExpression(node.class.expression);
const extend = getClassExtendsHeritageElement(classLike);
if (extend) {
const className = getIdentifierFromEntityNameExpression(extend.expression);
if (className && name.escapedText !== className.escapedText) {
error(name, Diagnostics.JSDoc_0_1_does_not_match_the_extends_2_clause, idText(node.tagName), idText(name), idText(className));
}
}
}
function getIdentifierFromEntityNameExpression(node: Identifier | PropertyAccessExpression): Identifier;
function getIdentifierFromEntityNameExpression(node: Expression): Identifier | undefined;
function getIdentifierFromEntityNameExpression(node: Expression): Identifier | undefined {
switch (node.kind) {
case SyntaxKind.Identifier:
return node as Identifier;
case SyntaxKind.PropertyAccessExpression:
return (node as PropertyAccessExpression).name;
default:
return undefined;
}
}
function checkFunctionOrMethodDeclaration(node: FunctionDeclaration | MethodDeclaration | MethodSignature): void {
checkDecorators(node);
checkSignatureDeclaration(node);
const functionFlags = getFunctionFlags(node);
// Do not use hasDynamicName here, because that returns false for well known symbols.
// We want to perform checkComputedPropertyName for all computed properties, including
// well known symbols.
if (node.name && node.name.kind === SyntaxKind.ComputedPropertyName) {
// This check will account for methods in class/interface declarations,
// as well as accessors in classes/object literals
checkComputedPropertyName(node.name);
}
if (!hasNonBindableDynamicName(node)) {
// first we want to check the local symbol that contain this declaration
// - if node.localSymbol !== undefined - this is current declaration is exported and localSymbol points to the local symbol
// - if node.localSymbol === undefined - this node is non-exported so we can just pick the result of getSymbolOfNode
const symbol = getSymbolOfNode(node);
const localSymbol = node.localSymbol || symbol;
// Since the javascript won't do semantic analysis like typescript,
// if the javascript file comes before the typescript file and both contain same name functions,
// checkFunctionOrConstructorSymbol wouldn't be called if we didnt ignore javascript function.
const firstDeclaration = find(localSymbol.declarations,
// Get first non javascript function declaration
declaration => declaration.kind === node.kind && !(declaration.flags & NodeFlags.JavaScriptFile));
// Only type check the symbol once
if (node === firstDeclaration) {
checkFunctionOrConstructorSymbol(localSymbol);
}
if (symbol.parent) {
// run check once for the first declaration
if (getDeclarationOfKind(symbol, node.kind) === node) {
// run check on export symbol to check that modifiers agree across all exported declarations
checkFunctionOrConstructorSymbol(symbol);
}
}
}
const body = node.kind === SyntaxKind.MethodSignature ? undefined : node.body;
checkSourceElement(body);
if ((functionFlags & FunctionFlags.Generator) === 0) { // Async function or normal function
const returnOrPromisedType = getReturnOrPromisedType(node, functionFlags);
checkAllCodePathsInNonVoidFunctionReturnOrThrow(node, returnOrPromisedType);
}
if (produceDiagnostics && !getEffectiveReturnTypeNode(node)) {
// Report an implicit any error if there is no body, no explicit return type, and node is not a private method
// in an ambient context
if (nodeIsMissing(body) && !isPrivateWithinAmbient(node)) {
reportImplicitAny(node, anyType);
}
if (functionFlags & FunctionFlags.Generator && nodeIsPresent(body)) {
// A generator with a body and no type annotation can still cause errors. It can error if the
// yielded values have no common supertype, or it can give an implicit any error if it has no
// yielded values. The only way to trigger these errors is to try checking its return type.
getReturnTypeOfSignature(getSignatureFromDeclaration(node));
}
}
// A js function declaration can have a @type tag instead of a return type node, but that type must have a call signature
if (isInJSFile(node)) {
const typeTag = getJSDocTypeTag(node);
if (typeTag && typeTag.typeExpression && !getContextualCallSignature(getTypeFromTypeNode(typeTag.typeExpression), node)) {
error(typeTag, Diagnostics.The_type_of_a_function_declaration_must_match_the_function_s_signature);
}
}
}
function registerForUnusedIdentifiersCheck(node: PotentiallyUnusedIdentifier): void {
// May be in a call such as getTypeOfNode that happened to call this. But potentiallyUnusedIdentifiers is only defined in the scope of `checkSourceFile`.
if (produceDiagnostics && !(node.flags & NodeFlags.Ambient)) {
const sourceFile = getSourceFileOfNode(node);
let potentiallyUnusedIdentifiers = allPotentiallyUnusedIdentifiers.get(sourceFile.path);
if (!potentiallyUnusedIdentifiers) {
potentiallyUnusedIdentifiers = [];
allPotentiallyUnusedIdentifiers.set(sourceFile.path, potentiallyUnusedIdentifiers);
}
// TODO: GH#22580
// Debug.assert(addToSeen(seenPotentiallyUnusedIdentifiers, getNodeId(node)), "Adding potentially-unused identifier twice");
potentiallyUnusedIdentifiers.push(node);
}
}
type PotentiallyUnusedIdentifier =
| SourceFile | ModuleDeclaration | ClassLikeDeclaration | InterfaceDeclaration
| Block | CaseBlock | ForStatement | ForInStatement | ForOfStatement
| Exclude<SignatureDeclaration, IndexSignatureDeclaration | JSDocFunctionType> | TypeAliasDeclaration
| InferTypeNode;
function checkUnusedIdentifiers(potentiallyUnusedIdentifiers: ReadonlyArray<PotentiallyUnusedIdentifier>, addDiagnostic: AddUnusedDiagnostic) {
for (const node of potentiallyUnusedIdentifiers) {
switch (node.kind) {
case SyntaxKind.ClassDeclaration:
case SyntaxKind.ClassExpression:
checkUnusedClassMembers(node, addDiagnostic);
checkUnusedTypeParameters(node, addDiagnostic);
break;
case SyntaxKind.SourceFile:
case SyntaxKind.ModuleDeclaration:
case SyntaxKind.Block:
case SyntaxKind.CaseBlock:
case SyntaxKind.ForStatement:
case SyntaxKind.ForInStatement:
case SyntaxKind.ForOfStatement:
checkUnusedLocalsAndParameters(node, addDiagnostic);
break;
case SyntaxKind.Constructor:
case SyntaxKind.FunctionExpression:
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.ArrowFunction:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
if (node.body) { // Don't report unused parameters in overloads
checkUnusedLocalsAndParameters(node, addDiagnostic);
}
checkUnusedTypeParameters(node, addDiagnostic);
break;
case SyntaxKind.MethodSignature:
case SyntaxKind.CallSignature:
case SyntaxKind.ConstructSignature:
case SyntaxKind.FunctionType:
case SyntaxKind.ConstructorType:
case SyntaxKind.TypeAliasDeclaration:
case SyntaxKind.InterfaceDeclaration:
checkUnusedTypeParameters(node, addDiagnostic);
break;
case SyntaxKind.InferType:
checkUnusedInferTypeParameter(node, addDiagnostic);
break;
default:
Debug.assertNever(node, "Node should not have been registered for unused identifiers check");
}
}
}
function errorUnusedLocal(declaration: Declaration, name: string, addDiagnostic: AddUnusedDiagnostic) {
const node = getNameOfDeclaration(declaration) || declaration;
const message = isTypeDeclaration(declaration) ? Diagnostics._0_is_declared_but_never_used : Diagnostics._0_is_declared_but_its_value_is_never_read;
addDiagnostic(declaration, UnusedKind.Local, createDiagnosticForNode(node, message, name));
}
function isIdentifierThatStartsWithUnderscore(node: Node) {
return isIdentifier(node) && idText(node).charCodeAt(0) === CharacterCodes._;
}
function checkUnusedClassMembers(node: ClassDeclaration | ClassExpression, addDiagnostic: AddUnusedDiagnostic): void {
for (const member of node.members) {
switch (member.kind) {
case SyntaxKind.MethodDeclaration:
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
if (member.kind === SyntaxKind.SetAccessor && member.symbol.flags & SymbolFlags.GetAccessor) {
// Already would have reported an error on the getter.
break;
}
const symbol = getSymbolOfNode(member);
if (!symbol.isReferenced && hasModifier(member, ModifierFlags.Private)) {
addDiagnostic(member, UnusedKind.Local, createDiagnosticForNode(member.name!, Diagnostics._0_is_declared_but_its_value_is_never_read, symbolToString(symbol)));
}
break;
case SyntaxKind.Constructor:
for (const parameter of (<ConstructorDeclaration>member).parameters) {
if (!parameter.symbol.isReferenced && hasModifier(parameter, ModifierFlags.Private)) {
addDiagnostic(parameter, UnusedKind.Local, createDiagnosticForNode(parameter.name, Diagnostics.Property_0_is_declared_but_its_value_is_never_read, symbolName(parameter.symbol)));
}
}
break;
case SyntaxKind.IndexSignature:
case SyntaxKind.SemicolonClassElement:
// Can't be private
break;
default:
Debug.fail();
}
}
}
function checkUnusedInferTypeParameter(node: InferTypeNode, addDiagnostic: AddUnusedDiagnostic): void {
const { typeParameter } = node;
if (isTypeParameterUnused(typeParameter)) {
addDiagnostic(node, UnusedKind.Parameter, createDiagnosticForNode(node, Diagnostics._0_is_declared_but_its_value_is_never_read, idText(typeParameter.name)));
}
}
function checkUnusedTypeParameters(node: ClassLikeDeclaration | SignatureDeclaration | InterfaceDeclaration | TypeAliasDeclaration, addDiagnostic: AddUnusedDiagnostic): void {
// Only report errors on the last declaration for the type parameter container;
// this ensures that all uses have been accounted for.
if (last(getSymbolOfNode(node).declarations) !== node) return;
const typeParameters = getEffectiveTypeParameterDeclarations(node);
const seenParentsWithEveryUnused = new NodeSet<DeclarationWithTypeParameterChildren>();
for (const typeParameter of typeParameters) {
if (!isTypeParameterUnused(typeParameter)) continue;
const name = idText(typeParameter.name);
const { parent } = typeParameter;
if (parent.kind !== SyntaxKind.InferType && parent.typeParameters!.every(isTypeParameterUnused)) {
if (seenParentsWithEveryUnused.tryAdd(parent)) {
const range = isJSDocTemplateTag(parent)
// Whole @template tag
? rangeOfNode(parent)
// Include the `<>` in the error message
: rangeOfTypeParameters(parent.typeParameters!);
const only = typeParameters.length === 1;
const message = only ? Diagnostics._0_is_declared_but_its_value_is_never_read : Diagnostics.All_type_parameters_are_unused;
const arg0 = only ? name : undefined;
addDiagnostic(typeParameter, UnusedKind.Parameter, createFileDiagnostic(getSourceFileOfNode(parent), range.pos, range.end - range.pos, message, arg0));
}
}
else {
addDiagnostic(typeParameter, UnusedKind.Parameter, createDiagnosticForNode(typeParameter, Diagnostics._0_is_declared_but_its_value_is_never_read, name));
}
}
}
function isTypeParameterUnused(typeParameter: TypeParameterDeclaration): boolean {
return !(getMergedSymbol(typeParameter.symbol).isReferenced! & SymbolFlags.TypeParameter) && !isIdentifierThatStartsWithUnderscore(typeParameter.name);
}
function addToGroup<K, V>(map: Map<[K, V[]]>, key: K, value: V, getKey: (key: K) => number | string): void {
const keyString = String(getKey(key));
const group = map.get(keyString);
if (group) {
group[1].push(value);
}
else {
map.set(keyString, [key, [value]]);
}
}
function tryGetRootParameterDeclaration(node: Node): ParameterDeclaration | undefined {
return tryCast(getRootDeclaration(node), isParameter);
}
function checkUnusedLocalsAndParameters(nodeWithLocals: Node, addDiagnostic: AddUnusedDiagnostic): void {
if (nodeWithLocals.flags & NodeFlags.Ambient) return;
// Ideally we could use the ImportClause directly as a key, but must wait until we have full ES6 maps. So must store key along with value.
const unusedImports = createMap<[ImportClause, ImportedDeclaration[]]>();
const unusedDestructures = createMap<[ObjectBindingPattern, BindingElement[]]>();
const unusedVariables = createMap<[VariableDeclarationList, VariableDeclaration[]]>();
nodeWithLocals.locals!.forEach(local => {
// If it's purely a type parameter, ignore, will be checked in `checkUnusedTypeParameters`.
// If it's a type parameter merged with a parameter, check if the parameter-side is used.
if (local.flags & SymbolFlags.TypeParameter ? !(local.flags & SymbolFlags.Variable && !(local.isReferenced! & SymbolFlags.Variable)) : local.isReferenced || local.exportSymbol) {
return;
}
for (const declaration of local.declarations) {
if (isAmbientModule(declaration) ||
(isVariableDeclaration(declaration) && isForInOrOfStatement(declaration.parent.parent) || isImportedDeclaration(declaration)) && isIdentifierThatStartsWithUnderscore(declaration.name!)) {
continue;
}
if (isImportedDeclaration(declaration)) {
addToGroup(unusedImports, importClauseFromImported(declaration), declaration, getNodeId);
}
else if (isBindingElement(declaration) && isObjectBindingPattern(declaration.parent)) {
// In `{ a, ...b }, `a` is considered used since it removes a property from `b`. `b` may still be unused though.
const lastElement = last(declaration.parent.elements);
if (declaration === lastElement || !last(declaration.parent.elements).dotDotDotToken) {
addToGroup(unusedDestructures, declaration.parent, declaration, getNodeId);
}
}
else if (isVariableDeclaration(declaration)) {
addToGroup(unusedVariables, declaration.parent, declaration, getNodeId);
}
else {
const parameter = local.valueDeclaration && tryGetRootParameterDeclaration(local.valueDeclaration);
const name = local.valueDeclaration && getNameOfDeclaration(local.valueDeclaration);
if (parameter && name) {
if (!isParameterPropertyDeclaration(parameter) && !parameterIsThisKeyword(parameter) && !isIdentifierThatStartsWithUnderscore(name)) {
addDiagnostic(parameter, UnusedKind.Parameter, createDiagnosticForNode(name, Diagnostics._0_is_declared_but_its_value_is_never_read, symbolName(local)));
}
}
else {
errorUnusedLocal(declaration, symbolName(local), addDiagnostic);
}
}
}
});
unusedImports.forEach(([importClause, unuseds]) => {
const importDecl = importClause.parent;
const nDeclarations = (importClause.name ? 1 : 0) +
(importClause.namedBindings ?
(importClause.namedBindings.kind === SyntaxKind.NamespaceImport ? 1 : importClause.namedBindings.elements.length)
: 0);
if (nDeclarations === unuseds.length) {
addDiagnostic(importDecl, UnusedKind.Local, unuseds.length === 1
? createDiagnosticForNode(importDecl, Diagnostics._0_is_declared_but_its_value_is_never_read, idText(first(unuseds).name!))
: createDiagnosticForNode(importDecl, Diagnostics.All_imports_in_import_declaration_are_unused));
}
else {
for (const unused of unuseds) errorUnusedLocal(unused, idText(unused.name!), addDiagnostic);
}
});
unusedDestructures.forEach(([bindingPattern, bindingElements]) => {
const kind = tryGetRootParameterDeclaration(bindingPattern.parent) ? UnusedKind.Parameter : UnusedKind.Local;
if (bindingPattern.elements.length === bindingElements.length) {
if (bindingElements.length === 1 && bindingPattern.parent.kind === SyntaxKind.VariableDeclaration && bindingPattern.parent.parent.kind === SyntaxKind.VariableDeclarationList) {
addToGroup(unusedVariables, bindingPattern.parent.parent, bindingPattern.parent, getNodeId);
}
else {
addDiagnostic(bindingPattern, kind, bindingElements.length === 1
? createDiagnosticForNode(bindingPattern, Diagnostics._0_is_declared_but_its_value_is_never_read, bindingNameText(first(bindingElements).name))
: createDiagnosticForNode(bindingPattern, Diagnostics.All_destructured_elements_are_unused));
}
}
else {
for (const e of bindingElements) {
addDiagnostic(e, kind, createDiagnosticForNode(e, Diagnostics._0_is_declared_but_its_value_is_never_read, bindingNameText(e.name)));
}
}
});
unusedVariables.forEach(([declarationList, declarations]) => {
if (declarationList.declarations.length === declarations.length) {
addDiagnostic(declarationList, UnusedKind.Local, declarations.length === 1
? createDiagnosticForNode(first(declarations).name, Diagnostics._0_is_declared_but_its_value_is_never_read, bindingNameText(first(declarations).name))
: createDiagnosticForNode(declarationList.parent.kind === SyntaxKind.VariableStatement ? declarationList.parent : declarationList, Diagnostics.All_variables_are_unused));
}
else {
for (const decl of declarations) {
addDiagnostic(decl, UnusedKind.Local, createDiagnosticForNode(decl, Diagnostics._0_is_declared_but_its_value_is_never_read, bindingNameText(decl.name)));
}
}
});
}
function bindingNameText(name: BindingName): string {
switch (name.kind) {
case SyntaxKind.Identifier:
return idText(name);
case SyntaxKind.ArrayBindingPattern:
case SyntaxKind.ObjectBindingPattern:
return bindingNameText(cast(first(name.elements), isBindingElement).name);
default:
return Debug.assertNever(name);
}
}
type ImportedDeclaration = ImportClause | ImportSpecifier | NamespaceImport;
function isImportedDeclaration(node: Node): node is ImportedDeclaration {
return node.kind === SyntaxKind.ImportClause || node.kind === SyntaxKind.ImportSpecifier || node.kind === SyntaxKind.NamespaceImport;
}
function importClauseFromImported(decl: ImportedDeclaration): ImportClause {
return decl.kind === SyntaxKind.ImportClause ? decl : decl.kind === SyntaxKind.NamespaceImport ? decl.parent : decl.parent.parent;
}
function checkBlock(node: Block) {
// Grammar checking for SyntaxKind.Block
if (node.kind === SyntaxKind.Block) {
checkGrammarStatementInAmbientContext(node);
}
if (isFunctionOrModuleBlock(node)) {
const saveFlowAnalysisDisabled = flowAnalysisDisabled;
forEach(node.statements, checkSourceElement);
flowAnalysisDisabled = saveFlowAnalysisDisabled;
}
else {
forEach(node.statements, checkSourceElement);
}
if (node.locals) {
registerForUnusedIdentifiersCheck(node);
}
}
function checkCollisionWithArgumentsInGeneratedCode(node: SignatureDeclaration) {
// no rest parameters \ declaration context \ overload - no codegen impact
if (languageVersion >= ScriptTarget.ES2015 || compilerOptions.noEmit || !hasRestParameter(node) || node.flags & NodeFlags.Ambient || nodeIsMissing((<FunctionLikeDeclaration>node).body)) {
return;
}
forEach(node.parameters, p => {
if (p.name && !isBindingPattern(p.name) && p.name.escapedText === argumentsSymbol.escapedName) {
error(p, Diagnostics.Duplicate_identifier_arguments_Compiler_uses_arguments_to_initialize_rest_parameters);
}
});
}
function needCollisionCheckForIdentifier(node: Node, identifier: Identifier | undefined, name: string): boolean {
if (!(identifier && identifier.escapedText === name)) {
return false;
}
if (node.kind === SyntaxKind.PropertyDeclaration ||
node.kind === SyntaxKind.PropertySignature ||
node.kind === SyntaxKind.MethodDeclaration ||
node.kind === SyntaxKind.MethodSignature ||
node.kind === SyntaxKind.GetAccessor ||
node.kind === SyntaxKind.SetAccessor) {
// it is ok to have member named '_super' or '_this' - member access is always qualified
return false;
}
if (node.flags & NodeFlags.Ambient) {
// ambient context - no codegen impact
return false;
}
const root = getRootDeclaration(node);
if (root.kind === SyntaxKind.Parameter && nodeIsMissing((<FunctionLikeDeclaration>root.parent).body)) {
// just an overload - no codegen impact
return false;
}
return true;
}
// this function will run after checking the source file so 'CaptureThis' is correct for all nodes
function checkIfThisIsCapturedInEnclosingScope(node: Node): void {
findAncestor(node, current => {
if (getNodeCheckFlags(current) & NodeCheckFlags.CaptureThis) {
const isDeclaration = node.kind !== SyntaxKind.Identifier;
if (isDeclaration) {
error(getNameOfDeclaration(<Declaration>node), Diagnostics.Duplicate_identifier_this_Compiler_uses_variable_declaration_this_to_capture_this_reference);
}
else {
error(node, Diagnostics.Expression_resolves_to_variable_declaration_this_that_compiler_uses_to_capture_this_reference);
}
return true;
}
return false;
});
}
function checkIfNewTargetIsCapturedInEnclosingScope(node: Node): void {
findAncestor(node, current => {
if (getNodeCheckFlags(current) & NodeCheckFlags.CaptureNewTarget) {
const isDeclaration = node.kind !== SyntaxKind.Identifier;
if (isDeclaration) {
error(getNameOfDeclaration(<Declaration>node), Diagnostics.Duplicate_identifier_newTarget_Compiler_uses_variable_declaration_newTarget_to_capture_new_target_meta_property_reference);
}
else {
error(node, Diagnostics.Expression_resolves_to_variable_declaration_newTarget_that_compiler_uses_to_capture_new_target_meta_property_reference);
}
return true;
}
return false;
});
}
function checkCollisionWithRequireExportsInGeneratedCode(node: Node, name: Identifier) {
// No need to check for require or exports for ES6 modules and later
if (moduleKind >= ModuleKind.ES2015 || compilerOptions.noEmit) {
return;
}
if (!needCollisionCheckForIdentifier(node, name, "require") && !needCollisionCheckForIdentifier(node, name, "exports")) {
return;
}
// Uninstantiated modules shouldnt do this check
if (isModuleDeclaration(node) && getModuleInstanceState(node) !== ModuleInstanceState.Instantiated) {
return;
}
// In case of variable declaration, node.parent is variable statement so look at the variable statement's parent
const parent = getDeclarationContainer(node);
if (parent.kind === SyntaxKind.SourceFile && isExternalOrCommonJsModule(<SourceFile>parent)) {
// If the declaration happens to be in external module, report error that require and exports are reserved keywords
error(name, Diagnostics.Duplicate_identifier_0_Compiler_reserves_name_1_in_top_level_scope_of_a_module,
declarationNameToString(name), declarationNameToString(name));
}
}
function checkCollisionWithGlobalPromiseInGeneratedCode(node: Node, name: Identifier): void {
if (languageVersion >= ScriptTarget.ES2017 || compilerOptions.noEmit || !needCollisionCheckForIdentifier(node, name, "Promise")) {
return;
}
// Uninstantiated modules shouldnt do this check
if (isModuleDeclaration(node) && getModuleInstanceState(node) !== ModuleInstanceState.Instantiated) {
return;
}
// In case of variable declaration, node.parent is variable statement so look at the variable statement's parent
const parent = getDeclarationContainer(node);
if (parent.kind === SyntaxKind.SourceFile && isExternalOrCommonJsModule(<SourceFile>parent) && parent.flags & NodeFlags.HasAsyncFunctions) {
// If the declaration happens to be in external module, report error that Promise is a reserved identifier.
error(name, Diagnostics.Duplicate_identifier_0_Compiler_reserves_name_1_in_top_level_scope_of_a_module_containing_async_functions,
declarationNameToString(name), declarationNameToString(name));
}
}
function checkVarDeclaredNamesNotShadowed(node: VariableDeclaration | BindingElement) {
// - ScriptBody : StatementList
// It is a Syntax Error if any element of the LexicallyDeclaredNames of StatementList
// also occurs in the VarDeclaredNames of StatementList.
// - Block : { StatementList }
// It is a Syntax Error if any element of the LexicallyDeclaredNames of StatementList
// also occurs in the VarDeclaredNames of StatementList.
// Variable declarations are hoisted to the top of their function scope. They can shadow
// block scoped declarations, which bind tighter. this will not be flagged as duplicate definition
// by the binder as the declaration scope is different.
// A non-initialized declaration is a no-op as the block declaration will resolve before the var
// declaration. the problem is if the declaration has an initializer. this will act as a write to the
// block declared value. this is fine for let, but not const.
// Only consider declarations with initializers, uninitialized const declarations will not
// step on a let/const variable.
// Do not consider const and const declarations, as duplicate block-scoped declarations
// are handled by the binder.
// We are only looking for const declarations that step on let\const declarations from a
// different scope. e.g.:
// {
// const x = 0; // localDeclarationSymbol obtained after name resolution will correspond to this declaration
// const x = 0; // symbol for this declaration will be 'symbol'
// }
// skip block-scoped variables and parameters
if ((getCombinedNodeFlags(node) & NodeFlags.BlockScoped) !== 0 || isParameterDeclaration(node)) {
return;
}
// skip variable declarations that don't have initializers
// NOTE: in ES6 spec initializer is required in variable declarations where name is binding pattern
// so we'll always treat binding elements as initialized
if (node.kind === SyntaxKind.VariableDeclaration && !node.initializer) {
return;
}
const symbol = getSymbolOfNode(node);
if (symbol.flags & SymbolFlags.FunctionScopedVariable) {
if (!isIdentifier(node.name)) return Debug.fail();
const localDeclarationSymbol = resolveName(node, node.name.escapedText, SymbolFlags.Variable, /*nodeNotFoundErrorMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ false);
if (localDeclarationSymbol &&
localDeclarationSymbol !== symbol &&
localDeclarationSymbol.flags & SymbolFlags.BlockScopedVariable) {
if (getDeclarationNodeFlagsFromSymbol(localDeclarationSymbol) & NodeFlags.BlockScoped) {
const varDeclList = getAncestor(localDeclarationSymbol.valueDeclaration, SyntaxKind.VariableDeclarationList)!;
const container =
varDeclList.parent.kind === SyntaxKind.VariableStatement && varDeclList.parent.parent
? varDeclList.parent.parent
: undefined;
// names of block-scoped and function scoped variables can collide only
// if block scoped variable is defined in the function\module\source file scope (because of variable hoisting)
const namesShareScope =
container &&
(container.kind === SyntaxKind.Block && isFunctionLike(container.parent) ||
container.kind === SyntaxKind.ModuleBlock ||
container.kind === SyntaxKind.ModuleDeclaration ||
container.kind === SyntaxKind.SourceFile);
// here we know that function scoped variable is shadowed by block scoped one
// if they are defined in the same scope - binder has already reported redeclaration error
// otherwise if variable has an initializer - show error that initialization will fail
// since LHS will be block scoped name instead of function scoped
if (!namesShareScope) {
const name = symbolToString(localDeclarationSymbol);
error(node, Diagnostics.Cannot_initialize_outer_scoped_variable_0_in_the_same_scope_as_block_scoped_declaration_1, name, name);
}
}
}
}
}
// Check that a parameter initializer contains no references to parameters declared to the right of itself
function checkParameterInitializer(node: HasExpressionInitializer): void {
if (getRootDeclaration(node).kind !== SyntaxKind.Parameter) {
return;
}
const func = getContainingFunction(node);
visit(node.initializer!);
function visit(n: Node): void {
if (isTypeNode(n) || isDeclarationName(n)) {
// do not dive in types
// skip declaration names (i.e. in object literal expressions)
return;
}
if (n.kind === SyntaxKind.PropertyAccessExpression) {
// skip property names in property access expression
return visit((<PropertyAccessExpression>n).expression);
}
else if (n.kind === SyntaxKind.Identifier) {
// check FunctionLikeDeclaration.locals (stores parameters\function local variable)
// if it contains entry with a specified name
const symbol = resolveName(n, (<Identifier>n).escapedText, SymbolFlags.Value | SymbolFlags.Alias, /*nameNotFoundMessage*/undefined, /*nameArg*/undefined, /*isUse*/ false);
if (!symbol || symbol === unknownSymbol || !symbol.valueDeclaration) {
return;
}
if (symbol.valueDeclaration === node) {
error(n, Diagnostics.Parameter_0_cannot_be_referenced_in_its_initializer, declarationNameToString(node.name));
return;
}
// locals map for function contain both parameters and function locals
// so we need to do a bit of extra work to check if reference is legal
const enclosingContainer = getEnclosingBlockScopeContainer(symbol.valueDeclaration);
if (enclosingContainer === func) {
if (symbol.valueDeclaration.kind === SyntaxKind.Parameter ||
symbol.valueDeclaration.kind === SyntaxKind.BindingElement) {
// it is ok to reference parameter in initializer if either
// - parameter is located strictly on the left of current parameter declaration
if (symbol.valueDeclaration.pos < node.pos) {
return;
}
// - parameter is wrapped in function-like entity
if (findAncestor(
n,
current => {
if (current === node.initializer) {
return "quit";
}
return isFunctionLike(current.parent) ||
// computed property names/initializers in instance property declaration of class like entities
// are executed in constructor and thus deferred
(current.parent.kind === SyntaxKind.PropertyDeclaration &&
!(hasModifier(current.parent, ModifierFlags.Static)) &&
isClassLike(current.parent.parent));
})) {
return;
}
// fall through to report error
}
error(n, Diagnostics.Initializer_of_parameter_0_cannot_reference_identifier_1_declared_after_it, declarationNameToString(node.name), declarationNameToString(<Identifier>n));
}
}
else {
return forEachChild(n, visit);
}
}
}
function convertAutoToAny(type: Type) {
return type === autoType ? anyType : type === autoArrayType ? anyArrayType : type;
}
// Check variable, parameter, or property declaration
function checkVariableLikeDeclaration(node: ParameterDeclaration | PropertyDeclaration | PropertySignature | VariableDeclaration | BindingElement) {
checkDecorators(node);
if (!isBindingElement(node)) {
checkSourceElement(node.type);
}
// JSDoc `function(string, string): string` syntax results in parameters with no name
if (!node.name) {
return;
}
// For a computed property, just check the initializer and exit
// Do not use hasDynamicName here, because that returns false for well known symbols.
// We want to perform checkComputedPropertyName for all computed properties, including
// well known symbols.
if (node.name.kind === SyntaxKind.ComputedPropertyName) {
checkComputedPropertyName(node.name);
if (node.initializer) {
checkExpressionCached(node.initializer);
}
}
if (node.kind === SyntaxKind.BindingElement) {
if (node.parent.kind === SyntaxKind.ObjectBindingPattern && languageVersion < ScriptTarget.ESNext) {
checkExternalEmitHelpers(node, ExternalEmitHelpers.Rest);
}
// check computed properties inside property names of binding elements
if (node.propertyName && node.propertyName.kind === SyntaxKind.ComputedPropertyName) {
checkComputedPropertyName(node.propertyName);
}
// check private/protected variable access
const parent = node.parent.parent;
const parentType = getTypeForBindingElementParent(parent);
const name = node.propertyName || node.name;
if (parentType && !isBindingPattern(name)) {
const exprType = getLiteralTypeFromPropertyName(name);
if (isTypeUsableAsPropertyName(exprType)) {
const nameText = getPropertyNameFromType(exprType);
const property = getPropertyOfType(parentType, nameText);
if (property) {
markPropertyAsReferenced(property, /*nodeForCheckWriteOnly*/ undefined, /*isThisAccess*/ false); // A destructuring is never a write-only reference.
checkPropertyAccessibility(parent, !!parent.initializer && parent.initializer.kind === SyntaxKind.SuperKeyword, parentType, property);
}
}
}
}
// For a binding pattern, check contained binding elements
if (isBindingPattern(node.name)) {
if (node.name.kind === SyntaxKind.ArrayBindingPattern && languageVersion < ScriptTarget.ES2015 && compilerOptions.downlevelIteration) {
checkExternalEmitHelpers(node, ExternalEmitHelpers.Read);
}
forEach(node.name.elements, checkSourceElement);
}
// For a parameter declaration with an initializer, error and exit if the containing function doesn't have a body
if (node.initializer && getRootDeclaration(node).kind === SyntaxKind.Parameter && nodeIsMissing((getContainingFunction(node) as FunctionLikeDeclaration).body)) {
error(node, Diagnostics.A_parameter_initializer_is_only_allowed_in_a_function_or_constructor_implementation);
return;
}
// For a binding pattern, validate the initializer and exit
if (isBindingPattern(node.name)) {
// Don't validate for-in initializer as it is already an error
if (node.initializer && node.parent.parent.kind !== SyntaxKind.ForInStatement) {
const initializerType = checkExpressionCached(node.initializer);
if (strictNullChecks && node.name.elements.length === 0) {
checkNonNullType(initializerType, node);
}
else {
checkTypeAssignableToAndOptionallyElaborate(initializerType, getWidenedTypeForVariableLikeDeclaration(node), node, node.initializer);
}
checkParameterInitializer(node);
}
return;
}
const symbol = getSymbolOfNode(node);
const type = convertAutoToAny(getTypeOfSymbol(symbol));
if (node === symbol.valueDeclaration) {
// Node is the primary declaration of the symbol, just validate the initializer
// Don't validate for-in initializer as it is already an error
const initializer = getEffectiveInitializer(node);
if (initializer) {
const isJSObjectLiteralInitializer = isInJSFile(node) &&
isObjectLiteralExpression(initializer) &&
(initializer.properties.length === 0 || isPrototypeAccess(node.name)) &&
hasEntries(symbol.exports);
if (!isJSObjectLiteralInitializer && node.parent.parent.kind !== SyntaxKind.ForInStatement) {
checkTypeAssignableToAndOptionallyElaborate(checkExpressionCached(initializer), type, node, initializer, /*headMessage*/ undefined);
checkParameterInitializer(node);
}
}
if (symbol.declarations.length > 1) {
if (some(symbol.declarations, d => d !== node && isVariableLike(d) && !areDeclarationFlagsIdentical(d, node))) {
error(node.name, Diagnostics.All_declarations_of_0_must_have_identical_modifiers, declarationNameToString(node.name));
}
}
}
else {
// Node is a secondary declaration, check that type is identical to primary declaration and check that
// initializer is consistent with type associated with the node
const declarationType = convertAutoToAny(getWidenedTypeForVariableLikeDeclaration(node));
if (type !== errorType && declarationType !== errorType &&
!isTypeIdenticalTo(type, declarationType) &&
!(symbol.flags & SymbolFlags.Assignment)) {
errorNextVariableOrPropertyDeclarationMustHaveSameType(type, node, declarationType);
}
if (node.initializer) {
checkTypeAssignableToAndOptionallyElaborate(checkExpressionCached(node.initializer), declarationType, node, node.initializer, /*headMessage*/ undefined);
}
if (!areDeclarationFlagsIdentical(node, symbol.valueDeclaration)) {
error(node.name, Diagnostics.All_declarations_of_0_must_have_identical_modifiers, declarationNameToString(node.name));
}
}
if (node.kind !== SyntaxKind.PropertyDeclaration && node.kind !== SyntaxKind.PropertySignature) {
// We know we don't have a binding pattern or computed name here
checkExportsOnMergedDeclarations(node);
if (node.kind === SyntaxKind.VariableDeclaration || node.kind === SyntaxKind.BindingElement) {
checkVarDeclaredNamesNotShadowed(node);
}
checkCollisionWithRequireExportsInGeneratedCode(node, <Identifier>node.name);
checkCollisionWithGlobalPromiseInGeneratedCode(node, <Identifier>node.name);
}
}
function errorNextVariableOrPropertyDeclarationMustHaveSameType(firstType: Type, nextDeclaration: Declaration, nextType: Type): void {
const nextDeclarationName = getNameOfDeclaration(nextDeclaration);
const message = nextDeclaration.kind === SyntaxKind.PropertyDeclaration || nextDeclaration.kind === SyntaxKind.PropertySignature
? Diagnostics.Subsequent_property_declarations_must_have_the_same_type_Property_0_must_be_of_type_1_but_here_has_type_2
: Diagnostics.Subsequent_variable_declarations_must_have_the_same_type_Variable_0_must_be_of_type_1_but_here_has_type_2;
error(
nextDeclarationName,
message,
declarationNameToString(nextDeclarationName),
typeToString(firstType),
typeToString(nextType));
}
function areDeclarationFlagsIdentical(left: Declaration, right: Declaration) {
if ((left.kind === SyntaxKind.Parameter && right.kind === SyntaxKind.VariableDeclaration) ||
(left.kind === SyntaxKind.VariableDeclaration && right.kind === SyntaxKind.Parameter)) {
// Differences in optionality between parameters and variables are allowed.
return true;
}
if (hasQuestionToken(left) !== hasQuestionToken(right)) {
return false;
}
const interestingFlags = ModifierFlags.Private |
ModifierFlags.Protected |
ModifierFlags.Async |
ModifierFlags.Abstract |
ModifierFlags.Readonly |
ModifierFlags.Static;
return getSelectedModifierFlags(left, interestingFlags) === getSelectedModifierFlags(right, interestingFlags);
}
function checkVariableDeclaration(node: VariableDeclaration) {
checkGrammarVariableDeclaration(node);
return checkVariableLikeDeclaration(node);
}
function checkBindingElement(node: BindingElement) {
checkGrammarBindingElement(node);
return checkVariableLikeDeclaration(node);
}
function checkVariableStatement(node: VariableStatement) {
// Grammar checking
if (!checkGrammarDecoratorsAndModifiers(node) && !checkGrammarVariableDeclarationList(node.declarationList)) checkGrammarForDisallowedLetOrConstStatement(node);
forEach(node.declarationList.declarations, checkSourceElement);
}
function checkExpressionStatement(node: ExpressionStatement) {
// Grammar checking
checkGrammarStatementInAmbientContext(node);
checkExpression(node.expression);
}
function checkIfStatement(node: IfStatement) {
// Grammar checking
checkGrammarStatementInAmbientContext(node);
checkTruthinessExpression(node.expression);
checkSourceElement(node.thenStatement);
if (node.thenStatement.kind === SyntaxKind.EmptyStatement) {
error(node.thenStatement, Diagnostics.The_body_of_an_if_statement_cannot_be_the_empty_statement);
}
checkSourceElement(node.elseStatement);
}
function checkDoStatement(node: DoStatement) {
// Grammar checking
checkGrammarStatementInAmbientContext(node);
checkSourceElement(node.statement);
checkTruthinessExpression(node.expression);
}
function checkWhileStatement(node: WhileStatement) {
// Grammar checking
checkGrammarStatementInAmbientContext(node);
checkTruthinessExpression(node.expression);
checkSourceElement(node.statement);
}
function checkTruthinessExpression(node: Expression, checkMode?: CheckMode) {
const type = checkExpression(node, checkMode);
if (type.flags & TypeFlags.Void) {
error(node, Diagnostics.An_expression_of_type_void_cannot_be_tested_for_truthiness);
}
return type;
}
function checkForStatement(node: ForStatement) {
// Grammar checking
if (!checkGrammarStatementInAmbientContext(node)) {
if (node.initializer && node.initializer.kind === SyntaxKind.VariableDeclarationList) {
checkGrammarVariableDeclarationList(<VariableDeclarationList>node.initializer);
}
}
if (node.initializer) {
if (node.initializer.kind === SyntaxKind.VariableDeclarationList) {
forEach((<VariableDeclarationList>node.initializer).declarations, checkVariableDeclaration);
}
else {
checkExpression(node.initializer);
}
}
if (node.condition) checkTruthinessExpression(node.condition);
if (node.incrementor) checkExpression(node.incrementor);
checkSourceElement(node.statement);
if (node.locals) {
registerForUnusedIdentifiersCheck(node);
}
}
function checkForOfStatement(node: ForOfStatement): void {
checkGrammarForInOrForOfStatement(node);
if (node.awaitModifier) {
const functionFlags = getFunctionFlags(getContainingFunction(node));
if ((functionFlags & (FunctionFlags.Invalid | FunctionFlags.Async)) === FunctionFlags.Async && languageVersion < ScriptTarget.ESNext) {
// for..await..of in an async function or async generator function prior to ESNext requires the __asyncValues helper
checkExternalEmitHelpers(node, ExternalEmitHelpers.ForAwaitOfIncludes);
}
}
else if (compilerOptions.downlevelIteration && languageVersion < ScriptTarget.ES2015) {
// for..of prior to ES2015 requires the __values helper when downlevelIteration is enabled
checkExternalEmitHelpers(node, ExternalEmitHelpers.ForOfIncludes);
}
// Check the LHS and RHS
// If the LHS is a declaration, just check it as a variable declaration, which will in turn check the RHS
// via checkRightHandSideOfForOf.
// If the LHS is an expression, check the LHS, as a destructuring assignment or as a reference.
// Then check that the RHS is assignable to it.
if (node.initializer.kind === SyntaxKind.VariableDeclarationList) {
checkForInOrForOfVariableDeclaration(node);
}
else {
const varExpr = node.initializer;
const iteratedType = checkRightHandSideOfForOf(node.expression, node.awaitModifier);
// There may be a destructuring assignment on the left side
if (varExpr.kind === SyntaxKind.ArrayLiteralExpression || varExpr.kind === SyntaxKind.ObjectLiteralExpression) {
// iteratedType may be undefined. In this case, we still want to check the structure of
// varExpr, in particular making sure it's a valid LeftHandSideExpression. But we'd like
// to short circuit the type relation checking as much as possible, so we pass the unknownType.
checkDestructuringAssignment(varExpr, iteratedType || errorType);
}
else {
const leftType = checkExpression(varExpr);
checkReferenceExpression(varExpr, Diagnostics.The_left_hand_side_of_a_for_of_statement_must_be_a_variable_or_a_property_access);
// iteratedType will be undefined if the rightType was missing properties/signatures
// required to get its iteratedType (like [Symbol.iterator] or next). This may be
// because we accessed properties from anyType, or it may have led to an error inside
// getElementTypeOfIterable.
if (iteratedType) {
checkTypeAssignableToAndOptionallyElaborate(iteratedType, leftType, varExpr, node.expression);
}
}
}
checkSourceElement(node.statement);
if (node.locals) {
registerForUnusedIdentifiersCheck(node);
}
}
function checkForInStatement(node: ForInStatement) {
// Grammar checking
checkGrammarForInOrForOfStatement(node);
const rightType = getNonNullableTypeIfNeeded(checkExpression(node.expression));
// TypeScript 1.0 spec (April 2014): 5.4
// In a 'for-in' statement of the form
// for (let VarDecl in Expr) Statement
// VarDecl must be a variable declaration without a type annotation that declares a variable of type Any,
// and Expr must be an expression of type Any, an object type, or a type parameter type.
if (node.initializer.kind === SyntaxKind.VariableDeclarationList) {
const variable = (<VariableDeclarationList>node.initializer).declarations[0];
if (variable && isBindingPattern(variable.name)) {
error(variable.name, Diagnostics.The_left_hand_side_of_a_for_in_statement_cannot_be_a_destructuring_pattern);
}
checkForInOrForOfVariableDeclaration(node);
}
else {
// In a 'for-in' statement of the form
// for (Var in Expr) Statement
// Var must be an expression classified as a reference of type Any or the String primitive type,
// and Expr must be an expression of type Any, an object type, or a type parameter type.
const varExpr = node.initializer;
const leftType = checkExpression(varExpr);
if (varExpr.kind === SyntaxKind.ArrayLiteralExpression || varExpr.kind === SyntaxKind.ObjectLiteralExpression) {
error(varExpr, Diagnostics.The_left_hand_side_of_a_for_in_statement_cannot_be_a_destructuring_pattern);
}
else if (!isTypeAssignableTo(getIndexTypeOrString(rightType), leftType)) {
error(varExpr, Diagnostics.The_left_hand_side_of_a_for_in_statement_must_be_of_type_string_or_any);
}
else {
// run check only former check succeeded to avoid cascading errors
checkReferenceExpression(varExpr, Diagnostics.The_left_hand_side_of_a_for_in_statement_must_be_a_variable_or_a_property_access);
}
}
// unknownType is returned i.e. if node.expression is identifier whose name cannot be resolved
// in this case error about missing name is already reported - do not report extra one
if (rightType === neverType || !isTypeAssignableToKind(rightType, TypeFlags.NonPrimitive | TypeFlags.InstantiableNonPrimitive)) {
error(node.expression, Diagnostics.The_right_hand_side_of_a_for_in_statement_must_be_of_type_any_an_object_type_or_a_type_parameter_but_here_has_type_0, typeToString(rightType));
}
checkSourceElement(node.statement);
if (node.locals) {
registerForUnusedIdentifiersCheck(node);
}
}
function checkForInOrForOfVariableDeclaration(iterationStatement: ForInOrOfStatement): void {
const variableDeclarationList = <VariableDeclarationList>iterationStatement.initializer;
// checkGrammarForInOrForOfStatement will check that there is exactly one declaration.
if (variableDeclarationList.declarations.length >= 1) {
const decl = variableDeclarationList.declarations[0];
checkVariableDeclaration(decl);
}
}
function checkRightHandSideOfForOf(rhsExpression: Expression, awaitModifier: AwaitKeywordToken | undefined): Type {
const expressionType = checkNonNullExpression(rhsExpression);
return checkIteratedTypeOrElementType(expressionType, rhsExpression, /*allowStringInput*/ true, awaitModifier !== undefined);
}
function checkIteratedTypeOrElementType(inputType: Type, errorNode: Node | undefined, allowStringInput: boolean, allowAsyncIterables: boolean): Type {
if (isTypeAny(inputType)) {
return inputType;
}
return getIteratedTypeOrElementType(inputType, errorNode, allowStringInput, allowAsyncIterables, /*checkAssignability*/ true) || anyType;
}
/**
* When consuming an iterable type in a for..of, spread, or iterator destructuring assignment
* we want to get the iterated type of an iterable for ES2015 or later, or the iterated type
* of a iterable (if defined globally) or element type of an array like for ES2015 or earlier.
*/
function getIteratedTypeOrElementType(inputType: Type, errorNode: Node | undefined, allowStringInput: boolean, allowAsyncIterables: boolean, checkAssignability: boolean): Type | undefined {
if (inputType === neverType) {
reportTypeNotIterableError(errorNode!, inputType, allowAsyncIterables); // TODO: GH#18217
return undefined;
}
const uplevelIteration = languageVersion >= ScriptTarget.ES2015;
const downlevelIteration = !uplevelIteration && compilerOptions.downlevelIteration;
// Get the iterated type of an `Iterable<T>` or `IterableIterator<T>` only in ES2015
// or higher, when inside of an async generator or for-await-if, or when
// downlevelIteration is requested.
if (uplevelIteration || downlevelIteration || allowAsyncIterables) {
// We only report errors for an invalid iterable type in ES2015 or higher.
const iteratedType = getIteratedTypeOfIterable(inputType, uplevelIteration ? errorNode : undefined, allowAsyncIterables, /*allowSyncIterables*/ true, checkAssignability);
if (iteratedType || uplevelIteration) {
return iteratedType;
}
}
let arrayType = inputType;
let reportedError = false;
let hasStringConstituent = false;
// If strings are permitted, remove any string-like constituents from the array type.
// This allows us to find other non-string element types from an array unioned with
// a string.
if (allowStringInput) {
if (arrayType.flags & TypeFlags.Union) {
// After we remove all types that are StringLike, we will know if there was a string constituent
// based on whether the result of filter is a new array.
const arrayTypes = (<UnionType>inputType).types;
const filteredTypes = filter(arrayTypes, t => !(t.flags & TypeFlags.StringLike));
if (filteredTypes !== arrayTypes) {
arrayType = getUnionType(filteredTypes, UnionReduction.Subtype);
}
}
else if (arrayType.flags & TypeFlags.StringLike) {
arrayType = neverType;
}
hasStringConstituent = arrayType !== inputType;
if (hasStringConstituent) {
if (languageVersion < ScriptTarget.ES5) {
if (errorNode) {
error(errorNode, Diagnostics.Using_a_string_in_a_for_of_statement_is_only_supported_in_ECMAScript_5_and_higher);
reportedError = true;
}
}
// Now that we've removed all the StringLike types, if no constituents remain, then the entire
// arrayOrStringType was a string.
if (arrayType.flags & TypeFlags.Never) {
return stringType;
}
}
}
if (!isArrayLikeType(arrayType)) {
if (errorNode && !reportedError) {
// Which error we report depends on whether we allow strings or if there was a
// string constituent. For example, if the input type is number | string, we
// want to say that number is not an array type. But if the input was just
// number and string input is allowed, we want to say that number is not an
// array type or a string type.
const isIterable = !!getIteratedTypeOfIterable(inputType, /* errorNode */ undefined, allowAsyncIterables, /*allowSyncIterables*/ true, checkAssignability);
const diagnostic = !allowStringInput || hasStringConstituent
? downlevelIteration
? Diagnostics.Type_0_is_not_an_array_type_or_does_not_have_a_Symbol_iterator_method_that_returns_an_iterator
: isIterable
? Diagnostics.Type_0_is_not_an_array_type_or_a_string_type_Use_compiler_option_downlevelIteration_to_allow_iterating_of_iterators
: Diagnostics.Type_0_is_not_an_array_type
: downlevelIteration
? Diagnostics.Type_0_is_not_an_array_type_or_a_string_type_or_does_not_have_a_Symbol_iterator_method_that_returns_an_iterator
: isIterable
? Diagnostics.Type_0_is_not_an_array_type_or_a_string_type_Use_compiler_option_downlevelIteration_to_allow_iterating_of_iterators
: Diagnostics.Type_0_is_not_an_array_type_or_a_string_type;
error(errorNode, diagnostic, typeToString(arrayType));
}
return hasStringConstituent ? stringType : undefined;
}
const arrayElementType = getIndexTypeOfType(arrayType, IndexKind.Number);
if (hasStringConstituent && arrayElementType) {
// This is just an optimization for the case where arrayOrStringType is string | string[]
if (arrayElementType.flags & TypeFlags.StringLike) {
return stringType;
}
return getUnionType([arrayElementType, stringType], UnionReduction.Subtype);
}
return arrayElementType;
}
/**
* We want to treat type as an iterable, and get the type it is an iterable of. The iterable
* must have the following structure (annotated with the names of the variables below):
*
* { // iterable
* [Symbol.iterator]: { // iteratorMethod
* (): Iterator<T>
* }
* }
*
* For an async iterable, we expect the following structure:
*
* { // iterable
* [Symbol.asyncIterator]: { // iteratorMethod
* (): AsyncIterator<T>
* }
* }
*
* T is the type we are after. At every level that involves analyzing return types
* of signatures, we union the return types of all the signatures.
*
* Another thing to note is that at any step of this process, we could run into a dead end,
* meaning either the property is missing, or we run into the anyType. If either of these things
* happens, we return undefined to signal that we could not find the iterated type. If a property
* is missing, and the previous step did not result in 'any', then we also give an error if the
* caller requested it. Then the caller can decide what to do in the case where there is no iterated
* type. This is different from returning anyType, because that would signify that we have matched the
* whole pattern and that T (above) is 'any'.
*
* For a **for-of** statement, `yield*` (in a normal generator), spread, array
* destructuring, or normal generator we will only ever look for a `[Symbol.iterator]()`
* method.
*
* For an async generator we will only ever look at the `[Symbol.asyncIterator]()` method.
*
* For a **for-await-of** statement or a `yield*` in an async generator we will look for
* the `[Symbol.asyncIterator]()` method first, and then the `[Symbol.iterator]()` method.
*/
function getIteratedTypeOfIterable(type: Type, errorNode: Node | undefined, allowAsyncIterables: boolean, allowSyncIterables: boolean, checkAssignability: boolean): Type | undefined {
if (isTypeAny(type)) {
return undefined;
}
return mapType(type, getIteratedType);
function getIteratedType(type: Type) {
const typeAsIterable = <IterableOrIteratorType>type;
if (allowAsyncIterables) {
if (typeAsIterable.iteratedTypeOfAsyncIterable) {
return typeAsIterable.iteratedTypeOfAsyncIterable;
}
// As an optimization, if the type is an instantiation of the global `AsyncIterable<T>`
// or the global `AsyncIterableIterator<T>` then just grab its type argument.
if (isReferenceToType(type, getGlobalAsyncIterableType(/*reportErrors*/ false)) ||
isReferenceToType(type, getGlobalAsyncIterableIteratorType(/*reportErrors*/ false))) {
return typeAsIterable.iteratedTypeOfAsyncIterable = (<GenericType>type).typeArguments![0];
}
}
if (allowSyncIterables) {
if (typeAsIterable.iteratedTypeOfIterable) {
return allowAsyncIterables
? typeAsIterable.iteratedTypeOfAsyncIterable = getAwaitedType(typeAsIterable.iteratedTypeOfIterable)
: typeAsIterable.iteratedTypeOfIterable;
}
// As an optimization, if the type is an instantiation of the global `Iterable<T>` or
// `IterableIterator<T>` then just grab its type argument.
if (isReferenceToType(type, getGlobalIterableType(/*reportErrors*/ false)) ||
isReferenceToType(type, getGlobalIterableIteratorType(/*reportErrors*/ false))) {
return allowAsyncIterables
? typeAsIterable.iteratedTypeOfAsyncIterable = getAwaitedType((<GenericType>type).typeArguments![0])
: typeAsIterable.iteratedTypeOfIterable = (<GenericType>type).typeArguments![0];
}
}
const asyncMethodType = allowAsyncIterables && getTypeOfPropertyOfType(type, getPropertyNameForKnownSymbolName("asyncIterator"));
const methodType = asyncMethodType || (allowSyncIterables ? getTypeOfPropertyOfType(type, getPropertyNameForKnownSymbolName("iterator")) : undefined);
if (isTypeAny(methodType)) {
return undefined;
}
const signatures = methodType ? getSignaturesOfType(methodType, SignatureKind.Call) : undefined;
if (!some(signatures)) {
if (errorNode) {
// only report on the first error
reportTypeNotIterableError(errorNode, type, allowAsyncIterables);
errorNode = undefined;
}
return undefined;
}
const returnType = getUnionType(map(signatures, getReturnTypeOfSignature), UnionReduction.Subtype);
const iteratedType = getIteratedTypeOfIterator(returnType, errorNode, /*isAsyncIterator*/ !!asyncMethodType);
if (checkAssignability && errorNode && iteratedType) {
// If `checkAssignability` was specified, we were called from
// `checkIteratedTypeOrElementType`. As such, we need to validate that
// the type passed in is actually an Iterable.
checkTypeAssignableTo(type, asyncMethodType
? createAsyncIterableType(iteratedType)
: createIterableType(iteratedType), errorNode);
}
if (iteratedType) {
return allowAsyncIterables
? typeAsIterable.iteratedTypeOfAsyncIterable = asyncMethodType ? iteratedType : getAwaitedType(iteratedType)
: typeAsIterable.iteratedTypeOfIterable = iteratedType;
}
}
}
function reportTypeNotIterableError(errorNode: Node, type: Type, allowAsyncIterables: boolean): void {
error(errorNode, allowAsyncIterables
? Diagnostics.Type_0_must_have_a_Symbol_asyncIterator_method_that_returns_an_async_iterator
: Diagnostics.Type_0_must_have_a_Symbol_iterator_method_that_returns_an_iterator, typeToString(type));
}
/**
* This function has very similar logic as getIteratedTypeOfIterable, except that it operates on
* Iterators instead of Iterables. Here is the structure:
*
* { // iterator
* next: { // nextMethod
* (): { // nextResult
* value: T // nextValue
* }
* }
* }
*
* For an async iterator, we expect the following structure:
*
* { // iterator
* next: { // nextMethod
* (): PromiseLike<{ // nextResult
* value: T // nextValue
* }>
* }
* }
*/
function getIteratedTypeOfIterator(type: Type, errorNode: Node | undefined, isAsyncIterator: boolean): Type | undefined {
if (isTypeAny(type)) {
return undefined;
}
const typeAsIterator = <IterableOrIteratorType>type;
if (isAsyncIterator ? typeAsIterator.iteratedTypeOfAsyncIterator : typeAsIterator.iteratedTypeOfIterator) {
return isAsyncIterator ? typeAsIterator.iteratedTypeOfAsyncIterator : typeAsIterator.iteratedTypeOfIterator;
}
// As an optimization, if the type is an instantiation of the global `Iterator<T>` (for
// a non-async iterator) or the global `AsyncIterator<T>` (for an async-iterator) then
// just grab its type argument.
const getIteratorType = isAsyncIterator ? getGlobalAsyncIteratorType : getGlobalIteratorType;
if (isReferenceToType(type, getIteratorType(/*reportErrors*/ false))) {
return isAsyncIterator
? typeAsIterator.iteratedTypeOfAsyncIterator = (<GenericType>type).typeArguments![0]
: typeAsIterator.iteratedTypeOfIterator = (<GenericType>type).typeArguments![0];
}
// Both async and non-async iterators must have a `next` method.
const nextMethod = getTypeOfPropertyOfType(type, "next" as __String);
if (isTypeAny(nextMethod)) {
return undefined;
}
const nextMethodSignatures = nextMethod ? getSignaturesOfType(nextMethod, SignatureKind.Call) : emptyArray;
if (nextMethodSignatures.length === 0) {
if (errorNode) {
error(errorNode, isAsyncIterator
? Diagnostics.An_async_iterator_must_have_a_next_method
: Diagnostics.An_iterator_must_have_a_next_method);
}
return undefined;
}
let nextResult: Type | undefined = getUnionType(map(nextMethodSignatures, getReturnTypeOfSignature), UnionReduction.Subtype);
if (isTypeAny(nextResult)) {
return undefined;
}
// For an async iterator, we must get the awaited type of the return type.
if (isAsyncIterator) {
nextResult = getAwaitedTypeOfPromise(nextResult, errorNode, Diagnostics.The_type_returned_by_the_next_method_of_an_async_iterator_must_be_a_promise_for_a_type_with_a_value_property);
if (isTypeAny(nextResult)) {
return undefined;
}
}
const nextValue = nextResult && getTypeOfPropertyOfType(nextResult, "value" as __String);
if (!nextValue) {
if (errorNode) {
error(errorNode, isAsyncIterator
? Diagnostics.The_type_returned_by_the_next_method_of_an_async_iterator_must_be_a_promise_for_a_type_with_a_value_property
: Diagnostics.The_type_returned_by_the_next_method_of_an_iterator_must_have_a_value_property);
}
return undefined;
}
return isAsyncIterator
? typeAsIterator.iteratedTypeOfAsyncIterator = nextValue
: typeAsIterator.iteratedTypeOfIterator = nextValue;
}
/**
* A generator may have a return type of `Iterator<T>`, `Iterable<T>`, or
* `IterableIterator<T>`. An async generator may have a return type of `AsyncIterator<T>`,
* `AsyncIterable<T>`, or `AsyncIterableIterator<T>`. This function can be used to extract
* the iterated type from this return type for contextual typing and verifying signatures.
*/
function getIteratedTypeOfGenerator(returnType: Type, isAsyncGenerator: boolean): Type | undefined {
if (isTypeAny(returnType)) {
return undefined;
}
return getIteratedTypeOfIterable(returnType, /*errorNode*/ undefined, /*allowAsyncIterables*/ isAsyncGenerator, /*allowSyncIterables*/ !isAsyncGenerator, /*checkAssignability*/ false)
|| getIteratedTypeOfIterator(returnType, /*errorNode*/ undefined, isAsyncGenerator);
}
function checkBreakOrContinueStatement(node: BreakOrContinueStatement) {
// Grammar checking
if (!checkGrammarStatementInAmbientContext(node)) checkGrammarBreakOrContinueStatement(node);
// TODO: Check that target label is valid
}
function isUnwrappedReturnTypeVoidOrAny(func: SignatureDeclaration, returnType: Type): boolean {
const unwrappedReturnType = (getFunctionFlags(func) & FunctionFlags.AsyncGenerator) === FunctionFlags.Async
? getPromisedTypeOfPromise(returnType) // Async function
: returnType; // AsyncGenerator function, Generator function, or normal function
return !!unwrappedReturnType && maybeTypeOfKind(unwrappedReturnType, TypeFlags.Void | TypeFlags.AnyOrUnknown);
}
function checkReturnStatement(node: ReturnStatement) {
// Grammar checking
if (checkGrammarStatementInAmbientContext(node)) {
return;
}
const func = getContainingFunction(node);
if (!func) {
grammarErrorOnFirstToken(node, Diagnostics.A_return_statement_can_only_be_used_within_a_function_body);
return;
}
const signature = getSignatureFromDeclaration(func);
const returnType = getReturnTypeOfSignature(signature);
const functionFlags = getFunctionFlags(func);
const isGenerator = functionFlags & FunctionFlags.Generator;
if (strictNullChecks || node.expression || returnType.flags & TypeFlags.Never) {
const exprType = node.expression ? checkExpressionCached(node.expression) : undefinedType;
if (isGenerator) { // AsyncGenerator function or Generator function
// A generator does not need its return expressions checked against its return type.
// Instead, the yield expressions are checked against the element type.
// TODO: Check return types of generators when return type tracking is added
// for generators.
return;
}
else if (func.kind === SyntaxKind.SetAccessor) {
if (node.expression) {
error(node, Diagnostics.Setters_cannot_return_a_value);
}
}
else if (func.kind === SyntaxKind.Constructor) {
if (node.expression && !checkTypeAssignableToAndOptionallyElaborate(exprType, returnType, node, node.expression)) {
error(node, Diagnostics.Return_type_of_constructor_signature_must_be_assignable_to_the_instance_type_of_the_class);
}
}
else if (getReturnTypeFromAnnotation(func)) {
if (functionFlags & FunctionFlags.Async) { // Async function
const promisedType = getPromisedTypeOfPromise(returnType);
const awaitedType = checkAwaitedType(exprType, node, Diagnostics.The_return_type_of_an_async_function_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);
if (promisedType) {
// If the function has a return type, but promisedType is
// undefined, an error will be reported in checkAsyncFunctionReturnType
// so we don't need to report one here.
checkTypeAssignableTo(awaitedType, promisedType, node);
}
}
else {
checkTypeAssignableToAndOptionallyElaborate(exprType, returnType, node, node.expression);
}
}
}
else if (func.kind !== SyntaxKind.Constructor && compilerOptions.noImplicitReturns && !isUnwrappedReturnTypeVoidOrAny(func, returnType) && !isGenerator) {
// The function has a return type, but the return statement doesn't have an expression.
error(node, Diagnostics.Not_all_code_paths_return_a_value);
}
}
function checkWithStatement(node: WithStatement) {
// Grammar checking for withStatement
if (!checkGrammarStatementInAmbientContext(node)) {
if (node.flags & NodeFlags.AwaitContext) {
grammarErrorOnFirstToken(node, Diagnostics.with_statements_are_not_allowed_in_an_async_function_block);
}
}
checkExpression(node.expression);
const sourceFile = getSourceFileOfNode(node);
if (!hasParseDiagnostics(sourceFile)) {
const start = getSpanOfTokenAtPosition(sourceFile, node.pos).start;
const end = node.statement.pos;
grammarErrorAtPos(sourceFile, start, end - start, Diagnostics.The_with_statement_is_not_supported_All_symbols_in_a_with_block_will_have_type_any);
}
}
function checkSwitchStatement(node: SwitchStatement) {
// Grammar checking
checkGrammarStatementInAmbientContext(node);
let firstDefaultClause: CaseOrDefaultClause;
let hasDuplicateDefaultClause = false;
const expressionType = checkExpression(node.expression);
const expressionIsLiteral = isLiteralType(expressionType);
forEach(node.caseBlock.clauses, clause => {
// Grammar check for duplicate default clauses, skip if we already report duplicate default clause
if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
if (firstDefaultClause === undefined) {
firstDefaultClause = clause;
}
else {
const sourceFile = getSourceFileOfNode(node);
const start = skipTrivia(sourceFile.text, clause.pos);
const end = clause.statements.length > 0 ? clause.statements[0].pos : clause.end;
grammarErrorAtPos(sourceFile, start, end - start, Diagnostics.A_default_clause_cannot_appear_more_than_once_in_a_switch_statement);
hasDuplicateDefaultClause = true;
}
}
if (produceDiagnostics && clause.kind === SyntaxKind.CaseClause) {
// TypeScript 1.0 spec (April 2014): 5.9
// In a 'switch' statement, each 'case' expression must be of a type that is comparable
// to or from the type of the 'switch' expression.
let caseType = checkExpression(clause.expression);
const caseIsLiteral = isLiteralType(caseType);
let comparedExpressionType = expressionType;
if (!caseIsLiteral || !expressionIsLiteral) {
caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
comparedExpressionType = getBaseTypeOfLiteralType(expressionType);
}
if (!isTypeEqualityComparableTo(comparedExpressionType, caseType)) {
// expressionType is not comparable to caseType, try the reversed check and report errors if it fails
checkTypeComparableTo(caseType, comparedExpressionType, clause.expression, /*headMessage*/ undefined);
}
}
forEach(clause.statements, checkSourceElement);
});
if (node.caseBlock.locals) {
registerForUnusedIdentifiersCheck(node.caseBlock);
}
}
function checkLabeledStatement(node: LabeledStatement) {
// Grammar checking
if (!checkGrammarStatementInAmbientContext(node)) {
findAncestor(node.parent,
current => {
if (isFunctionLike(current)) {
return "quit";
}
if (current.kind === SyntaxKind.LabeledStatement && (<LabeledStatement>current).label.escapedText === node.label.escapedText) {
grammarErrorOnNode(node.label, Diagnostics.Duplicate_label_0, getTextOfNode(node.label));
return true;
}
return false;
});
}
// ensure that label is unique
checkSourceElement(node.statement);
}
function checkThrowStatement(node: ThrowStatement) {
// Grammar checking
if (!checkGrammarStatementInAmbientContext(node)) {
if (node.expression === undefined) {
grammarErrorAfterFirstToken(node, Diagnostics.Line_break_not_permitted_here);
}
}
if (node.expression) {
checkExpression(node.expression);
}
}
function checkTryStatement(node: TryStatement) {
// Grammar checking
checkGrammarStatementInAmbientContext(node);
checkBlock(node.tryBlock);
const catchClause = node.catchClause;
if (catchClause) {
// Grammar checking
if (catchClause.variableDeclaration) {
if (catchClause.variableDeclaration.type) {
grammarErrorOnFirstToken(catchClause.variableDeclaration.type, Diagnostics.Catch_clause_variable_cannot_have_a_type_annotation);
}
else if (catchClause.variableDeclaration.initializer) {
grammarErrorOnFirstToken(catchClause.variableDeclaration.initializer, Diagnostics.Catch_clause_variable_cannot_have_an_initializer);
}
else {
const blockLocals = catchClause.block.locals;
if (blockLocals) {
forEachKey(catchClause.locals!, caughtName => {
const blockLocal = blockLocals.get(caughtName);
if (blockLocal && (blockLocal.flags & SymbolFlags.BlockScopedVariable) !== 0) {
grammarErrorOnNode(blockLocal.valueDeclaration, Diagnostics.Cannot_redeclare_identifier_0_in_catch_clause, caughtName);
}
});
}
}
}
checkBlock(catchClause.block);
}
if (node.finallyBlock) {
checkBlock(node.finallyBlock);
}
}
function checkIndexConstraints(type: Type) {
const declaredNumberIndexer = getIndexDeclarationOfSymbol(type.symbol, IndexKind.Number);
const declaredStringIndexer = getIndexDeclarationOfSymbol(type.symbol, IndexKind.String);
const stringIndexType = getIndexTypeOfType(type, IndexKind.String);
const numberIndexType = getIndexTypeOfType(type, IndexKind.Number);
if (stringIndexType || numberIndexType) {
forEach(getPropertiesOfObjectType(type), prop => {
const propType = getTypeOfSymbol(prop);
checkIndexConstraintForProperty(prop, propType, type, declaredStringIndexer, stringIndexType, IndexKind.String);
checkIndexConstraintForProperty(prop, propType, type, declaredNumberIndexer, numberIndexType, IndexKind.Number);
});
const classDeclaration = type.symbol.valueDeclaration;
if (getObjectFlags(type) & ObjectFlags.Class && isClassLike(classDeclaration)) {
for (const member of classDeclaration.members) {
// Only process instance properties with computed names here.
// Static properties cannot be in conflict with indexers,
// and properties with literal names were already checked.
if (!hasModifier(member, ModifierFlags.Static) && hasNonBindableDynamicName(member)) {
const symbol = getSymbolOfNode(member);
const propType = getTypeOfSymbol(symbol);
checkIndexConstraintForProperty(symbol, propType, type, declaredStringIndexer, stringIndexType, IndexKind.String);
checkIndexConstraintForProperty(symbol, propType, type, declaredNumberIndexer, numberIndexType, IndexKind.Number);
}
}
}
}
let errorNode: Node | undefined;
if (stringIndexType && numberIndexType) {
errorNode = declaredNumberIndexer || declaredStringIndexer;
// condition 'errorNode === undefined' may appear if types does not declare nor string neither number indexer
if (!errorNode && (getObjectFlags(type) & ObjectFlags.Interface)) {
const someBaseTypeHasBothIndexers = forEach(getBaseTypes(<InterfaceType>type), base => getIndexTypeOfType(base, IndexKind.String) && getIndexTypeOfType(base, IndexKind.Number));
errorNode = someBaseTypeHasBothIndexers ? undefined : type.symbol.declarations[0];
}
}
if (errorNode && !isTypeAssignableTo(numberIndexType!, stringIndexType!)) { // TODO: GH#18217
error(errorNode, Diagnostics.Numeric_index_type_0_is_not_assignable_to_string_index_type_1,
typeToString(numberIndexType!), typeToString(stringIndexType!));
}
function checkIndexConstraintForProperty(
prop: Symbol,
propertyType: Type,
containingType: Type,
indexDeclaration: Declaration | undefined,
indexType: Type | undefined,
indexKind: IndexKind): void {
// ESSymbol properties apply to neither string nor numeric indexers.
if (!indexType || isKnownSymbol(prop)) {
return;
}
const propDeclaration = prop.valueDeclaration;
const name = propDeclaration && getNameOfDeclaration(propDeclaration);
// index is numeric and property name is not valid numeric literal
if (indexKind === IndexKind.Number && !(name ? isNumericName(name) : isNumericLiteralName(prop.escapedName))) {
return;
}
// perform property check if property or indexer is declared in 'type'
// this allows us to rule out cases when both property and indexer are inherited from the base class
let errorNode: Node | undefined;
if (propDeclaration && name &&
(propDeclaration.kind === SyntaxKind.BinaryExpression ||
name.kind === SyntaxKind.ComputedPropertyName ||
prop.parent === containingType.symbol)) {
errorNode = propDeclaration;
}
else if (indexDeclaration) {
errorNode = indexDeclaration;
}
else if (getObjectFlags(containingType) & ObjectFlags.Interface) {
// for interfaces property and indexer might be inherited from different bases
// check if any base class already has both property and indexer.
// check should be performed only if 'type' is the first type that brings property\indexer together
const someBaseClassHasBothPropertyAndIndexer = forEach(getBaseTypes(<InterfaceType>containingType), base => getPropertyOfObjectType(base, prop.escapedName) && getIndexTypeOfType(base, indexKind));
errorNode = someBaseClassHasBothPropertyAndIndexer ? undefined : containingType.symbol.declarations[0];
}
if (errorNode && !isTypeAssignableTo(propertyType, indexType)) {
const errorMessage =
indexKind === IndexKind.String
? Diagnostics.Property_0_of_type_1_is_not_assignable_to_string_index_type_2
: Diagnostics.Property_0_of_type_1_is_not_assignable_to_numeric_index_type_2;
error(errorNode, errorMessage, symbolToString(prop), typeToString(propertyType), typeToString(indexType));
}
}
}
function checkTypeNameIsReserved(name: Identifier, message: DiagnosticMessage): void {
// TS 1.0 spec (April 2014): 3.6.1
// The predefined type keywords are reserved and cannot be used as names of user defined types.
switch (name.escapedText) {
case "any":
case "unknown":
case "number":
case "bigint":
case "boolean":
case "string":
case "symbol":
case "void":
case "object":
error(name, message, name.escapedText as string);
}
}
/**
* The name cannot be used as 'Object' of user defined types with special target.
*/
function checkClassNameCollisionWithObject(name: Identifier): void {
if (languageVersion === ScriptTarget.ES5 && name.escapedText === "Object"
&& moduleKind !== ModuleKind.ES2015 && moduleKind !== ModuleKind.ESNext) {
error(name, Diagnostics.Class_name_cannot_be_Object_when_targeting_ES5_with_module_0, ModuleKind[moduleKind]); // https://github.com/Microsoft/TypeScript/issues/17494
}
}
/**
* Check each type parameter and check that type parameters have no duplicate type parameter declarations
*/
function checkTypeParameters(typeParameterDeclarations: ReadonlyArray<TypeParameterDeclaration> | undefined) {
if (typeParameterDeclarations) {
let seenDefault = false;
for (let i = 0; i < typeParameterDeclarations.length; i++) {
const node = typeParameterDeclarations[i];
checkTypeParameter(node);
if (produceDiagnostics) {
if (node.default) {
seenDefault = true;
checkTypeParametersNotReferenced(node.default, typeParameterDeclarations, i);
}
else if (seenDefault) {
error(node, Diagnostics.Required_type_parameters_may_not_follow_optional_type_parameters);
}
for (let j = 0; j < i; j++) {
if (typeParameterDeclarations[j].symbol === node.symbol) {
error(node.name, Diagnostics.Duplicate_identifier_0, declarationNameToString(node.name));
}
}
}
}
}
}
/** Check that type parameter defaults only reference previously declared type parameters */
function checkTypeParametersNotReferenced(root: TypeNode, typeParameters: ReadonlyArray<TypeParameterDeclaration>, index: number) {
visit(root);
function visit(node: Node) {
if (node.kind === SyntaxKind.TypeReference) {
const type = getTypeFromTypeReference(<TypeReferenceNode>node);
if (type.flags & TypeFlags.TypeParameter) {
for (let i = index; i < typeParameters.length; i++) {
if (type.symbol === getSymbolOfNode(typeParameters[i])) {
error(node, Diagnostics.Type_parameter_defaults_can_only_reference_previously_declared_type_parameters);
}
}
}
}
forEachChild(node, visit);
}
}
/** Check that type parameter lists are identical across multiple declarations */
function checkTypeParameterListsIdentical(symbol: Symbol) {
if (symbol.declarations.length === 1) {
return;
}
const links = getSymbolLinks(symbol);
if (!links.typeParametersChecked) {
links.typeParametersChecked = true;
const declarations = getClassOrInterfaceDeclarationsOfSymbol(symbol);
if (declarations.length <= 1) {
return;
}
const type = <InterfaceType>getDeclaredTypeOfSymbol(symbol);
if (!areTypeParametersIdentical(declarations, type.localTypeParameters!)) {
// Report an error on every conflicting declaration.
const name = symbolToString(symbol);
for (const declaration of declarations) {
error(declaration.name, Diagnostics.All_declarations_of_0_must_have_identical_type_parameters, name);
}
}
}
}
function areTypeParametersIdentical(declarations: ReadonlyArray<ClassDeclaration | InterfaceDeclaration>, targetParameters: TypeParameter[]) {
const maxTypeArgumentCount = length(targetParameters);
const minTypeArgumentCount = getMinTypeArgumentCount(targetParameters);
for (const declaration of declarations) {
// If this declaration has too few or too many type parameters, we report an error
const sourceParameters = getEffectiveTypeParameterDeclarations(declaration);
const numTypeParameters = sourceParameters.length;
if (numTypeParameters < minTypeArgumentCount || numTypeParameters > maxTypeArgumentCount) {
return false;
}
for (let i = 0; i < numTypeParameters; i++) {
const source = sourceParameters[i];
const target = targetParameters[i];
// If the type parameter node does not have the same as the resolved type
// parameter at this position, we report an error.
if (source.name.escapedText !== target.symbol.escapedName) {
return false;
}
// If the type parameter node does not have an identical constraint as the resolved
// type parameter at this position, we report an error.
const constraint = getEffectiveConstraintOfTypeParameter(source);
const sourceConstraint = constraint && getTypeFromTypeNode(constraint);
const targetConstraint = getConstraintOfTypeParameter(target);
if (sourceConstraint) {
// relax check if later interface augmentation has no constraint
if (!targetConstraint || !isTypeIdenticalTo(sourceConstraint, targetConstraint)) {
return false;
}
}
// If the type parameter node has a default and it is not identical to the default
// for the type parameter at this position, we report an error.
const sourceDefault = source.default && getTypeFromTypeNode(source.default);
const targetDefault = getDefaultFromTypeParameter(target);
if (sourceDefault && targetDefault && !isTypeIdenticalTo(sourceDefault, targetDefault)) {
return false;
}
}
}
return true;
}
function checkClassExpression(node: ClassExpression): Type {
checkClassLikeDeclaration(node);
checkNodeDeferred(node);
return getTypeOfSymbol(getSymbolOfNode(node));
}
function checkClassExpressionDeferred(node: ClassExpression) {
forEach(node.members, checkSourceElement);
registerForUnusedIdentifiersCheck(node);
}
function checkClassDeclaration(node: ClassDeclaration) {
if (!node.name && !hasModifier(node, ModifierFlags.Default)) {
grammarErrorOnFirstToken(node, Diagnostics.A_class_declaration_without_the_default_modifier_must_have_a_name);
}
checkClassLikeDeclaration(node);
forEach(node.members, checkSourceElement);
registerForUnusedIdentifiersCheck(node);
}
function checkClassLikeDeclaration(node: ClassLikeDeclaration) {
checkGrammarClassLikeDeclaration(node);
checkDecorators(node);
if (node.name) {
checkTypeNameIsReserved(node.name, Diagnostics.Class_name_cannot_be_0);
checkCollisionWithRequireExportsInGeneratedCode(node, node.name);
checkCollisionWithGlobalPromiseInGeneratedCode(node, node.name);
if (!(node.flags & NodeFlags.Ambient)) {
checkClassNameCollisionWithObject(node.name);
}
}
checkTypeParameters(getEffectiveTypeParameterDeclarations(node));
checkExportsOnMergedDeclarations(node);
const symbol = getSymbolOfNode(node);
const type = <InterfaceType>getDeclaredTypeOfSymbol(symbol);
const typeWithThis = getTypeWithThisArgument(type);
const staticType = <ObjectType>getTypeOfSymbol(symbol);
checkTypeParameterListsIdentical(symbol);
checkClassForDuplicateDeclarations(node);
// Only check for reserved static identifiers on non-ambient context.
if (!(node.flags & NodeFlags.Ambient)) {
checkClassForStaticPropertyNameConflicts(node);
}
const baseTypeNode = getEffectiveBaseTypeNode(node);
if (baseTypeNode) {
if (languageVersion < ScriptTarget.ES2015) {
checkExternalEmitHelpers(baseTypeNode.parent, ExternalEmitHelpers.Extends);
}
const baseTypes = getBaseTypes(type);
if (baseTypes.length && produceDiagnostics) {
const baseType = baseTypes[0];
const baseConstructorType = getBaseConstructorTypeOfClass(type);
const staticBaseType = getApparentType(baseConstructorType);
checkBaseTypeAccessibility(staticBaseType, baseTypeNode);
checkSourceElement(baseTypeNode.expression);
const extendsNode = getClassExtendsHeritageElement(node);
if (extendsNode && extendsNode !== baseTypeNode) {
checkExpression(extendsNode.expression);
}
if (some(baseTypeNode.typeArguments)) {
forEach(baseTypeNode.typeArguments, checkSourceElement);
for (const constructor of getConstructorsForTypeArguments(staticBaseType, baseTypeNode.typeArguments, baseTypeNode)) {
if (!checkTypeArgumentConstraints(baseTypeNode, constructor.typeParameters!)) {
break;
}
}
}
const baseWithThis = getTypeWithThisArgument(baseType, type.thisType);
if (!checkTypeAssignableTo(typeWithThis, baseWithThis, /*errorNode*/ undefined)) {
issueMemberSpecificError(node, typeWithThis, baseWithThis, Diagnostics.Class_0_incorrectly_extends_base_class_1);
}
else {
// Report static side error only when instance type is assignable
checkTypeAssignableTo(staticType, getTypeWithoutSignatures(staticBaseType), node.name || node,
Diagnostics.Class_static_side_0_incorrectly_extends_base_class_static_side_1);
}
if (baseConstructorType.flags & TypeFlags.TypeVariable && !isMixinConstructorType(staticType)) {
error(node.name || node, Diagnostics.A_mixin_class_must_have_a_constructor_with_a_single_rest_parameter_of_type_any);
}
if (!(staticBaseType.symbol && staticBaseType.symbol.flags & SymbolFlags.Class) && !(baseConstructorType.flags & TypeFlags.TypeVariable)) {
// When the static base type is a "class-like" constructor function (but not actually a class), we verify
// that all instantiated base constructor signatures return the same type. We can simply compare the type
// references (as opposed to checking the structure of the types) because elsewhere we have already checked
// that the base type is a class or interface type (and not, for example, an anonymous object type).
// (Javascript constructor functions have this property trivially true since their return type is ignored.)
const constructors = getInstantiatedConstructorsForTypeArguments(staticBaseType, baseTypeNode.typeArguments, baseTypeNode);
if (forEach(constructors, sig => !isJSConstructor(sig.declaration) && getReturnTypeOfSignature(sig) !== baseType)) {
error(baseTypeNode.expression, Diagnostics.Base_constructors_must_all_have_the_same_return_type);
}
}
checkKindsOfPropertyMemberOverrides(type, baseType);
}
}
const implementedTypeNodes = getClassImplementsHeritageClauseElements(node);
if (implementedTypeNodes) {
for (const typeRefNode of implementedTypeNodes) {
if (!isEntityNameExpression(typeRefNode.expression)) {
error(typeRefNode.expression, Diagnostics.A_class_can_only_implement_an_identifier_Slashqualified_name_with_optional_type_arguments);
}
checkTypeReferenceNode(typeRefNode);
if (produceDiagnostics) {
const t = getTypeFromTypeNode(typeRefNode);
if (t !== errorType) {
if (isValidBaseType(t)) {
const genericDiag = t.symbol && t.symbol.flags & SymbolFlags.Class ?
Diagnostics.Class_0_incorrectly_implements_class_1_Did_you_mean_to_extend_1_and_inherit_its_members_as_a_subclass :
Diagnostics.Class_0_incorrectly_implements_interface_1;
const baseWithThis = getTypeWithThisArgument(t, type.thisType);
if (!checkTypeAssignableTo(typeWithThis, baseWithThis, /*errorNode*/ undefined)) {
issueMemberSpecificError(node, typeWithThis, baseWithThis, genericDiag);
}
}
else {
error(typeRefNode, Diagnostics.A_class_can_only_implement_an_object_type_or_intersection_of_object_types_with_statically_known_members);
}
}
}
}
}
if (produceDiagnostics) {
checkIndexConstraints(type);
checkTypeForDuplicateIndexSignatures(node);
checkPropertyInitialization(node);
}
}
function issueMemberSpecificError(node: ClassLikeDeclaration, typeWithThis: Type, baseWithThis: Type, broadDiag: DiagnosticMessage) {
// iterate over all implemented properties and issue errors on each one which isn't compatible, rather than the class as a whole, if possible
let issuedMemberError = false;
for (const member of node.members) {
if (hasStaticModifier(member)) {
continue;
}
const declaredProp = member.name && getSymbolAtLocation(member.name) || getSymbolAtLocation(member);
if (declaredProp) {
const prop = getPropertyOfType(typeWithThis, declaredProp.escapedName);
const baseProp = getPropertyOfType(baseWithThis, declaredProp.escapedName);
if (prop && baseProp) {
const rootChain = () => chainDiagnosticMessages(
/*details*/ undefined,
Diagnostics.Property_0_in_type_1_is_not_assignable_to_the_same_property_in_base_type_2,
symbolToString(declaredProp),
typeToString(typeWithThis),
typeToString(baseWithThis)
);
if (!checkTypeAssignableTo(getTypeOfSymbol(prop), getTypeOfSymbol(baseProp), member.name || member, /*message*/ undefined, rootChain)) {
issuedMemberError = true;
}
}
}
}
if (!issuedMemberError) {
// check again with diagnostics to generate a less-specific error
checkTypeAssignableTo(typeWithThis, baseWithThis, node.name || node, broadDiag);
}
}
function checkBaseTypeAccessibility(type: Type, node: ExpressionWithTypeArguments) {
const signatures = getSignaturesOfType(type, SignatureKind.Construct);
if (signatures.length) {
const declaration = signatures[0].declaration;
if (declaration && hasModifier(declaration, ModifierFlags.Private)) {
const typeClassDeclaration = getClassLikeDeclarationOfSymbol(type.symbol)!;
if (!isNodeWithinClass(node, typeClassDeclaration)) {
error(node, Diagnostics.Cannot_extend_a_class_0_Class_constructor_is_marked_as_private, getFullyQualifiedName(type.symbol));
}
}
}
}
function getTargetSymbol(s: Symbol) {
// if symbol is instantiated its flags are not copied from the 'target'
// so we'll need to get back original 'target' symbol to work with correct set of flags
return getCheckFlags(s) & CheckFlags.Instantiated ? (<TransientSymbol>s).target! : s;
}
function getClassOrInterfaceDeclarationsOfSymbol(symbol: Symbol) {
return filter(symbol.declarations, (d: Declaration): d is ClassDeclaration | InterfaceDeclaration =>
d.kind === SyntaxKind.ClassDeclaration || d.kind === SyntaxKind.InterfaceDeclaration);
}
function checkKindsOfPropertyMemberOverrides(type: InterfaceType, baseType: BaseType): void {
// TypeScript 1.0 spec (April 2014): 8.2.3
// A derived class inherits all members from its base class it doesn't override.
// Inheritance means that a derived class implicitly contains all non - overridden members of the base class.
// Both public and private property members are inherited, but only public property members can be overridden.
// A property member in a derived class is said to override a property member in a base class
// when the derived class property member has the same name and kind(instance or static)
// as the base class property member.
// The type of an overriding property member must be assignable(section 3.8.4)
// to the type of the overridden property member, or otherwise a compile - time error occurs.
// Base class instance member functions can be overridden by derived class instance member functions,
// but not by other kinds of members.
// Base class instance member variables and accessors can be overridden by
// derived class instance member variables and accessors, but not by other kinds of members.
// NOTE: assignability is checked in checkClassDeclaration
const baseProperties = getPropertiesOfType(baseType);
for (const baseProperty of baseProperties) {
const base = getTargetSymbol(baseProperty);
if (base.flags & SymbolFlags.Prototype) {
continue;
}
const derived = getTargetSymbol(getPropertyOfObjectType(type, base.escapedName)!); // TODO: GH#18217
const baseDeclarationFlags = getDeclarationModifierFlagsFromSymbol(base);
Debug.assert(!!derived, "derived should point to something, even if it is the base class' declaration.");
if (derived) {
// In order to resolve whether the inherited method was overridden in the base class or not,
// we compare the Symbols obtained. Since getTargetSymbol returns the symbol on the *uninstantiated*
// type declaration, derived and base resolve to the same symbol even in the case of generic classes.
if (derived === base) {
// derived class inherits base without override/redeclaration
const derivedClassDecl = getClassLikeDeclarationOfSymbol(type.symbol)!;
// It is an error to inherit an abstract member without implementing it or being declared abstract.
// If there is no declaration for the derived class (as in the case of class expressions),
// then the class cannot be declared abstract.
if (baseDeclarationFlags & ModifierFlags.Abstract && (!derivedClassDecl || !hasModifier(derivedClassDecl, ModifierFlags.Abstract))) {
if (derivedClassDecl.kind === SyntaxKind.ClassExpression) {
error(derivedClassDecl, Diagnostics.Non_abstract_class_expression_does_not_implement_inherited_abstract_member_0_from_class_1,
symbolToString(baseProperty), typeToString(baseType));
}
else {
error(derivedClassDecl, Diagnostics.Non_abstract_class_0_does_not_implement_inherited_abstract_member_1_from_class_2,
typeToString(type), symbolToString(baseProperty), typeToString(baseType));
}
}
}
else {
// derived overrides base.
const derivedDeclarationFlags = getDeclarationModifierFlagsFromSymbol(derived);
if (baseDeclarationFlags & ModifierFlags.Private || derivedDeclarationFlags & ModifierFlags.Private) {
// either base or derived property is private - not override, skip it
continue;
}
if (isPrototypeProperty(base) || base.flags & SymbolFlags.PropertyOrAccessor && derived.flags & SymbolFlags.PropertyOrAccessor) {
// method is overridden with method or property/accessor is overridden with property/accessor - correct case
continue;
}
let errorMessage: DiagnosticMessage;
if (isPrototypeProperty(base)) {
if (derived.flags & SymbolFlags.Accessor) {
errorMessage = Diagnostics.Class_0_defines_instance_member_function_1_but_extended_class_2_defines_it_as_instance_member_accessor;
}
else {
errorMessage = Diagnostics.Class_0_defines_instance_member_function_1_but_extended_class_2_defines_it_as_instance_member_property;
}
}
else if (base.flags & SymbolFlags.Accessor) {
errorMessage = Diagnostics.Class_0_defines_instance_member_accessor_1_but_extended_class_2_defines_it_as_instance_member_function;
}
else {
errorMessage = Diagnostics.Class_0_defines_instance_member_property_1_but_extended_class_2_defines_it_as_instance_member_function;
}
error(getNameOfDeclaration(derived.valueDeclaration) || derived.valueDeclaration, errorMessage, typeToString(baseType), symbolToString(base), typeToString(type));
}
}
}
}
function checkInheritedPropertiesAreIdentical(type: InterfaceType, typeNode: Node): boolean {
const baseTypes = getBaseTypes(type);
if (baseTypes.length < 2) {
return true;
}
interface InheritanceInfoMap { prop: Symbol; containingType: Type; }
const seen = createUnderscoreEscapedMap<InheritanceInfoMap>();
forEach(resolveDeclaredMembers(type).declaredProperties, p => { seen.set(p.escapedName, { prop: p, containingType: type }); });
let ok = true;
for (const base of baseTypes) {
const properties = getPropertiesOfType(getTypeWithThisArgument(base, type.thisType));
for (const prop of properties) {
const existing = seen.get(prop.escapedName);
if (!existing) {
seen.set(prop.escapedName, { prop, containingType: base });
}
else {
const isInheritedProperty = existing.containingType !== type;
if (isInheritedProperty && !isPropertyIdenticalTo(existing.prop, prop)) {
ok = false;
const typeName1 = typeToString(existing.containingType);
const typeName2 = typeToString(base);
let errorInfo = chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Named_property_0_of_types_1_and_2_are_not_identical, symbolToString(prop), typeName1, typeName2);
errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Interface_0_cannot_simultaneously_extend_types_1_and_2, typeToString(type), typeName1, typeName2);
diagnostics.add(createDiagnosticForNodeFromMessageChain(typeNode, errorInfo));
}
}
}
}
return ok;
}
function checkPropertyInitialization(node: ClassLikeDeclaration) {
if (!strictNullChecks || !strictPropertyInitialization || node.flags & NodeFlags.Ambient) {
return;
}
const constructor = findConstructorDeclaration(node);
for (const member of node.members) {
if (isInstancePropertyWithoutInitializer(member)) {
const propName = (<PropertyDeclaration>member).name;
if (isIdentifier(propName)) {
const type = getTypeOfSymbol(getSymbolOfNode(member));
if (!(type.flags & TypeFlags.AnyOrUnknown || getFalsyFlags(type) & TypeFlags.Undefined)) {
if (!constructor || !isPropertyInitializedInConstructor(propName, type, constructor)) {
error(member.name, Diagnostics.Property_0_has_no_initializer_and_is_not_definitely_assigned_in_the_constructor, declarationNameToString(propName));
}
}
}
}
}
}
function isInstancePropertyWithoutInitializer(node: Node) {
return node.kind === SyntaxKind.PropertyDeclaration &&
!hasModifier(node, ModifierFlags.Static | ModifierFlags.Abstract) &&
!(<PropertyDeclaration>node).exclamationToken &&
!(<PropertyDeclaration>node).initializer;
}
function isPropertyInitializedInConstructor(propName: Identifier, propType: Type, constructor: ConstructorDeclaration) {
const reference = createPropertyAccess(createThis(), propName);
reference.expression.parent = reference;
reference.parent = constructor;
reference.flowNode = constructor.returnFlowNode;
const flowType = getFlowTypeOfReference(reference, propType, getOptionalType(propType));
return !(getFalsyFlags(flowType) & TypeFlags.Undefined);
}
function checkInterfaceDeclaration(node: InterfaceDeclaration) {
// Grammar checking
if (!checkGrammarDecoratorsAndModifiers(node)) checkGrammarInterfaceDeclaration(node);
checkTypeParameters(node.typeParameters);
if (produceDiagnostics) {
checkTypeNameIsReserved(node.name, Diagnostics.Interface_name_cannot_be_0);
checkExportsOnMergedDeclarations(node);
const symbol = getSymbolOfNode(node);
checkTypeParameterListsIdentical(symbol);
// Only check this symbol once
const firstInterfaceDecl = getDeclarationOfKind<InterfaceDeclaration>(symbol, SyntaxKind.InterfaceDeclaration);
if (node === firstInterfaceDecl) {
const type = <InterfaceType>getDeclaredTypeOfSymbol(symbol);
const typeWithThis = getTypeWithThisArgument(type);
// run subsequent checks only if first set succeeded
if (checkInheritedPropertiesAreIdentical(type, node.name)) {
for (const baseType of getBaseTypes(type)) {
checkTypeAssignableTo(typeWithThis, getTypeWithThisArgument(baseType, type.thisType), node.name, Diagnostics.Interface_0_incorrectly_extends_interface_1);
}
checkIndexConstraints(type);
}
}
checkObjectTypeForDuplicateDeclarations(node);
}
forEach(getInterfaceBaseTypeNodes(node), heritageElement => {
if (!isEntityNameExpression(heritageElement.expression)) {
error(heritageElement.expression, Diagnostics.An_interface_can_only_extend_an_identifier_Slashqualified_name_with_optional_type_arguments);
}
checkTypeReferenceNode(heritageElement);
});
forEach(node.members, checkSourceElement);
if (produceDiagnostics) {
checkTypeForDuplicateIndexSignatures(node);
registerForUnusedIdentifiersCheck(node);
}
}
function checkTypeAliasDeclaration(node: TypeAliasDeclaration) {
// Grammar checking
checkGrammarDecoratorsAndModifiers(node);
checkTypeNameIsReserved(node.name, Diagnostics.Type_alias_name_cannot_be_0);
checkTypeParameters(node.typeParameters);
checkSourceElement(node.type);
registerForUnusedIdentifiersCheck(node);
}
function computeEnumMemberValues(node: EnumDeclaration) {
const nodeLinks = getNodeLinks(node);
if (!(nodeLinks.flags & NodeCheckFlags.EnumValuesComputed)) {
nodeLinks.flags |= NodeCheckFlags.EnumValuesComputed;
let autoValue: number | undefined = 0;
for (const member of node.members) {
const value = computeMemberValue(member, autoValue);
getNodeLinks(member).enumMemberValue = value;
autoValue = typeof value === "number" ? value + 1 : undefined;
}
}
}
function computeMemberValue(member: EnumMember, autoValue: number | undefined) {
if (isComputedNonLiteralName(member.name)) {
error(member.name, Diagnostics.Computed_property_names_are_not_allowed_in_enums);
}
else {
const text = getTextOfPropertyName(member.name);
if (isNumericLiteralName(text) && !isInfinityOrNaNString(text)) {
error(member.name, Diagnostics.An_enum_member_cannot_have_a_numeric_name);
}
}
if (member.initializer) {
return computeConstantValue(member);
}
// In ambient enum declarations that specify no const modifier, enum member declarations that omit
// a value are considered computed members (as opposed to having auto-incremented values).
if (member.parent.flags & NodeFlags.Ambient && !isEnumConst(member.parent)) {
return undefined;
}
// If the member declaration specifies no value, the member is considered a constant enum member.
// If the member is the first member in the enum declaration, it is assigned the value zero.
// Otherwise, it is assigned the value of the immediately preceding member plus one, and an error
// occurs if the immediately preceding member is not a constant enum member.
if (autoValue !== undefined) {
return autoValue;
}
error(member.name, Diagnostics.Enum_member_must_have_initializer);
return undefined;
}
function computeConstantValue(member: EnumMember): string | number | undefined {
const enumKind = getEnumKind(getSymbolOfNode(member.parent));
const isConstEnum = isEnumConst(member.parent);
const initializer = member.initializer!;
const value = enumKind === EnumKind.Literal && !isLiteralEnumMember(member) ? undefined : evaluate(initializer);
if (value !== undefined) {
if (isConstEnum && typeof value === "number" && !isFinite(value)) {
error(initializer, isNaN(value) ?
Diagnostics.const_enum_member_initializer_was_evaluated_to_disallowed_value_NaN :
Diagnostics.const_enum_member_initializer_was_evaluated_to_a_non_finite_value);
}
}
else if (enumKind === EnumKind.Literal) {
error(initializer, Diagnostics.Computed_values_are_not_permitted_in_an_enum_with_string_valued_members);
return 0;
}
else if (isConstEnum) {
error(initializer, Diagnostics.const_enum_member_initializers_can_only_contain_literal_values_and_other_computed_enum_values);
}
else if (member.parent.flags & NodeFlags.Ambient) {
error(initializer, Diagnostics.In_ambient_enum_declarations_member_initializer_must_be_constant_expression);
}
else {
// Only here do we need to check that the initializer is assignable to the enum type.
checkTypeAssignableTo(checkExpression(initializer), getDeclaredTypeOfSymbol(getSymbolOfNode(member.parent)), initializer, /*headMessage*/ undefined);
}
return value;
function evaluate(expr: Expression): string | number | undefined {
switch (expr.kind) {
case SyntaxKind.PrefixUnaryExpression:
const value = evaluate((<PrefixUnaryExpression>expr).operand);
if (typeof value === "number") {
switch ((<PrefixUnaryExpression>expr).operator) {
case SyntaxKind.PlusToken: return value;
case SyntaxKind.MinusToken: return -value;
case SyntaxKind.TildeToken: return ~value;
}
}
break;
case SyntaxKind.BinaryExpression:
const left = evaluate((<BinaryExpression>expr).left);
const right = evaluate((<BinaryExpression>expr).right);
if (typeof left === "number" && typeof right === "number") {
switch ((<BinaryExpression>expr).operatorToken.kind) {
case SyntaxKind.BarToken: return left | right;
case SyntaxKind.AmpersandToken: return left & right;
case SyntaxKind.GreaterThanGreaterThanToken: return left >> right;
case SyntaxKind.GreaterThanGreaterThanGreaterThanToken: return left >>> right;
case SyntaxKind.LessThanLessThanToken: return left << right;
case SyntaxKind.CaretToken: return left ^ right;
case SyntaxKind.AsteriskToken: return left * right;
case SyntaxKind.SlashToken: return left / right;
case SyntaxKind.PlusToken: return left + right;
case SyntaxKind.MinusToken: return left - right;
case SyntaxKind.PercentToken: return left % right;
case SyntaxKind.AsteriskAsteriskToken: return left ** right;
}
}
else if (typeof left === "string" && typeof right === "string" && (<BinaryExpression>expr).operatorToken.kind === SyntaxKind.PlusToken) {
return left + right;
}
break;
case SyntaxKind.StringLiteral:
return (<StringLiteral>expr).text;
case SyntaxKind.NumericLiteral:
checkGrammarNumericLiteral(<NumericLiteral>expr);
return +(<NumericLiteral>expr).text;
case SyntaxKind.ParenthesizedExpression:
return evaluate((<ParenthesizedExpression>expr).expression);
case SyntaxKind.Identifier:
const identifier = <Identifier>expr;
if (isInfinityOrNaNString(identifier.escapedText)) {
return +(identifier.escapedText);
}
return nodeIsMissing(expr) ? 0 : evaluateEnumMember(expr, getSymbolOfNode(member.parent), identifier.escapedText);
case SyntaxKind.ElementAccessExpression:
case SyntaxKind.PropertyAccessExpression:
const ex = <AccessExpression>expr;
if (isConstantMemberAccess(ex)) {
const type = getTypeOfExpression(ex.expression);
if (type.symbol && type.symbol.flags & SymbolFlags.Enum) {
let name: __String;
if (ex.kind === SyntaxKind.PropertyAccessExpression) {
name = ex.name.escapedText;
}
else {
const argument = ex.argumentExpression;
Debug.assert(isLiteralExpression(argument));
name = escapeLeadingUnderscores((argument as LiteralExpression).text);
}
return evaluateEnumMember(expr, type.symbol, name);
}
}
break;
}
return undefined;
}
function evaluateEnumMember(expr: Expression, enumSymbol: Symbol, name: __String) {
const memberSymbol = enumSymbol.exports!.get(name);
if (memberSymbol) {
const declaration = memberSymbol.valueDeclaration;
if (declaration !== member) {
if (isBlockScopedNameDeclaredBeforeUse(declaration, member)) {
return getEnumMemberValue(declaration as EnumMember);
}
error(expr, Diagnostics.A_member_initializer_in_a_enum_declaration_cannot_reference_members_declared_after_it_including_members_defined_in_other_enums);
return 0;
}
}
return undefined;
}
}
function isConstantMemberAccess(node: Expression): boolean {
return node.kind === SyntaxKind.Identifier ||
node.kind === SyntaxKind.PropertyAccessExpression && isConstantMemberAccess((<PropertyAccessExpression>node).expression) ||
node.kind === SyntaxKind.ElementAccessExpression && isConstantMemberAccess((<ElementAccessExpression>node).expression) &&
(<ElementAccessExpression>node).argumentExpression.kind === SyntaxKind.StringLiteral;
}
function checkEnumDeclaration(node: EnumDeclaration) {
if (!produceDiagnostics) {
return;
}
// Grammar checking
checkGrammarDecoratorsAndModifiers(node);
checkTypeNameIsReserved(node.name, Diagnostics.Enum_name_cannot_be_0);
checkCollisionWithRequireExportsInGeneratedCode(node, node.name);
checkCollisionWithGlobalPromiseInGeneratedCode(node, node.name);
checkExportsOnMergedDeclarations(node);
computeEnumMemberValues(node);
// Spec 2014 - Section 9.3:
// It isn't possible for one enum declaration to continue the automatic numbering sequence of another,
// and when an enum type has multiple declarations, only one declaration is permitted to omit a value
// for the first member.
//
// Only perform this check once per symbol
const enumSymbol = getSymbolOfNode(node);
const firstDeclaration = getDeclarationOfKind(enumSymbol, node.kind);
if (node === firstDeclaration) {
if (enumSymbol.declarations.length > 1) {
const enumIsConst = isEnumConst(node);
// check that const is placed\omitted on all enum declarations
forEach(enumSymbol.declarations, decl => {
if (isEnumDeclaration(decl) && isEnumConst(decl) !== enumIsConst) {
error(getNameOfDeclaration(decl), Diagnostics.Enum_declarations_must_all_be_const_or_non_const);
}
});
}
let seenEnumMissingInitialInitializer = false;
forEach(enumSymbol.declarations, declaration => {
// return true if we hit a violation of the rule, false otherwise
if (declaration.kind !== SyntaxKind.EnumDeclaration) {
return false;
}
const enumDeclaration = <EnumDeclaration>declaration;
if (!enumDeclaration.members.length) {
return false;
}
const firstEnumMember = enumDeclaration.members[0];
if (!firstEnumMember.initializer) {
if (seenEnumMissingInitialInitializer) {
error(firstEnumMember.name, Diagnostics.In_an_enum_with_multiple_declarations_only_one_declaration_can_omit_an_initializer_for_its_first_enum_element);
}
else {
seenEnumMissingInitialInitializer = true;
}
}
});
}
}
function getFirstNonAmbientClassOrFunctionDeclaration(symbol: Symbol): Declaration | undefined {
const declarations = symbol.declarations;
for (const declaration of declarations) {
if ((declaration.kind === SyntaxKind.ClassDeclaration ||
(declaration.kind === SyntaxKind.FunctionDeclaration && nodeIsPresent((<FunctionLikeDeclaration>declaration).body))) &&
!(declaration.flags & NodeFlags.Ambient)) {
return declaration;
}
}
return undefined;
}
function inSameLexicalScope(node1: Node, node2: Node) {
const container1 = getEnclosingBlockScopeContainer(node1);
const container2 = getEnclosingBlockScopeContainer(node2);
if (isGlobalSourceFile(container1)) {
return isGlobalSourceFile(container2);
}
else if (isGlobalSourceFile(container2)) {
return false;
}
else {
return container1 === container2;
}
}
function checkModuleDeclaration(node: ModuleDeclaration) {
if (produceDiagnostics) {
// Grammar checking
const isGlobalAugmentation = isGlobalScopeAugmentation(node);
const inAmbientContext = node.flags & NodeFlags.Ambient;
if (isGlobalAugmentation && !inAmbientContext) {
error(node.name, Diagnostics.Augmentations_for_the_global_scope_should_have_declare_modifier_unless_they_appear_in_already_ambient_context);
}
const isAmbientExternalModule = isAmbientModule(node);
const contextErrorMessage = isAmbientExternalModule
? Diagnostics.An_ambient_module_declaration_is_only_allowed_at_the_top_level_in_a_file
: Diagnostics.A_namespace_declaration_is_only_allowed_in_a_namespace_or_module;
if (checkGrammarModuleElementContext(node, contextErrorMessage)) {
// If we hit a module declaration in an illegal context, just bail out to avoid cascading errors.
return;
}
if (!checkGrammarDecoratorsAndModifiers(node)) {
if (!inAmbientContext && node.name.kind === SyntaxKind.StringLiteral) {
grammarErrorOnNode(node.name, Diagnostics.Only_ambient_modules_can_use_quoted_names);
}
}
if (isIdentifier(node.name)) {
checkCollisionWithRequireExportsInGeneratedCode(node, node.name);
checkCollisionWithGlobalPromiseInGeneratedCode(node, node.name);
}
checkExportsOnMergedDeclarations(node);
const symbol = getSymbolOfNode(node);
// The following checks only apply on a non-ambient instantiated module declaration.
if (symbol.flags & SymbolFlags.ValueModule
&& symbol.declarations.length > 1
&& !inAmbientContext
&& isInstantiatedModule(node, !!compilerOptions.preserveConstEnums || !!compilerOptions.isolatedModules)) {
const firstNonAmbientClassOrFunc = getFirstNonAmbientClassOrFunctionDeclaration(symbol);
if (firstNonAmbientClassOrFunc) {
if (getSourceFileOfNode(node) !== getSourceFileOfNode(firstNonAmbientClassOrFunc)) {
error(node.name, Diagnostics.A_namespace_declaration_cannot_be_in_a_different_file_from_a_class_or_function_with_which_it_is_merged);
}
else if (node.pos < firstNonAmbientClassOrFunc.pos) {
error(node.name, Diagnostics.A_namespace_declaration_cannot_be_located_prior_to_a_class_or_function_with_which_it_is_merged);
}
}
// if the module merges with a class declaration in the same lexical scope,
// we need to track this to ensure the correct emit.
const mergedClass = getDeclarationOfKind(symbol, SyntaxKind.ClassDeclaration);
if (mergedClass &&
inSameLexicalScope(node, mergedClass)) {
getNodeLinks(node).flags |= NodeCheckFlags.LexicalModuleMergesWithClass;
}
}
if (isAmbientExternalModule) {
if (isExternalModuleAugmentation(node)) {
// body of the augmentation should be checked for consistency only if augmentation was applied to its target (either global scope or module)
// otherwise we'll be swamped in cascading errors.
// We can detect if augmentation was applied using following rules:
// - augmentation for a global scope is always applied
// - augmentation for some external module is applied if symbol for augmentation is merged (it was combined with target module).
const checkBody = isGlobalAugmentation || (getSymbolOfNode(node).flags & SymbolFlags.Transient);
if (checkBody && node.body) {
for (const statement of node.body.statements) {
checkModuleAugmentationElement(statement, isGlobalAugmentation);
}
}
}
else if (isGlobalSourceFile(node.parent)) {
if (isGlobalAugmentation) {
error(node.name, Diagnostics.Augmentations_for_the_global_scope_can_only_be_directly_nested_in_external_modules_or_ambient_module_declarations);
}
else if (isExternalModuleNameRelative(getTextOfIdentifierOrLiteral(node.name))) {
error(node.name, Diagnostics.Ambient_module_declaration_cannot_specify_relative_module_name);
}
}
else {
if (isGlobalAugmentation) {
error(node.name, Diagnostics.Augmentations_for_the_global_scope_can_only_be_directly_nested_in_external_modules_or_ambient_module_declarations);
}
else {
// Node is not an augmentation and is not located on the script level.
// This means that this is declaration of ambient module that is located in other module or namespace which is prohibited.
error(node.name, Diagnostics.Ambient_modules_cannot_be_nested_in_other_modules_or_namespaces);
}
}
}
}
if (node.body) {
checkSourceElement(node.body);
if (!isGlobalScopeAugmentation(node)) {
registerForUnusedIdentifiersCheck(node);
}
}
}
function checkModuleAugmentationElement(node: Node, isGlobalAugmentation: boolean): void {
switch (node.kind) {
case SyntaxKind.VariableStatement:
// error each individual name in variable statement instead of marking the entire variable statement
for (const decl of (<VariableStatement>node).declarationList.declarations) {
checkModuleAugmentationElement(decl, isGlobalAugmentation);
}
break;
case SyntaxKind.ExportAssignment:
case SyntaxKind.ExportDeclaration:
grammarErrorOnFirstToken(node, Diagnostics.Exports_and_export_assignments_are_not_permitted_in_module_augmentations);
break;
case SyntaxKind.ImportEqualsDeclaration:
case SyntaxKind.ImportDeclaration:
grammarErrorOnFirstToken(node, Diagnostics.Imports_are_not_permitted_in_module_augmentations_Consider_moving_them_to_the_enclosing_external_module);
break;
case SyntaxKind.BindingElement:
case SyntaxKind.VariableDeclaration:
const name = (<VariableDeclaration | BindingElement>node).name;
if (isBindingPattern(name)) {
for (const el of name.elements) {
// mark individual names in binding pattern
checkModuleAugmentationElement(el, isGlobalAugmentation);
}
break;
}
// falls through
case SyntaxKind.ClassDeclaration:
case SyntaxKind.EnumDeclaration:
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.InterfaceDeclaration:
case SyntaxKind.ModuleDeclaration:
case SyntaxKind.TypeAliasDeclaration:
if (isGlobalAugmentation) {
return;
}
const symbol = getSymbolOfNode(node);
if (symbol) {
// module augmentations cannot introduce new names on the top level scope of the module
// this is done it two steps
// 1. quick check - if symbol for node is not merged - this is local symbol to this augmentation - report error
// 2. main check - report error if value declaration of the parent symbol is module augmentation)
let reportError = !(symbol.flags & SymbolFlags.Transient);
if (!reportError) {
// symbol should not originate in augmentation
reportError = !!symbol.parent && isExternalModuleAugmentation(symbol.parent.declarations[0]);
}
}
break;
}
}
function getFirstIdentifier(node: EntityNameOrEntityNameExpression): Identifier {
switch (node.kind) {
case SyntaxKind.Identifier:
return node;
case SyntaxKind.QualifiedName:
do {
node = node.left;
} while (node.kind !== SyntaxKind.Identifier);
return node;
case SyntaxKind.PropertyAccessExpression:
do {
node = node.expression;
} while (node.kind !== SyntaxKind.Identifier);
return node;
}
}
function checkExternalImportOrExportDeclaration(node: ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration): boolean {
const moduleName = getExternalModuleName(node);
if (!moduleName || nodeIsMissing(moduleName)) {
// Should be a parse error.
return false;
}
if (!isStringLiteral(moduleName)) {
error(moduleName, Diagnostics.String_literal_expected);
return false;
}
const inAmbientExternalModule = node.parent.kind === SyntaxKind.ModuleBlock && isAmbientModule(node.parent.parent);
if (node.parent.kind !== SyntaxKind.SourceFile && !inAmbientExternalModule) {
error(moduleName, node.kind === SyntaxKind.ExportDeclaration ?
Diagnostics.Export_declarations_are_not_permitted_in_a_namespace :
Diagnostics.Import_declarations_in_a_namespace_cannot_reference_a_module);
return false;
}
if (inAmbientExternalModule && isExternalModuleNameRelative(moduleName.text)) {
// we have already reported errors on top level imports\exports in external module augmentations in checkModuleDeclaration
// no need to do this again.
if (!isTopLevelInExternalModuleAugmentation(node)) {
// TypeScript 1.0 spec (April 2013): 12.1.6
// An ExternalImportDeclaration in an AmbientExternalModuleDeclaration may reference
// other external modules only through top - level external module names.
// Relative external module names are not permitted.
error(node, Diagnostics.Import_or_export_declaration_in_an_ambient_module_declaration_cannot_reference_module_through_relative_module_name);
return false;
}
}
return true;
}
function checkAliasSymbol(node: ImportEqualsDeclaration | ImportClause | NamespaceImport | ImportSpecifier | ExportSpecifier) {
const symbol = getSymbolOfNode(node);
const target = resolveAlias(symbol);
if (target !== unknownSymbol) {
// For external modules symbol represent local symbol for an alias.
// This local symbol will merge any other local declarations (excluding other aliases)
// and symbol.flags will contains combined representation for all merged declaration.
// Based on symbol.flags we can compute a set of excluded meanings (meaning that resolved alias should not have,
// otherwise it will conflict with some local declaration). Note that in addition to normal flags we include matching SymbolFlags.Export*
// in order to prevent collisions with declarations that were exported from the current module (they still contribute to local names).
const excludedMeanings =
(symbol.flags & (SymbolFlags.Value | SymbolFlags.ExportValue) ? SymbolFlags.Value : 0) |
(symbol.flags & SymbolFlags.Type ? SymbolFlags.Type : 0) |
(symbol.flags & SymbolFlags.Namespace ? SymbolFlags.Namespace : 0);
if (target.flags & excludedMeanings) {
const message = node.kind === SyntaxKind.ExportSpecifier ?
Diagnostics.Export_declaration_conflicts_with_exported_declaration_of_0 :
Diagnostics.Import_declaration_conflicts_with_local_declaration_of_0;
error(node, message, symbolToString(symbol));
}
// Don't allow to re-export something with no value side when `--isolatedModules` is set.
if (compilerOptions.isolatedModules
&& node.kind === SyntaxKind.ExportSpecifier
&& !(target.flags & SymbolFlags.Value)
&& !(node.flags & NodeFlags.Ambient)) {
error(node, Diagnostics.Cannot_re_export_a_type_when_the_isolatedModules_flag_is_provided);
}
}
}
function checkImportBinding(node: ImportEqualsDeclaration | ImportClause | NamespaceImport | ImportSpecifier) {
checkCollisionWithRequireExportsInGeneratedCode(node, node.name!);
checkCollisionWithGlobalPromiseInGeneratedCode(node, node.name!);
checkAliasSymbol(node);
}
function checkImportDeclaration(node: ImportDeclaration) {
if (checkGrammarModuleElementContext(node, Diagnostics.An_import_declaration_can_only_be_used_in_a_namespace_or_module)) {
// If we hit an import declaration in an illegal context, just bail out to avoid cascading errors.
return;
}
if (!checkGrammarDecoratorsAndModifiers(node) && hasModifiers(node)) {
grammarErrorOnFirstToken(node, Diagnostics.An_import_declaration_cannot_have_modifiers);
}
if (checkExternalImportOrExportDeclaration(node)) {
const importClause = node.importClause;
if (importClause) {
if (importClause.name) {
checkImportBinding(importClause);
}
if (importClause.namedBindings) {
if (importClause.namedBindings.kind === SyntaxKind.NamespaceImport) {
checkImportBinding(importClause.namedBindings);
}
else {
const moduleExisted = resolveExternalModuleName(node, node.moduleSpecifier);
if (moduleExisted) {
forEach(importClause.namedBindings.elements, checkImportBinding);
}
}
}
}
}
}
function checkImportEqualsDeclaration(node: ImportEqualsDeclaration) {
if (checkGrammarModuleElementContext(node, Diagnostics.An_import_declaration_can_only_be_used_in_a_namespace_or_module)) {
// If we hit an import declaration in an illegal context, just bail out to avoid cascading errors.
return;
}
checkGrammarDecoratorsAndModifiers(node);
if (isInternalModuleImportEqualsDeclaration(node) || checkExternalImportOrExportDeclaration(node)) {
checkImportBinding(node);
if (hasModifier(node, ModifierFlags.Export)) {
markExportAsReferenced(node);
}
if (node.moduleReference.kind !== SyntaxKind.ExternalModuleReference) {
const target = resolveAlias(getSymbolOfNode(node));
if (target !== unknownSymbol) {
if (target.flags & SymbolFlags.Value) {
// Target is a value symbol, check that it is not hidden by a local declaration with the same name
const moduleName = getFirstIdentifier(node.moduleReference);
if (!(resolveEntityName(moduleName, SymbolFlags.Value | SymbolFlags.Namespace)!.flags & SymbolFlags.Namespace)) {
error(moduleName, Diagnostics.Module_0_is_hidden_by_a_local_declaration_with_the_same_name, declarationNameToString(moduleName));
}
}
if (target.flags & SymbolFlags.Type) {
checkTypeNameIsReserved(node.name, Diagnostics.Import_name_cannot_be_0);
}
}
}
else {
if (moduleKind >= ModuleKind.ES2015 && !(node.flags & NodeFlags.Ambient)) {
// Import equals declaration is deprecated in es6 or above
grammarErrorOnNode(node, Diagnostics.Import_assignment_cannot_be_used_when_targeting_ECMAScript_modules_Consider_using_import_Asterisk_as_ns_from_mod_import_a_from_mod_import_d_from_mod_or_another_module_format_instead);
}
}
}
}
function checkExportDeclaration(node: ExportDeclaration) {
if (checkGrammarModuleElementContext(node, Diagnostics.An_export_declaration_can_only_be_used_in_a_module)) {
// If we hit an export in an illegal context, just bail out to avoid cascading errors.
return;
}
if (!checkGrammarDecoratorsAndModifiers(node) && hasModifiers(node)) {
grammarErrorOnFirstToken(node, Diagnostics.An_export_declaration_cannot_have_modifiers);
}
if (!node.moduleSpecifier || checkExternalImportOrExportDeclaration(node)) {
if (node.exportClause) {
// export { x, y }
// export { x, y } from "foo"
forEach(node.exportClause.elements, checkExportSpecifier);
const inAmbientExternalModule = node.parent.kind === SyntaxKind.ModuleBlock && isAmbientModule(node.parent.parent);
const inAmbientNamespaceDeclaration = !inAmbientExternalModule && node.parent.kind === SyntaxKind.ModuleBlock &&
!node.moduleSpecifier && node.flags & NodeFlags.Ambient;
if (node.parent.kind !== SyntaxKind.SourceFile && !inAmbientExternalModule && !inAmbientNamespaceDeclaration) {
error(node, Diagnostics.Export_declarations_are_not_permitted_in_a_namespace);
}
}
else {
// export * from "foo"
const moduleSymbol = resolveExternalModuleName(node, node.moduleSpecifier!);
if (moduleSymbol && hasExportAssignmentSymbol(moduleSymbol)) {
error(node.moduleSpecifier, Diagnostics.Module_0_uses_export_and_cannot_be_used_with_export_Asterisk, symbolToString(moduleSymbol));
}
if (moduleKind !== ModuleKind.System && moduleKind !== ModuleKind.ES2015 && moduleKind !== ModuleKind.ESNext) {
checkExternalEmitHelpers(node, ExternalEmitHelpers.ExportStar);
}
}
}
}
function checkGrammarModuleElementContext(node: Statement, errorMessage: DiagnosticMessage): boolean {
const isInAppropriateContext = node.parent.kind === SyntaxKind.SourceFile || node.parent.kind === SyntaxKind.ModuleBlock || node.parent.kind === SyntaxKind.ModuleDeclaration;
if (!isInAppropriateContext) {
grammarErrorOnFirstToken(node, errorMessage);
}
return !isInAppropriateContext;
}
function checkExportSpecifier(node: ExportSpecifier) {
checkAliasSymbol(node);
if (getEmitDeclarations(compilerOptions)) {
collectLinkedAliases(node.propertyName || node.name, /*setVisibility*/ true);
}
if (!node.parent.parent.moduleSpecifier) {
const exportedName = node.propertyName || node.name;
// find immediate value referenced by exported name (SymbolFlags.Alias is set so we don't chase down aliases)
const symbol = resolveName(exportedName, exportedName.escapedText, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace | SymbolFlags.Alias,
/*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ true);
if (symbol && (symbol === undefinedSymbol || isGlobalSourceFile(getDeclarationContainer(symbol.declarations[0])))) {
error(exportedName, Diagnostics.Cannot_export_0_Only_local_declarations_can_be_exported_from_a_module, idText(exportedName));
}
else {
markExportAsReferenced(node);
}
}
}
function checkExportAssignment(node: ExportAssignment) {
if (checkGrammarModuleElementContext(node, Diagnostics.An_export_assignment_can_only_be_used_in_a_module)) {
// If we hit an export assignment in an illegal context, just bail out to avoid cascading errors.
return;
}
const container = node.parent.kind === SyntaxKind.SourceFile ? node.parent : <ModuleDeclaration>node.parent.parent;
if (container.kind === SyntaxKind.ModuleDeclaration && !isAmbientModule(container)) {
if (node.isExportEquals) {
error(node, Diagnostics.An_export_assignment_cannot_be_used_in_a_namespace);
}
else {
error(node, Diagnostics.A_default_export_can_only_be_used_in_an_ECMAScript_style_module);
}
return;
}
// Grammar checking
if (!checkGrammarDecoratorsAndModifiers(node) && hasModifiers(node)) {
grammarErrorOnFirstToken(node, Diagnostics.An_export_assignment_cannot_have_modifiers);
}
if (node.expression.kind === SyntaxKind.Identifier) {
markExportAsReferenced(node);
if (getEmitDeclarations(compilerOptions)) {
collectLinkedAliases(node.expression as Identifier, /*setVisibility*/ true);
}
}
else {
checkExpressionCached(node.expression);
}
checkExternalModuleExports(container);
if ((node.flags & NodeFlags.Ambient) && !isEntityNameExpression(node.expression)) {
grammarErrorOnNode(node.expression, Diagnostics.The_expression_of_an_export_assignment_must_be_an_identifier_or_qualified_name_in_an_ambient_context);
}
if (node.isExportEquals && !(node.flags & NodeFlags.Ambient)) {
if (moduleKind >= ModuleKind.ES2015) {
// export assignment is not supported in es6 modules
grammarErrorOnNode(node, Diagnostics.Export_assignment_cannot_be_used_when_targeting_ECMAScript_modules_Consider_using_export_default_or_another_module_format_instead);
}
else if (moduleKind === ModuleKind.System) {
// system modules does not support export assignment
grammarErrorOnNode(node, Diagnostics.Export_assignment_is_not_supported_when_module_flag_is_system);
}
}
}
function hasExportedMembers(moduleSymbol: Symbol) {
return forEachEntry(moduleSymbol.exports!, (_, id) => id !== "export=");
}
function checkExternalModuleExports(node: SourceFile | ModuleDeclaration) {
const moduleSymbol = getSymbolOfNode(node);
const links = getSymbolLinks(moduleSymbol);
if (!links.exportsChecked) {
const exportEqualsSymbol = moduleSymbol.exports!.get("export=" as __String);
if (exportEqualsSymbol && hasExportedMembers(moduleSymbol)) {
const declaration = getDeclarationOfAliasSymbol(exportEqualsSymbol) || exportEqualsSymbol.valueDeclaration;
if (!isTopLevelInExternalModuleAugmentation(declaration) && !isInJSFile(declaration)) {
error(declaration, Diagnostics.An_export_assignment_cannot_be_used_in_a_module_with_other_exported_elements);
}
}
// Checks for export * conflicts
const exports = getExportsOfModule(moduleSymbol);
if (exports) {
exports.forEach(({ declarations, flags }, id) => {
if (id === "__export") {
return;
}
// ECMA262: 15.2.1.1 It is a Syntax Error if the ExportedNames of ModuleItemList contains any duplicate entries.
// (TS Exceptions: namespaces, function overloads, enums, and interfaces)
if (flags & (SymbolFlags.Namespace | SymbolFlags.Interface | SymbolFlags.Enum)) {
return;
}
const exportedDeclarationsCount = countWhere(declarations, isNotOverloadAndNotAccessor);
if (flags & SymbolFlags.TypeAlias && exportedDeclarationsCount <= 2) {
// it is legal to merge type alias with other values
// so count should be either 1 (just type alias) or 2 (type alias + merged value)
return;
}
if (exportedDeclarationsCount > 1) {
for (const declaration of declarations) {
if (isNotOverload(declaration)) {
diagnostics.add(createDiagnosticForNode(declaration, Diagnostics.Cannot_redeclare_exported_variable_0, unescapeLeadingUnderscores(id)));
}
}
}
});
}
links.exportsChecked = true;
}
}
function isNotAccessor(declaration: Declaration): boolean {
// Accessors check for their own matching duplicates, and in contexts where they are valid, there are already duplicate identifier checks
return !isAccessor(declaration);
}
function isNotOverload(declaration: Declaration): boolean {
return (declaration.kind !== SyntaxKind.FunctionDeclaration && declaration.kind !== SyntaxKind.MethodDeclaration) ||
!!(declaration as FunctionDeclaration).body;
}
function checkSourceElement(node: Node | undefined): void {
if (node) {
const saveCurrentNode = currentNode;
currentNode = node;
checkSourceElementWorker(node);
currentNode = saveCurrentNode;
}
}
function checkSourceElementWorker(node: Node): void {
if (isInJSFile(node)) {
forEach((node as JSDocContainer).jsDoc, ({ tags }) => forEach(tags, checkSourceElement));
}
const kind = node.kind;
if (cancellationToken) {
// Only bother checking on a few construct kinds. We don't want to be excessively
// hitting the cancellation token on every node we check.
switch (kind) {
case SyntaxKind.ModuleDeclaration:
case SyntaxKind.ClassDeclaration:
case SyntaxKind.InterfaceDeclaration:
case SyntaxKind.FunctionDeclaration:
cancellationToken.throwIfCancellationRequested();
}
}
switch (kind) {
case SyntaxKind.TypeParameter:
return checkTypeParameter(<TypeParameterDeclaration>node);
case SyntaxKind.Parameter:
return checkParameter(<ParameterDeclaration>node);
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.PropertySignature:
return checkPropertyDeclaration(<PropertyDeclaration | PropertySignature>node);
case SyntaxKind.FunctionType:
case SyntaxKind.ConstructorType:
case SyntaxKind.CallSignature:
case SyntaxKind.ConstructSignature:
case SyntaxKind.IndexSignature:
return checkSignatureDeclaration(<SignatureDeclaration>node);
case SyntaxKind.MethodDeclaration:
case SyntaxKind.MethodSignature:
return checkMethodDeclaration(<MethodDeclaration | MethodSignature>node);
case SyntaxKind.Constructor:
return checkConstructorDeclaration(<ConstructorDeclaration>node);
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
return checkAccessorDeclaration(<AccessorDeclaration>node);
case SyntaxKind.TypeReference:
return checkTypeReferenceNode(<TypeReferenceNode>node);
case SyntaxKind.TypePredicate:
return checkTypePredicate(<TypePredicateNode>node);
case SyntaxKind.TypeQuery:
return checkTypeQuery(<TypeQueryNode>node);
case SyntaxKind.TypeLiteral:
return checkTypeLiteral(<TypeLiteralNode>node);
case SyntaxKind.ArrayType:
return checkArrayType(<ArrayTypeNode>node);
case SyntaxKind.TupleType:
return checkTupleType(<TupleTypeNode>node);
case SyntaxKind.UnionType:
case SyntaxKind.IntersectionType:
return checkUnionOrIntersectionType(<UnionOrIntersectionTypeNode>node);
case SyntaxKind.ParenthesizedType:
case SyntaxKind.OptionalType:
case SyntaxKind.RestType:
return checkSourceElement((<ParenthesizedTypeNode | OptionalTypeNode | RestTypeNode>node).type);
case SyntaxKind.ThisType:
return checkThisType(<ThisTypeNode>node);
case SyntaxKind.TypeOperator:
return checkTypeOperator(<TypeOperatorNode>node);
case SyntaxKind.ConditionalType:
return checkConditionalType(<ConditionalTypeNode>node);
case SyntaxKind.InferType:
return checkInferType(<InferTypeNode>node);
case SyntaxKind.ImportType:
return checkImportType(<ImportTypeNode>node);
case SyntaxKind.JSDocAugmentsTag:
return checkJSDocAugmentsTag(node as JSDocAugmentsTag);
case SyntaxKind.JSDocTypedefTag:
case SyntaxKind.JSDocCallbackTag:
return checkJSDocTypeAliasTag(node as JSDocTypedefTag);
case SyntaxKind.JSDocTemplateTag:
return checkJSDocTemplateTag(node as JSDocTemplateTag);
case SyntaxKind.JSDocTypeTag:
return checkJSDocTypeTag(node as JSDocTypeTag);
case SyntaxKind.JSDocParameterTag:
return checkJSDocParameterTag(node as JSDocParameterTag);
case SyntaxKind.JSDocFunctionType:
checkJSDocFunctionType(node as JSDocFunctionType);
// falls through
case SyntaxKind.JSDocNonNullableType:
case SyntaxKind.JSDocNullableType:
case SyntaxKind.JSDocAllType:
case SyntaxKind.JSDocUnknownType:
case SyntaxKind.JSDocTypeLiteral:
checkJSDocTypeIsInJsFile(node);
forEachChild(node, checkSourceElement);
return;
case SyntaxKind.JSDocVariadicType:
checkJSDocVariadicType(node as JSDocVariadicType);
return;
case SyntaxKind.JSDocTypeExpression:
return checkSourceElement((node as JSDocTypeExpression).type);
case SyntaxKind.IndexedAccessType:
return checkIndexedAccessType(<IndexedAccessTypeNode>node);
case SyntaxKind.MappedType:
return checkMappedType(<MappedTypeNode>node);
case SyntaxKind.FunctionDeclaration:
return checkFunctionDeclaration(<FunctionDeclaration>node);
case SyntaxKind.Block:
case SyntaxKind.ModuleBlock:
return checkBlock(<Block>node);
case SyntaxKind.VariableStatement:
return checkVariableStatement(<VariableStatement>node);
case SyntaxKind.ExpressionStatement:
return checkExpressionStatement(<ExpressionStatement>node);
case SyntaxKind.IfStatement:
return checkIfStatement(<IfStatement>node);
case SyntaxKind.DoStatement:
return checkDoStatement(<DoStatement>node);
case SyntaxKind.WhileStatement:
return checkWhileStatement(<WhileStatement>node);
case SyntaxKind.ForStatement:
return checkForStatement(<ForStatement>node);
case SyntaxKind.ForInStatement:
return checkForInStatement(<ForInStatement>node);
case SyntaxKind.ForOfStatement:
return checkForOfStatement(<ForOfStatement>node);
case SyntaxKind.ContinueStatement:
case SyntaxKind.BreakStatement:
return checkBreakOrContinueStatement(<BreakOrContinueStatement>node);
case SyntaxKind.ReturnStatement:
return checkReturnStatement(<ReturnStatement>node);
case SyntaxKind.WithStatement:
return checkWithStatement(<WithStatement>node);
case SyntaxKind.SwitchStatement:
return checkSwitchStatement(<SwitchStatement>node);
case SyntaxKind.LabeledStatement:
return checkLabeledStatement(<LabeledStatement>node);
case SyntaxKind.ThrowStatement:
return checkThrowStatement(<ThrowStatement>node);
case SyntaxKind.TryStatement:
return checkTryStatement(<TryStatement>node);
case SyntaxKind.VariableDeclaration:
return checkVariableDeclaration(<VariableDeclaration>node);
case SyntaxKind.BindingElement:
return checkBindingElement(<BindingElement>node);
case SyntaxKind.ClassDeclaration:
return checkClassDeclaration(<ClassDeclaration>node);
case SyntaxKind.InterfaceDeclaration:
return checkInterfaceDeclaration(<InterfaceDeclaration>node);
case SyntaxKind.TypeAliasDeclaration:
return checkTypeAliasDeclaration(<TypeAliasDeclaration>node);
case SyntaxKind.EnumDeclaration:
return checkEnumDeclaration(<EnumDeclaration>node);
case SyntaxKind.ModuleDeclaration:
return checkModuleDeclaration(<ModuleDeclaration>node);
case SyntaxKind.ImportDeclaration:
return checkImportDeclaration(<ImportDeclaration>node);
case SyntaxKind.ImportEqualsDeclaration:
return checkImportEqualsDeclaration(<ImportEqualsDeclaration>node);
case SyntaxKind.ExportDeclaration:
return checkExportDeclaration(<ExportDeclaration>node);
case SyntaxKind.ExportAssignment:
return checkExportAssignment(<ExportAssignment>node);
case SyntaxKind.EmptyStatement:
case SyntaxKind.DebuggerStatement:
checkGrammarStatementInAmbientContext(node);
return;
case SyntaxKind.MissingDeclaration:
return checkMissingDeclaration(node);
}
}
function checkJSDocTypeIsInJsFile(node: Node): void {
if (!isInJSFile(node)) {
grammarErrorOnNode(node, Diagnostics.JSDoc_types_can_only_be_used_inside_documentation_comments);
}
}
function checkJSDocVariadicType(node: JSDocVariadicType): void {
checkJSDocTypeIsInJsFile(node);
checkSourceElement(node.type);
// Only legal location is in the *last* parameter tag or last parameter of a JSDoc function.
const { parent } = node;
if (isParameter(parent) && isJSDocFunctionType(parent.parent)) {
if (last(parent.parent.parameters) !== parent) {
error(node, Diagnostics.A_rest_parameter_must_be_last_in_a_parameter_list);
}
return;
}
if (!isJSDocTypeExpression(parent)) {
error(node, Diagnostics.JSDoc_may_only_appear_in_the_last_parameter_of_a_signature);
}
const paramTag = node.parent.parent;
if (!isJSDocParameterTag(paramTag)) {
error(node, Diagnostics.JSDoc_may_only_appear_in_the_last_parameter_of_a_signature);
return;
}
const param = getParameterSymbolFromJSDoc(paramTag);
if (!param) {
// We will error in `checkJSDocParameterTag`.
return;
}
const host = getHostSignatureFromJSDoc(paramTag);
if (!host || last(host.parameters).symbol !== param) {
error(node, Diagnostics.A_rest_parameter_must_be_last_in_a_parameter_list);
}
}
function getTypeFromJSDocVariadicType(node: JSDocVariadicType): Type {
const type = getTypeFromTypeNode(node.type);
const { parent } = node;
const paramTag = node.parent.parent;
if (isJSDocTypeExpression(node.parent) && isJSDocParameterTag(paramTag)) {
// Else we will add a diagnostic, see `checkJSDocVariadicType`.
const host = getHostSignatureFromJSDoc(paramTag);
if (host) {
/*
Only return an array type if the corresponding parameter is marked as a rest parameter, or if there are no parameters.
So in the following situation we will not create an array type:
/** @param {...number} a * /
function f(a) {}
Because `a` will just be of type `number | undefined`. A synthetic `...args` will also be added, which *will* get an array type.
*/
const lastParamDeclaration = lastOrUndefined(host.parameters);
const symbol = getParameterSymbolFromJSDoc(paramTag);
if (!lastParamDeclaration ||
symbol && lastParamDeclaration.symbol === symbol && isRestParameter(lastParamDeclaration)) {
return createArrayType(type);
}
}
}
if (isParameter(parent) && isJSDocFunctionType(parent.parent)) {
return createArrayType(type);
}
return addOptionality(type);
}
// Function and class expression bodies are checked after all statements in the enclosing body. This is
// to ensure constructs like the following are permitted:
// const foo = function () {
// const s = foo();
// return "hello";
// }
// Here, performing a full type check of the body of the function expression whilst in the process of
// determining the type of foo would cause foo to be given type any because of the recursive reference.
// Delaying the type check of the body ensures foo has been assigned a type.
function checkNodeDeferred(node: Node) {
const enclosingFile = getSourceFileOfNode(node);
const links = getNodeLinks(enclosingFile);
if (!(links.flags & NodeCheckFlags.TypeChecked)) {
links.deferredNodes = links.deferredNodes || createMap();
const id = "" + getNodeId(node);
links.deferredNodes.set(id, node);
}
}
function checkDeferredNodes(context: SourceFile) {
const links = getNodeLinks(context);
if (links.deferredNodes) {
links.deferredNodes.forEach(checkDeferredNode);
}
}
function checkDeferredNode(node: Node) {
const saveCurrentNode = currentNode;
currentNode = node;
switch (node.kind) {
case SyntaxKind.FunctionExpression:
case SyntaxKind.ArrowFunction:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.MethodSignature:
checkFunctionExpressionOrObjectLiteralMethodDeferred(<FunctionExpression>node);
break;
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
checkAccessorDeclaration(<AccessorDeclaration>node);
break;
case SyntaxKind.ClassExpression:
checkClassExpressionDeferred(<ClassExpression>node);
break;
case SyntaxKind.JsxSelfClosingElement:
checkJsxSelfClosingElementDeferred(<JsxSelfClosingElement>node);
break;
case SyntaxKind.JsxElement:
checkJsxElementDeferred(<JsxElement>node);
break;
}
currentNode = saveCurrentNode;
}
function checkSourceFile(node: SourceFile) {
performance.mark("beforeCheck");
checkSourceFileWorker(node);
performance.mark("afterCheck");
performance.measure("Check", "beforeCheck", "afterCheck");
}
function unusedIsError(kind: UnusedKind): boolean {
switch (kind) {
case UnusedKind.Local:
return !!compilerOptions.noUnusedLocals;
case UnusedKind.Parameter:
return !!compilerOptions.noUnusedParameters;
default:
return Debug.assertNever(kind);
}
}
function getPotentiallyUnusedIdentifiers(sourceFile: SourceFile): ReadonlyArray<PotentiallyUnusedIdentifier> {
return allPotentiallyUnusedIdentifiers.get(sourceFile.path) || emptyArray;
}
// Fully type check a source file and collect the relevant diagnostics.
function checkSourceFileWorker(node: SourceFile) {
const links = getNodeLinks(node);
if (!(links.flags & NodeCheckFlags.TypeChecked)) {
if (skipTypeChecking(node, compilerOptions)) {
return;
}
// Grammar checking
checkGrammarSourceFile(node);
clear(potentialThisCollisions);
clear(potentialNewTargetCollisions);
forEach(node.statements, checkSourceElement);
checkSourceElement(node.endOfFileToken);
checkDeferredNodes(node);
if (isExternalOrCommonJsModule(node)) {
registerForUnusedIdentifiersCheck(node);
}
if (!node.isDeclarationFile && (compilerOptions.noUnusedLocals || compilerOptions.noUnusedParameters)) {
checkUnusedIdentifiers(getPotentiallyUnusedIdentifiers(node), (containingNode, kind, diag) => {
if (!containsParseError(containingNode) && unusedIsError(kind)) {
diagnostics.add(diag);
}
});
}
if (isExternalOrCommonJsModule(node)) {
checkExternalModuleExports(node);
}
if (potentialThisCollisions.length) {
forEach(potentialThisCollisions, checkIfThisIsCapturedInEnclosingScope);
clear(potentialThisCollisions);
}
if (potentialNewTargetCollisions.length) {
forEach(potentialNewTargetCollisions, checkIfNewTargetIsCapturedInEnclosingScope);
clear(potentialNewTargetCollisions);
}
links.flags |= NodeCheckFlags.TypeChecked;
}
}
function getDiagnostics(sourceFile: SourceFile, ct: CancellationToken): Diagnostic[] {
try {
// Record the cancellation token so it can be checked later on during checkSourceElement.
// Do this in a finally block so we can ensure that it gets reset back to nothing after
// this call is done.
cancellationToken = ct;
return getDiagnosticsWorker(sourceFile);
}
finally {
cancellationToken = undefined;
}
}
function getDiagnosticsWorker(sourceFile: SourceFile): Diagnostic[] {
throwIfNonDiagnosticsProducing();
if (sourceFile) {
// Some global diagnostics are deferred until they are needed and
// may not be reported in the first call to getGlobalDiagnostics.
// We should catch these changes and report them.
const previousGlobalDiagnostics = diagnostics.getGlobalDiagnostics();
const previousGlobalDiagnosticsSize = previousGlobalDiagnostics.length;
checkSourceFile(sourceFile);
const semanticDiagnostics = diagnostics.getDiagnostics(sourceFile.fileName);
const currentGlobalDiagnostics = diagnostics.getGlobalDiagnostics();
if (currentGlobalDiagnostics !== previousGlobalDiagnostics) {
// If the arrays are not the same reference, new diagnostics were added.
const deferredGlobalDiagnostics = relativeComplement(previousGlobalDiagnostics, currentGlobalDiagnostics, compareDiagnostics);
return concatenate(deferredGlobalDiagnostics, semanticDiagnostics);
}
else if (previousGlobalDiagnosticsSize === 0 && currentGlobalDiagnostics.length > 0) {
// If the arrays are the same reference, but the length has changed, a single
// new diagnostic was added as DiagnosticCollection attempts to reuse the
// same array.
return concatenate(currentGlobalDiagnostics, semanticDiagnostics);
}
return semanticDiagnostics;
}
// Global diagnostics are always added when a file is not provided to
// getDiagnostics
forEach(host.getSourceFiles(), checkSourceFile);
return diagnostics.getDiagnostics();
}
function getGlobalDiagnostics(): Diagnostic[] {
throwIfNonDiagnosticsProducing();
return diagnostics.getGlobalDiagnostics();
}
function throwIfNonDiagnosticsProducing() {
if (!produceDiagnostics) {
throw new Error("Trying to get diagnostics from a type checker that does not produce them.");
}
}
// Language service support
function getSymbolsInScope(location: Node, meaning: SymbolFlags): Symbol[] {
if (location.flags & NodeFlags.InWithStatement) {
// We cannot answer semantic questions within a with block, do not proceed any further
return [];
}
const symbols = createSymbolTable();
let isStatic = false;
populateSymbols();
symbols.delete(InternalSymbolName.This); // Not a symbol, a keyword
return symbolsToArray(symbols);
function populateSymbols() {
while (location) {
if (location.locals && !isGlobalSourceFile(location)) {
copySymbols(location.locals, meaning);
}
switch (location.kind) {
case SyntaxKind.SourceFile:
if (!isExternalOrCommonJsModule(<SourceFile>location)) break;
// falls through
case SyntaxKind.ModuleDeclaration:
copySymbols(getSymbolOfNode(location as ModuleDeclaration | SourceFile).exports!, meaning & SymbolFlags.ModuleMember);
break;
case SyntaxKind.EnumDeclaration:
copySymbols(getSymbolOfNode(location as EnumDeclaration).exports!, meaning & SymbolFlags.EnumMember);
break;
case SyntaxKind.ClassExpression:
const className = (location as ClassExpression).name;
if (className) {
copySymbol(location.symbol, meaning);
}
// falls through
// this fall-through is necessary because we would like to handle
// type parameter inside class expression similar to how we handle it in classDeclaration and interface Declaration
case SyntaxKind.ClassDeclaration:
case SyntaxKind.InterfaceDeclaration:
// If we didn't come from static member of class or interface,
// add the type parameters into the symbol table
// (type parameters of classDeclaration/classExpression and interface are in member property of the symbol.
// Note: that the memberFlags come from previous iteration.
if (!isStatic) {
copySymbols(getMembersOfSymbol(getSymbolOfNode(location as ClassDeclaration | InterfaceDeclaration)), meaning & SymbolFlags.Type);
}
break;
case SyntaxKind.FunctionExpression:
const funcName = (location as FunctionExpression).name;
if (funcName) {
copySymbol(location.symbol, meaning);
}
break;
}
if (introducesArgumentsExoticObject(location)) {
copySymbol(argumentsSymbol, meaning);
}
isStatic = hasModifier(location, ModifierFlags.Static);
location = location.parent;
}
copySymbols(globals, meaning);
}
/**
* Copy the given symbol into symbol tables if the symbol has the given meaning
* and it doesn't already existed in the symbol table
* @param key a key for storing in symbol table; if undefined, use symbol.name
* @param symbol the symbol to be added into symbol table
* @param meaning meaning of symbol to filter by before adding to symbol table
*/
function copySymbol(symbol: Symbol, meaning: SymbolFlags): void {
if (getCombinedLocalAndExportSymbolFlags(symbol) & meaning) {
const id = symbol.escapedName;
// We will copy all symbol regardless of its reserved name because
// symbolsToArray will check whether the key is a reserved name and
// it will not copy symbol with reserved name to the array
if (!symbols.has(id)) {
symbols.set(id, symbol);
}
}
}
function copySymbols(source: SymbolTable, meaning: SymbolFlags): void {
if (meaning) {
source.forEach(symbol => {
copySymbol(symbol, meaning);
});
}
}
}
function isTypeDeclarationName(name: Node): boolean {
return name.kind === SyntaxKind.Identifier &&
isTypeDeclaration(name.parent) &&
(<NamedDeclaration>name.parent).name === name;
}
function isTypeDeclaration(node: Node): node is TypeParameterDeclaration | ClassDeclaration | InterfaceDeclaration | TypeAliasDeclaration | EnumDeclaration {
switch (node.kind) {
case SyntaxKind.TypeParameter:
case SyntaxKind.ClassDeclaration:
case SyntaxKind.InterfaceDeclaration:
case SyntaxKind.TypeAliasDeclaration:
case SyntaxKind.EnumDeclaration:
return true;
default:
return false;
}
}
// True if the given identifier is part of a type reference
function isTypeReferenceIdentifier(node: EntityName): boolean {
while (node.parent.kind === SyntaxKind.QualifiedName) {
node = node.parent as QualifiedName;
}
return node.parent.kind === SyntaxKind.TypeReference;
}
function isHeritageClauseElementIdentifier(node: Node): boolean {
while (node.parent.kind === SyntaxKind.PropertyAccessExpression) {
node = node.parent;
}
return node.parent.kind === SyntaxKind.ExpressionWithTypeArguments;
}
function forEachEnclosingClass<T>(node: Node, callback: (node: Node) => T | undefined): T | undefined {
let result: T | undefined;
while (true) {
node = getContainingClass(node)!;
if (!node) break;
if (result = callback(node)) break;
}
return result;
}
function isNodeUsedDuringClassInitialization(node: Node) {
return !!findAncestor(node, element => {
if (isConstructorDeclaration(element) && nodeIsPresent(element.body) || isPropertyDeclaration(element)) {
return true;
}
else if (isClassLike(element) || isFunctionLikeDeclaration(element)) {
return "quit";
}
return false;
});
}
function isNodeWithinClass(node: Node, classDeclaration: ClassLikeDeclaration) {
return !!forEachEnclosingClass(node, n => n === classDeclaration);
}
function getLeftSideOfImportEqualsOrExportAssignment(nodeOnRightSide: EntityName): ImportEqualsDeclaration | ExportAssignment | undefined {
while (nodeOnRightSide.parent.kind === SyntaxKind.QualifiedName) {
nodeOnRightSide = <QualifiedName>nodeOnRightSide.parent;
}
if (nodeOnRightSide.parent.kind === SyntaxKind.ImportEqualsDeclaration) {
return (<ImportEqualsDeclaration>nodeOnRightSide.parent).moduleReference === nodeOnRightSide ? <ImportEqualsDeclaration>nodeOnRightSide.parent : undefined;
}
if (nodeOnRightSide.parent.kind === SyntaxKind.ExportAssignment) {
return (<ExportAssignment>nodeOnRightSide.parent).expression === <Node>nodeOnRightSide ? <ExportAssignment>nodeOnRightSide.parent : undefined;
}
return undefined;
}
function isInRightSideOfImportOrExportAssignment(node: EntityName) {
return getLeftSideOfImportEqualsOrExportAssignment(node) !== undefined;
}
function getSpecialPropertyAssignmentSymbolFromEntityName(entityName: EntityName | PropertyAccessExpression) {
const specialPropertyAssignmentKind = getAssignmentDeclarationKind(entityName.parent.parent as BinaryExpression);
switch (specialPropertyAssignmentKind) {
case AssignmentDeclarationKind.ExportsProperty:
case AssignmentDeclarationKind.PrototypeProperty:
return getSymbolOfNode(entityName.parent);
case AssignmentDeclarationKind.ThisProperty:
case AssignmentDeclarationKind.ModuleExports:
case AssignmentDeclarationKind.Property:
return getSymbolOfNode(entityName.parent.parent);
}
}
function isImportTypeQualifierPart(node: EntityName): ImportTypeNode | undefined {
let parent = node.parent;
while (isQualifiedName(parent)) {
node = parent;
parent = parent.parent;
}
if (parent && parent.kind === SyntaxKind.ImportType && (parent as ImportTypeNode).qualifier === node) {
return parent as ImportTypeNode;
}
return undefined;
}
function getSymbolOfEntityNameOrPropertyAccessExpression(entityName: EntityName | PropertyAccessExpression): Symbol | undefined {
if (isDeclarationName(entityName)) {
return getSymbolOfNode(entityName.parent);
}
if (isInJSFile(entityName) &&
entityName.parent.kind === SyntaxKind.PropertyAccessExpression &&
entityName.parent === (entityName.parent.parent as BinaryExpression).left) {
// Check if this is a special property assignment
const specialPropertyAssignmentSymbol = getSpecialPropertyAssignmentSymbolFromEntityName(entityName);
if (specialPropertyAssignmentSymbol) {
return specialPropertyAssignmentSymbol;
}
}
if (entityName.parent.kind === SyntaxKind.ExportAssignment && isEntityNameExpression(entityName)) {
// Even an entity name expression that doesn't resolve as an entityname may still typecheck as a property access expression
const success = resolveEntityName(entityName,
/*all meanings*/ SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace | SymbolFlags.Alias, /*ignoreErrors*/ true);
if (success && success !== unknownSymbol) {
return success;
}
}
else if (!isPropertyAccessExpression(entityName) && isInRightSideOfImportOrExportAssignment(entityName)) {
// Since we already checked for ExportAssignment, this really could only be an Import
const importEqualsDeclaration = getAncestor(entityName, SyntaxKind.ImportEqualsDeclaration);
Debug.assert(importEqualsDeclaration !== undefined);
return getSymbolOfPartOfRightHandSideOfImportEquals(entityName, /*dontResolveAlias*/ true);
}
if (!isPropertyAccessExpression(entityName)) {
const possibleImportNode = isImportTypeQualifierPart(entityName);
if (possibleImportNode) {
getTypeFromTypeNode(possibleImportNode);
const sym = getNodeLinks(entityName).resolvedSymbol;
return sym === unknownSymbol ? undefined : sym;
}
}
while (isRightSideOfQualifiedNameOrPropertyAccess(entityName)) {
entityName = <QualifiedName | PropertyAccessEntityNameExpression>entityName.parent;
}
if (isHeritageClauseElementIdentifier(entityName)) {
let meaning = SymbolFlags.None;
// In an interface or class, we're definitely interested in a type.
if (entityName.parent.kind === SyntaxKind.ExpressionWithTypeArguments) {
meaning = SymbolFlags.Type;
// In a class 'extends' clause we are also looking for a value.
if (isExpressionWithTypeArgumentsInClassExtendsClause(entityName.parent)) {
meaning |= SymbolFlags.Value;
}
}
else {
meaning = SymbolFlags.Namespace;
}
meaning |= SymbolFlags.Alias;
const entityNameSymbol = isEntityNameExpression(entityName) ? resolveEntityName(entityName, meaning) : undefined;
if (entityNameSymbol) {
return entityNameSymbol;
}
}
if (entityName.parent.kind === SyntaxKind.JSDocParameterTag) {
return getParameterSymbolFromJSDoc(entityName.parent as JSDocParameterTag);
}
if (entityName.parent.kind === SyntaxKind.TypeParameter && entityName.parent.parent.kind === SyntaxKind.JSDocTemplateTag) {
Debug.assert(!isInJSFile(entityName)); // Otherwise `isDeclarationName` would have been true.
const typeParameter = getTypeParameterFromJsDoc(entityName.parent as TypeParameterDeclaration & { parent: JSDocTemplateTag });
return typeParameter && typeParameter.symbol;
}
if (isExpressionNode(entityName)) {
if (nodeIsMissing(entityName)) {
// Missing entity name.
return undefined;
}
if (entityName.kind === SyntaxKind.Identifier) {
if (isJSXTagName(entityName) && isJsxIntrinsicIdentifier(entityName)) {
const symbol = getIntrinsicTagSymbol(<JsxOpeningLikeElement>entityName.parent);
return symbol === unknownSymbol ? undefined : symbol;
}
return resolveEntityName(entityName, SymbolFlags.Value, /*ignoreErrors*/ false, /*dontResolveAlias*/ true);
}
else if (entityName.kind === SyntaxKind.PropertyAccessExpression || entityName.kind === SyntaxKind.QualifiedName) {
const links = getNodeLinks(entityName);
if (links.resolvedSymbol) {
return links.resolvedSymbol;
}
if (entityName.kind === SyntaxKind.PropertyAccessExpression) {
checkPropertyAccessExpression(entityName);
}
else {
checkQualifiedName(entityName);
}
return links.resolvedSymbol;
}
}
else if (isTypeReferenceIdentifier(<EntityName>entityName)) {
const meaning = entityName.parent.kind === SyntaxKind.TypeReference ? SymbolFlags.Type : SymbolFlags.Namespace;
return resolveEntityName(<EntityName>entityName, meaning, /*ignoreErrors*/ false, /*dontResolveAlias*/ true);
}
if (entityName.parent.kind === SyntaxKind.TypePredicate) {
return resolveEntityName(<Identifier>entityName, /*meaning*/ SymbolFlags.FunctionScopedVariable);
}
// Do we want to return undefined here?
return undefined;
}
function getSymbolAtLocation(node: Node): Symbol | undefined {
if (node.kind === SyntaxKind.SourceFile) {
return isExternalModule(<SourceFile>node) ? getMergedSymbol(node.symbol) : undefined;
}
const { parent } = node;
const grandParent = parent.parent;
if (node.flags & NodeFlags.InWithStatement) {
// We cannot answer semantic questions within a with block, do not proceed any further
return undefined;
}
if (isDeclarationNameOrImportPropertyName(node)) {
// This is a declaration, call getSymbolOfNode
const parentSymbol = getSymbolOfNode(parent)!;
return isImportOrExportSpecifier(node.parent) && node.parent.propertyName === node
? getImmediateAliasedSymbol(parentSymbol)
: parentSymbol;
}
else if (isLiteralComputedPropertyDeclarationName(node)) {
return getSymbolOfNode(parent.parent);
}
if (node.kind === SyntaxKind.Identifier) {
if (isInRightSideOfImportOrExportAssignment(<Identifier>node)) {
return getSymbolOfEntityNameOrPropertyAccessExpression(<Identifier>node);
}
else if (parent.kind === SyntaxKind.BindingElement &&
grandParent.kind === SyntaxKind.ObjectBindingPattern &&
node === (<BindingElement>parent).propertyName) {
const typeOfPattern = getTypeOfNode(grandParent);
const propertyDeclaration = getPropertyOfType(typeOfPattern, (<Identifier>node).escapedText);
if (propertyDeclaration) {
return propertyDeclaration;
}
}
}
switch (node.kind) {
case SyntaxKind.Identifier:
case SyntaxKind.PropertyAccessExpression:
case SyntaxKind.QualifiedName:
return getSymbolOfEntityNameOrPropertyAccessExpression(<EntityName | PropertyAccessExpression>node);
case SyntaxKind.ThisKeyword:
const container = getThisContainer(node, /*includeArrowFunctions*/ false);
if (isFunctionLike(container)) {
const sig = getSignatureFromDeclaration(container);
if (sig.thisParameter) {
return sig.thisParameter;
}
}
if (isInExpressionContext(node)) {
return checkExpression(node as Expression).symbol;
}
// falls through
case SyntaxKind.ThisType:
return getTypeFromThisTypeNode(node as ThisExpression | ThisTypeNode).symbol;
case SyntaxKind.SuperKeyword:
return checkExpression(node as Expression).symbol;
case SyntaxKind.ConstructorKeyword:
// constructor keyword for an overload, should take us to the definition if it exist
const constructorDeclaration = node.parent;
if (constructorDeclaration && constructorDeclaration.kind === SyntaxKind.Constructor) {
return (<ClassDeclaration>constructorDeclaration.parent).symbol;
}
return undefined;
case SyntaxKind.StringLiteral:
case SyntaxKind.NoSubstitutionTemplateLiteral:
// 1). import x = require("./mo/*gotToDefinitionHere*/d")
// 2). External module name in an import declaration
// 3). Dynamic import call or require in javascript
// 4). type A = import("./f/*gotToDefinitionHere*/oo")
if ((isExternalModuleImportEqualsDeclaration(node.parent.parent) && getExternalModuleImportEqualsDeclarationExpression(node.parent.parent) === node) ||
((node.parent.kind === SyntaxKind.ImportDeclaration || node.parent.kind === SyntaxKind.ExportDeclaration) && (<ImportDeclaration>node.parent).moduleSpecifier === node) ||
((isInJSFile(node) && isRequireCall(node.parent, /*checkArgumentIsStringLiteralLike*/ false)) || isImportCall(node.parent)) ||
(isLiteralTypeNode(node.parent) && isLiteralImportTypeNode(node.parent.parent) && node.parent.parent.argument === node.parent)
) {
return resolveExternalModuleName(node, <LiteralExpression>node);
}
if (isCallExpression(parent) && isBindableObjectDefinePropertyCall(parent) && parent.arguments[1] === node) {
return getSymbolOfNode(parent);
}
// falls through
case SyntaxKind.NumericLiteral:
// index access
const objectType = isElementAccessExpression(parent)
? parent.argumentExpression === node ? getTypeOfExpression(parent.expression) : undefined
: isLiteralTypeNode(parent) && isIndexedAccessTypeNode(grandParent)
? getTypeFromTypeNode(grandParent.objectType)
: undefined;
return objectType && getPropertyOfType(objectType, escapeLeadingUnderscores((node as StringLiteral | NumericLiteral).text));
case SyntaxKind.DefaultKeyword:
case SyntaxKind.FunctionKeyword:
case SyntaxKind.EqualsGreaterThanToken:
case SyntaxKind.ClassKeyword:
return getSymbolOfNode(node.parent);
case SyntaxKind.ImportType:
return isLiteralImportTypeNode(node) ? getSymbolAtLocation(node.argument.literal) : undefined;
case SyntaxKind.ExportKeyword:
return isExportAssignment(node.parent) ? Debug.assertDefined(node.parent.symbol) : undefined;
default:
return undefined;
}
}
function getShorthandAssignmentValueSymbol(location: Node): Symbol | undefined {
if (location && location.kind === SyntaxKind.ShorthandPropertyAssignment) {
return resolveEntityName((<ShorthandPropertyAssignment>location).name, SymbolFlags.Value | SymbolFlags.Alias);
}
return undefined;
}
/** Returns the target of an export specifier without following aliases */
function getExportSpecifierLocalTargetSymbol(node: ExportSpecifier): Symbol | undefined {
return node.parent.parent.moduleSpecifier ?
getExternalModuleMember(node.parent.parent, node) :
resolveEntityName(node.propertyName || node.name, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace | SymbolFlags.Alias);
}
function getTypeOfNode(node: Node): Type {
if (node.flags & NodeFlags.InWithStatement) {
// We cannot answer semantic questions within a with block, do not proceed any further
return errorType;
}
const classDecl = tryGetClassImplementingOrExtendingExpressionWithTypeArguments(node);
const classType = classDecl && getDeclaredTypeOfClassOrInterface(getSymbolOfNode(classDecl.class));
if (isPartOfTypeNode(node)) {
const typeFromTypeNode = getTypeFromTypeNode(<TypeNode>node);
return classType ? getTypeWithThisArgument(typeFromTypeNode, classType.thisType) : typeFromTypeNode;
}
if (isExpressionNode(node)) {
return getRegularTypeOfExpression(<Expression>node);
}
if (classType && !classDecl!.isImplements) {
// A SyntaxKind.ExpressionWithTypeArguments is considered a type node, except when it occurs in the
// extends clause of a class. We handle that case here.
const baseType = firstOrUndefined(getBaseTypes(classType));
return baseType ? getTypeWithThisArgument(baseType, classType.thisType) : errorType;
}
if (isTypeDeclaration(node)) {
// In this case, we call getSymbolOfNode instead of getSymbolAtLocation because it is a declaration
const symbol = getSymbolOfNode(node);
return getDeclaredTypeOfSymbol(symbol);
}
if (isTypeDeclarationName(node)) {
const symbol = getSymbolAtLocation(node);
return symbol ? getDeclaredTypeOfSymbol(symbol) : errorType;
}
if (isDeclaration(node)) {
// In this case, we call getSymbolOfNode instead of getSymbolAtLocation because it is a declaration
const symbol = getSymbolOfNode(node);
return getTypeOfSymbol(symbol);
}
if (isDeclarationNameOrImportPropertyName(node)) {
const symbol = getSymbolAtLocation(node);
return symbol ? getTypeOfSymbol(symbol) : errorType;
}
if (isBindingPattern(node)) {
return getTypeForVariableLikeDeclaration(node.parent, /*includeOptionality*/ true) || errorType;
}
if (isInRightSideOfImportOrExportAssignment(<Identifier>node)) {
const symbol = getSymbolAtLocation(node);
if (symbol) {
const declaredType = getDeclaredTypeOfSymbol(symbol);
return declaredType !== errorType ? declaredType : getTypeOfSymbol(symbol);
}
}
return errorType;
}
// Gets the type of object literal or array literal of destructuring assignment.
// { a } from
// for ( { a } of elems) {
// }
// [ a ] from
// [a] = [ some array ...]
function getTypeOfArrayLiteralOrObjectLiteralDestructuringAssignment(expr: Expression): Type {
Debug.assert(expr.kind === SyntaxKind.ObjectLiteralExpression || expr.kind === SyntaxKind.ArrayLiteralExpression);
// If this is from "for of"
// for ( { a } of elems) {
// }
if (expr.parent.kind === SyntaxKind.ForOfStatement) {
const iteratedType = checkRightHandSideOfForOf((<ForOfStatement>expr.parent).expression, (<ForOfStatement>expr.parent).awaitModifier);
return checkDestructuringAssignment(expr, iteratedType || errorType);
}
// If this is from "for" initializer
// for ({a } = elems[0];.....) { }
if (expr.parent.kind === SyntaxKind.BinaryExpression) {
const iteratedType = getTypeOfExpression((<BinaryExpression>expr.parent).right);
return checkDestructuringAssignment(expr, iteratedType || errorType);
}
// If this is from nested object binding pattern
// for ({ skills: { primary, secondary } } = multiRobot, i = 0; i < 1; i++) {
if (expr.parent.kind === SyntaxKind.PropertyAssignment) {
const typeOfParentObjectLiteral = getTypeOfArrayLiteralOrObjectLiteralDestructuringAssignment(<Expression>expr.parent.parent);
return checkObjectLiteralDestructuringPropertyAssignment(typeOfParentObjectLiteral || errorType, <ObjectLiteralElementLike>expr.parent)!; // TODO: GH#18217
}
// Array literal assignment - array destructuring pattern
Debug.assert(expr.parent.kind === SyntaxKind.ArrayLiteralExpression);
// [{ property1: p1, property2 }] = elems;
const typeOfArrayLiteral = getTypeOfArrayLiteralOrObjectLiteralDestructuringAssignment(<Expression>expr.parent);
const elementType = checkIteratedTypeOrElementType(typeOfArrayLiteral || errorType, expr.parent, /*allowStringInput*/ false, /*allowAsyncIterables*/ false) || errorType;
return checkArrayLiteralDestructuringElementAssignment(<ArrayLiteralExpression>expr.parent, typeOfArrayLiteral,
(<ArrayLiteralExpression>expr.parent).elements.indexOf(expr), elementType || errorType)!; // TODO: GH#18217
}
// Gets the property symbol corresponding to the property in destructuring assignment
// 'property1' from
// for ( { property1: a } of elems) {
// }
// 'property1' at location 'a' from:
// [a] = [ property1, property2 ]
function getPropertySymbolOfDestructuringAssignment(location: Identifier) {
// Get the type of the object or array literal and then look for property of given name in the type
const typeOfObjectLiteral = getTypeOfArrayLiteralOrObjectLiteralDestructuringAssignment(<Expression>location.parent.parent);
return typeOfObjectLiteral && getPropertyOfType(typeOfObjectLiteral, location.escapedText);
}
function getRegularTypeOfExpression(expr: Expression): Type {
if (isRightSideOfQualifiedNameOrPropertyAccess(expr)) {
expr = <Expression>expr.parent;
}
return getRegularTypeOfLiteralType(getTypeOfExpression(expr));
}
/**
* Gets either the static or instance type of a class element, based on
* whether the element is declared as "static".
*/
function getParentTypeOfClassElement(node: ClassElement) {
const classSymbol = getSymbolOfNode(node.parent)!;
return hasModifier(node, ModifierFlags.Static)
? getTypeOfSymbol(classSymbol)
: getDeclaredTypeOfSymbol(classSymbol);
}
function getClassElementPropertyKeyType(element: ClassElement) {
const name = element.name!;
switch (name.kind) {
case SyntaxKind.Identifier:
return getLiteralType(idText(name));
case SyntaxKind.NumericLiteral:
case SyntaxKind.StringLiteral:
return getLiteralType(name.text);
case SyntaxKind.ComputedPropertyName:
const nameType = checkComputedPropertyName(name);
return isTypeAssignableToKind(nameType, TypeFlags.ESSymbolLike) ? nameType : stringType;
default:
Debug.fail("Unsupported property name.");
return errorType;
}
}
// Return the list of properties of the given type, augmented with properties from Function
// if the type has call or construct signatures
function getAugmentedPropertiesOfType(type: Type): Symbol[] {
type = getApparentType(type);
const propsByName = createSymbolTable(getPropertiesOfType(type));
const functionType = getSignaturesOfType(type, SignatureKind.Call).length ? globalCallableFunctionType :
getSignaturesOfType(type, SignatureKind.Construct).length ? globalNewableFunctionType :
undefined;
if (functionType) {
forEach(getPropertiesOfType(functionType), p => {
if (!propsByName.has(p.escapedName)) {
propsByName.set(p.escapedName, p);
}
});
}
return getNamedMembers(propsByName);
}
function typeHasCallOrConstructSignatures(type: Type): boolean {
return ts.typeHasCallOrConstructSignatures(type, checker);
}
function getRootSymbols(symbol: Symbol): ReadonlyArray<Symbol> {
const roots = getImmediateRootSymbols(symbol);
return roots ? flatMap(roots, getRootSymbols) : [symbol];
}
function getImmediateRootSymbols(symbol: Symbol): ReadonlyArray<Symbol> | undefined {
if (getCheckFlags(symbol) & CheckFlags.Synthetic) {
return mapDefined(getSymbolLinks(symbol).containingType!.types, type => getPropertyOfType(type, symbol.escapedName));
}
else if (symbol.flags & SymbolFlags.Transient) {
const { leftSpread, rightSpread, syntheticOrigin } = symbol as TransientSymbol;
return leftSpread ? [leftSpread, rightSpread!]
: syntheticOrigin ? [syntheticOrigin]
: singleElementArray(tryGetAliasTarget(symbol));
}
return undefined;
}
function tryGetAliasTarget(symbol: Symbol): Symbol | undefined {
let target: Symbol | undefined;
let next: Symbol | undefined = symbol;
while (next = getSymbolLinks(next).target) {
target = next;
}
return target;
}
// Emitter support
function isArgumentsLocalBinding(nodeIn: Identifier): boolean {
if (!isGeneratedIdentifier(nodeIn)) {
const node = getParseTreeNode(nodeIn, isIdentifier);
if (node) {
const isPropertyName = node.parent.kind === SyntaxKind.PropertyAccessExpression && (<PropertyAccessExpression>node.parent).name === node;
return !isPropertyName && getReferencedValueSymbol(node) === argumentsSymbol;
}
}
return false;
}
function moduleExportsSomeValue(moduleReferenceExpression: Expression): boolean {
let moduleSymbol = resolveExternalModuleName(moduleReferenceExpression.parent, moduleReferenceExpression);
if (!moduleSymbol || isShorthandAmbientModuleSymbol(moduleSymbol)) {
// If the module is not found or is shorthand, assume that it may export a value.
return true;
}
const hasExportAssignment = hasExportAssignmentSymbol(moduleSymbol);
// if module has export assignment then 'resolveExternalModuleSymbol' will return resolved symbol for export assignment
// otherwise it will return moduleSymbol itself
moduleSymbol = resolveExternalModuleSymbol(moduleSymbol);
const symbolLinks = getSymbolLinks(moduleSymbol);
if (symbolLinks.exportsSomeValue === undefined) {
// for export assignments - check if resolved symbol for RHS is itself a value
// otherwise - check if at least one export is value
symbolLinks.exportsSomeValue = hasExportAssignment
? !!(moduleSymbol.flags & SymbolFlags.Value)
: forEachEntry(getExportsOfModule(moduleSymbol), isValue);
}
return symbolLinks.exportsSomeValue!;
function isValue(s: Symbol): boolean {
s = resolveSymbol(s);
return s && !!(s.flags & SymbolFlags.Value);
}
}
function isNameOfModuleOrEnumDeclaration(node: Identifier) {
return isModuleOrEnumDeclaration(node.parent) && node === node.parent.name;
}
// When resolved as an expression identifier, if the given node references an exported entity, return the declaration
// node of the exported entity's container. Otherwise, return undefined.
function getReferencedExportContainer(nodeIn: Identifier, prefixLocals?: boolean): SourceFile | ModuleDeclaration | EnumDeclaration | undefined {
const node = getParseTreeNode(nodeIn, isIdentifier);
if (node) {
// When resolving the export container for the name of a module or enum
// declaration, we need to start resolution at the declaration's container.
// Otherwise, we could incorrectly resolve the export container as the
// declaration if it contains an exported member with the same name.
let symbol = getReferencedValueSymbol(node, /*startInDeclarationContainer*/ isNameOfModuleOrEnumDeclaration(node));
if (symbol) {
if (symbol.flags & SymbolFlags.ExportValue) {
// If we reference an exported entity within the same module declaration, then whether
// we prefix depends on the kind of entity. SymbolFlags.ExportHasLocal encompasses all the
// kinds that we do NOT prefix.
const exportSymbol = getMergedSymbol(symbol.exportSymbol!);
if (!prefixLocals && exportSymbol.flags & SymbolFlags.ExportHasLocal && !(exportSymbol.flags & SymbolFlags.Variable)) {
return undefined;
}
symbol = exportSymbol;
}
const parentSymbol = getParentOfSymbol(symbol);
if (parentSymbol) {
if (parentSymbol.flags & SymbolFlags.ValueModule && parentSymbol.valueDeclaration.kind === SyntaxKind.SourceFile) {
const symbolFile = <SourceFile>parentSymbol.valueDeclaration;
const referenceFile = getSourceFileOfNode(node);
// If `node` accesses an export and that export isn't in the same file, then symbol is a namespace export, so return undefined.
const symbolIsUmdExport = symbolFile !== referenceFile;
return symbolIsUmdExport ? undefined : symbolFile;
}
return findAncestor(node.parent, (n): n is ModuleDeclaration | EnumDeclaration => isModuleOrEnumDeclaration(n) && getSymbolOfNode(n) === parentSymbol);
}
}
}
}
// When resolved as an expression identifier, if the given node references an import, return the declaration of
// that import. Otherwise, return undefined.
function getReferencedImportDeclaration(nodeIn: Identifier): Declaration | undefined {
const node = getParseTreeNode(nodeIn, isIdentifier);
if (node) {
const symbol = getReferencedValueSymbol(node);
// We should only get the declaration of an alias if there isn't a local value
// declaration for the symbol
if (isNonLocalAlias(symbol, /*excludes*/ SymbolFlags.Value)) {
return getDeclarationOfAliasSymbol(symbol);
}
}
return undefined;
}
function isSymbolOfDeclarationWithCollidingName(symbol: Symbol): boolean {
if (symbol.flags & SymbolFlags.BlockScoped) {
const links = getSymbolLinks(symbol);
if (links.isDeclarationWithCollidingName === undefined) {
const container = getEnclosingBlockScopeContainer(symbol.valueDeclaration);
if (isStatementWithLocals(container)) {
const nodeLinks = getNodeLinks(symbol.valueDeclaration);
if (resolveName(container.parent, symbol.escapedName, SymbolFlags.Value, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ false)) {
// redeclaration - always should be renamed
links.isDeclarationWithCollidingName = true;
}
else if (nodeLinks.flags & NodeCheckFlags.CapturedBlockScopedBinding) {
// binding is captured in the function
// should be renamed if:
// - binding is not top level - top level bindings never collide with anything
// AND
// - binding is not declared in loop, should be renamed to avoid name reuse across siblings
// let a, b
// { let x = 1; a = () => x; }
// { let x = 100; b = () => x; }
// console.log(a()); // should print '1'
// console.log(b()); // should print '100'
// OR
// - binding is declared inside loop but not in inside initializer of iteration statement or directly inside loop body
// * variables from initializer are passed to rewritten loop body as parameters so they are not captured directly
// * variables that are declared immediately in loop body will become top level variable after loop is rewritten and thus
// they will not collide with anything
const isDeclaredInLoop = nodeLinks.flags & NodeCheckFlags.BlockScopedBindingInLoop;
const inLoopInitializer = isIterationStatement(container, /*lookInLabeledStatements*/ false);
const inLoopBodyBlock = container.kind === SyntaxKind.Block && isIterationStatement(container.parent, /*lookInLabeledStatements*/ false);
links.isDeclarationWithCollidingName = !isBlockScopedContainerTopLevel(container) && (!isDeclaredInLoop || (!inLoopInitializer && !inLoopBodyBlock));
}
else {
links.isDeclarationWithCollidingName = false;
}
}
}
return links.isDeclarationWithCollidingName!;
}
return false;
}
// When resolved as an expression identifier, if the given node references a nested block scoped entity with
// a name that either hides an existing name or might hide it when compiled downlevel,
// return the declaration of that entity. Otherwise, return undefined.
function getReferencedDeclarationWithCollidingName(nodeIn: Identifier): Declaration | undefined {
if (!isGeneratedIdentifier(nodeIn)) {
const node = getParseTreeNode(nodeIn, isIdentifier);
if (node) {
const symbol = getReferencedValueSymbol(node);
if (symbol && isSymbolOfDeclarationWithCollidingName(symbol)) {
return symbol.valueDeclaration;
}
}
}
return undefined;
}
// Return true if the given node is a declaration of a nested block scoped entity with a name that either hides an
// existing name or might hide a name when compiled downlevel
function isDeclarationWithCollidingName(nodeIn: Declaration): boolean {
const node = getParseTreeNode(nodeIn, isDeclaration);
if (node) {
const symbol = getSymbolOfNode(node);
if (symbol) {
return isSymbolOfDeclarationWithCollidingName(symbol);
}
}
return false;
}
function isValueAliasDeclaration(node: Node): boolean {
switch (node.kind) {
case SyntaxKind.ImportEqualsDeclaration:
case SyntaxKind.ImportClause:
case SyntaxKind.NamespaceImport:
case SyntaxKind.ImportSpecifier:
case SyntaxKind.ExportSpecifier:
return isAliasResolvedToValue(getSymbolOfNode(node) || unknownSymbol);
case SyntaxKind.ExportDeclaration:
const exportClause = (<ExportDeclaration>node).exportClause;
return !!exportClause && some(exportClause.elements, isValueAliasDeclaration);
case SyntaxKind.ExportAssignment:
return (<ExportAssignment>node).expression
&& (<ExportAssignment>node).expression.kind === SyntaxKind.Identifier
? isAliasResolvedToValue(getSymbolOfNode(node) || unknownSymbol)
: true;
}
return false;
}
function isTopLevelValueImportEqualsWithEntityName(nodeIn: ImportEqualsDeclaration): boolean {
const node = getParseTreeNode(nodeIn, isImportEqualsDeclaration);
if (node === undefined || node.parent.kind !== SyntaxKind.SourceFile || !isInternalModuleImportEqualsDeclaration(node)) {
// parent is not source file or it is not reference to internal module
return false;
}
const isValue = isAliasResolvedToValue(getSymbolOfNode(node));
return isValue && node.moduleReference && !nodeIsMissing(node.moduleReference);
}
function isAliasResolvedToValue(symbol: Symbol): boolean {
const target = resolveAlias(symbol);
if (target === unknownSymbol) {
return true;
}
// const enums and modules that contain only const enums are not considered values from the emit perspective
// unless 'preserveConstEnums' option is set to true
return !!(target.flags & SymbolFlags.Value) &&
(compilerOptions.preserveConstEnums || !isConstEnumOrConstEnumOnlyModule(target));
}
function isConstEnumOrConstEnumOnlyModule(s: Symbol): boolean {
return isConstEnumSymbol(s) || !!s.constEnumOnlyModule;
}
function isReferencedAliasDeclaration(node: Node, checkChildren?: boolean): boolean {
if (isAliasSymbolDeclaration(node)) {
const symbol = getSymbolOfNode(node);
if (symbol && getSymbolLinks(symbol).referenced) {
return true;
}
const target = getSymbolLinks(symbol!).target; // TODO: GH#18217
if (target && getModifierFlags(node) & ModifierFlags.Export &&
target.flags & SymbolFlags.Value && (compilerOptions.preserveConstEnums || !isConstEnumOrConstEnumOnlyModule(target))) {
// An `export import ... =` of a value symbol is always considered referenced
return true;
}
}
if (checkChildren) {
return !!forEachChild(node, node => isReferencedAliasDeclaration(node, checkChildren));
}
return false;
}
function isImplementationOfOverload(node: SignatureDeclaration) {
if (nodeIsPresent((node as FunctionLikeDeclaration).body)) {
if (isGetAccessor(node) || isSetAccessor(node)) return false; // Get or set accessors can never be overload implementations, but can have up to 2 signatures
const symbol = getSymbolOfNode(node);
const signaturesOfSymbol = getSignaturesOfSymbol(symbol);
// If this function body corresponds to function with multiple signature, it is implementation of overload
// e.g.: function foo(a: string): string;
// function foo(a: number): number;
// function foo(a: any) { // This is implementation of the overloads
// return a;
// }
return signaturesOfSymbol.length > 1 ||
// If there is single signature for the symbol, it is overload if that signature isn't coming from the node
// e.g.: function foo(a: string): string;
// function foo(a: any) { // This is implementation of the overloads
// return a;
// }
(signaturesOfSymbol.length === 1 && signaturesOfSymbol[0].declaration !== node);
}
return false;
}
function isRequiredInitializedParameter(parameter: ParameterDeclaration | JSDocParameterTag): boolean {
return !!strictNullChecks &&
!isOptionalParameter(parameter) &&
!isJSDocParameterTag(parameter) &&
!!parameter.initializer &&
!hasModifier(parameter, ModifierFlags.ParameterPropertyModifier);
}
function isOptionalUninitializedParameterProperty(parameter: ParameterDeclaration) {
return strictNullChecks &&
isOptionalParameter(parameter) &&
!parameter.initializer &&
hasModifier(parameter, ModifierFlags.ParameterPropertyModifier);
}
function isExpandoFunctionDeclaration(node: Declaration): boolean {
const declaration = getParseTreeNode(node, isFunctionDeclaration);
if (!declaration) {
return false;
}
const symbol = getSymbolOfNode(declaration);
if (!symbol || !(symbol.flags & SymbolFlags.Function)) {
return false;
}
return !!forEachEntry(getExportsOfSymbol(symbol), p => p.flags & SymbolFlags.Value && isPropertyAccessExpression(p.valueDeclaration));
}
function getPropertiesOfContainerFunction(node: Declaration): Symbol[] {
const declaration = getParseTreeNode(node, isFunctionDeclaration);
if (!declaration) {
return emptyArray;
}
const symbol = getSymbolOfNode(declaration);
return symbol && getPropertiesOfType(getTypeOfSymbol(symbol)) || emptyArray;
}
function getNodeCheckFlags(node: Node): NodeCheckFlags {
return getNodeLinks(node).flags || 0;
}
function getEnumMemberValue(node: EnumMember): string | number | undefined {
computeEnumMemberValues(node.parent);
return getNodeLinks(node).enumMemberValue;
}
function canHaveConstantValue(node: Node): node is EnumMember | AccessExpression {
switch (node.kind) {
case SyntaxKind.EnumMember:
case SyntaxKind.PropertyAccessExpression:
case SyntaxKind.ElementAccessExpression:
return true;
}
return false;
}
function getConstantValue(node: EnumMember | AccessExpression): string | number | undefined {
if (node.kind === SyntaxKind.EnumMember) {
return getEnumMemberValue(node);
}
const symbol = getNodeLinks(node).resolvedSymbol;
if (symbol && (symbol.flags & SymbolFlags.EnumMember)) {
// inline property\index accesses only for const enums
const member = symbol.valueDeclaration as EnumMember;
if (isEnumConst(member.parent)) {
return getEnumMemberValue(member);
}
}
return undefined;
}
function isFunctionType(type: Type): boolean {
return !!(type.flags & TypeFlags.Object) && getSignaturesOfType(type, SignatureKind.Call).length > 0;
}
function getTypeReferenceSerializationKind(typeNameIn: EntityName, location?: Node): TypeReferenceSerializationKind {
// ensure both `typeName` and `location` are parse tree nodes.
const typeName = getParseTreeNode(typeNameIn, isEntityName);
if (!typeName) return TypeReferenceSerializationKind.Unknown;
if (location) {
location = getParseTreeNode(location);
if (!location) return TypeReferenceSerializationKind.Unknown;
}
// Resolve the symbol as a value to ensure the type can be reached at runtime during emit.
const valueSymbol = resolveEntityName(typeName, SymbolFlags.Value, /*ignoreErrors*/ true, /*dontResolveAlias*/ false, location);
// Resolve the symbol as a type so that we can provide a more useful hint for the type serializer.
const typeSymbol = resolveEntityName(typeName, SymbolFlags.Type, /*ignoreErrors*/ true, /*dontResolveAlias*/ false, location);
if (valueSymbol && valueSymbol === typeSymbol) {
const globalPromiseSymbol = getGlobalPromiseConstructorSymbol(/*reportErrors*/ false);
if (globalPromiseSymbol && valueSymbol === globalPromiseSymbol) {
return TypeReferenceSerializationKind.Promise;
}
const constructorType = getTypeOfSymbol(valueSymbol);
if (constructorType && isConstructorType(constructorType)) {
return TypeReferenceSerializationKind.TypeWithConstructSignatureAndValue;
}
}
// We might not be able to resolve type symbol so use unknown type in that case (eg error case)
if (!typeSymbol) {
return TypeReferenceSerializationKind.Unknown;
}
const type = getDeclaredTypeOfSymbol(typeSymbol);
if (type === errorType) {
return TypeReferenceSerializationKind.Unknown;
}
else if (type.flags & TypeFlags.AnyOrUnknown) {
return TypeReferenceSerializationKind.ObjectType;
}
else if (isTypeAssignableToKind(type, TypeFlags.Void | TypeFlags.Nullable | TypeFlags.Never)) {
return TypeReferenceSerializationKind.VoidNullableOrNeverType;
}
else if (isTypeAssignableToKind(type, TypeFlags.BooleanLike)) {
return TypeReferenceSerializationKind.BooleanType;
}
else if (isTypeAssignableToKind(type, TypeFlags.NumberLike)) {
return TypeReferenceSerializationKind.NumberLikeType;
}
else if (isTypeAssignableToKind(type, TypeFlags.BigIntLike)) {
return TypeReferenceSerializationKind.BigIntLikeType;
}
else if (isTypeAssignableToKind(type, TypeFlags.StringLike)) {
return TypeReferenceSerializationKind.StringLikeType;
}
else if (isTupleType(type)) {
return TypeReferenceSerializationKind.ArrayLikeType;
}
else if (isTypeAssignableToKind(type, TypeFlags.ESSymbolLike)) {
return TypeReferenceSerializationKind.ESSymbolType;
}
else if (isFunctionType(type)) {
return TypeReferenceSerializationKind.TypeWithCallSignature;
}
else if (isArrayType(type)) {
return TypeReferenceSerializationKind.ArrayLikeType;
}
else {
return TypeReferenceSerializationKind.ObjectType;
}
}
function createTypeOfDeclaration(declarationIn: AccessorDeclaration | VariableLikeDeclaration | PropertyAccessExpression, enclosingDeclaration: Node, flags: NodeBuilderFlags, tracker: SymbolTracker, addUndefined?: boolean) {
const declaration = getParseTreeNode(declarationIn, isVariableLikeOrAccessor);
if (!declaration) {
return createToken(SyntaxKind.AnyKeyword) as KeywordTypeNode;
}
// Get type of the symbol if this is the valid symbol otherwise get type at location
const symbol = getSymbolOfNode(declaration);
let type = symbol && !(symbol.flags & (SymbolFlags.TypeLiteral | SymbolFlags.Signature))
? getWidenedLiteralType(getTypeOfSymbol(symbol))
: errorType;
if (type.flags & TypeFlags.UniqueESSymbol &&
type.symbol === symbol) {
flags |= NodeBuilderFlags.AllowUniqueESSymbolType;
}
if (addUndefined) {
type = getOptionalType(type);
}
return nodeBuilder.typeToTypeNode(type, enclosingDeclaration, flags | NodeBuilderFlags.MultilineObjectLiterals, tracker);
}
function createReturnTypeOfSignatureDeclaration(signatureDeclarationIn: SignatureDeclaration, enclosingDeclaration: Node, flags: NodeBuilderFlags, tracker: SymbolTracker) {
const signatureDeclaration = getParseTreeNode(signatureDeclarationIn, isFunctionLike);
if (!signatureDeclaration) {
return createToken(SyntaxKind.AnyKeyword) as KeywordTypeNode;
}
const signature = getSignatureFromDeclaration(signatureDeclaration);
return nodeBuilder.typeToTypeNode(getReturnTypeOfSignature(signature), enclosingDeclaration, flags | NodeBuilderFlags.MultilineObjectLiterals, tracker);
}
function createTypeOfExpression(exprIn: Expression, enclosingDeclaration: Node, flags: NodeBuilderFlags, tracker: SymbolTracker) {
const expr = getParseTreeNode(exprIn, isExpression);
if (!expr) {
return createToken(SyntaxKind.AnyKeyword) as KeywordTypeNode;
}
const type = getWidenedType(getRegularTypeOfExpression(expr));
return nodeBuilder.typeToTypeNode(type, enclosingDeclaration, flags | NodeBuilderFlags.MultilineObjectLiterals, tracker);
}
function hasGlobalName(name: string): boolean {
return globals.has(escapeLeadingUnderscores(name));
}
function getReferencedValueSymbol(reference: Identifier, startInDeclarationContainer?: boolean): Symbol | undefined {
const resolvedSymbol = getNodeLinks(reference).resolvedSymbol;
if (resolvedSymbol) {
return resolvedSymbol;
}
let location: Node = reference;
if (startInDeclarationContainer) {
// When resolving the name of a declaration as a value, we need to start resolution
// at a point outside of the declaration.
const parent = reference.parent;
if (isDeclaration(parent) && reference === parent.name) {
location = getDeclarationContainer(parent);
}
}
return resolveName(location, reference.escapedText, SymbolFlags.Value | SymbolFlags.ExportValue | SymbolFlags.Alias, /*nodeNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ true);
}
function getReferencedValueDeclaration(referenceIn: Identifier): Declaration | undefined {
if (!isGeneratedIdentifier(referenceIn)) {
const reference = getParseTreeNode(referenceIn, isIdentifier);
if (reference) {
const symbol = getReferencedValueSymbol(reference);
if (symbol) {
return getExportSymbolOfValueSymbolIfExported(symbol).valueDeclaration;
}
}
}
return undefined;
}
function isLiteralConstDeclaration(node: VariableDeclaration | PropertyDeclaration | PropertySignature | ParameterDeclaration): boolean {
if (isDeclarationReadonly(node) || isVariableDeclaration(node) && isVarConst(node)) {
return isFreshLiteralType(getTypeOfSymbol(getSymbolOfNode(node)));
}
return false;
}
function literalTypeToNode(type: FreshableType, enclosing: Node, tracker: SymbolTracker): Expression {
const enumResult = type.flags & TypeFlags.EnumLiteral ? nodeBuilder.symbolToExpression(type.symbol, SymbolFlags.Value, enclosing, /*flags*/ undefined, tracker)
: type === trueType ? createTrue() : type === falseType && createFalse();
return enumResult || createLiteral((type as LiteralType).value);
}
function createLiteralConstValue(node: VariableDeclaration | PropertyDeclaration | PropertySignature | ParameterDeclaration, tracker: SymbolTracker) {
const type = getTypeOfSymbol(getSymbolOfNode(node));
return literalTypeToNode(<FreshableType>type, node, tracker);
}
function createResolver(): EmitResolver {
// this variable and functions that use it are deliberately moved here from the outer scope
// to avoid scope pollution
const resolvedTypeReferenceDirectives = host.getResolvedTypeReferenceDirectives();
let fileToDirective: Map<string>;
if (resolvedTypeReferenceDirectives) {
// populate reverse mapping: file path -> type reference directive that was resolved to this file
fileToDirective = createMap<string>();
resolvedTypeReferenceDirectives.forEach((resolvedDirective, key) => {
if (!resolvedDirective || !resolvedDirective.resolvedFileName) {
return;
}
const file = host.getSourceFile(resolvedDirective.resolvedFileName)!;
// Add the transitive closure of path references loaded by this file (as long as they are not)
// part of an existing type reference.
addReferencedFilesToTypeDirective(file, key);
});
}
return {
getReferencedExportContainer,
getReferencedImportDeclaration,
getReferencedDeclarationWithCollidingName,
isDeclarationWithCollidingName,
isValueAliasDeclaration: node => {
node = getParseTreeNode(node);
// Synthesized nodes are always treated like values.
return node ? isValueAliasDeclaration(node) : true;
},
hasGlobalName,
isReferencedAliasDeclaration: (node, checkChildren?) => {
node = getParseTreeNode(node);
// Synthesized nodes are always treated as referenced.
return node ? isReferencedAliasDeclaration(node, checkChildren) : true;
},
getNodeCheckFlags: node => {
node = getParseTreeNode(node);
return node ? getNodeCheckFlags(node) : 0;
},
isTopLevelValueImportEqualsWithEntityName,
isDeclarationVisible,
isImplementationOfOverload,
isRequiredInitializedParameter,
isOptionalUninitializedParameterProperty,
isExpandoFunctionDeclaration,
getPropertiesOfContainerFunction,
createTypeOfDeclaration,
createReturnTypeOfSignatureDeclaration,
createTypeOfExpression,
createLiteralConstValue,
isSymbolAccessible,
isEntityNameVisible,
getConstantValue: nodeIn => {
const node = getParseTreeNode(nodeIn, canHaveConstantValue);
return node ? getConstantValue(node) : undefined;
},
collectLinkedAliases,
getReferencedValueDeclaration,
getTypeReferenceSerializationKind,
isOptionalParameter,
moduleExportsSomeValue,
isArgumentsLocalBinding,
getExternalModuleFileFromDeclaration,
getTypeReferenceDirectivesForEntityName,
getTypeReferenceDirectivesForSymbol,
isLiteralConstDeclaration,
isLateBound: (nodeIn: Declaration): nodeIn is LateBoundDeclaration => {
const node = getParseTreeNode(nodeIn, isDeclaration);
const symbol = node && getSymbolOfNode(node);
return !!(symbol && getCheckFlags(symbol) & CheckFlags.Late);
},
getJsxFactoryEntity: location => location ? (getJsxNamespace(location), (getSourceFileOfNode(location).localJsxFactory || _jsxFactoryEntity)) : _jsxFactoryEntity,
getAllAccessorDeclarations(accessor: AccessorDeclaration): AllAccessorDeclarations {
accessor = getParseTreeNode(accessor, isGetOrSetAccessorDeclaration)!; // TODO: GH#18217
const otherKind = accessor.kind === SyntaxKind.SetAccessor ? SyntaxKind.GetAccessor : SyntaxKind.SetAccessor;
const otherAccessor = getDeclarationOfKind<AccessorDeclaration>(getSymbolOfNode(accessor), otherKind);
const firstAccessor = otherAccessor && (otherAccessor.pos < accessor.pos) ? otherAccessor : accessor;
const secondAccessor = otherAccessor && (otherAccessor.pos < accessor.pos) ? accessor : otherAccessor;
const setAccessor = accessor.kind === SyntaxKind.SetAccessor ? accessor : otherAccessor as SetAccessorDeclaration;
const getAccessor = accessor.kind === SyntaxKind.GetAccessor ? accessor : otherAccessor as GetAccessorDeclaration;
return {
firstAccessor,
secondAccessor,
setAccessor,
getAccessor
};
},
getSymbolOfExternalModuleSpecifier: moduleName => resolveExternalModuleNameWorker(moduleName, moduleName, /*moduleNotFoundError*/ undefined),
isBindingCapturedByNode: (node, decl) => {
const parseNode = getParseTreeNode(node);
const parseDecl = getParseTreeNode(decl);
return !!parseNode && !!parseDecl && (isVariableDeclaration(parseDecl) || isBindingElement(parseDecl)) && isBindingCapturedByNode(parseNode, parseDecl);
}
};
function isInHeritageClause(node: PropertyAccessEntityNameExpression) {
return node.parent && node.parent.kind === SyntaxKind.ExpressionWithTypeArguments && node.parent.parent && node.parent.parent.kind === SyntaxKind.HeritageClause;
}
// defined here to avoid outer scope pollution
function getTypeReferenceDirectivesForEntityName(node: EntityNameOrEntityNameExpression): string[] | undefined {
// program does not have any files with type reference directives - bail out
if (!fileToDirective) {
return undefined;
}
// property access can only be used as values, or types when within an expression with type arguments inside a heritage clause
// qualified names can only be used as types\namespaces
// identifiers are treated as values only if they appear in type queries
let meaning = SymbolFlags.Type | SymbolFlags.Namespace;
if ((node.kind === SyntaxKind.Identifier && isInTypeQuery(node)) || (node.kind === SyntaxKind.PropertyAccessExpression && !isInHeritageClause(node))) {
meaning = SymbolFlags.Value | SymbolFlags.ExportValue;
}
const symbol = resolveEntityName(node, meaning, /*ignoreErrors*/ true);
return symbol && symbol !== unknownSymbol ? getTypeReferenceDirectivesForSymbol(symbol, meaning) : undefined;
}
// defined here to avoid outer scope pollution
function getTypeReferenceDirectivesForSymbol(symbol: Symbol, meaning?: SymbolFlags): string[] | undefined {
// program does not have any files with type reference directives - bail out
if (!fileToDirective) {
return undefined;
}
if (!isSymbolFromTypeDeclarationFile(symbol)) {
return undefined;
}
// check what declarations in the symbol can contribute to the target meaning
let typeReferenceDirectives: string[] | undefined;
for (const decl of symbol.declarations) {
// check meaning of the local symbol to see if declaration needs to be analyzed further
if (decl.symbol && decl.symbol.flags & meaning!) {
const file = getSourceFileOfNode(decl);
const typeReferenceDirective = fileToDirective.get(file.path);
if (typeReferenceDirective) {
(typeReferenceDirectives || (typeReferenceDirectives = [])).push(typeReferenceDirective);
}
else {
// found at least one entry that does not originate from type reference directive
return undefined;
}
}
}
return typeReferenceDirectives;
}
function isSymbolFromTypeDeclarationFile(symbol: Symbol): boolean {
// bail out if symbol does not have associated declarations (i.e. this is transient symbol created for property in binding pattern)
if (!symbol.declarations) {
return false;
}
// walk the parent chain for symbols to make sure that top level parent symbol is in the global scope
// external modules cannot define or contribute to type declaration files
let current = symbol;
while (true) {
const parent = getParentOfSymbol(current);
if (parent) {
current = parent;
}
else {
break;
}
}
if (current.valueDeclaration && current.valueDeclaration.kind === SyntaxKind.SourceFile && current.flags & SymbolFlags.ValueModule) {
return false;
}
// check that at least one declaration of top level symbol originates from type declaration file
for (const decl of symbol.declarations) {
const file = getSourceFileOfNode(decl);
if (fileToDirective.has(file.path)) {
return true;
}
}
return false;
}
function addReferencedFilesToTypeDirective(file: SourceFile, key: string) {
if (fileToDirective.has(file.path)) return;
fileToDirective.set(file.path, key);
for (const { fileName } of file.referencedFiles) {
const resolvedFile = resolveTripleslashReference(fileName, file.originalFileName);
const referencedFile = host.getSourceFile(resolvedFile);
if (referencedFile) {
addReferencedFilesToTypeDirective(referencedFile, key);
}
}
}
}
function getExternalModuleFileFromDeclaration(declaration: AnyImportOrReExport | ModuleDeclaration | ImportTypeNode): SourceFile | undefined {
const specifier = declaration.kind === SyntaxKind.ModuleDeclaration ? tryCast(declaration.name, isStringLiteral) : getExternalModuleName(declaration);
const moduleSymbol = resolveExternalModuleNameWorker(specifier!, specifier!, /*moduleNotFoundError*/ undefined); // TODO: GH#18217
if (!moduleSymbol) {
return undefined;
}
return getDeclarationOfKind(moduleSymbol, SyntaxKind.SourceFile);
}
function initializeTypeChecker() {
// Bind all source files and propagate errors
for (const file of host.getSourceFiles()) {
bindSourceFile(file, compilerOptions);
}
amalgamatedDuplicates = createMap();
// Initialize global symbol table
let augmentations: ReadonlyArray<StringLiteral | Identifier>[] | undefined;
for (const file of host.getSourceFiles()) {
if (file.redirectInfo) {
continue;
}
if (!isExternalOrCommonJsModule(file)) {
mergeSymbolTable(globals, file.locals!);
}
if (file.jsGlobalAugmentations) {
mergeSymbolTable(globals, file.jsGlobalAugmentations);
}
if (file.patternAmbientModules && file.patternAmbientModules.length) {
patternAmbientModules = concatenate(patternAmbientModules, file.patternAmbientModules);
}
if (file.moduleAugmentations.length) {
(augmentations || (augmentations = [])).push(file.moduleAugmentations);
}
if (file.symbol && file.symbol.globalExports) {
// Merge in UMD exports with first-in-wins semantics (see #9771)
const source = file.symbol.globalExports;
source.forEach((sourceSymbol, id) => {
if (!globals.has(id)) {
globals.set(id, sourceSymbol);
}
});
}
}
// We do global augmentations separately from module augmentations (and before creating global types) because they
// 1. Affect global types. We won't have the correct global types until global augmentations are merged. Also,
// 2. Module augmentation instantiation requires creating the type of a module, which, in turn, can require
// checking for an export or property on the module (if export=) which, in turn, can fall back to the
// apparent type of the module - either globalObjectType or globalFunctionType - which wouldn't exist if we
// did module augmentations prior to finalizing the global types.
if (augmentations) {
// merge _global_ module augmentations.
// this needs to be done after global symbol table is initialized to make sure that all ambient modules are indexed
for (const list of augmentations) {
for (const augmentation of list) {
if (!isGlobalScopeAugmentation(augmentation.parent as ModuleDeclaration)) continue;
mergeModuleAugmentation(augmentation);
}
}
}
// Setup global builtins
addToSymbolTable(globals, builtinGlobals, Diagnostics.Declaration_name_conflicts_with_built_in_global_identifier_0);
getSymbolLinks(undefinedSymbol).type = undefinedWideningType;
getSymbolLinks(argumentsSymbol).type = getGlobalType("IArguments" as __String, /*arity*/ 0, /*reportErrors*/ true);
getSymbolLinks(unknownSymbol).type = errorType;
// Initialize special types
globalArrayType = getGlobalType("Array" as __String, /*arity*/ 1, /*reportErrors*/ true);
globalObjectType = getGlobalType("Object" as __String, /*arity*/ 0, /*reportErrors*/ true);
globalFunctionType = getGlobalType("Function" as __String, /*arity*/ 0, /*reportErrors*/ true);
globalCallableFunctionType = strictBindCallApply && getGlobalType("CallableFunction" as __String, /*arity*/ 0, /*reportErrors*/ true) || globalFunctionType;
globalNewableFunctionType = strictBindCallApply && getGlobalType("NewableFunction" as __String, /*arity*/ 0, /*reportErrors*/ true) || globalFunctionType;
globalStringType = getGlobalType("String" as __String, /*arity*/ 0, /*reportErrors*/ true);
globalNumberType = getGlobalType("Number" as __String, /*arity*/ 0, /*reportErrors*/ true);
globalBooleanType = getGlobalType("Boolean" as __String, /*arity*/ 0, /*reportErrors*/ true);
globalRegExpType = getGlobalType("RegExp" as __String, /*arity*/ 0, /*reportErrors*/ true);
anyArrayType = createArrayType(anyType);
autoArrayType = createArrayType(autoType);
if (autoArrayType === emptyObjectType) {
// autoArrayType is used as a marker, so even if global Array type is not defined, it needs to be a unique type
autoArrayType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
}
globalReadonlyArrayType = <GenericType>getGlobalTypeOrUndefined("ReadonlyArray" as __String, /*arity*/ 1);
anyReadonlyArrayType = globalReadonlyArrayType ? createTypeFromGenericGlobalType(globalReadonlyArrayType, [anyType]) : anyArrayType;
globalThisType = <GenericType>getGlobalTypeOrUndefined("ThisType" as __String, /*arity*/ 1);
if (augmentations) {
// merge _nonglobal_ module augmentations.
// this needs to be done after global symbol table is initialized to make sure that all ambient modules are indexed
for (const list of augmentations) {
for (const augmentation of list) {
if (isGlobalScopeAugmentation(augmentation.parent as ModuleDeclaration)) continue;
mergeModuleAugmentation(augmentation);
}
}
}
amalgamatedDuplicates.forEach(({ firstFile, secondFile, conflictingSymbols }) => {
// If not many things conflict, issue individual errors
if (conflictingSymbols.size < 8) {
conflictingSymbols.forEach(({ isBlockScoped, firstFileLocations, secondFileLocations }, symbolName) => {
const message = isBlockScoped ? Diagnostics.Cannot_redeclare_block_scoped_variable_0 : Diagnostics.Duplicate_identifier_0;
for (const node of firstFileLocations) {
addDuplicateDeclarationError(node, message, symbolName, secondFileLocations);
}
for (const node of secondFileLocations) {
addDuplicateDeclarationError(node, message, symbolName, firstFileLocations);
}
});
}
else {
// Otherwise issue top-level error since the files appear very identical in terms of what they contain
const list = arrayFrom(conflictingSymbols.keys()).join(", ");
diagnostics.add(addRelatedInfo(
createDiagnosticForNode(firstFile, Diagnostics.Definitions_of_the_following_identifiers_conflict_with_those_in_another_file_Colon_0, list),
createDiagnosticForNode(secondFile, Diagnostics.Conflicts_are_in_this_file)
));
diagnostics.add(addRelatedInfo(
createDiagnosticForNode(secondFile, Diagnostics.Definitions_of_the_following_identifiers_conflict_with_those_in_another_file_Colon_0, list),
createDiagnosticForNode(firstFile, Diagnostics.Conflicts_are_in_this_file)
));
}
});
amalgamatedDuplicates = undefined;
}
function checkExternalEmitHelpers(location: Node, helpers: ExternalEmitHelpers) {
if ((requestedExternalEmitHelpers & helpers) !== helpers && compilerOptions.importHelpers) {
const sourceFile = getSourceFileOfNode(location);
if (isEffectiveExternalModule(sourceFile, compilerOptions) && !(location.flags & NodeFlags.Ambient)) {
const helpersModule = resolveHelpersModule(sourceFile, location);
if (helpersModule !== unknownSymbol) {
const uncheckedHelpers = helpers & ~requestedExternalEmitHelpers;
for (let helper = ExternalEmitHelpers.FirstEmitHelper; helper <= ExternalEmitHelpers.LastEmitHelper; helper <<= 1) {
if (uncheckedHelpers & helper) {
const name = getHelperName(helper);
const symbol = getSymbol(helpersModule.exports!, escapeLeadingUnderscores(name), SymbolFlags.Value);
if (!symbol) {
error(location, Diagnostics.This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1, externalHelpersModuleNameText, name);
}
}
}
}
requestedExternalEmitHelpers |= helpers;
}
}
}
function getHelperName(helper: ExternalEmitHelpers) {
switch (helper) {
case ExternalEmitHelpers.Extends: return "__extends";
case ExternalEmitHelpers.Assign: return "__assign";
case ExternalEmitHelpers.Rest: return "__rest";
case ExternalEmitHelpers.Decorate: return "__decorate";
case ExternalEmitHelpers.Metadata: return "__metadata";
case ExternalEmitHelpers.Param: return "__param";
case ExternalEmitHelpers.Awaiter: return "__awaiter";
case ExternalEmitHelpers.Generator: return "__generator";
case ExternalEmitHelpers.Values: return "__values";
case ExternalEmitHelpers.Read: return "__read";
case ExternalEmitHelpers.Spread: return "__spread";
case ExternalEmitHelpers.Await: return "__await";
case ExternalEmitHelpers.AsyncGenerator: return "__asyncGenerator";
case ExternalEmitHelpers.AsyncDelegator: return "__asyncDelegator";
case ExternalEmitHelpers.AsyncValues: return "__asyncValues";
case ExternalEmitHelpers.ExportStar: return "__exportStar";
case ExternalEmitHelpers.MakeTemplateObject: return "__makeTemplateObject";
default: return Debug.fail("Unrecognized helper");
}
}
function resolveHelpersModule(node: SourceFile, errorNode: Node) {
if (!externalHelpersModule) {
externalHelpersModule = resolveExternalModule(node, externalHelpersModuleNameText, Diagnostics.This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found, errorNode) || unknownSymbol;
}
return externalHelpersModule;
}
// GRAMMAR CHECKING
function checkGrammarDecoratorsAndModifiers(node: Node): boolean {
return checkGrammarDecorators(node) || checkGrammarModifiers(node);
}
function checkGrammarDecorators(node: Node): boolean {
if (!node.decorators) {
return false;
}
if (!nodeCanBeDecorated(node, node.parent, node.parent.parent)) {
if (node.kind === SyntaxKind.MethodDeclaration && !nodeIsPresent((<MethodDeclaration>node).body)) {
return grammarErrorOnFirstToken(node, Diagnostics.A_decorator_can_only_decorate_a_method_implementation_not_an_overload);
}
else {
return grammarErrorOnFirstToken(node, Diagnostics.Decorators_are_not_valid_here);
}
}
else if (node.kind === SyntaxKind.GetAccessor || node.kind === SyntaxKind.SetAccessor) {
const accessors = getAllAccessorDeclarations((<ClassDeclaration>node.parent).members, <AccessorDeclaration>node);
if (accessors.firstAccessor.decorators && node === accessors.secondAccessor) {
return grammarErrorOnFirstToken(node, Diagnostics.Decorators_cannot_be_applied_to_multiple_get_Slashset_accessors_of_the_same_name);
}
}
return false;
}
function checkGrammarModifiers(node: Node): boolean {
const quickResult = reportObviousModifierErrors(node);
if (quickResult !== undefined) {
return quickResult;
}
let lastStatic: Node | undefined, lastDeclare: Node | undefined, lastAsync: Node | undefined, lastReadonly: Node | undefined;
let flags = ModifierFlags.None;
for (const modifier of node.modifiers!) {
if (modifier.kind !== SyntaxKind.ReadonlyKeyword) {
if (node.kind === SyntaxKind.PropertySignature || node.kind === SyntaxKind.MethodSignature) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_appear_on_a_type_member, tokenToString(modifier.kind));
}
if (node.kind === SyntaxKind.IndexSignature) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_appear_on_an_index_signature, tokenToString(modifier.kind));
}
}
switch (modifier.kind) {
case SyntaxKind.ConstKeyword:
if (node.kind !== SyntaxKind.EnumDeclaration) {
return grammarErrorOnNode(node, Diagnostics.A_class_member_cannot_have_the_0_keyword, tokenToString(SyntaxKind.ConstKeyword));
}
break;
case SyntaxKind.PublicKeyword:
case SyntaxKind.ProtectedKeyword:
case SyntaxKind.PrivateKeyword:
const text = visibilityToString(modifierToFlag(modifier.kind));
if (flags & ModifierFlags.AccessibilityModifier) {
return grammarErrorOnNode(modifier, Diagnostics.Accessibility_modifier_already_seen);
}
else if (flags & ModifierFlags.Static) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_must_precede_1_modifier, text, "static");
}
else if (flags & ModifierFlags.Readonly) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_must_precede_1_modifier, text, "readonly");
}
else if (flags & ModifierFlags.Async) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_must_precede_1_modifier, text, "async");
}
else if (node.parent.kind === SyntaxKind.ModuleBlock || node.parent.kind === SyntaxKind.SourceFile) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_appear_on_a_module_or_namespace_element, text);
}
else if (flags & ModifierFlags.Abstract) {
if (modifier.kind === SyntaxKind.PrivateKeyword) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_be_used_with_1_modifier, text, "abstract");
}
else {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_must_precede_1_modifier, text, "abstract");
}
}
flags |= modifierToFlag(modifier.kind);
break;
case SyntaxKind.StaticKeyword:
if (flags & ModifierFlags.Static) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_already_seen, "static");
}
else if (flags & ModifierFlags.Readonly) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_must_precede_1_modifier, "static", "readonly");
}
else if (flags & ModifierFlags.Async) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_must_precede_1_modifier, "static", "async");
}
else if (node.parent.kind === SyntaxKind.ModuleBlock || node.parent.kind === SyntaxKind.SourceFile) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_appear_on_a_module_or_namespace_element, "static");
}
else if (node.kind === SyntaxKind.Parameter) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_appear_on_a_parameter, "static");
}
else if (flags & ModifierFlags.Abstract) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_be_used_with_1_modifier, "static", "abstract");
}
flags |= ModifierFlags.Static;
lastStatic = modifier;
break;
case SyntaxKind.ReadonlyKeyword:
if (flags & ModifierFlags.Readonly) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_already_seen, "readonly");
}
else if (node.kind !== SyntaxKind.PropertyDeclaration && node.kind !== SyntaxKind.PropertySignature && node.kind !== SyntaxKind.IndexSignature && node.kind !== SyntaxKind.Parameter) {
// If node.kind === SyntaxKind.Parameter, checkParameter report an error if it's not a parameter property.
return grammarErrorOnNode(modifier, Diagnostics.readonly_modifier_can_only_appear_on_a_property_declaration_or_index_signature);
}
flags |= ModifierFlags.Readonly;
lastReadonly = modifier;
break;
case SyntaxKind.ExportKeyword:
if (flags & ModifierFlags.Export) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_already_seen, "export");
}
else if (flags & ModifierFlags.Ambient) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_must_precede_1_modifier, "export", "declare");
}
else if (flags & ModifierFlags.Abstract) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_must_precede_1_modifier, "export", "abstract");
}
else if (flags & ModifierFlags.Async) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_must_precede_1_modifier, "export", "async");
}
else if (node.parent.kind === SyntaxKind.ClassDeclaration) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_appear_on_a_class_element, "export");
}
else if (node.kind === SyntaxKind.Parameter) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_appear_on_a_parameter, "export");
}
flags |= ModifierFlags.Export;
break;
case SyntaxKind.DefaultKeyword:
const container = node.parent.kind === SyntaxKind.SourceFile ? node.parent : node.parent.parent;
if (container.kind === SyntaxKind.ModuleDeclaration && !isAmbientModule(container)) {
return grammarErrorOnNode(modifier, Diagnostics.A_default_export_can_only_be_used_in_an_ECMAScript_style_module);
}
flags |= ModifierFlags.Default;
break;
case SyntaxKind.DeclareKeyword:
if (flags & ModifierFlags.Ambient) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_already_seen, "declare");
}
else if (flags & ModifierFlags.Async) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_be_used_in_an_ambient_context, "async");
}
else if (node.parent.kind === SyntaxKind.ClassDeclaration) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_appear_on_a_class_element, "declare");
}
else if (node.kind === SyntaxKind.Parameter) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_appear_on_a_parameter, "declare");
}
else if ((node.parent.flags & NodeFlags.Ambient) && node.parent.kind === SyntaxKind.ModuleBlock) {
return grammarErrorOnNode(modifier, Diagnostics.A_declare_modifier_cannot_be_used_in_an_already_ambient_context);
}
flags |= ModifierFlags.Ambient;
lastDeclare = modifier;
break;
case SyntaxKind.AbstractKeyword:
if (flags & ModifierFlags.Abstract) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_already_seen, "abstract");
}
if (node.kind !== SyntaxKind.ClassDeclaration) {
if (node.kind !== SyntaxKind.MethodDeclaration &&
node.kind !== SyntaxKind.PropertyDeclaration &&
node.kind !== SyntaxKind.GetAccessor &&
node.kind !== SyntaxKind.SetAccessor) {
return grammarErrorOnNode(modifier, Diagnostics.abstract_modifier_can_only_appear_on_a_class_method_or_property_declaration);
}
if (!(node.parent.kind === SyntaxKind.ClassDeclaration && hasModifier(node.parent, ModifierFlags.Abstract))) {
return grammarErrorOnNode(modifier, Diagnostics.Abstract_methods_can_only_appear_within_an_abstract_class);
}
if (flags & ModifierFlags.Static) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_be_used_with_1_modifier, "static", "abstract");
}
if (flags & ModifierFlags.Private) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_be_used_with_1_modifier, "private", "abstract");
}
}
flags |= ModifierFlags.Abstract;
break;
case SyntaxKind.AsyncKeyword:
if (flags & ModifierFlags.Async) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_already_seen, "async");
}
else if (flags & ModifierFlags.Ambient || node.parent.flags & NodeFlags.Ambient) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_be_used_in_an_ambient_context, "async");
}
else if (node.kind === SyntaxKind.Parameter) {
return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_appear_on_a_parameter, "async");
}
flags |= ModifierFlags.Async;
lastAsync = modifier;
break;
}
}
if (node.kind === SyntaxKind.Constructor) {
if (flags & ModifierFlags.Static) {
return grammarErrorOnNode(lastStatic!, Diagnostics._0_modifier_cannot_appear_on_a_constructor_declaration, "static");
}
if (flags & ModifierFlags.Abstract) {
return grammarErrorOnNode(lastStatic!, Diagnostics._0_modifier_cannot_appear_on_a_constructor_declaration, "abstract"); // TODO: GH#18217
}
else if (flags & ModifierFlags.Async) {
return grammarErrorOnNode(lastAsync!, Diagnostics._0_modifier_cannot_appear_on_a_constructor_declaration, "async");
}
else if (flags & ModifierFlags.Readonly) {
return grammarErrorOnNode(lastReadonly!, Diagnostics._0_modifier_cannot_appear_on_a_constructor_declaration, "readonly");
}
return false;
}
else if ((node.kind === SyntaxKind.ImportDeclaration || node.kind === SyntaxKind.ImportEqualsDeclaration) && flags & ModifierFlags.Ambient) {
return grammarErrorOnNode(lastDeclare!, Diagnostics.A_0_modifier_cannot_be_used_with_an_import_declaration, "declare");
}
else if (node.kind === SyntaxKind.Parameter && (flags & ModifierFlags.ParameterPropertyModifier) && isBindingPattern((<ParameterDeclaration>node).name)) {
return grammarErrorOnNode(node, Diagnostics.A_parameter_property_may_not_be_declared_using_a_binding_pattern);
}
else if (node.kind === SyntaxKind.Parameter && (flags & ModifierFlags.ParameterPropertyModifier) && (<ParameterDeclaration>node).dotDotDotToken) {
return grammarErrorOnNode(node, Diagnostics.A_parameter_property_cannot_be_declared_using_a_rest_parameter);
}
if (flags & ModifierFlags.Async) {
return checkGrammarAsyncModifier(node, lastAsync!);
}
return false;
}
/**
* true | false: Early return this value from checkGrammarModifiers.
* undefined: Need to do full checking on the modifiers.
*/
function reportObviousModifierErrors(node: Node): boolean | undefined {
return !node.modifiers
? false
: shouldReportBadModifier(node)
? grammarErrorOnFirstToken(node, Diagnostics.Modifiers_cannot_appear_here)
: undefined;
}
function shouldReportBadModifier(node: Node): boolean {
switch (node.kind) {
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
case SyntaxKind.Constructor:
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.PropertySignature:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.MethodSignature:
case SyntaxKind.IndexSignature:
case SyntaxKind.ModuleDeclaration:
case SyntaxKind.ImportDeclaration:
case SyntaxKind.ImportEqualsDeclaration:
case SyntaxKind.ExportDeclaration:
case SyntaxKind.ExportAssignment:
case SyntaxKind.FunctionExpression:
case SyntaxKind.ArrowFunction:
case SyntaxKind.Parameter:
return false;
default:
if (node.parent.kind === SyntaxKind.ModuleBlock || node.parent.kind === SyntaxKind.SourceFile) {
return false;
}
switch (node.kind) {
case SyntaxKind.FunctionDeclaration:
return nodeHasAnyModifiersExcept(node, SyntaxKind.AsyncKeyword);
case SyntaxKind.ClassDeclaration:
return nodeHasAnyModifiersExcept(node, SyntaxKind.AbstractKeyword);
case SyntaxKind.InterfaceDeclaration:
case SyntaxKind.VariableStatement:
case SyntaxKind.TypeAliasDeclaration:
return true;
case SyntaxKind.EnumDeclaration:
return nodeHasAnyModifiersExcept(node, SyntaxKind.ConstKeyword);
default:
Debug.fail();
return false;
}
}
}
function nodeHasAnyModifiersExcept(node: Node, allowedModifier: SyntaxKind): boolean {
return node.modifiers!.length > 1 || node.modifiers![0].kind !== allowedModifier;
}
function checkGrammarAsyncModifier(node: Node, asyncModifier: Node): boolean {
switch (node.kind) {
case SyntaxKind.MethodDeclaration:
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.FunctionExpression:
case SyntaxKind.ArrowFunction:
return false;
}
return grammarErrorOnNode(asyncModifier, Diagnostics._0_modifier_cannot_be_used_here, "async");
}
function checkGrammarForDisallowedTrailingComma(list: NodeArray<Node> | undefined, diag = Diagnostics.Trailing_comma_not_allowed): boolean {
if (list && list.hasTrailingComma) {
return grammarErrorAtPos(list[0], list.end - ",".length, ",".length, diag);
}
return false;
}
function checkGrammarTypeParameterList(typeParameters: NodeArray<TypeParameterDeclaration> | undefined, file: SourceFile): boolean {
if (typeParameters && typeParameters.length === 0) {
const start = typeParameters.pos - "<".length;
const end = skipTrivia(file.text, typeParameters.end) + ">".length;
return grammarErrorAtPos(file, start, end - start, Diagnostics.Type_parameter_list_cannot_be_empty);
}
return false;
}
function checkGrammarParameterList(parameters: NodeArray<ParameterDeclaration>) {
let seenOptionalParameter = false;
const parameterCount = parameters.length;
for (let i = 0; i < parameterCount; i++) {
const parameter = parameters[i];
if (parameter.dotDotDotToken) {
if (i !== (parameterCount - 1)) {
return grammarErrorOnNode(parameter.dotDotDotToken, Diagnostics.A_rest_parameter_must_be_last_in_a_parameter_list);
}
if (!(parameter.flags & NodeFlags.Ambient)) { // Allow `...foo,` in ambient declarations; see GH#23070
checkGrammarForDisallowedTrailingComma(parameters, Diagnostics.A_rest_parameter_or_binding_pattern_may_not_have_a_trailing_comma);
}
if (parameter.questionToken) {
return grammarErrorOnNode(parameter.questionToken, Diagnostics.A_rest_parameter_cannot_be_optional);
}
if (parameter.initializer) {
return grammarErrorOnNode(parameter.name, Diagnostics.A_rest_parameter_cannot_have_an_initializer);
}
}
else if (parameter.questionToken) {
seenOptionalParameter = true;
if (parameter.initializer) {
return grammarErrorOnNode(parameter.name, Diagnostics.Parameter_cannot_have_question_mark_and_initializer);
}
}
else if (seenOptionalParameter && !parameter.initializer) {
return grammarErrorOnNode(parameter.name, Diagnostics.A_required_parameter_cannot_follow_an_optional_parameter);
}
}
}
function getNonSimpleParameters(parameters: ReadonlyArray<ParameterDeclaration>): ReadonlyArray<ParameterDeclaration> {
return filter(parameters, parameter => !!parameter.initializer || isBindingPattern(parameter.name) || isRestParameter(parameter));
}
function checkGrammarForUseStrictSimpleParameterList(node: FunctionLikeDeclaration): boolean {
if (languageVersion >= ScriptTarget.ES2016) {
const useStrictDirective = node.body && isBlock(node.body) && findUseStrictPrologue(node.body.statements);
if (useStrictDirective) {
const nonSimpleParameters = getNonSimpleParameters(node.parameters);
if (length(nonSimpleParameters)) {
forEach(nonSimpleParameters, parameter => {
addRelatedInfo(
error(parameter, Diagnostics.This_parameter_is_not_allowed_with_use_strict_directive),
createDiagnosticForNode(useStrictDirective, Diagnostics.use_strict_directive_used_here)
);
});
const diagnostics = nonSimpleParameters.map((parameter, index) => (
index === 0 ? createDiagnosticForNode(parameter, Diagnostics.Non_simple_parameter_declared_here) : createDiagnosticForNode(parameter, Diagnostics.and_here)
)) as [DiagnosticWithLocation, ...DiagnosticWithLocation[]];
addRelatedInfo(error(useStrictDirective, Diagnostics.use_strict_directive_cannot_be_used_with_non_simple_parameter_list), ...diagnostics);
return true;
}
}
}
return false;
}
function checkGrammarFunctionLikeDeclaration(node: FunctionLikeDeclaration | MethodSignature): boolean {
// Prevent cascading error by short-circuit
const file = getSourceFileOfNode(node);
return checkGrammarDecoratorsAndModifiers(node) || checkGrammarTypeParameterList(node.typeParameters, file) ||
checkGrammarParameterList(node.parameters) || checkGrammarArrowFunction(node, file) ||
(isFunctionLikeDeclaration(node) && checkGrammarForUseStrictSimpleParameterList(node));
}
function checkGrammarClassLikeDeclaration(node: ClassLikeDeclaration): boolean {
const file = getSourceFileOfNode(node);
return checkGrammarClassDeclarationHeritageClauses(node) || checkGrammarTypeParameterList(node.typeParameters, file);
}
function checkGrammarArrowFunction(node: Node, file: SourceFile): boolean {
if (!isArrowFunction(node)) {
return false;
}
const { equalsGreaterThanToken } = node;
const startLine = getLineAndCharacterOfPosition(file, equalsGreaterThanToken.pos).line;
const endLine = getLineAndCharacterOfPosition(file, equalsGreaterThanToken.end).line;
return startLine !== endLine && grammarErrorOnNode(equalsGreaterThanToken, Diagnostics.Line_terminator_not_permitted_before_arrow);
}
function checkGrammarIndexSignatureParameters(node: SignatureDeclaration): boolean {
const parameter = node.parameters[0];
if (node.parameters.length !== 1) {
if (parameter) {
return grammarErrorOnNode(parameter.name, Diagnostics.An_index_signature_must_have_exactly_one_parameter);
}
else {
return grammarErrorOnNode(node, Diagnostics.An_index_signature_must_have_exactly_one_parameter);
}
}
if (parameter.dotDotDotToken) {
return grammarErrorOnNode(parameter.dotDotDotToken, Diagnostics.An_index_signature_cannot_have_a_rest_parameter);
}
if (hasModifiers(parameter)) {
return grammarErrorOnNode(parameter.name, Diagnostics.An_index_signature_parameter_cannot_have_an_accessibility_modifier);
}
if (parameter.questionToken) {
return grammarErrorOnNode(parameter.questionToken, Diagnostics.An_index_signature_parameter_cannot_have_a_question_mark);
}
if (parameter.initializer) {
return grammarErrorOnNode(parameter.name, Diagnostics.An_index_signature_parameter_cannot_have_an_initializer);
}
if (!parameter.type) {
return grammarErrorOnNode(parameter.name, Diagnostics.An_index_signature_parameter_must_have_a_type_annotation);
}
if (parameter.type.kind !== SyntaxKind.StringKeyword && parameter.type.kind !== SyntaxKind.NumberKeyword) {
const type = getTypeFromTypeNode(parameter.type);
if (type.flags & TypeFlags.String || type.flags & TypeFlags.Number) {
return grammarErrorOnNode(parameter.name,
Diagnostics.An_index_signature_parameter_type_cannot_be_a_type_alias_Consider_writing_0_Colon_1_Colon_2_instead,
getTextOfNode(parameter.name),
typeToString(type),
typeToString(getTypeFromTypeNode(node.type!)));
}
if (type.flags & TypeFlags.Union && allTypesAssignableToKind(type, TypeFlags.StringLiteral, /*strict*/ true)) {
return grammarErrorOnNode(parameter.name,
Diagnostics.An_index_signature_parameter_type_cannot_be_a_union_type_Consider_using_a_mapped_object_type_instead);
}
return grammarErrorOnNode(parameter.name, Diagnostics.An_index_signature_parameter_type_must_be_string_or_number);
}
if (!node.type) {
return grammarErrorOnNode(node, Diagnostics.An_index_signature_must_have_a_type_annotation);
}
return false;
}
function checkGrammarIndexSignature(node: SignatureDeclaration) {
// Prevent cascading error by short-circuit
return checkGrammarDecoratorsAndModifiers(node) || checkGrammarIndexSignatureParameters(node);
}
function checkGrammarForAtLeastOneTypeArgument(node: Node, typeArguments: NodeArray<TypeNode> | undefined): boolean {
if (typeArguments && typeArguments.length === 0) {
const sourceFile = getSourceFileOfNode(node);
const start = typeArguments.pos - "<".length;
const end = skipTrivia(sourceFile.text, typeArguments.end) + ">".length;
return grammarErrorAtPos(sourceFile, start, end - start, Diagnostics.Type_argument_list_cannot_be_empty);
}
return false;
}
function checkGrammarTypeArguments(node: Node, typeArguments: NodeArray<TypeNode> | undefined): boolean {
return checkGrammarForDisallowedTrailingComma(typeArguments) ||
checkGrammarForAtLeastOneTypeArgument(node, typeArguments);
}
function checkGrammarForOmittedArgument(args: NodeArray<Expression> | undefined): boolean {
if (args) {
for (const arg of args) {
if (arg.kind === SyntaxKind.OmittedExpression) {
return grammarErrorAtPos(arg, arg.pos, 0, Diagnostics.Argument_expression_expected);
}
}
}
return false;
}
function checkGrammarArguments(args: NodeArray<Expression> | undefined): boolean {
return checkGrammarForOmittedArgument(args);
}
function checkGrammarHeritageClause(node: HeritageClause): boolean {
const types = node.types;
if (checkGrammarForDisallowedTrailingComma(types)) {
return true;
}
if (types && types.length === 0) {
const listType = tokenToString(node.token);
return grammarErrorAtPos(node, types.pos, 0, Diagnostics._0_list_cannot_be_empty, listType);
}
return some(types, checkGrammarExpressionWithTypeArguments);
}
function checkGrammarExpressionWithTypeArguments(node: ExpressionWithTypeArguments) {
return checkGrammarTypeArguments(node, node.typeArguments);
}
function checkGrammarClassDeclarationHeritageClauses(node: ClassLikeDeclaration) {
let seenExtendsClause = false;
let seenImplementsClause = false;
if (!checkGrammarDecoratorsAndModifiers(node) && node.heritageClauses) {
for (const heritageClause of node.heritageClauses) {
if (heritageClause.token === SyntaxKind.ExtendsKeyword) {
if (seenExtendsClause) {
return grammarErrorOnFirstToken(heritageClause, Diagnostics.extends_clause_already_seen);
}
if (seenImplementsClause) {
return grammarErrorOnFirstToken(heritageClause, Diagnostics.extends_clause_must_precede_implements_clause);
}
if (heritageClause.types.length > 1) {
return grammarErrorOnFirstToken(heritageClause.types[1], Diagnostics.Classes_can_only_extend_a_single_class);
}
seenExtendsClause = true;
}
else {
Debug.assert(heritageClause.token === SyntaxKind.ImplementsKeyword);
if (seenImplementsClause) {
return grammarErrorOnFirstToken(heritageClause, Diagnostics.implements_clause_already_seen);
}
seenImplementsClause = true;
}
// Grammar checking heritageClause inside class declaration
checkGrammarHeritageClause(heritageClause);
}
}
}
function checkGrammarInterfaceDeclaration(node: InterfaceDeclaration) {
let seenExtendsClause = false;
if (node.heritageClauses) {
for (const heritageClause of node.heritageClauses) {
if (heritageClause.token === SyntaxKind.ExtendsKeyword) {
if (seenExtendsClause) {
return grammarErrorOnFirstToken(heritageClause, Diagnostics.extends_clause_already_seen);
}
seenExtendsClause = true;
}
else {
Debug.assert(heritageClause.token === SyntaxKind.ImplementsKeyword);
return grammarErrorOnFirstToken(heritageClause, Diagnostics.Interface_declaration_cannot_have_implements_clause);
}
// Grammar checking heritageClause inside class declaration
checkGrammarHeritageClause(heritageClause);
}
}
return false;
}
function checkGrammarComputedPropertyName(node: Node): boolean {
// If node is not a computedPropertyName, just skip the grammar checking
if (node.kind !== SyntaxKind.ComputedPropertyName) {
return false;
}
const computedPropertyName = <ComputedPropertyName>node;
if (computedPropertyName.expression.kind === SyntaxKind.BinaryExpression && (<BinaryExpression>computedPropertyName.expression).operatorToken.kind === SyntaxKind.CommaToken) {
return grammarErrorOnNode(computedPropertyName.expression, Diagnostics.A_comma_expression_is_not_allowed_in_a_computed_property_name);
}
return false;
}
function checkGrammarForGenerator(node: FunctionLikeDeclaration) {
if (node.asteriskToken) {
Debug.assert(
node.kind === SyntaxKind.FunctionDeclaration ||
node.kind === SyntaxKind.FunctionExpression ||
node.kind === SyntaxKind.MethodDeclaration);
if (node.flags & NodeFlags.Ambient) {
return grammarErrorOnNode(node.asteriskToken!, Diagnostics.Generators_are_not_allowed_in_an_ambient_context);
}
if (!node.body) {
return grammarErrorOnNode(node.asteriskToken!, Diagnostics.An_overload_signature_cannot_be_declared_as_a_generator);
}
}
}
function checkGrammarForInvalidQuestionMark(questionToken: QuestionToken | undefined, message: DiagnosticMessage): boolean {
return !!questionToken && grammarErrorOnNode(questionToken, message);
}
function checkGrammarForInvalidExclamationToken(exclamationToken: ExclamationToken | undefined, message: DiagnosticMessage): boolean {
return !!exclamationToken && grammarErrorOnNode(exclamationToken, message);
}
function checkGrammarObjectLiteralExpression(node: ObjectLiteralExpression, inDestructuring: boolean) {
const enum Flags {
Property = 1,
GetAccessor = 2,
SetAccessor = 4,
GetOrSetAccessor = GetAccessor | SetAccessor,
}
const seen = createUnderscoreEscapedMap<Flags>();
for (const prop of node.properties) {
if (prop.kind === SyntaxKind.SpreadAssignment) {
continue;
}
const name = prop.name;
if (name.kind === SyntaxKind.ComputedPropertyName) {
// If the name is not a ComputedPropertyName, the grammar checking will skip it
checkGrammarComputedPropertyName(name);
}
if (prop.kind === SyntaxKind.ShorthandPropertyAssignment && !inDestructuring && prop.objectAssignmentInitializer) {
// having objectAssignmentInitializer is only valid in ObjectAssignmentPattern
// outside of destructuring it is a syntax error
return grammarErrorOnNode(prop.equalsToken!, Diagnostics.can_only_be_used_in_an_object_literal_property_inside_a_destructuring_assignment);
}
// Modifiers are never allowed on properties except for 'async' on a method declaration
if (prop.modifiers) {
for (const mod of prop.modifiers!) { // TODO: GH#19955
if (mod.kind !== SyntaxKind.AsyncKeyword || prop.kind !== SyntaxKind.MethodDeclaration) {
grammarErrorOnNode(mod, Diagnostics._0_modifier_cannot_be_used_here, getTextOfNode(mod));
}
}
}
// ECMA-262 11.1.5 Object Initializer
// If previous is not undefined then throw a SyntaxError exception if any of the following conditions are true
// a.This production is contained in strict code and IsDataDescriptor(previous) is true and
// IsDataDescriptor(propId.descriptor) is true.
// b.IsDataDescriptor(previous) is true and IsAccessorDescriptor(propId.descriptor) is true.
// c.IsAccessorDescriptor(previous) is true and IsDataDescriptor(propId.descriptor) is true.
// d.IsAccessorDescriptor(previous) is true and IsAccessorDescriptor(propId.descriptor) is true
// and either both previous and propId.descriptor have[[Get]] fields or both previous and propId.descriptor have[[Set]] fields
let currentKind: Flags;
switch (prop.kind) {
case SyntaxKind.ShorthandPropertyAssignment:
checkGrammarForInvalidExclamationToken(prop.exclamationToken, Diagnostics.A_definite_assignment_assertion_is_not_permitted_in_this_context);
/* tslint:disable:no-switch-case-fall-through */
case SyntaxKind.PropertyAssignment:
// Grammar checking for computedPropertyName and shorthandPropertyAssignment
checkGrammarForInvalidQuestionMark(prop.questionToken, Diagnostics.An_object_member_cannot_be_declared_optional);
if (name.kind === SyntaxKind.NumericLiteral) {
checkGrammarNumericLiteral(name);
}
// falls through
case SyntaxKind.MethodDeclaration:
currentKind = Flags.Property;
break;
case SyntaxKind.GetAccessor:
currentKind = Flags.GetAccessor;
break;
case SyntaxKind.SetAccessor:
currentKind = Flags.SetAccessor;
break;
default:
throw Debug.assertNever(prop, "Unexpected syntax kind:" + (<Node>prop).kind);
}
const effectiveName = getPropertyNameForPropertyNameNode(name);
if (effectiveName === undefined) {
continue;
}
const existingKind = seen.get(effectiveName);
if (!existingKind) {
seen.set(effectiveName, currentKind);
}
else {
if (currentKind === Flags.Property && existingKind === Flags.Property) {
grammarErrorOnNode(name, Diagnostics.Duplicate_identifier_0, getTextOfNode(name));
}
else if ((currentKind & Flags.GetOrSetAccessor) && (existingKind & Flags.GetOrSetAccessor)) {
if (existingKind !== Flags.GetOrSetAccessor && currentKind !== existingKind) {
seen.set(effectiveName, currentKind | existingKind);
}
else {
return grammarErrorOnNode(name, Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name);
}
}
else {
return grammarErrorOnNode(name, Diagnostics.An_object_literal_cannot_have_property_and_accessor_with_the_same_name);
}
}
}
}
function checkGrammarJsxElement(node: JsxOpeningLikeElement) {
checkGrammarTypeArguments(node, node.typeArguments);
const seen = createUnderscoreEscapedMap<boolean>();
for (const attr of node.attributes.properties) {
if (attr.kind === SyntaxKind.JsxSpreadAttribute) {
continue;
}
const { name, initializer } = attr;
if (!seen.get(name.escapedText)) {
seen.set(name.escapedText, true);
}
else {
return grammarErrorOnNode(name, Diagnostics.JSX_elements_cannot_have_multiple_attributes_with_the_same_name);
}
if (initializer && initializer.kind === SyntaxKind.JsxExpression && !initializer.expression) {
return grammarErrorOnNode(initializer, Diagnostics.JSX_attributes_must_only_be_assigned_a_non_empty_expression);
}
}
}
function checkGrammarForInOrForOfStatement(forInOrOfStatement: ForInOrOfStatement): boolean {
if (checkGrammarStatementInAmbientContext(forInOrOfStatement)) {
return true;
}
if (forInOrOfStatement.kind === SyntaxKind.ForOfStatement && forInOrOfStatement.awaitModifier) {
if ((forInOrOfStatement.flags & NodeFlags.AwaitContext) === NodeFlags.None) {
return grammarErrorOnNode(forInOrOfStatement.awaitModifier, Diagnostics.A_for_await_of_statement_is_only_allowed_within_an_async_function_or_async_generator);
}
}
if (forInOrOfStatement.initializer.kind === SyntaxKind.VariableDeclarationList) {
const variableList = <VariableDeclarationList>forInOrOfStatement.initializer;
if (!checkGrammarVariableDeclarationList(variableList)) {
const declarations = variableList.declarations;
// declarations.length can be zero if there is an error in variable declaration in for-of or for-in
// See http://www.ecma-international.org/ecma-262/6.0/#sec-for-in-and-for-of-statements for details
// For example:
// var let = 10;
// for (let of [1,2,3]) {} // this is invalid ES6 syntax
// for (let in [1,2,3]) {} // this is invalid ES6 syntax
// We will then want to skip on grammar checking on variableList declaration
if (!declarations.length) {
return false;
}
if (declarations.length > 1) {
const diagnostic = forInOrOfStatement.kind === SyntaxKind.ForInStatement
? Diagnostics.Only_a_single_variable_declaration_is_allowed_in_a_for_in_statement
: Diagnostics.Only_a_single_variable_declaration_is_allowed_in_a_for_of_statement;
return grammarErrorOnFirstToken(variableList.declarations[1], diagnostic);
}
const firstDeclaration = declarations[0];
if (firstDeclaration.initializer) {
const diagnostic = forInOrOfStatement.kind === SyntaxKind.ForInStatement
? Diagnostics.The_variable_declaration_of_a_for_in_statement_cannot_have_an_initializer
: Diagnostics.The_variable_declaration_of_a_for_of_statement_cannot_have_an_initializer;
return grammarErrorOnNode(firstDeclaration.name, diagnostic);
}
if (firstDeclaration.type) {
const diagnostic = forInOrOfStatement.kind === SyntaxKind.ForInStatement
? Diagnostics.The_left_hand_side_of_a_for_in_statement_cannot_use_a_type_annotation
: Diagnostics.The_left_hand_side_of_a_for_of_statement_cannot_use_a_type_annotation;
return grammarErrorOnNode(firstDeclaration, diagnostic);
}
}
}
return false;
}
function checkGrammarAccessor(accessor: AccessorDeclaration): boolean {
const kind = accessor.kind;
if (languageVersion < ScriptTarget.ES5) {
return grammarErrorOnNode(accessor.name, Diagnostics.Accessors_are_only_available_when_targeting_ECMAScript_5_and_higher);
}
else if (accessor.flags & NodeFlags.Ambient) {
return grammarErrorOnNode(accessor.name, Diagnostics.An_accessor_cannot_be_declared_in_an_ambient_context);
}
else if (accessor.body === undefined && !hasModifier(accessor, ModifierFlags.Abstract)) {
return grammarErrorAtPos(accessor, accessor.end - 1, ";".length, Diagnostics._0_expected, "{");
}
else if (accessor.body && hasModifier(accessor, ModifierFlags.Abstract)) {
return grammarErrorOnNode(accessor, Diagnostics.An_abstract_accessor_cannot_have_an_implementation);
}
else if (accessor.typeParameters) {
return grammarErrorOnNode(accessor.name, Diagnostics.An_accessor_cannot_have_type_parameters);
}
else if (!doesAccessorHaveCorrectParameterCount(accessor)) {
return grammarErrorOnNode(accessor.name,
kind === SyntaxKind.GetAccessor ?
Diagnostics.A_get_accessor_cannot_have_parameters :
Diagnostics.A_set_accessor_must_have_exactly_one_parameter);
}
else if (kind === SyntaxKind.SetAccessor) {
if (accessor.type) {
return grammarErrorOnNode(accessor.name, Diagnostics.A_set_accessor_cannot_have_a_return_type_annotation);
}
else {
const parameter = accessor.parameters[0];
if (parameter.dotDotDotToken) {
return grammarErrorOnNode(parameter.dotDotDotToken, Diagnostics.A_set_accessor_cannot_have_rest_parameter);
}
else if (parameter.questionToken) {
return grammarErrorOnNode(parameter.questionToken, Diagnostics.A_set_accessor_cannot_have_an_optional_parameter);
}
else if (parameter.initializer) {
return grammarErrorOnNode(accessor.name, Diagnostics.A_set_accessor_parameter_cannot_have_an_initializer);
}
}
}
return false;
}
/** Does the accessor have the right number of parameters?
* A get accessor has no parameters or a single `this` parameter.
* A set accessor has one parameter or a `this` parameter and one more parameter.
*/
function doesAccessorHaveCorrectParameterCount(accessor: AccessorDeclaration) {
return getAccessorThisParameter(accessor) || accessor.parameters.length === (accessor.kind === SyntaxKind.GetAccessor ? 0 : 1);
}
function getAccessorThisParameter(accessor: AccessorDeclaration): ParameterDeclaration | undefined {
if (accessor.parameters.length === (accessor.kind === SyntaxKind.GetAccessor ? 1 : 2)) {
return getThisParameter(accessor);
}
}
function checkGrammarTypeOperatorNode(node: TypeOperatorNode) {
if (node.operator === SyntaxKind.UniqueKeyword) {
if (node.type.kind !== SyntaxKind.SymbolKeyword) {
return grammarErrorOnNode(node.type, Diagnostics._0_expected, tokenToString(SyntaxKind.SymbolKeyword));
}
const parent = walkUpParenthesizedTypes(node.parent);
switch (parent.kind) {
case SyntaxKind.VariableDeclaration:
const decl = parent as VariableDeclaration;
if (decl.name.kind !== SyntaxKind.Identifier) {
return grammarErrorOnNode(node, Diagnostics.unique_symbol_types_may_not_be_used_on_a_variable_declaration_with_a_binding_name);
}
if (!isVariableDeclarationInVariableStatement(decl)) {
return grammarErrorOnNode(node, Diagnostics.unique_symbol_types_are_only_allowed_on_variables_in_a_variable_statement);
}
if (!(decl.parent.flags & NodeFlags.Const)) {
return grammarErrorOnNode((<VariableDeclaration>parent).name, Diagnostics.A_variable_whose_type_is_a_unique_symbol_type_must_be_const);
}
break;
case SyntaxKind.PropertyDeclaration:
if (!hasModifier(parent, ModifierFlags.Static) ||
!hasModifier(parent, ModifierFlags.Readonly)) {
return grammarErrorOnNode((<PropertyDeclaration>parent).name, Diagnostics.A_property_of_a_class_whose_type_is_a_unique_symbol_type_must_be_both_static_and_readonly);
}
break;
case SyntaxKind.PropertySignature:
if (!hasModifier(parent, ModifierFlags.Readonly)) {
return grammarErrorOnNode((<PropertySignature>parent).name, Diagnostics.A_property_of_an_interface_or_type_literal_whose_type_is_a_unique_symbol_type_must_be_readonly);
}
break;
default:
return grammarErrorOnNode(node, Diagnostics.unique_symbol_types_are_not_allowed_here);
}
}
else if (node.operator === SyntaxKind.ReadonlyKeyword) {
if (node.type.kind !== SyntaxKind.ArrayType && node.type.kind !== SyntaxKind.TupleType) {
return grammarErrorOnFirstToken(node, Diagnostics.readonly_type_modifier_is_only_permitted_on_array_and_tuple_literal_types, tokenToString(SyntaxKind.SymbolKeyword));
}
}
}
function checkGrammarForInvalidDynamicName(node: DeclarationName, message: DiagnosticMessage) {
if (isNonBindableDynamicName(node)) {
return grammarErrorOnNode(node, message);
}
}
function checkGrammarMethod(node: MethodDeclaration | MethodSignature) {
if (checkGrammarFunctionLikeDeclaration(node)) {
return true;
}
if (node.kind === SyntaxKind.MethodDeclaration) {
if (node.parent.kind === SyntaxKind.ObjectLiteralExpression) {
// We only disallow modifier on a method declaration if it is a property of object-literal-expression
if (node.modifiers && !(node.modifiers.length === 1 && first(node.modifiers).kind === SyntaxKind.AsyncKeyword)) {
return grammarErrorOnFirstToken(node, Diagnostics.Modifiers_cannot_appear_here);
}
else if (checkGrammarForInvalidQuestionMark(node.questionToken, Diagnostics.An_object_member_cannot_be_declared_optional)) {
return true;
}
else if (checkGrammarForInvalidExclamationToken(node.exclamationToken, Diagnostics.A_definite_assignment_assertion_is_not_permitted_in_this_context)) {
return true;
}
else if (node.body === undefined) {
return grammarErrorAtPos(node, node.end - 1, ";".length, Diagnostics._0_expected, "{");
}
}
if (checkGrammarForGenerator(node)) {
return true;
}
}
if (isClassLike(node.parent)) {
// Technically, computed properties in ambient contexts is disallowed
// for property declarations and accessors too, not just methods.
// However, property declarations disallow computed names in general,
// and accessors are not allowed in ambient contexts in general,
// so this error only really matters for methods.
if (node.flags & NodeFlags.Ambient) {
return checkGrammarForInvalidDynamicName(node.name, Diagnostics.A_computed_property_name_in_an_ambient_context_must_refer_to_an_expression_whose_type_is_a_literal_type_or_a_unique_symbol_type);
}
else if (node.kind === SyntaxKind.MethodDeclaration && !node.body) {
return checkGrammarForInvalidDynamicName(node.name, Diagnostics.A_computed_property_name_in_a_method_overload_must_refer_to_an_expression_whose_type_is_a_literal_type_or_a_unique_symbol_type);
}
}
else if (node.parent.kind === SyntaxKind.InterfaceDeclaration) {
return checkGrammarForInvalidDynamicName(node.name, Diagnostics.A_computed_property_name_in_an_interface_must_refer_to_an_expression_whose_type_is_a_literal_type_or_a_unique_symbol_type);
}
else if (node.parent.kind === SyntaxKind.TypeLiteral) {
return checkGrammarForInvalidDynamicName(node.name, Diagnostics.A_computed_property_name_in_a_type_literal_must_refer_to_an_expression_whose_type_is_a_literal_type_or_a_unique_symbol_type);
}
}
function checkGrammarBreakOrContinueStatement(node: BreakOrContinueStatement): boolean {
let current: Node = node;
while (current) {
if (isFunctionLike(current)) {
return grammarErrorOnNode(node, Diagnostics.Jump_target_cannot_cross_function_boundary);
}
switch (current.kind) {
case SyntaxKind.LabeledStatement:
if (node.label && (<LabeledStatement>current).label.escapedText === node.label.escapedText) {
// found matching label - verify that label usage is correct
// continue can only target labels that are on iteration statements
const isMisplacedContinueLabel = node.kind === SyntaxKind.ContinueStatement
&& !isIterationStatement((<LabeledStatement>current).statement, /*lookInLabeledStatement*/ true);
if (isMisplacedContinueLabel) {
return grammarErrorOnNode(node, Diagnostics.A_continue_statement_can_only_jump_to_a_label_of_an_enclosing_iteration_statement);
}
return false;
}
break;
case SyntaxKind.SwitchStatement:
if (node.kind === SyntaxKind.BreakStatement && !node.label) {
// unlabeled break within switch statement - ok
return false;
}
break;
default:
if (isIterationStatement(current, /*lookInLabeledStatement*/ false) && !node.label) {
// unlabeled break or continue within iteration statement - ok
return false;
}
break;
}
current = current.parent;
}
if (node.label) {
const message = node.kind === SyntaxKind.BreakStatement
? Diagnostics.A_break_statement_can_only_jump_to_a_label_of_an_enclosing_statement
: Diagnostics.A_continue_statement_can_only_jump_to_a_label_of_an_enclosing_iteration_statement;
return grammarErrorOnNode(node, message);
}
else {
const message = node.kind === SyntaxKind.BreakStatement
? Diagnostics.A_break_statement_can_only_be_used_within_an_enclosing_iteration_or_switch_statement
: Diagnostics.A_continue_statement_can_only_be_used_within_an_enclosing_iteration_statement;
return grammarErrorOnNode(node, message);
}
}
function checkGrammarBindingElement(node: BindingElement) {
if (node.dotDotDotToken) {
const elements = node.parent.elements;
if (node !== last(elements)) {
return grammarErrorOnNode(node, Diagnostics.A_rest_element_must_be_last_in_a_destructuring_pattern);
}
checkGrammarForDisallowedTrailingComma(elements, Diagnostics.A_rest_parameter_or_binding_pattern_may_not_have_a_trailing_comma);
if (node.propertyName) {
return grammarErrorOnNode(node.name, Diagnostics.A_rest_element_cannot_have_a_property_name);
}
if (node.initializer) {
// Error on equals token which immediately precedes the initializer
return grammarErrorAtPos(node, node.initializer.pos - 1, 1, Diagnostics.A_rest_element_cannot_have_an_initializer);
}
}
}
function isStringOrNumberLiteralExpression(expr: Expression) {
return expr.kind === SyntaxKind.StringLiteral || expr.kind === SyntaxKind.NumericLiteral ||
expr.kind === SyntaxKind.PrefixUnaryExpression && (<PrefixUnaryExpression>expr).operator === SyntaxKind.MinusToken &&
(<PrefixUnaryExpression>expr).operand.kind === SyntaxKind.NumericLiteral;
}
function isBigIntLiteralExpression(expr: Expression) {
return expr.kind === SyntaxKind.BigIntLiteral ||
expr.kind === SyntaxKind.PrefixUnaryExpression && (<PrefixUnaryExpression>expr).operator === SyntaxKind.MinusToken &&
(<PrefixUnaryExpression>expr).operand.kind === SyntaxKind.BigIntLiteral;
}
function isSimpleLiteralEnumReference(expr: Expression) {
if (
(isPropertyAccessExpression(expr) || (isElementAccessExpression(expr) && isStringOrNumberLiteralExpression(expr.argumentExpression))) &&
isEntityNameExpression(expr.expression)
) return !!(checkExpressionCached(expr).flags & TypeFlags.EnumLiteral);
}
function checkAmbientInitializer(node: VariableDeclaration | PropertyDeclaration | PropertySignature) {
const {initializer} = node;
if (initializer) {
const isInvalidInitializer = !(
isStringOrNumberLiteralExpression(initializer) ||
isSimpleLiteralEnumReference(initializer) ||
initializer.kind === SyntaxKind.TrueKeyword || initializer.kind === SyntaxKind.FalseKeyword ||
isBigIntLiteralExpression(initializer)
);
const isConstOrReadonly = isDeclarationReadonly(node) || isVariableDeclaration(node) && isVarConst(node);
if (isConstOrReadonly && !node.type) {
if (isInvalidInitializer) {
return grammarErrorOnNode(initializer, Diagnostics.A_const_initializer_in_an_ambient_context_must_be_a_string_or_numeric_literal_or_literal_enum_reference);
}
}
else {
return grammarErrorOnNode(initializer, Diagnostics.Initializers_are_not_allowed_in_ambient_contexts);
}
if (!isConstOrReadonly || isInvalidInitializer) {
return grammarErrorOnNode(initializer, Diagnostics.Initializers_are_not_allowed_in_ambient_contexts);
}
}
}
function checkGrammarVariableDeclaration(node: VariableDeclaration) {
if (node.parent.parent.kind !== SyntaxKind.ForInStatement && node.parent.parent.kind !== SyntaxKind.ForOfStatement) {
if (node.flags & NodeFlags.Ambient) {
checkAmbientInitializer(node);
}
else if (!node.initializer) {
if (isBindingPattern(node.name) && !isBindingPattern(node.parent)) {
return grammarErrorOnNode(node, Diagnostics.A_destructuring_declaration_must_have_an_initializer);
}
if (isVarConst(node)) {
return grammarErrorOnNode(node, Diagnostics.const_declarations_must_be_initialized);
}
}
}
if (node.exclamationToken && (node.parent.parent.kind !== SyntaxKind.VariableStatement || !node.type || node.initializer || node.flags & NodeFlags.Ambient)) {
return grammarErrorOnNode(node.exclamationToken, Diagnostics.A_definite_assignment_assertion_is_not_permitted_in_this_context);
}
if (compilerOptions.module !== ModuleKind.ES2015 && compilerOptions.module !== ModuleKind.ESNext && compilerOptions.module !== ModuleKind.System && !compilerOptions.noEmit &&
!(node.parent.parent.flags & NodeFlags.Ambient) && hasModifier(node.parent.parent, ModifierFlags.Export)) {
checkESModuleMarker(node.name);
}
const checkLetConstNames = (isLet(node) || isVarConst(node));
// 1. LexicalDeclaration : LetOrConst BindingList ;
// It is a Syntax Error if the BoundNames of BindingList contains "let".
// 2. ForDeclaration: ForDeclaration : LetOrConst ForBinding
// It is a Syntax Error if the BoundNames of ForDeclaration contains "let".
// It is a SyntaxError if a VariableDeclaration or VariableDeclarationNoIn occurs within strict code
// and its Identifier is eval or arguments
return checkLetConstNames && checkGrammarNameInLetOrConstDeclarations(node.name);
}
function checkESModuleMarker(name: Identifier | BindingPattern): boolean {
if (name.kind === SyntaxKind.Identifier) {
if (idText(name) === "__esModule") {
return grammarErrorOnNode(name, Diagnostics.Identifier_expected_esModule_is_reserved_as_an_exported_marker_when_transforming_ECMAScript_modules);
}
}
else {
const elements = name.elements;
for (const element of elements) {
if (!isOmittedExpression(element)) {
return checkESModuleMarker(element.name);
}
}
}
return false;
}
function checkGrammarNameInLetOrConstDeclarations(name: Identifier | BindingPattern): boolean {
if (name.kind === SyntaxKind.Identifier) {
if (name.originalKeywordKind === SyntaxKind.LetKeyword) {
return grammarErrorOnNode(name, Diagnostics.let_is_not_allowed_to_be_used_as_a_name_in_let_or_const_declarations);
}
}
else {
const elements = name.elements;
for (const element of elements) {
if (!isOmittedExpression(element)) {
checkGrammarNameInLetOrConstDeclarations(element.name);
}
}
}
return false;
}
function checkGrammarVariableDeclarationList(declarationList: VariableDeclarationList): boolean {
const declarations = declarationList.declarations;
if (checkGrammarForDisallowedTrailingComma(declarationList.declarations)) {
return true;
}
if (!declarationList.declarations.length) {
return grammarErrorAtPos(declarationList, declarations.pos, declarations.end - declarations.pos, Diagnostics.Variable_declaration_list_cannot_be_empty);
}
return false;
}
function allowLetAndConstDeclarations(parent: Node): boolean {
switch (parent.kind) {
case SyntaxKind.IfStatement:
case SyntaxKind.DoStatement:
case SyntaxKind.WhileStatement:
case SyntaxKind.WithStatement:
case SyntaxKind.ForStatement:
case SyntaxKind.ForInStatement:
case SyntaxKind.ForOfStatement:
return false;
case SyntaxKind.LabeledStatement:
return allowLetAndConstDeclarations(parent.parent);
}
return true;
}
function checkGrammarForDisallowedLetOrConstStatement(node: VariableStatement) {
if (!allowLetAndConstDeclarations(node.parent)) {
if (isLet(node.declarationList)) {
return grammarErrorOnNode(node, Diagnostics.let_declarations_can_only_be_declared_inside_a_block);
}
else if (isVarConst(node.declarationList)) {
return grammarErrorOnNode(node, Diagnostics.const_declarations_can_only_be_declared_inside_a_block);
}
}
}
function checkGrammarMetaProperty(node: MetaProperty) {
const escapedText = node.name.escapedText;
switch (node.keywordToken) {
case SyntaxKind.NewKeyword:
if (escapedText !== "target") {
return grammarErrorOnNode(node.name, Diagnostics._0_is_not_a_valid_meta_property_for_keyword_1_Did_you_mean_2, node.name.escapedText, tokenToString(node.keywordToken), "target");
}
break;
case SyntaxKind.ImportKeyword:
if (escapedText !== "meta") {
return grammarErrorOnNode(node.name, Diagnostics._0_is_not_a_valid_meta_property_for_keyword_1_Did_you_mean_2, node.name.escapedText, tokenToString(node.keywordToken), "meta");
}
break;
}
}
function hasParseDiagnostics(sourceFile: SourceFile): boolean {
return sourceFile.parseDiagnostics.length > 0;
}
function grammarErrorOnFirstToken(node: Node, message: DiagnosticMessage, arg0?: any, arg1?: any, arg2?: any): boolean {
const sourceFile = getSourceFileOfNode(node);
if (!hasParseDiagnostics(sourceFile)) {
const span = getSpanOfTokenAtPosition(sourceFile, node.pos);
diagnostics.add(createFileDiagnostic(sourceFile, span.start, span.length, message, arg0, arg1, arg2));
return true;
}
return false;
}
function grammarErrorAtPos(nodeForSourceFile: Node, start: number, length: number, message: DiagnosticMessage, arg0?: any, arg1?: any, arg2?: any): boolean {
const sourceFile = getSourceFileOfNode(nodeForSourceFile);
if (!hasParseDiagnostics(sourceFile)) {
diagnostics.add(createFileDiagnostic(sourceFile, start, length, message, arg0, arg1, arg2));
return true;
}
return false;
}
function grammarErrorOnNode(node: Node, message: DiagnosticMessage, arg0?: any, arg1?: any, arg2?: any): boolean {
const sourceFile = getSourceFileOfNode(node);
if (!hasParseDiagnostics(sourceFile)) {
diagnostics.add(createDiagnosticForNode(node, message, arg0, arg1, arg2));
return true;
}
return false;
}
function checkGrammarConstructorTypeParameters(node: ConstructorDeclaration) {
const jsdocTypeParameters = isInJSFile(node) ? getJSDocTypeParameterDeclarations(node) : undefined;
const range = node.typeParameters || jsdocTypeParameters && firstOrUndefined(jsdocTypeParameters);
if (range) {
const pos = range.pos === range.end ? range.pos : skipTrivia(getSourceFileOfNode(node).text, range.pos);
return grammarErrorAtPos(node, pos, range.end - pos, Diagnostics.Type_parameters_cannot_appear_on_a_constructor_declaration);
}
}
function checkGrammarConstructorTypeAnnotation(node: ConstructorDeclaration) {
const type = getEffectiveReturnTypeNode(node);
if (type) {
return grammarErrorOnNode(type, Diagnostics.Type_annotation_cannot_appear_on_a_constructor_declaration);
}
}
function checkGrammarProperty(node: PropertyDeclaration | PropertySignature) {
if (isClassLike(node.parent)) {
if (checkGrammarForInvalidDynamicName(node.name, Diagnostics.A_computed_property_name_in_a_class_property_declaration_must_refer_to_an_expression_whose_type_is_a_literal_type_or_a_unique_symbol_type)) {
return true;
}
}
else if (node.parent.kind === SyntaxKind.InterfaceDeclaration) {
if (checkGrammarForInvalidDynamicName(node.name, Diagnostics.A_computed_property_name_in_an_interface_must_refer_to_an_expression_whose_type_is_a_literal_type_or_a_unique_symbol_type)) {
return true;
}
if (node.initializer) {
return grammarErrorOnNode(node.initializer, Diagnostics.An_interface_property_cannot_have_an_initializer);
}
}
else if (node.parent.kind === SyntaxKind.TypeLiteral) {
if (checkGrammarForInvalidDynamicName(node.name, Diagnostics.A_computed_property_name_in_a_type_literal_must_refer_to_an_expression_whose_type_is_a_literal_type_or_a_unique_symbol_type)) {
return true;
}
if (node.initializer) {
return grammarErrorOnNode(node.initializer, Diagnostics.A_type_literal_property_cannot_have_an_initializer);
}
}
if (node.flags & NodeFlags.Ambient) {
checkAmbientInitializer(node);
}
if (isPropertyDeclaration(node) && node.exclamationToken && (!isClassLike(node.parent) || !node.type || node.initializer ||
node.flags & NodeFlags.Ambient || hasModifier(node, ModifierFlags.Static | ModifierFlags.Abstract))) {
return grammarErrorOnNode(node.exclamationToken, Diagnostics.A_definite_assignment_assertion_is_not_permitted_in_this_context);
}
}
function checkGrammarTopLevelElementForRequiredDeclareModifier(node: Node): boolean {
// A declare modifier is required for any top level .d.ts declaration except export=, export default, export as namespace
// interfaces and imports categories:
//
// DeclarationElement:
// ExportAssignment
// export_opt InterfaceDeclaration
// export_opt TypeAliasDeclaration
// export_opt ImportDeclaration
// export_opt ExternalImportDeclaration
// export_opt AmbientDeclaration
//
// TODO: The spec needs to be amended to reflect this grammar.
if (node.kind === SyntaxKind.InterfaceDeclaration ||
node.kind === SyntaxKind.TypeAliasDeclaration ||
node.kind === SyntaxKind.ImportDeclaration ||
node.kind === SyntaxKind.ImportEqualsDeclaration ||
node.kind === SyntaxKind.ExportDeclaration ||
node.kind === SyntaxKind.ExportAssignment ||
node.kind === SyntaxKind.NamespaceExportDeclaration ||
hasModifier(node, ModifierFlags.Ambient | ModifierFlags.Export | ModifierFlags.Default)) {
return false;
}
return grammarErrorOnFirstToken(node, Diagnostics.A_declare_modifier_is_required_for_a_top_level_declaration_in_a_d_ts_file);
}
function checkGrammarTopLevelElementsForRequiredDeclareModifier(file: SourceFile): boolean {
for (const decl of file.statements) {
if (isDeclaration(decl) || decl.kind === SyntaxKind.VariableStatement) {
if (checkGrammarTopLevelElementForRequiredDeclareModifier(decl)) {
return true;
}
}
}
return false;
}
function checkGrammarSourceFile(node: SourceFile): boolean {
return !!(node.flags & NodeFlags.Ambient) && checkGrammarTopLevelElementsForRequiredDeclareModifier(node);
}
function checkGrammarStatementInAmbientContext(node: Node): boolean {
if (node.flags & NodeFlags.Ambient) {
// An accessors is already reported about the ambient context
if (isAccessor(node.parent)) {
return getNodeLinks(node).hasReportedStatementInAmbientContext = true;
}
// Find containing block which is either Block, ModuleBlock, SourceFile
const links = getNodeLinks(node);
if (!links.hasReportedStatementInAmbientContext && isFunctionLike(node.parent)) {
return getNodeLinks(node).hasReportedStatementInAmbientContext = grammarErrorOnFirstToken(node, Diagnostics.An_implementation_cannot_be_declared_in_ambient_contexts);
}
// We are either parented by another statement, or some sort of block.
// If we're in a block, we only want to really report an error once
// to prevent noisiness. So use a bit on the block to indicate if
// this has already been reported, and don't report if it has.
//
if (node.parent.kind === SyntaxKind.Block || node.parent.kind === SyntaxKind.ModuleBlock || node.parent.kind === SyntaxKind.SourceFile) {
const links = getNodeLinks(node.parent);
// Check if the containing block ever report this error
if (!links.hasReportedStatementInAmbientContext) {
return links.hasReportedStatementInAmbientContext = grammarErrorOnFirstToken(node, Diagnostics.Statements_are_not_allowed_in_ambient_contexts);
}
}
else {
// We must be parented by a statement. If so, there's no need
// to report the error as our parent will have already done it.
// Debug.assert(isStatement(node.parent));
}
}
return false;
}
function checkGrammarNumericLiteral(node: NumericLiteral): boolean {
// Grammar checking
if (node.numericLiteralFlags & TokenFlags.Octal) {
let diagnosticMessage: DiagnosticMessage | undefined;
if (languageVersion >= ScriptTarget.ES5) {
diagnosticMessage = Diagnostics.Octal_literals_are_not_available_when_targeting_ECMAScript_5_and_higher_Use_the_syntax_0;
}
else if (isChildOfNodeWithKind(node, SyntaxKind.LiteralType)) {
diagnosticMessage = Diagnostics.Octal_literal_types_must_use_ES2015_syntax_Use_the_syntax_0;
}
else if (isChildOfNodeWithKind(node, SyntaxKind.EnumMember)) {
diagnosticMessage = Diagnostics.Octal_literals_are_not_allowed_in_enums_members_initializer_Use_the_syntax_0;
}
if (diagnosticMessage) {
const withMinus = isPrefixUnaryExpression(node.parent) && node.parent.operator === SyntaxKind.MinusToken;
const literal = (withMinus ? "-" : "") + "0o" + node.text;
return grammarErrorOnNode(withMinus ? node.parent : node, diagnosticMessage, literal);
}
}
return false;
}
function checkGrammarBigIntLiteral(node: BigIntLiteral): boolean {
const literalType = isLiteralTypeNode(node.parent) ||
isPrefixUnaryExpression(node.parent) && isLiteralTypeNode(node.parent.parent);
if (!literalType) {
if (languageVersion < ScriptTarget.ESNext) {
if (grammarErrorOnNode(node, Diagnostics.BigInt_literals_are_not_available_when_targeting_lower_than_ESNext)) {
return true;
}
}
}
return false;
}
function grammarErrorAfterFirstToken(node: Node, message: DiagnosticMessage, arg0?: any, arg1?: any, arg2?: any): boolean {
const sourceFile = getSourceFileOfNode(node);
if (!hasParseDiagnostics(sourceFile)) {
const span = getSpanOfTokenAtPosition(sourceFile, node.pos);
diagnostics.add(createFileDiagnostic(sourceFile, textSpanEnd(span), /*length*/ 0, message, arg0, arg1, arg2));
return true;
}
return false;
}
function getAmbientModules(): Symbol[] {
if (!ambientModulesCache) {
ambientModulesCache = [];
globals.forEach((global, sym) => {
// No need to `unescapeLeadingUnderscores`, an escaped symbol is never an ambient module.
if (ambientModuleSymbolRegex.test(sym as string)) {
ambientModulesCache!.push(global);
}
});
}
return ambientModulesCache;
}
function checkGrammarImportCallExpression(node: ImportCall): boolean {
if (moduleKind === ModuleKind.ES2015) {
return grammarErrorOnNode(node, Diagnostics.Dynamic_import_is_only_supported_when_module_flag_is_commonjs_or_esNext);
}
if (node.typeArguments) {
return grammarErrorOnNode(node, Diagnostics.Dynamic_import_cannot_have_type_arguments);
}
const nodeArguments = node.arguments;
if (nodeArguments.length !== 1) {
return grammarErrorOnNode(node, Diagnostics.Dynamic_import_must_have_one_specifier_as_an_argument);
}
checkGrammarForDisallowedTrailingComma(nodeArguments);
// see: parseArgumentOrArrayLiteralElement...we use this function which parse arguments of callExpression to parse specifier for dynamic import.
// parseArgumentOrArrayLiteralElement allows spread element to be in an argument list which is not allowed as specifier in dynamic import.
if (isSpreadElement(nodeArguments[0])) {
return grammarErrorOnNode(nodeArguments[0], Diagnostics.Specifier_of_dynamic_import_cannot_be_spread_element);
}
return false;
}
}
/** Like 'isDeclarationName', but returns true for LHS of `import { x as y }` or `export { x as y }`. */
function isDeclarationNameOrImportPropertyName(name: Node): boolean {
switch (name.parent.kind) {
case SyntaxKind.ImportSpecifier:
case SyntaxKind.ExportSpecifier:
return isIdentifier(name);
default:
return isDeclarationName(name);
}
}
function isSomeImportDeclaration(decl: Node): boolean {
switch (decl.kind) {
case SyntaxKind.ImportClause: // For default import
case SyntaxKind.ImportEqualsDeclaration:
case SyntaxKind.NamespaceImport:
case SyntaxKind.ImportSpecifier: // For rename import `x as y`
return true;
case SyntaxKind.Identifier:
// For regular import, `decl` is an Identifier under the ImportSpecifier.
return decl.parent.kind === SyntaxKind.ImportSpecifier;
default:
return false;
}
}
namespace JsxNames {
// tslint:disable variable-name
export const JSX = "JSX" as __String;
export const IntrinsicElements = "IntrinsicElements" as __String;
export const ElementClass = "ElementClass" as __String;
export const ElementAttributesPropertyNameContainer = "ElementAttributesProperty" as __String; // TODO: Deprecate and remove support
export const ElementChildrenAttributeNameContainer = "ElementChildrenAttribute" as __String;
export const Element = "Element" as __String;
export const IntrinsicAttributes = "IntrinsicAttributes" as __String;
export const IntrinsicClassAttributes = "IntrinsicClassAttributes" as __String;
export const LibraryManagedAttributes = "LibraryManagedAttributes" as __String;
// tslint:enable variable-name
}
}