import { __String, AccessExpression, AccessFlags, AccessorDeclaration, addRange, addRelatedInfo, addSyntheticLeadingComment, AliasDeclarationNode, AllAccessorDeclarations, AmbientModuleDeclaration, and, AnonymousType, AnyImportOrReExport, AnyImportSyntax, append, appendIfUnique, ArrayBindingPattern, arrayFrom, arrayIsHomogeneous, ArrayLiteralExpression, arrayOf, arraysEqual, arrayToMultiMap, ArrayTypeNode, ArrowFunction, AsExpression, AssertionExpression, AssignmentDeclarationKind, AssignmentKind, AssignmentPattern, AwaitExpression, BaseType, BigIntLiteral, BigIntLiteralType, BinaryExpression, BinaryOperatorToken, binarySearch, BindableObjectDefinePropertyCall, BindableStaticNameExpression, BindingElement, BindingElementGrandparent, BindingName, BindingPattern, bindSourceFile, Block, BreakOrContinueStatement, CallChain, CallExpression, CallLikeExpression, CallSignatureDeclaration, CancellationToken, canHaveDecorators, canHaveExportModifier, canHaveFlowNode, canHaveIllegalDecorators, canHaveIllegalModifiers, canHaveJSDoc, canHaveLocals, canHaveModifiers, canHaveSymbol, canUsePropertyAccess, cartesianProduct, CaseBlock, CaseClause, CaseOrDefaultClause, cast, chainDiagnosticMessages, CharacterCodes, CheckFlags, ClassDeclaration, ClassElement, classElementOrClassElementParameterIsDecorated, ClassExpression, ClassLikeDeclaration, classOrConstructorParameterIsDecorated, ClassStaticBlockDeclaration, clear, combinePaths, compareDiagnostics, comparePaths, compareValues, Comparison, CompilerOptions, ComputedPropertyName, concatenate, concatenateDiagnosticMessageChains, ConditionalExpression, ConditionalRoot, ConditionalType, ConditionalTypeNode, ConstructorDeclaration, ConstructorTypeNode, ConstructSignatureDeclaration, contains, containsParseError, ContextFlags, copyEntries, countWhere, createBinaryExpressionTrampoline, createCompilerDiagnostic, createDiagnosticCollection, createDiagnosticForFileFromMessageChain, createDiagnosticForNode, createDiagnosticForNodeArray, createDiagnosticForNodeArrayFromMessageChain, createDiagnosticForNodeFromMessageChain, createDiagnosticMessageChainFromDiagnostic, createEmptyExports, createFileDiagnostic, createGetCanonicalFileName, createGetSymbolWalker, createModeAwareCacheKey, createModuleNotFoundChain, createMultiMap, createPrinterWithDefaults, createPrinterWithRemoveComments, createPrinterWithRemoveCommentsNeverAsciiEscape, createPrinterWithRemoveCommentsOmitTrailingSemicolon, createPropertyNameNodeForIdentifierOrLiteral, createSymbolTable, createTextWriter, Debug, Declaration, DeclarationName, declarationNameToString, DeclarationStatement, DeclarationWithTypeParameterChildren, DeclarationWithTypeParameters, Decorator, deduplicate, DefaultClause, defaultMaximumTruncationLength, DeferredTypeReference, DeleteExpression, Diagnostic, DiagnosticAndArguments, DiagnosticArguments, DiagnosticCategory, DiagnosticMessage, DiagnosticMessageChain, DiagnosticRelatedInformation, Diagnostics, DiagnosticWithLocation, DoStatement, DynamicNamedDeclaration, ElementAccessChain, ElementAccessExpression, ElementFlags, EmitFlags, EmitHint, emitModuleKindIsNonNodeESM, EmitResolver, EmitTextWriter, emptyArray, endsWith, EntityName, EntityNameExpression, EntityNameOrEntityNameExpression, entityNameToString, EnumDeclaration, EnumMember, EnumType, equateValues, escapeLeadingUnderscores, escapeString, every, EvolvingArrayType, ExclamationToken, ExportAssignment, exportAssignmentIsAlias, ExportDeclaration, ExportSpecifier, Expression, expressionResultIsUnused, ExpressionStatement, ExpressionWithTypeArguments, Extension, ExternalEmitHelpers, externalHelpersModuleNameText, factory, fileExtensionIs, fileExtensionIsOneOf, filter, find, findAncestor, findBestPatternMatch, findIndex, findLast, findLastIndex, findUseStrictPrologue, first, firstDefined, firstIterator, firstOrUndefined, firstOrUndefinedIterator, flatMap, flatten, FlowArrayMutation, FlowAssignment, FlowCall, FlowCondition, FlowFlags, FlowLabel, FlowNode, FlowReduceLabel, FlowStart, FlowSwitchClause, FlowType, forEach, forEachChild, forEachChildRecursively, forEachEnclosingBlockScopeContainer, forEachEntry, forEachImportClauseDeclaration, forEachKey, forEachReturnStatement, forEachYieldExpression, ForInOrOfStatement, ForInStatement, formatMessage, ForOfStatement, ForStatement, FreshableIntrinsicType, FreshableType, FreshObjectLiteralType, FunctionDeclaration, FunctionExpression, FunctionFlags, FunctionLikeDeclaration, FunctionOrConstructorTypeNode, FunctionTypeNode, GenericType, GetAccessorDeclaration, getAliasDeclarationFromName, getAllAccessorDeclarations, getAllJSDocTags, getAllowSyntheticDefaultImports, getAncestor, getAssignedExpandoInitializer, getAssignmentDeclarationKind, getAssignmentDeclarationPropertyAccessKind, getAssignmentTargetKind, getCheckFlags, getClassExtendsHeritageElement, getClassLikeDeclarationOfSymbol, getCombinedLocalAndExportSymbolFlags, getCombinedModifierFlags, getCombinedNodeFlags, getContainingClass, getContainingClassStaticBlock, getContainingFunction, getContainingFunctionOrClassStaticBlock, getDeclarationModifierFlagsFromSymbol, getDeclarationOfKind, getDeclarationsOfKind, getDeclaredExpandoInitializer, getDecorators, getDirectoryPath, getEffectiveBaseTypeNode, getEffectiveConstraintOfTypeParameter, getEffectiveContainerForJSDocTemplateTag, getEffectiveImplementsTypeNodes, getEffectiveInitializer, getEffectiveJSDocHost, getEffectiveModifierFlags, getEffectiveReturnTypeNode, getEffectiveSetAccessorTypeAnnotationNode, getEffectiveTypeAnnotationNode, getEffectiveTypeParameterDeclarations, getElementOrPropertyAccessName, getEmitDeclarations, getEmitModuleKind, getEmitModuleResolutionKind, getEmitScriptTarget, getEnclosingBlockScopeContainer, getEntityNameFromTypeNode, getErrorSpanForNode, getEscapedTextOfIdentifierOrLiteral, getEscapedTextOfJsxAttributeName, getEscapedTextOfJsxNamespacedName, getESModuleInterop, getExpandoInitializer, getExportAssignmentExpression, getExternalModuleImportEqualsDeclarationExpression, getExternalModuleName, getExternalModuleRequireArgument, getFirstConstructorWithBody, getFirstIdentifier, getFunctionFlags, getHostSignatureFromJSDoc, getIdentifierGeneratedImportReference, getIdentifierTypeArguments, getImmediatelyInvokedFunctionExpression, getInitializerOfBinaryExpression, getInterfaceBaseTypeNodes, getInvokedExpression, getIsolatedModules, getJSDocClassTag, getJSDocDeprecatedTag, getJSDocEnumTag, getJSDocHost, getJSDocParameterTags, getJSDocRoot, getJSDocSatisfiesExpressionType, getJSDocTags, getJSDocThisTag, getJSDocType, getJSDocTypeAssertionType, getJSDocTypeParameterDeclarations, getJSDocTypeTag, getJSXImplicitImportBase, getJSXRuntimeImport, getJSXTransformEnabled, getLeftmostAccessExpression, getLineAndCharacterOfPosition, getLocalSymbolForExportDefault, getMembersOfDeclaration, getModeForUsageLocation, getModifiers, getModuleInstanceState, getNameFromIndexInfo, getNameOfDeclaration, getNameOfExpando, getNamespaceDeclarationNode, getNewTargetContainer, getNonAugmentationDeclaration, getNormalizedAbsolutePath, getObjectFlags, getOriginalNode, getOrUpdate, getParameterSymbolFromJSDoc, getParseTreeNode, getPropertyAssignmentAliasLikeExpression, getPropertyNameForPropertyNameNode, getResolutionDiagnostic, getResolutionModeOverrideForClause, getResolvedExternalModuleName, getResolvedModule, getResolveJsonModule, getRestParameterElementType, getRootDeclaration, getScriptTargetFeatures, getSelectedEffectiveModifierFlags, getSemanticJsxChildren, getSetAccessorValueParameter, getSingleVariableOfVariableStatement, getSourceFileOfModule, getSourceFileOfNode, getSpanOfTokenAtPosition, getSpellingSuggestion, getStrictOptionValue, getSuperContainer, getSymbolNameForPrivateIdentifier, getTextOfIdentifierOrLiteral, getTextOfJSDocComment, getTextOfJsxAttributeName, getTextOfNode, getTextOfPropertyName, getThisContainer, getThisParameter, getTrailingSemicolonDeferringWriter, getTypeParameterFromJsDoc, getUseDefineForClassFields, group, hasAbstractModifier, hasAccessorModifier, hasAmbientModifier, hasContextSensitiveParameters, HasDecorators, hasDecorators, hasDynamicName, hasEffectiveModifier, hasEffectiveModifiers, hasEffectiveReadonlyModifier, HasExpressionInitializer, hasExtension, HasIllegalDecorators, HasIllegalModifiers, HasInitializer, hasInitializer, hasJSDocNodes, hasJSDocParameterTags, hasJsonModuleEmitEnabled, HasLocals, HasModifiers, hasOnlyExpressionInitializer, hasOverrideModifier, hasPossibleExternalModuleReference, hasQuestionToken, hasRestParameter, hasScopeMarker, hasStaticModifier, hasSyntacticModifier, hasSyntacticModifiers, hasType, HeritageClause, Identifier, identifierToKeywordKind, IdentifierTypePredicate, idText, IfStatement, ImportCall, ImportClause, ImportDeclaration, ImportEqualsDeclaration, ImportOrExportSpecifier, ImportsNotUsedAsValues, ImportSpecifier, ImportTypeAssertionContainer, ImportTypeNode, IndexedAccessType, IndexedAccessTypeNode, IndexFlags, IndexInfo, IndexKind, indexOfNode, IndexSignatureDeclaration, IndexType, indicesOf, InferenceContext, InferenceFlags, InferenceInfo, InferencePriority, InferTypeNode, InstantiableType, InstantiationExpressionType, InterfaceDeclaration, InterfaceType, InterfaceTypeWithDeclaredMembers, InternalSymbolName, IntersectionType, IntersectionTypeNode, intrinsicTagNameToString, IntrinsicType, introducesArgumentsExoticObject, isAccessExpression, isAccessor, isAliasableExpression, isAmbientModule, isArray, isArrayBindingPattern, isArrayLiteralExpression, isArrowFunction, isAssertionExpression, isAssignmentDeclaration, isAssignmentExpression, isAssignmentOperator, isAssignmentPattern, isAssignmentTarget, isAsyncFunction, isAutoAccessorPropertyDeclaration, isAwaitExpression, isBinaryExpression, isBindableObjectDefinePropertyCall, isBindableStaticElementAccessExpression, isBindableStaticNameExpression, isBindingElement, isBindingElementOfBareOrAccessedRequire, isBindingPattern, isBlock, isBlockOrCatchScoped, isBlockScopedContainerTopLevel, isBooleanLiteral, isCallChain, isCallExpression, isCallLikeExpression, isCallOrNewExpression, isCallSignatureDeclaration, isCatchClause, isCatchClauseVariableDeclarationOrBindingElement, isCheckJsEnabledForFile, isClassDeclaration, isClassElement, isClassExpression, isClassLike, isClassStaticBlockDeclaration, isCommaSequence, isCommonJsExportedExpression, isCommonJsExportPropertyAssignment, isCompoundAssignment, isComputedNonLiteralName, isComputedPropertyName, isConstructorDeclaration, isConstructorTypeNode, isConstructSignatureDeclaration, isConstTypeReference, isDeclaration, isDeclarationFileName, isDeclarationName, isDeclarationReadonly, isDecorator, isDefaultedExpandoInitializer, isDeleteTarget, isDottedName, isDynamicName, isEffectiveExternalModule, isElementAccessExpression, isEntityName, isEntityNameExpression, isEnumConst, isEnumDeclaration, isEnumMember, isExclusivelyTypeOnlyImportOrExport, isExportAssignment, isExportDeclaration, isExportsIdentifier, isExportSpecifier, isExpression, isExpressionNode, isExpressionOfOptionalChainRoot, isExpressionStatement, isExpressionWithTypeArguments, isExpressionWithTypeArgumentsInClassExtendsClause, isExternalModule, isExternalModuleAugmentation, isExternalModuleImportEqualsDeclaration, isExternalModuleIndicator, isExternalModuleNameRelative, isExternalModuleReference, isExternalOrCommonJsModule, isForInOrOfStatement, isForInStatement, isForOfStatement, isForStatement, isFunctionDeclaration, isFunctionExpression, isFunctionExpressionOrArrowFunction, isFunctionLike, isFunctionLikeDeclaration, isFunctionLikeOrClassStaticBlockDeclaration, isFunctionOrModuleBlock, isFunctionTypeNode, isGeneratedIdentifier, isGetAccessor, isGetAccessorDeclaration, isGetOrSetAccessorDeclaration, isGlobalScopeAugmentation, isHeritageClause, isIdentifier, isIdentifierText, isIdentifierTypePredicate, isIdentifierTypeReference, isIfStatement, isImportCall, isImportClause, isImportDeclaration, isImportEqualsDeclaration, isImportKeyword, isImportOrExportSpecifier, isImportSpecifier, isImportTypeNode, isIndexedAccessTypeNode, isInExpressionContext, isInfinityOrNaNString, isInitializedProperty, isInJSDoc, isInJSFile, isInJsonFile, isInterfaceDeclaration, isInternalModuleImportEqualsDeclaration, isInTopLevelContext, isIntrinsicJsxName, isIterationStatement, isJSDocAllType, isJSDocAugmentsTag, isJSDocCallbackTag, isJSDocConstructSignature, isJSDocFunctionType, isJSDocIndexSignature, isJSDocLinkLike, isJSDocMemberName, isJSDocNameReference, isJSDocNode, isJSDocNonNullableType, isJSDocNullableType, isJSDocOptionalParameter, isJSDocOptionalType, isJSDocOverloadTag, isJSDocParameterTag, isJSDocPropertyLikeTag, isJSDocPropertyTag, isJSDocReturnTag, isJSDocSatisfiesExpression, isJSDocSatisfiesTag, isJSDocSignature, isJSDocTemplateTag, isJSDocTypeAlias, isJSDocTypeAssertion, isJSDocTypedefTag, isJSDocTypeExpression, isJSDocTypeLiteral, isJSDocTypeTag, isJSDocUnknownType, isJSDocVariadicType, isJsonSourceFile, isJsxAttribute, isJsxAttributeLike, isJsxAttributes, isJsxElement, isJsxNamespacedName, isJsxOpeningElement, isJsxOpeningFragment, isJsxOpeningLikeElement, isJsxSelfClosingElement, isJsxSpreadAttribute, isJSXTagName, isKnownSymbol, isLateVisibilityPaintedStatement, isLeftHandSideExpression, isLet, isLineBreak, isLiteralComputedPropertyDeclarationName, isLiteralExpression, isLiteralExpressionOfObject, isLiteralImportTypeNode, isLiteralTypeNode, isLogicalOrCoalescingBinaryExpression, isLogicalOrCoalescingBinaryOperator, isMetaProperty, isMethodDeclaration, isMethodSignature, isModifier, isModuleBlock, isModuleDeclaration, isModuleExportsAccessExpression, isModuleIdentifier, isModuleOrEnumDeclaration, isModuleWithStringLiteralName, isNamedDeclaration, isNamedEvaluationSource, isNamedExports, isNamedTupleMember, isNamespaceExport, isNamespaceExportDeclaration, isNamespaceReexportDeclaration, isNewExpression, isNightly, isNodeDescendantOf, isNonNullAccess, isNullishCoalesce, isNumericLiteral, isNumericLiteralName, isObjectBindingPattern, isObjectLiteralElementLike, isObjectLiteralExpression, isObjectLiteralMethod, isObjectLiteralOrClassExpressionMethodOrAccessor, isOmittedExpression, isOptionalChain, isOptionalChainRoot, isOptionalDeclaration, isOptionalJSDocPropertyLikeTag, isOptionalTypeNode, isOutermostOptionalChain, isParameter, isParameterDeclaration, isParameterOrCatchClauseVariable, isParameterPropertyDeclaration, isParenthesizedExpression, isParenthesizedTypeNode, isPartOfTypeNode, isPartOfTypeQuery, isPlainJsFile, isPrefixUnaryExpression, isPrivateIdentifier, isPrivateIdentifierClassElementDeclaration, isPrivateIdentifierPropertyAccessExpression, isPropertyAccessEntityNameExpression, isPropertyAccessExpression, isPropertyAccessOrQualifiedNameOrImportTypeNode, isPropertyAssignment, isPropertyDeclaration, isPropertyName, isPropertyNameLiteral, isPropertySignature, isPrototypeAccess, isPrototypePropertyAssignment, isPushOrUnshiftIdentifier, isQualifiedName, isRequireCall, isRestParameter, isRestTypeNode, isRightSideOfQualifiedNameOrPropertyAccess, isRightSideOfQualifiedNameOrPropertyAccessOrJSDocMemberName, isSameEntityName, isSetAccessor, isSetAccessorDeclaration, isShorthandAmbientModuleSymbol, isShorthandPropertyAssignment, isSingleOrDoubleQuote, isSourceFile, isSourceFileJS, isSpreadAssignment, isSpreadElement, isStatement, isStatementWithLocals, isStatic, isString, isStringANonContextualKeyword, isStringLiteral, isStringLiteralLike, isStringOrNumericLiteralLike, isSuperCall, isSuperProperty, isTaggedTemplateExpression, isTemplateSpan, isThisContainerOrFunctionBlock, isThisIdentifier, isThisInitializedDeclaration, isThisInitializedObjectBindingExpression, isThisInTypeQuery, isThisProperty, isThisTypeParameter, isTransientSymbol, isTupleTypeNode, isTypeAlias, isTypeAliasDeclaration, isTypeDeclaration, isTypeLiteralNode, isTypeNode, isTypeNodeKind, isTypeOfExpression, isTypeOnlyImportOrExportDeclaration, isTypeOperatorNode, isTypeParameterDeclaration, isTypePredicateNode, isTypeQueryNode, isTypeReferenceNode, isTypeReferenceType, isUMDExportSymbol, isValidBigIntString, isValidESSymbolDeclaration, isValidTypeOnlyAliasUseSite, isValueSignatureDeclaration, isVarConst, isVariableDeclaration, isVariableDeclarationInitializedToBareOrAccessedRequire, isVariableDeclarationInVariableStatement, isVariableDeclarationList, isVariableLike, isVariableLikeOrAccessor, isVariableStatement, isWriteAccess, isWriteOnlyAccess, IterableOrIteratorType, IterationTypes, JSDoc, JSDocAugmentsTag, JSDocCallbackTag, JSDocComment, JSDocEnumTag, JSDocFunctionType, JSDocImplementsTag, JSDocLink, JSDocLinkCode, JSDocLinkPlain, JSDocMemberName, JSDocNullableType, JSDocOptionalType, JSDocOverloadTag, JSDocParameterTag, JSDocPrivateTag, JSDocPropertyLikeTag, JSDocPropertyTag, JSDocProtectedTag, JSDocPublicTag, JSDocSatisfiesTag, JSDocSignature, JSDocTemplateTag, JSDocTypeAssertion, JSDocTypedefTag, JSDocTypeExpression, JSDocTypeLiteral, JSDocTypeReferencingNode, JSDocTypeTag, JSDocVariadicType, JsxAttribute, JsxAttributeLike, JsxAttributeName, JsxAttributes, JsxChild, JsxClosingElement, JsxElement, JsxEmit, JsxExpression, JsxFlags, JsxFragment, JsxNamespacedName, JsxOpeningElement, JsxOpeningFragment, JsxOpeningLikeElement, JsxReferenceKind, JsxSelfClosingElement, JsxSpreadAttribute, JsxTagNameExpression, KeywordTypeNode, LabeledStatement, last, lastOrUndefined, LateBoundBinaryExpressionDeclaration, LateBoundDeclaration, LateBoundName, LateVisibilityPaintedStatement, LeftHandSideExpression, length, LiteralExpression, LiteralType, LiteralTypeNode, map, mapDefined, MappedSymbol, MappedType, MappedTypeNode, MatchingKeys, maybeBind, MemberOverrideStatus, MetaProperty, MethodDeclaration, MethodSignature, minAndMax, MinusToken, Modifier, ModifierFlags, modifiersToFlags, modifierToFlag, ModuleBlock, ModuleDeclaration, ModuleInstanceState, ModuleKind, ModuleResolutionKind, ModuleSpecifierResolutionHost, NamedDeclaration, NamedExports, NamedImportsOrExports, NamedTupleMember, NamespaceDeclaration, NamespaceExport, NamespaceExportDeclaration, NamespaceImport, needsScopeMarker, NewExpression, Node, NodeArray, NodeBuilderFlags, nodeCanBeDecorated, NodeCheckFlags, NodeFlags, nodeHasName, nodeIsDecorated, nodeIsMissing, nodeIsPresent, nodeIsSynthesized, NodeLinks, nodeStartsNewLexicalEnvironment, NodeWithTypeArguments, NonNullChain, NonNullExpression, not, noTruncationMaximumTruncationLength, nullTransformationContext, NumberLiteralType, NumericLiteral, objectAllocator, ObjectBindingPattern, ObjectFlags, ObjectFlagsType, ObjectLiteralElementLike, ObjectLiteralExpression, ObjectType, OptionalChain, OptionalTypeNode, or, orderedRemoveItemAt, OuterExpressionKinds, outFile, ParameterDeclaration, parameterIsThisKeyword, ParameterPropertyDeclaration, ParenthesizedExpression, ParenthesizedTypeNode, parseIsolatedEntityName, parseNodeFactory, parsePseudoBigInt, parseValidBigInt, Path, pathIsRelative, PatternAmbientModule, PlusToken, PostfixUnaryExpression, PrefixUnaryExpression, PrivateIdentifier, Program, PromiseOrAwaitableType, PropertyAccessChain, PropertyAccessEntityNameExpression, PropertyAccessExpression, PropertyAssignment, PropertyDeclaration, PropertyName, PropertySignature, PseudoBigInt, pseudoBigIntToString, PunctuationSyntaxKind, pushIfUnique, QualifiedName, QuestionToken, rangeEquals, rangeOfNode, rangeOfTypeParameters, ReadonlyKeyword, reduceLeft, RelationComparisonResult, relativeComplement, removeExtension, removePrefix, replaceElement, resolutionExtensionIsTSOrJson, ResolutionMode, ResolvedModuleFull, ResolvedType, resolveTripleslashReference, resolvingEmptyArray, RestTypeNode, ReturnStatement, ReverseMappedSymbol, ReverseMappedType, sameMap, SatisfiesExpression, scanTokenAtPosition, ScriptKind, ScriptTarget, SetAccessorDeclaration, setCommentRange, setEmitFlags, setIdentifierTypeArguments, setNodeFlags, setOriginalNode, setParent, setSyntheticLeadingComments, setTextRange, setTextRangePosEnd, setValueDeclaration, ShorthandPropertyAssignment, shouldAllowImportingTsExtension, shouldPreserveConstEnums, shouldResolveJsRequire, Signature, SignatureDeclaration, SignatureFlags, SignatureKind, singleElementArray, skipOuterExpressions, skipParentheses, skipTrivia, skipTypeChecking, some, SourceFile, SpreadAssignment, SpreadElement, startsWith, Statement, stringContains, StringLiteral, StringLiteralLike, StringLiteralType, StringMappingType, stripQuotes, StructuredType, SubstitutionType, SuperCall, SwitchStatement, Symbol, SymbolAccessibility, SymbolAccessibilityResult, SymbolFlags, SymbolFormatFlags, SymbolId, SymbolLinks, symbolName, SymbolTable, SymbolTracker, SymbolVisibilityResult, SyntaxKind, SyntheticDefaultModuleType, SyntheticExpression, TaggedTemplateExpression, TemplateExpression, TemplateLiteralType, TemplateLiteralTypeNode, Ternary, textRangeContainsPositionInclusive, TextSpan, textSpanContainsPosition, textSpanEnd, ThisExpression, ThisTypeNode, ThrowStatement, TokenFlags, tokenToString, tracing, TracingNode, TransientSymbol, TransientSymbolLinks, tryAddToSet, tryCast, tryExtractTSExtension, tryGetClassImplementingOrExtendingExpressionWithTypeArguments, tryGetExtensionFromPath, tryGetJSDocSatisfiesTypeNode, tryGetModuleSpecifierFromDeclaration, tryGetPropertyAccessOrIdentifierToString, TryStatement, TupleType, TupleTypeNode, TupleTypeReference, Type, TypeAliasDeclaration, TypeAssertion, TypeChecker, TypeCheckerHost, TypeComparer, TypeElement, TypeFlags, TypeFormatFlags, TypeId, TypeLiteralNode, TypeMapKind, TypeMapper, TypeNode, TypeNodeSyntaxKind, TypeOfExpression, TypeOnlyAliasDeclaration, TypeOnlyCompatibleAliasDeclaration, TypeOperatorNode, TypeParameter, TypeParameterDeclaration, TypePredicate, TypePredicateKind, TypePredicateNode, TypeQueryNode, TypeReference, TypeReferenceNode, TypeReferenceSerializationKind, TypeReferenceType, TypeVariable, unescapeLeadingUnderscores, UnionOrIntersectionType, UnionOrIntersectionTypeNode, UnionReduction, UnionType, UnionTypeNode, UniqueESSymbolType, usingSingleLineStringWriter, VariableDeclaration, VariableDeclarationList, VariableLikeDeclaration, VariableStatement, VarianceFlags, visitEachChild, visitNode, visitNodes, Visitor, VisitResult, VoidExpression, walkUpBindingElementsAndPatterns, walkUpOuterExpressions, walkUpParenthesizedExpressions, walkUpParenthesizedTypes, walkUpParenthesizedTypesAndGetParentAndChild, WhileStatement, WideningContext, WithStatement, YieldExpression, } from "./_namespaces/ts"; import * as moduleSpecifiers from "./_namespaces/ts.moduleSpecifiers"; import * as performance from "./_namespaces/ts.performance"; const ambientModuleSymbolRegex = /^".+"$/; const anon = "(anonymous)" as __String & string; let nextSymbolId = 1; let nextNodeId = 1; let nextMergeId = 1; let nextFlowId = 1; const enum IterationUse { AllowsSyncIterablesFlag = 1 << 0, AllowsAsyncIterablesFlag = 1 << 1, AllowsStringInputFlag = 1 << 2, ForOfFlag = 1 << 3, YieldStarFlag = 1 << 4, SpreadFlag = 1 << 5, DestructuringFlag = 1 << 6, PossiblyOutOfBounds = 1 << 7, // Spread, Destructuring, Array element assignment Element = AllowsSyncIterablesFlag, Spread = AllowsSyncIterablesFlag | SpreadFlag, Destructuring = AllowsSyncIterablesFlag | DestructuringFlag, ForOf = AllowsSyncIterablesFlag | AllowsStringInputFlag | ForOfFlag, ForAwaitOf = AllowsSyncIterablesFlag | AllowsAsyncIterablesFlag | AllowsStringInputFlag | ForOfFlag, YieldStar = AllowsSyncIterablesFlag | YieldStarFlag, AsyncYieldStar = AllowsSyncIterablesFlag | AllowsAsyncIterablesFlag | YieldStarFlag, GeneratorReturnType = AllowsSyncIterablesFlag, AsyncGeneratorReturnType = AllowsAsyncIterablesFlag, } const enum IterationTypeKind { Yield, Return, Next, } interface IterationTypesResolver { iterableCacheKey: "iterationTypesOfAsyncIterable" | "iterationTypesOfIterable"; iteratorCacheKey: "iterationTypesOfAsyncIterator" | "iterationTypesOfIterator"; iteratorSymbolName: "asyncIterator" | "iterator"; getGlobalIteratorType: (reportErrors: boolean) => GenericType; getGlobalIterableType: (reportErrors: boolean) => GenericType; getGlobalIterableIteratorType: (reportErrors: boolean) => GenericType; getGlobalGeneratorType: (reportErrors: boolean) => GenericType; resolveIterationType: (type: Type, errorNode: Node | undefined) => Type | undefined; mustHaveANextMethodDiagnostic: DiagnosticMessage; mustBeAMethodDiagnostic: DiagnosticMessage; mustHaveAValueDiagnostic: DiagnosticMessage; } const enum WideningKind { Normal, FunctionReturn, GeneratorNext, GeneratorYield, } /** @internal */ export 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 IsUndefined = 1 << 24, // Contains undefined or intersection with undefined IsNull = 1 << 25, // Contains null or intersection with null IsUndefinedOrNull = IsUndefined | IsNull, All = (1 << 27) - 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, VoidFacts = TypeofNEString | TypeofNENumber | TypeofNEBigInt | TypeofNEBoolean | TypeofNESymbol | TypeofNEObject | TypeofNEFunction | TypeofNEHostObject | EQUndefined | EQUndefinedOrNull | NENull | Falsy, UndefinedFacts = TypeofNEString | TypeofNENumber | TypeofNEBigInt | TypeofNEBoolean | TypeofNESymbol | TypeofNEObject | TypeofNEFunction | TypeofNEHostObject | EQUndefined | EQUndefinedOrNull | NENull | Falsy | IsUndefined, NullFacts = TypeofEQObject | TypeofNEString | TypeofNENumber | TypeofNEBigInt | TypeofNEBoolean | TypeofNESymbol | TypeofNEFunction | TypeofNEHostObject | EQNull | EQUndefinedOrNull | NEUndefined | Falsy | IsNull, EmptyObjectStrictFacts = All & ~(EQUndefined | EQNull | EQUndefinedOrNull | IsUndefinedOrNull), EmptyObjectFacts = All & ~IsUndefinedOrNull, UnknownFacts = All & ~IsUndefinedOrNull, AllTypeofNE = TypeofNEString | TypeofNENumber | TypeofNEBigInt | TypeofNEBoolean | TypeofNESymbol | TypeofNEObject | TypeofNEFunction | NEUndefined, // Masks OrFactsMask = TypeofEQFunction | TypeofNEObject, AndFactsMask = All & ~OrFactsMask, } const typeofNEFacts: ReadonlyMap = new Map(Object.entries({ string: TypeFacts.TypeofNEString, number: TypeFacts.TypeofNENumber, bigint: TypeFacts.TypeofNEBigInt, boolean: TypeFacts.TypeofNEBoolean, symbol: TypeFacts.TypeofNESymbol, undefined: TypeFacts.NEUndefined, object: TypeFacts.TypeofNEObject, function: TypeFacts.TypeofNEFunction })); type TypeSystemEntity = Node | Symbol | Type | Signature; const enum TypeSystemPropertyName { Type, ResolvedBaseConstructorType, DeclaredType, ResolvedReturnType, ImmediateBaseConstraint, EnumTagType, ResolvedTypeArguments, ResolvedBaseTypes, WriteType, ParameterInitializerContainsUndefined, } /** @internal */ export 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 IsForStringLiteralArgumentCompletions = 1 << 5, // Do not infer from the argument currently being typed RestBindingElement = 1 << 6, // Checking a type that is going to be used to determine the type of a rest binding element // e.g. in `const { a, ...rest } = foo`, when checking the type of `foo` to determine the type of `rest`, // we need to preserve generic types instead of substituting them for constraints TypeOnly = 1 << 7, // Called from getTypeOfExpression, diagnostics may be omitted } /** @internal */ export const enum SignatureCheckMode { None = 0, BivariantCallback = 1 << 0, StrictCallback = 1 << 1, IgnoreReturnTypes = 1 << 2, StrictArity = 1 << 3, StrictTopSignature = 1 << 4, Callback = BivariantCallback | StrictCallback, } const enum IntersectionState { None = 0, Source = 1 << 0, // Source type is a constituent of an outer intersection Target = 1 << 1, // Target type is a constituent of an outer intersection } const enum RecursionFlags { None = 0, Source = 1 << 0, Target = 1 << 1, Both = Source | Target, } 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 isNotOverloadAndNotAccessor = and(isNotOverload, isNotAccessor); const enum DeclarationMeaning { GetAccessor = 1, SetAccessor = 2, PropertyAssignment = 4, Method = 8, PrivateStatic = 16, GetOrSetAccessor = GetAccessor | SetAccessor, PropertyAssignmentOrMethod = PropertyAssignment | Method, } const enum DeclarationSpaces { None = 0, ExportValue = 1 << 0, ExportType = 1 << 1, ExportNamespace = 1 << 2, } const enum MinArgumentCountFlags { None = 0, StrongArityForUntypedJS = 1 << 0, VoidIsNonOptional = 1 << 1, } const enum IntrinsicTypeKind { Uppercase, Lowercase, Capitalize, Uncapitalize } const intrinsicTypeKinds: ReadonlyMap = new Map(Object.entries({ Uppercase: IntrinsicTypeKind.Uppercase, Lowercase: IntrinsicTypeKind.Lowercase, Capitalize: IntrinsicTypeKind.Capitalize, Uncapitalize: IntrinsicTypeKind.Uncapitalize })); const SymbolLinks = class implements SymbolLinks { declare _symbolLinksBrand: any; }; function NodeLinks(this: NodeLinks) { this.flags = NodeCheckFlags.None; } /** @internal */ export function getNodeId(node: Node): number { if (!node.id) { node.id = nextNodeId; nextNodeId++; } return node.id; } /** @internal */ export function getSymbolId(symbol: Symbol): SymbolId { if (!symbol.id) { symbol.id = nextSymbolId; nextSymbolId++; } return symbol.id; } /** @internal */ export function isInstantiatedModule(node: ModuleDeclaration, preserveConstEnums: boolean) { const moduleState = getModuleInstanceState(node); return moduleState === ModuleInstanceState.Instantiated || (preserveConstEnums && moduleState === ModuleInstanceState.ConstEnumOnly); } /** @internal */ export function createTypeChecker(host: TypeCheckerHost): TypeChecker { // Why var? It avoids TDZ checks in the runtime which can be costly. // See: https://github.com/microsoft/TypeScript/issues/52924 /* eslint-disable no-var */ var deferredDiagnosticsCallbacks: (() => void)[] = []; var addLazyDiagnostic = (arg: () => void) => { deferredDiagnosticsCallbacks.push(arg); }; // 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). var cancellationToken: CancellationToken | undefined; var requestedExternalEmitHelperNames = new Set(); var requestedExternalEmitHelpers: ExternalEmitHelpers; var externalHelpersModule: Symbol; var Symbol = objectAllocator.getSymbolConstructor(); var Type = objectAllocator.getTypeConstructor(); var Signature = objectAllocator.getSignatureConstructor(); var typeCount = 0; var symbolCount = 0; var totalInstantiationCount = 0; var instantiationCount = 0; var instantiationDepth = 0; var inlineLevel = 0; var currentNode: Node | undefined; var varianceTypeParameter: TypeParameter | undefined; var isInferencePartiallyBlocked = false; var emptySymbols = createSymbolTable(); var arrayVariances = [VarianceFlags.Covariant]; var compilerOptions = host.getCompilerOptions(); var languageVersion = getEmitScriptTarget(compilerOptions); var moduleKind = getEmitModuleKind(compilerOptions); var legacyDecorators = !!compilerOptions.experimentalDecorators; var useDefineForClassFields = getUseDefineForClassFields(compilerOptions); var allowSyntheticDefaultImports = getAllowSyntheticDefaultImports(compilerOptions); var strictNullChecks = getStrictOptionValue(compilerOptions, "strictNullChecks"); var strictFunctionTypes = getStrictOptionValue(compilerOptions, "strictFunctionTypes"); var strictBindCallApply = getStrictOptionValue(compilerOptions, "strictBindCallApply"); var strictPropertyInitialization = getStrictOptionValue(compilerOptions, "strictPropertyInitialization"); var noImplicitAny = getStrictOptionValue(compilerOptions, "noImplicitAny"); var noImplicitThis = getStrictOptionValue(compilerOptions, "noImplicitThis"); var useUnknownInCatchVariables = getStrictOptionValue(compilerOptions, "useUnknownInCatchVariables"); var keyofStringsOnly = !!compilerOptions.keyofStringsOnly; var defaultIndexFlags = keyofStringsOnly ? IndexFlags.StringsOnly : IndexFlags.None; var freshObjectLiteralFlag = compilerOptions.suppressExcessPropertyErrors ? 0 : ObjectFlags.FreshLiteral; var exactOptionalPropertyTypes = compilerOptions.exactOptionalPropertyTypes; var checkBinaryExpression = createCheckBinaryExpression(); var emitResolver = createResolver(); var nodeBuilder = createNodeBuilder(); var globals = createSymbolTable(); var undefinedSymbol = createSymbol(SymbolFlags.Property, "undefined" as __String); undefinedSymbol.declarations = []; var globalThisSymbol = createSymbol(SymbolFlags.Module, "globalThis" as __String, CheckFlags.Readonly); globalThisSymbol.exports = globals; globalThisSymbol.declarations = []; globals.set(globalThisSymbol.escapedName, globalThisSymbol); var argumentsSymbol = createSymbol(SymbolFlags.Property, "arguments" as __String); var requireSymbol = createSymbol(SymbolFlags.Property, "require" as __String); var isolatedModulesLikeFlagName = compilerOptions.verbatimModuleSyntax ? "verbatimModuleSyntax" : "isolatedModules"; // It is an error to use `importsNotUsedAsValues` alongside `verbatimModuleSyntax`, but we still need to not crash. // Given that, in such a scenario, `verbatimModuleSyntax` is basically disabled, as least as far as alias visibility tracking goes. var canCollectSymbolAliasAccessabilityData = !compilerOptions.verbatimModuleSyntax || !!compilerOptions.importsNotUsedAsValues; /** This will be set during calls to `getResolvedSignature` where services determines an apparent number of arguments greater than what is actually provided. */ var 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: () => reduceLeft(host.getSourceFiles(), (n, s) => n + s.nodeCount, 0), getIdentifierCount: () => reduceLeft(host.getSourceFiles(), (n, s) => n + s.identifierCount, 0), getSymbolCount: () => reduceLeft(host.getSourceFiles(), (n, s) => n + s.symbolCount, symbolCount), getTypeCount: () => typeCount, getInstantiationCount: () => totalInstantiationCount, getRelationCacheSizes: () => ({ assignable: assignableRelation.size, identity: identityRelation.size, subtype: subtypeRelation.size, strictSubtype: strictSubtypeRelation.size, }), isUndefinedSymbol: symbol => symbol === undefinedSymbol, isArgumentsSymbol: symbol => symbol === argumentsSymbol, isUnknownSymbol: symbol => symbol === unknownSymbol, getMergedSymbol, getDiagnostics, getGlobalDiagnostics, getRecursionIdentity, getUnmatchedProperties, getTypeOfSymbolAtLocation: (symbol, locationIn) => { const location = getParseTreeNode(locationIn); return location ? getTypeOfSymbolAtLocation(symbol, location) : errorType; }, getTypeOfSymbol, 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."); Debug.assert(isParameterPropertyDeclaration(parameter, parameter.parent)); return getSymbolsOfParameterPropertyDeclaration(parameter, escapeLeadingUnderscores(parameterName)); }, getDeclaredTypeOfSymbol, getPropertiesOfType, getPropertyOfType: (type, name) => getPropertyOfType(type, escapeLeadingUnderscores(name)), getPrivateIdentifierPropertyOfType: (leftType: Type, name: string, location: Node) => { const node = getParseTreeNode(location); if (!node) { return undefined; } const propName = escapeLeadingUnderscores(name); const lexicallyScopedIdentifier = lookupSymbolForPrivateIdentifierDeclaration(propName, node); return lexicallyScopedIdentifier ? getPrivateIdentifierPropertyOfType(leftType, lexicallyScopedIdentifier) : undefined; }, getTypeOfPropertyOfType: (type, name) => getTypeOfPropertyOfType(type, escapeLeadingUnderscores(name)), getIndexInfoOfType: (type, kind) => getIndexInfoOfType(type, kind === IndexKind.String ? stringType : numberType), getIndexInfosOfType, getIndexInfosOfIndexSymbol, getSignaturesOfType, getIndexTypeOfType: (type, kind) => getIndexTypeOfType(type, kind === IndexKind.String ? stringType : numberType), getIndexType: type => getIndexType(type), getBaseTypes, getBaseTypeOfLiteralType, getWidenedType, getTypeFromTypeNode: nodeIn => { const node = getParseTreeNode(nodeIn, isTypeNode); return node ? getTypeFromTypeNode(node) : errorType; }, getParameterType: getTypeAtPosition, getParameterIdentifierNameAtPosition, getPromisedTypeOfPromise, getAwaitedType: type => getAwaitedType(type), getReturnTypeOfSignature, isNullableType, getNullableType, getNonNullableType, getNonOptionalType: removeOptionalTypeMarker, getTypeArguments, typeToTypeNode: nodeBuilder.typeToTypeNode, indexInfoToIndexSignatureDeclaration: nodeBuilder.indexInfoToIndexSignatureDeclaration, signatureToSignatureDeclaration: nodeBuilder.signatureToSignatureDeclaration, symbolToEntityName: nodeBuilder.symbolToEntityName, symbolToExpression: nodeBuilder.symbolToExpression, symbolToNode: nodeBuilder.symbolToNode, symbolToTypeParameterDeclarations: nodeBuilder.symbolToTypeParameterDeclarations, symbolToParameterDeclaration: nodeBuilder.symbolToParameterDeclaration, typeParameterToDeclaration: nodeBuilder.typeParameterToDeclaration, getSymbolsInScope: (locationIn, meaning) => { const location = getParseTreeNode(locationIn); return location ? getSymbolsInScope(location, meaning) : []; }, getSymbolAtLocation: nodeIn => { const node = getParseTreeNode(nodeIn); // set ignoreErrors: true because any lookups invoked by the API shouldn't cause any new errors return node ? getSymbolAtLocation(node, /*ignoreErrors*/ true) : undefined; }, getIndexInfosAtLocation: nodeIn => { const node = getParseTreeNode(nodeIn); return node ? getIndexInfosAtLocation(node) : undefined; }, getShorthandAssignmentValueSymbol: nodeIn => { const node = getParseTreeNode(nodeIn); 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: nodeIn => { const node = getParseTreeNode(nodeIn); return node ? getTypeOfNode(node) : errorType; }, getTypeOfAssignmentPattern: nodeIn => { const node = getParseTreeNode(nodeIn, isAssignmentPattern); return node && getTypeOfAssignmentPattern(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, getSymbolOfExpando, getContextualType: (nodeIn: Expression, contextFlags?: ContextFlags) => { const node = getParseTreeNode(nodeIn, isExpression); if (!node) { return undefined; } if (contextFlags! & ContextFlags.Completions) { return runWithInferenceBlockedFromSourceNode(node, () => getContextualType(node, contextFlags)); } return getContextualType(node, contextFlags); }, getContextualTypeForObjectLiteralElement: nodeIn => { const node = getParseTreeNode(nodeIn, isObjectLiteralElementLike); return node ? getContextualTypeForObjectLiteralElement(node, /*contextFlags*/ undefined) : 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, /*contextFlags*/ undefined); }, isContextSensitive, getTypeOfPropertyOfContextualType, getFullyQualifiedName, getResolvedSignature: (node, candidatesOutArray, argumentCount) => getResolvedSignatureWorker(node, candidatesOutArray, argumentCount, CheckMode.Normal), getResolvedSignatureForStringLiteralCompletions: (call, editingArgument, candidatesOutArray) => runWithInferenceBlockedFromSourceNode(editingArgument, () => getResolvedSignatureWorker(call, candidatesOutArray, /*argumentCount*/ undefined, CheckMode.IsForStringLiteralArgumentCompletions)), getResolvedSignatureForSignatureHelp: (node, candidatesOutArray, argumentCount) => runWithoutResolvedSignatureCaching(node, () => getResolvedSignatureWorker(node, candidatesOutArray, argumentCount, CheckMode.IsForSignatureHelp)), getExpandedParameters, hasEffectiveRestParameter, containsArgumentsReference, 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: nodeIn => { const node = getParseTreeNode(nodeIn, isFunctionLike); return node ? isImplementationOfOverload(node) : undefined; }, getImmediateAliasedSymbol, getAliasedSymbol: resolveAlias, getEmitResolver, getExportsOfModule: getExportsOfModuleAsArray, getExportsAndPropertiesOfModule, forEachExportAndPropertyOfModule, getSymbolWalker: createGetSymbolWalker( getRestTypeOfSignature, getTypePredicateOfSignature, getReturnTypeOfSignature, getBaseTypes, resolveStructuredTypeMembers, getTypeOfSymbol, getResolvedSymbol, getConstraintOfTypeParameter, getFirstIdentifier, getTypeArguments, ), 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), tryFindAmbientModule: moduleName => tryFindAmbientModule(moduleName, /*withAugmentations*/ true), tryFindAmbientModuleWithoutAugmentations: moduleName => { // we deliberately exclude augmentations // since we are only interested in declarations of the module itself return tryFindAmbientModule(moduleName, /*withAugmentations*/ false); }, getApparentType, getUnionType, isTypeAssignableTo, createAnonymousType, createSignature, createSymbol, createIndexInfo, getAnyType: () => anyType, getStringType: () => stringType, getStringLiteralType, getNumberType: () => numberType, getNumberLiteralType, getBigIntType: () => bigintType, 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, getOptionalType: () => optionalType, getPromiseType: () => getGlobalPromiseType(/*reportErrors*/ false), getPromiseLikeType: () => getGlobalPromiseLikeType(/*reportErrors*/ false), getAsyncIterableType: () => { const type = getGlobalAsyncIterableType(/*reportErrors*/ false); if (type === emptyGenericType) return undefined; return type; }, isSymbolAccessible, isArrayType, isTupleType, isArrayLikeType, isEmptyAnonymousObjectType, isTypeInvalidDueToUnionDiscriminant, getExactOptionalProperties, getAllPossiblePropertiesOfTypes, getSuggestedSymbolForNonexistentProperty, getSuggestionForNonexistentProperty, getSuggestedSymbolForNonexistentJSXAttribute, getSuggestedSymbolForNonexistentSymbol: (location, name, meaning) => getSuggestedSymbolForNonexistentSymbol(location, escapeLeadingUnderscores(name), meaning), getSuggestionForNonexistentSymbol: (location, name, meaning) => getSuggestionForNonexistentSymbol(location, escapeLeadingUnderscores(name), meaning), getSuggestedSymbolForNonexistentModule, getSuggestionForNonexistentExport, getSuggestedSymbolForNonexistentClassMember, 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)), getJsxFragmentFactory: n => { const jsxFragmentFactory = getJsxFragmentFactoryEntity(n); return jsxFragmentFactory && unescapeLeadingUnderscores(getFirstIdentifier(jsxFragmentFactory).escapedText); }, getAccessibleSymbolChain, getTypePredicateOfSignature, resolveExternalModuleName: moduleSpecifierIn => { const moduleSpecifier = getParseTreeNode(moduleSpecifierIn, isExpression); return moduleSpecifier && resolveExternalModuleName(moduleSpecifier, moduleSpecifier, /*ignoreErrors*/ true); }, resolveExternalModuleSymbol, tryGetThisTypeAt: (nodeIn, includeGlobalThis, container) => { const node = getParseTreeNode(nodeIn); return node && tryGetThisTypeAt(node, includeGlobalThis, container); }, getTypeArgumentConstraint: nodeIn => { const node = getParseTreeNode(nodeIn, isTypeNode); return node && getTypeArgumentConstraint(node); }, getSuggestionDiagnostics: (fileIn, ct) => { const file = getParseTreeNode(fileIn, isSourceFile) || Debug.fail("Could not determine parsed source file."); if (skipTypeChecking(file, compilerOptions, host)) { 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, with _eager_ diagnostic production, so identifiers are registered as potentially unused checkSourceFileWithEagerDiagnostics(file); Debug.assert(!!(getNodeLinks(file).flags & NodeCheckFlags.TypeChecked)); diagnostics = addRange(diagnostics, suggestionDiagnostics.getDiagnostics(file.fileName)); checkUnusedIdentifiers(getPotentiallyUnusedIdentifiers(file), (containingNode, kind, diag) => { if (!containsParseError(containingNode) && !unusedIsError(kind, !!(containingNode.flags & NodeFlags.Ambient))) { (diagnostics || (diagnostics = [])).push({ ...diag, category: DiagnosticCategory.Suggestion }); } }); return diagnostics || emptyArray; } finally { cancellationToken = undefined; } }, runWithCancellationToken: (token, callback) => { try { cancellationToken = token; return callback(checker); } finally { cancellationToken = undefined; } }, getLocalTypeParametersOfClassOrInterfaceOrTypeAlias, isDeclarationVisible, isPropertyAccessible, getTypeOnlyAliasDeclaration, getMemberOverrideModifierStatus, isTypeParameterPossiblyReferenced, typeHasCallOrConstructSignatures, }; function runWithoutResolvedSignatureCaching(node: Node | undefined, fn: () => T): T { const containingCall = findAncestor(node, isCallLikeExpression); const containingCallResolvedSignature = containingCall && getNodeLinks(containingCall).resolvedSignature; if (containingCall) { getNodeLinks(containingCall).resolvedSignature = undefined; } const result = fn(); if (containingCall) { getNodeLinks(containingCall).resolvedSignature = containingCallResolvedSignature; } return result; } function runWithInferenceBlockedFromSourceNode(node: Node | undefined, fn: () => T): T { const containingCall = findAncestor(node, isCallLikeExpression); if (containingCall) { let toMarkSkip = node!; do { getNodeLinks(toMarkSkip).skipDirectInference = true; toMarkSkip = toMarkSkip.parent; } while (toMarkSkip && toMarkSkip !== containingCall); } isInferencePartiallyBlocked = true; const result = runWithoutResolvedSignatureCaching(node, fn); isInferencePartiallyBlocked = false; if (containingCall) { let toMarkSkip = node!; do { getNodeLinks(toMarkSkip).skipDirectInference = undefined; toMarkSkip = toMarkSkip.parent; } while (toMarkSkip && toMarkSkip !== containingCall); } return result; } function getResolvedSignatureWorker(nodeIn: CallLikeExpression, candidatesOutArray: Signature[] | undefined, argumentCount: number | undefined, checkMode: CheckMode): Signature | undefined { const node = getParseTreeNode(nodeIn, isCallLikeExpression); apparentArgumentCount = argumentCount; const res = !node ? undefined : getResolvedSignature(node, candidatesOutArray, checkMode); apparentArgumentCount = undefined; return res; } var tupleTypes = new Map(); var unionTypes = new Map(); var unionOfUnionTypes = new Map(); var intersectionTypes = new Map(); var stringLiteralTypes = new Map(); var numberLiteralTypes = new Map(); var bigIntLiteralTypes = new Map(); var enumLiteralTypes = new Map(); var indexedAccessTypes = new Map(); var templateLiteralTypes = new Map(); var stringMappingTypes = new Map(); var substitutionTypes = new Map(); var subtypeReductionCache = new Map(); var decoratorContextOverrideTypeCache = new Map(); var cachedTypes = new Map(); var evolvingArrayTypes: EvolvingArrayType[] = []; var undefinedProperties: SymbolTable = new Map(); var markerTypes = new Set(); var unknownSymbol = createSymbol(SymbolFlags.Property, "unknown" as __String); var resolvingSymbol = createSymbol(0, InternalSymbolName.Resolving); var unresolvedSymbols = new Map(); var errorTypes = new Map(); // We specifically create the `undefined` and `null` types before any other types that can occur in // unions such that they are given low type IDs and occur first in the sorted list of union constituents. // We can then just examine the first constituent(s) of a union to check for their presence. var anyType = createIntrinsicType(TypeFlags.Any, "any"); var autoType = createIntrinsicType(TypeFlags.Any, "any", ObjectFlags.NonInferrableType); var wildcardType = createIntrinsicType(TypeFlags.Any, "any"); var errorType = createIntrinsicType(TypeFlags.Any, "error"); var unresolvedType = createIntrinsicType(TypeFlags.Any, "unresolved"); var nonInferrableAnyType = createIntrinsicType(TypeFlags.Any, "any", ObjectFlags.ContainsWideningType); var intrinsicMarkerType = createIntrinsicType(TypeFlags.Any, "intrinsic"); var unknownType = createIntrinsicType(TypeFlags.Unknown, "unknown"); var nonNullUnknownType = createIntrinsicType(TypeFlags.Unknown, "unknown"); var undefinedType = createIntrinsicType(TypeFlags.Undefined, "undefined"); var undefinedWideningType = strictNullChecks ? undefinedType : createIntrinsicType(TypeFlags.Undefined, "undefined", ObjectFlags.ContainsWideningType); var missingType = createIntrinsicType(TypeFlags.Undefined, "undefined"); var undefinedOrMissingType = exactOptionalPropertyTypes ? missingType : undefinedType; var optionalType = createIntrinsicType(TypeFlags.Undefined, "undefined"); var nullType = createIntrinsicType(TypeFlags.Null, "null"); var nullWideningType = strictNullChecks ? nullType : createIntrinsicType(TypeFlags.Null, "null", ObjectFlags.ContainsWideningType); var stringType = createIntrinsicType(TypeFlags.String, "string"); var numberType = createIntrinsicType(TypeFlags.Number, "number"); var bigintType = createIntrinsicType(TypeFlags.BigInt, "bigint"); var falseType = createIntrinsicType(TypeFlags.BooleanLiteral, "false") as FreshableIntrinsicType; var regularFalseType = createIntrinsicType(TypeFlags.BooleanLiteral, "false") as FreshableIntrinsicType; var trueType = createIntrinsicType(TypeFlags.BooleanLiteral, "true") as FreshableIntrinsicType; var 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; var booleanType = getUnionType([regularFalseType, regularTrueType]); var esSymbolType = createIntrinsicType(TypeFlags.ESSymbol, "symbol"); var voidType = createIntrinsicType(TypeFlags.Void, "void"); var neverType = createIntrinsicType(TypeFlags.Never, "never"); var silentNeverType = createIntrinsicType(TypeFlags.Never, "never", ObjectFlags.NonInferrableType); var implicitNeverType = createIntrinsicType(TypeFlags.Never, "never"); var unreachableNeverType = createIntrinsicType(TypeFlags.Never, "never"); var nonPrimitiveType = createIntrinsicType(TypeFlags.NonPrimitive, "object"); var stringOrNumberType = getUnionType([stringType, numberType]); var stringNumberSymbolType = getUnionType([stringType, numberType, esSymbolType]); var keyofConstraintType = keyofStringsOnly ? stringType : stringNumberSymbolType; var numberOrBigIntType = getUnionType([numberType, bigintType]); var templateConstraintType = getUnionType([stringType, numberType, booleanType, bigintType, nullType, undefinedType]) as UnionType; var numericStringType = getTemplateLiteralType(["", ""], [numberType]); // The `${number}` type var restrictiveMapper: TypeMapper = makeFunctionTypeMapper(t => t.flags & TypeFlags.TypeParameter ? getRestrictiveTypeParameter(t as TypeParameter) : t, () => "(restrictive mapper)"); var permissiveMapper: TypeMapper = makeFunctionTypeMapper(t => t.flags & TypeFlags.TypeParameter ? wildcardType : t, () => "(permissive mapper)"); var uniqueLiteralType = createIntrinsicType(TypeFlags.Never, "never"); // `uniqueLiteralType` is a special `never` flagged by union reduction to behave as a literal var uniqueLiteralMapper: TypeMapper = makeFunctionTypeMapper(t => t.flags & TypeFlags.TypeParameter ? uniqueLiteralType : t, () => "(unique literal mapper)"); // replace all type parameters with the unique literal type (disregarding constraints) var outofbandVarianceMarkerHandler: ((onlyUnreliable: boolean) => void) | undefined; var reportUnreliableMapper = makeFunctionTypeMapper(t => { if (outofbandVarianceMarkerHandler && (t === markerSuperType || t === markerSubType || t === markerOtherType)) { outofbandVarianceMarkerHandler(/*onlyUnreliable*/ true); } return t; }, () => "(unmeasurable reporter)"); var reportUnmeasurableMapper = makeFunctionTypeMapper(t => { if (outofbandVarianceMarkerHandler && (t === markerSuperType || t === markerSubType || t === markerOtherType)) { outofbandVarianceMarkerHandler(/*onlyUnreliable*/ false); } return t; }, () => "(unreliable reporter)"); var emptyObjectType = createAnonymousType(/*symbol*/ undefined, emptySymbols, emptyArray, emptyArray, emptyArray); var emptyJsxObjectType = createAnonymousType(/*symbol*/ undefined, emptySymbols, emptyArray, emptyArray, emptyArray); emptyJsxObjectType.objectFlags |= ObjectFlags.JsxAttributes; var emptyTypeLiteralSymbol = createSymbol(SymbolFlags.TypeLiteral, InternalSymbolName.Type); emptyTypeLiteralSymbol.members = createSymbolTable(); var emptyTypeLiteralType = createAnonymousType(emptyTypeLiteralSymbol, emptySymbols, emptyArray, emptyArray, emptyArray); var unknownEmptyObjectType = createAnonymousType(/*symbol*/ undefined, emptySymbols, emptyArray, emptyArray, emptyArray); var unknownUnionType = strictNullChecks ? getUnionType([undefinedType, nullType, unknownEmptyObjectType]) : unknownType; var emptyGenericType = createAnonymousType(/*symbol*/ undefined, emptySymbols, emptyArray, emptyArray, emptyArray) as ObjectType as GenericType; emptyGenericType.instantiations = new Map(); var anyFunctionType = createAnonymousType(/*symbol*/ undefined, emptySymbols, emptyArray, emptyArray, emptyArray); // The anyFunctionType contains the anyFunctionType by definition. The flag is further propagated // in getPropagatingFlagsOfTypes, and it is checked in inferFromTypes. anyFunctionType.objectFlags |= ObjectFlags.NonInferrableType; var noConstraintType = createAnonymousType(/*symbol*/ undefined, emptySymbols, emptyArray, emptyArray, emptyArray); var circularConstraintType = createAnonymousType(/*symbol*/ undefined, emptySymbols, emptyArray, emptyArray, emptyArray); var resolvingDefaultType = createAnonymousType(/*symbol*/ undefined, emptySymbols, emptyArray, emptyArray, emptyArray); var markerSuperType = createTypeParameter(); var markerSubType = createTypeParameter(); markerSubType.constraint = markerSuperType; var markerOtherType = createTypeParameter(); var markerSuperTypeForCheck = createTypeParameter(); var markerSubTypeForCheck = createTypeParameter(); markerSubTypeForCheck.constraint = markerSuperTypeForCheck; var noTypePredicate = createTypePredicate(TypePredicateKind.Identifier, "<>", 0, anyType); var anySignature = createSignature(/*declaration*/ undefined, /*typeParameters*/ undefined, /*thisParameter*/ undefined, emptyArray, anyType, /*resolvedTypePredicate*/ undefined, 0, SignatureFlags.None); var unknownSignature = createSignature(/*declaration*/ undefined, /*typeParameters*/ undefined, /*thisParameter*/ undefined, emptyArray, errorType, /*resolvedTypePredicate*/ undefined, 0, SignatureFlags.None); var resolvingSignature = createSignature(/*declaration*/ undefined, /*typeParameters*/ undefined, /*thisParameter*/ undefined, emptyArray, anyType, /*resolvedTypePredicate*/ undefined, 0, SignatureFlags.None); var silentNeverSignature = createSignature(/*declaration*/ undefined, /*typeParameters*/ undefined, /*thisParameter*/ undefined, emptyArray, silentNeverType, /*resolvedTypePredicate*/ undefined, 0, SignatureFlags.None); var enumNumberIndexInfo = createIndexInfo(numberType, stringType, /*isReadonly*/ true); var iterationTypesCache = new Map(); // cache for common IterationTypes instances var noIterationTypes: IterationTypes = { get yieldType(): Type { return Debug.fail("Not supported"); }, get returnType(): Type { return Debug.fail("Not supported"); }, get nextType(): Type { return Debug.fail("Not supported"); }, }; var anyIterationTypes = createIterationTypes(anyType, anyType, anyType); var anyIterationTypesExceptNext = createIterationTypes(anyType, anyType, unknownType); var defaultIterationTypes = createIterationTypes(neverType, anyType, undefinedType); // default iteration types for `Iterator`. var asyncIterationTypesResolver: IterationTypesResolver = { iterableCacheKey: "iterationTypesOfAsyncIterable", iteratorCacheKey: "iterationTypesOfAsyncIterator", iteratorSymbolName: "asyncIterator", getGlobalIteratorType: getGlobalAsyncIteratorType, getGlobalIterableType: getGlobalAsyncIterableType, getGlobalIterableIteratorType: getGlobalAsyncIterableIteratorType, getGlobalGeneratorType: getGlobalAsyncGeneratorType, resolveIterationType: (type, errorNode) => getAwaitedType(type, errorNode, Diagnostics.Type_of_await_operand_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member), mustHaveANextMethodDiagnostic: Diagnostics.An_async_iterator_must_have_a_next_method, mustBeAMethodDiagnostic: Diagnostics.The_0_property_of_an_async_iterator_must_be_a_method, mustHaveAValueDiagnostic: Diagnostics.The_type_returned_by_the_0_method_of_an_async_iterator_must_be_a_promise_for_a_type_with_a_value_property, }; var syncIterationTypesResolver: IterationTypesResolver = { iterableCacheKey: "iterationTypesOfIterable", iteratorCacheKey: "iterationTypesOfIterator", iteratorSymbolName: "iterator", getGlobalIteratorType, getGlobalIterableType, getGlobalIterableIteratorType, getGlobalGeneratorType, resolveIterationType: (type, _errorNode) => type, mustHaveANextMethodDiagnostic: Diagnostics.An_iterator_must_have_a_next_method, mustBeAMethodDiagnostic: Diagnostics.The_0_property_of_an_iterator_must_be_a_method, mustHaveAValueDiagnostic: Diagnostics.The_type_returned_by_the_0_method_of_an_iterator_must_have_a_value_property, }; interface DuplicateInfoForSymbol { readonly firstFileLocations: Declaration[]; readonly secondFileLocations: Declaration[]; readonly isBlockScoped: boolean; } interface DuplicateInfoForFiles { readonly firstFile: SourceFile; readonly secondFile: SourceFile; /** Key is symbol name. */ readonly conflictingSymbols: Map; } /** Key is "/path/to/a.ts|/path/to/b.ts". */ var amalgamatedDuplicates: Map | undefined; var reverseMappedCache = new Map(); var inInferTypeForHomomorphicMappedType = false; var 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. */ var patternAmbientModules: PatternAmbientModule[]; var patternAmbientModuleAugmentations: Map | undefined; var globalObjectType: ObjectType; var globalFunctionType: ObjectType; var globalCallableFunctionType: ObjectType; var globalNewableFunctionType: ObjectType; var globalArrayType: GenericType; var globalReadonlyArrayType: GenericType; var globalStringType: ObjectType; var globalNumberType: ObjectType; var globalBooleanType: ObjectType; var globalRegExpType: ObjectType; var globalThisType: GenericType; var anyArrayType: Type; var autoArrayType: Type; var anyReadonlyArrayType: Type; var 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 var deferredGlobalESSymbolConstructorSymbol: Symbol | undefined; var deferredGlobalESSymbolConstructorTypeSymbol: Symbol | undefined; var deferredGlobalESSymbolType: ObjectType | undefined; var deferredGlobalTypedPropertyDescriptorType: GenericType; var deferredGlobalPromiseType: GenericType | undefined; var deferredGlobalPromiseLikeType: GenericType | undefined; var deferredGlobalPromiseConstructorSymbol: Symbol | undefined; var deferredGlobalPromiseConstructorLikeType: ObjectType | undefined; var deferredGlobalIterableType: GenericType | undefined; var deferredGlobalIteratorType: GenericType | undefined; var deferredGlobalIterableIteratorType: GenericType | undefined; var deferredGlobalGeneratorType: GenericType | undefined; var deferredGlobalIteratorYieldResultType: GenericType | undefined; var deferredGlobalIteratorReturnResultType: GenericType | undefined; var deferredGlobalAsyncIterableType: GenericType | undefined; var deferredGlobalAsyncIteratorType: GenericType | undefined; var deferredGlobalAsyncIterableIteratorType: GenericType | undefined; var deferredGlobalAsyncGeneratorType: GenericType | undefined; var deferredGlobalTemplateStringsArrayType: ObjectType | undefined; var deferredGlobalImportMetaType: ObjectType; var deferredGlobalImportMetaExpressionType: ObjectType; var deferredGlobalImportCallOptionsType: ObjectType | undefined; var deferredGlobalExtractSymbol: Symbol | undefined; var deferredGlobalOmitSymbol: Symbol | undefined; var deferredGlobalAwaitedSymbol: Symbol | undefined; var deferredGlobalBigIntType: ObjectType | undefined; var deferredGlobalNaNSymbol: Symbol | undefined; var deferredGlobalRecordSymbol: Symbol | undefined; var deferredGlobalClassDecoratorContextType: GenericType | undefined; var deferredGlobalClassMethodDecoratorContextType: GenericType | undefined; var deferredGlobalClassGetterDecoratorContextType: GenericType | undefined; var deferredGlobalClassSetterDecoratorContextType: GenericType | undefined; var deferredGlobalClassAccessorDecoratorContextType: GenericType | undefined; var deferredGlobalClassAccessorDecoratorTargetType: GenericType | undefined; var deferredGlobalClassAccessorDecoratorResultType: GenericType | undefined; var deferredGlobalClassFieldDecoratorContextType: GenericType | undefined; var allPotentiallyUnusedIdentifiers = new Map(); // key is file name var flowLoopStart = 0; var flowLoopCount = 0; var sharedFlowCount = 0; var flowAnalysisDisabled = false; var flowInvocationCount = 0; var lastFlowNode: FlowNode | undefined; var lastFlowNodeReachable: boolean; var flowTypeCache: Type[] | undefined; var contextualTypeNodes: Node[] = []; var contextualTypes: (Type | undefined)[] = []; var contextualIsCache: boolean[] = []; var contextualTypeCount = 0; var inferenceContextNodes: Node[] = []; var inferenceContexts: (InferenceContext | undefined)[] = []; var inferenceContextCount = 0; var emptyStringType = getStringLiteralType(""); var zeroType = getNumberLiteralType(0); var zeroBigIntType = getBigIntLiteralType({ negative: false, base10Value: "0" }); var resolutionTargets: TypeSystemEntity[] = []; var resolutionResults: boolean[] = []; var resolutionPropertyNames: TypeSystemPropertyName[] = []; var resolutionStart = 0; var inVarianceComputation = false; var suggestionCount = 0; var maximumSuggestionCount = 10; var mergedSymbols: Symbol[] = []; var symbolLinks: SymbolLinks[] = []; var nodeLinks: NodeLinks[] = []; var flowLoopCaches: Map[] = []; var flowLoopNodes: FlowNode[] = []; var flowLoopKeys: string[] = []; var flowLoopTypes: Type[][] = []; var sharedFlowNodes: FlowNode[] = []; var sharedFlowTypes: FlowType[] = []; var flowNodeReachable: (boolean | undefined)[] = []; var flowNodePostSuper: (boolean | undefined)[] = []; var potentialThisCollisions: Node[] = []; var potentialNewTargetCollisions: Node[] = []; var potentialWeakMapSetCollisions: Node[] = []; var potentialReflectCollisions: Node[] = []; var potentialUnusedRenamedBindingElementsInTypes: BindingElement[] = []; var awaitedTypeStack: number[] = []; var diagnostics = createDiagnosticCollection(); var suggestionDiagnostics = createDiagnosticCollection(); var typeofType = createTypeofType(); var _jsxNamespace: __String; var _jsxFactoryEntity: EntityName | undefined; var subtypeRelation = new Map(); var strictSubtypeRelation = new Map(); var assignableRelation = new Map(); var comparableRelation = new Map(); var identityRelation = new Map(); var enumRelation = new Map(); var builtinGlobals = createSymbolTable(); builtinGlobals.set(undefinedSymbol.escapedName, undefinedSymbol); // Extensions suggested for path imports when module resolution is node16 or higher. // The first element of each tuple is the extension a file has. // The second element of each tuple is the extension that should be used in a path import. // e.g. if we want to import file `foo.mts`, we should write `import {} from "./foo.mjs". var suggestedExtensions: [string, string][] = [ [".mts", ".mjs"], [".ts", ".js"], [".cts", ".cjs"], [".mjs", ".mjs"], [".js", ".js"], [".cjs", ".cjs"], [".tsx", compilerOptions.jsx === JsxEmit.Preserve ? ".jsx" : ".js"], [".jsx", ".jsx"], [".json", ".json"], ]; /* eslint-enable no-var */ initializeTypeChecker(); return checker; function getCachedType(key: string | undefined) { return key ? cachedTypes.get(key) : undefined; } function setCachedType(key: string | undefined, type: Type) { if (key) cachedTypes.set(key, type); return type; } function getJsxNamespace(location: Node | undefined): __String { if (location) { const file = getSourceFileOfNode(location); if (file) { if (isJsxOpeningFragment(location)) { if (file.localJsxFragmentNamespace) { return file.localJsxFragmentNamespace; } const jsxFragmentPragma = file.pragmas.get("jsxfrag"); if (jsxFragmentPragma) { const chosenPragma = isArray(jsxFragmentPragma) ? jsxFragmentPragma[0] : jsxFragmentPragma; file.localJsxFragmentFactory = parseIsolatedEntityName(chosenPragma.arguments.factory, languageVersion); visitNode(file.localJsxFragmentFactory, markAsSynthetic, isEntityName); if (file.localJsxFragmentFactory) { return file.localJsxFragmentNamespace = getFirstIdentifier(file.localJsxFragmentFactory).escapedText; } } const entity = getJsxFragmentFactoryEntity(location); if (entity) { file.localJsxFragmentFactory = entity; return file.localJsxFragmentNamespace = getFirstIdentifier(entity).escapedText; } } else { const localJsxNamespace = getLocalJsxNamespace(file); if (localJsxNamespace) { return file.localJsxNamespace = localJsxNamespace; } } } } if (!_jsxNamespace) { _jsxNamespace = "React" as __String; if (compilerOptions.jsxFactory) { _jsxFactoryEntity = parseIsolatedEntityName(compilerOptions.jsxFactory, languageVersion); visitNode(_jsxFactoryEntity, markAsSynthetic); if (_jsxFactoryEntity) { _jsxNamespace = getFirstIdentifier(_jsxFactoryEntity).escapedText; } } else if (compilerOptions.reactNamespace) { _jsxNamespace = escapeLeadingUnderscores(compilerOptions.reactNamespace); } } if (!_jsxFactoryEntity) { _jsxFactoryEntity = factory.createQualifiedName(factory.createIdentifier(unescapeLeadingUnderscores(_jsxNamespace)), "createElement"); } return _jsxNamespace; } function getLocalJsxNamespace(file: SourceFile): __String | undefined { if (file.localJsxNamespace) { return file.localJsxNamespace; } const jsxPragma = file.pragmas.get("jsx"); if (jsxPragma) { const chosenPragma = isArray(jsxPragma) ? jsxPragma[0] : jsxPragma; file.localJsxFactory = parseIsolatedEntityName(chosenPragma.arguments.factory, languageVersion); visitNode(file.localJsxFactory, markAsSynthetic, isEntityName); if (file.localJsxFactory) { return file.localJsxNamespace = getFirstIdentifier(file.localJsxFactory).escapedText; } } } function markAsSynthetic(node: T): VisitResult { setTextRangePosEnd(node, -1, -1); return visitEachChild(node, markAsSynthetic, nullTransformationContext); } 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, ...args: DiagnosticArguments): Diagnostic { const diagnostic = location ? createDiagnosticForNode(location, message, ...args) : createCompilerDiagnostic(message, ...args); const existing = diagnostics.lookup(diagnostic); if (existing) { return existing; } else { diagnostics.add(diagnostic); return diagnostic; } } function errorSkippedOn(key: keyof CompilerOptions, location: Node | undefined, message: DiagnosticMessage, ...args: DiagnosticArguments): Diagnostic { const diagnostic = error(location, message, ...args); diagnostic.skippedOn = key; return diagnostic; } function createError(location: Node | undefined, message: DiagnosticMessage, ...args: DiagnosticArguments): Diagnostic { return location ? createDiagnosticForNode(location, message, ...args) : createCompilerDiagnostic(message, ...args); } function error(location: Node | undefined, message: DiagnosticMessage, ...args: DiagnosticArguments): Diagnostic { const diagnostic = createError(location, message, ...args); diagnostics.add(diagnostic); return diagnostic; } function addErrorOrSuggestion(isError: boolean, diagnostic: Diagnostic) { if (isError) { diagnostics.add(diagnostic); } else { suggestionDiagnostics.add({ ...diagnostic, category: DiagnosticCategory.Suggestion }); } } function errorOrSuggestion(isError: boolean, location: Node, message: DiagnosticMessage | DiagnosticMessageChain, ...args: DiagnosticArguments): void { // Pseudo-synthesized input node if (location.pos < 0 || location.end < 0) { if (!isError) { return; // Drop suggestions (we have no span to suggest on) } // Issue errors globally const file = getSourceFileOfNode(location); addErrorOrSuggestion(isError, "message" in message ? createFileDiagnostic(file, 0, 0, message, ...args) : createDiagnosticForFileFromMessageChain(file, message)); // eslint-disable-line local/no-in-operator return; } addErrorOrSuggestion(isError, "message" in message ? createDiagnosticForNode(location, message, ...args) : createDiagnosticForNodeFromMessageChain(getSourceFileOfNode(location), location, message)); // eslint-disable-line local/no-in-operator } function errorAndMaybeSuggestAwait( location: Node, maybeMissingAwait: boolean, message: DiagnosticMessage, ...args: DiagnosticArguments): Diagnostic { const diagnostic = error(location, message, ...args); if (maybeMissingAwait) { const related = createDiagnosticForNode(location, Diagnostics.Did_you_forget_to_use_await); addRelatedInfo(diagnostic, related); } return diagnostic; } function addDeprecatedSuggestionWorker(declarations: Node | Node[], diagnostic: DiagnosticWithLocation) { const deprecatedTag = Array.isArray(declarations) ? forEach(declarations, getJSDocDeprecatedTag) : getJSDocDeprecatedTag(declarations); if (deprecatedTag) { addRelatedInfo( diagnostic, createDiagnosticForNode(deprecatedTag, Diagnostics.The_declaration_was_marked_as_deprecated_here) ); } // We call `addRelatedInfo()` before adding the diagnostic to prevent duplicates. suggestionDiagnostics.add(diagnostic); return diagnostic; } function isDeprecatedSymbol(symbol: Symbol) { const parentSymbol = getParentOfSymbol(symbol); if (parentSymbol && length(symbol.declarations) > 1) { return parentSymbol.flags & SymbolFlags.Interface ? some(symbol.declarations, isDeprecatedDeclaration) : every(symbol.declarations, isDeprecatedDeclaration); } return !!symbol.valueDeclaration && isDeprecatedDeclaration(symbol.valueDeclaration) || length(symbol.declarations) && every(symbol.declarations, isDeprecatedDeclaration); } function isDeprecatedDeclaration(declaration: Declaration) { return !!(getCombinedNodeFlags(declaration) & NodeFlags.Deprecated); } function addDeprecatedSuggestion(location: Node, declarations: Node[], deprecatedEntity: string) { const diagnostic = createDiagnosticForNode(location, Diagnostics._0_is_deprecated, deprecatedEntity); return addDeprecatedSuggestionWorker(declarations, diagnostic); } function addDeprecatedSuggestionWithSignature(location: Node, declaration: Node, deprecatedEntity: string | undefined, signatureString: string) { const diagnostic = deprecatedEntity ? createDiagnosticForNode(location, Diagnostics.The_signature_0_of_1_is_deprecated, signatureString, deprecatedEntity) : createDiagnosticForNode(location, Diagnostics._0_is_deprecated, signatureString); return addDeprecatedSuggestionWorker(declaration, diagnostic); } function createSymbol(flags: SymbolFlags, name: __String, checkFlags?: CheckFlags) { symbolCount++; const symbol = new Symbol(flags | SymbolFlags.Transient, name) as TransientSymbol; symbol.links = new SymbolLinks() as TransientSymbolLinks; symbol.links.checkFlags = checkFlags || CheckFlags.None; return symbol; } function createParameter(name: __String, type: Type) { const symbol = createSymbol(SymbolFlags.FunctionScopedVariable, name); symbol.links.type = type; return symbol; } function createProperty(name: __String, type: Type) { const symbol = createSymbol(SymbolFlags.Property, name); symbol.links.type = type; return symbol; } 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): TransientSymbol { 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 = new Map(symbol.members); if (symbol.exports) result.exports = new Map(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, unidirectional = false): Symbol { if (!(target.flags & getExcludedSymbolFlags(source.flags)) || (source.flags | target.flags) & SymbolFlags.Assignment) { if (source === target) { // This can happen when an export assigned namespace exports something also erroneously exported at the top level // See `declarationFileNoCrashOnExtraExportModifier` for an example return 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) { setValueDeclaration(target, source.valueDeclaration); } addRange(target.declarations, source.declarations); if (source.members) { if (!target.members) target.members = createSymbolTable(); mergeSymbolTable(target.members, source.members, unidirectional); } if (source.exports) { if (!target.exports) target.exports = createSymbolTable(); mergeSymbolTable(target.exports, source.exports, unidirectional); } if (!unidirectional) { recordMergedSymbol(target, source); } } else if (target.flags & SymbolFlags.NamespaceModule) { // Do not report an error when merging `var globalThis` with the built-in `globalThis`, // as we will already report a "Declaration name conflicts..." error, and this error // won't make much sense. if (target !== globalThisSymbol) { error( source.declarations && 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 isSourcePlainJs = isPlainJsFile(sourceSymbolFile, compilerOptions.checkJs); const isTargetPlainJs = isPlainJsFile(targetSymbolFile, compilerOptions.checkJs); 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(amalgamatedDuplicates, `${firstFile.path}|${secondFile.path}`, (): DuplicateInfoForFiles => ({ firstFile, secondFile, conflictingSymbols: new Map() })); const conflictingSymbolInfo = getOrUpdate(filesDuplicates.conflictingSymbols, symbolName, (): DuplicateInfoForSymbol => ({ isBlockScoped: isEitherBlockScoped, firstFileLocations: [], secondFileLocations: [] })); if (!isSourcePlainJs) addDuplicateLocations(conflictingSymbolInfo.firstFileLocations, source); if (!isTargetPlainJs) addDuplicateLocations(conflictingSymbolInfo.secondFileLocations, target); } else { if (!isSourcePlainJs) addDuplicateDeclarationErrorsForSymbols(source, message, symbolName, target); if (!isTargetPlainJs) addDuplicateDeclarationErrorsForSymbols(target, message, symbolName, source); } } return target; function addDuplicateLocations(locs: Declaration[], symbol: Symbol): void { if (symbol.declarations) { for (const decl of symbol.declarations) { pushIfUnique(locs, decl); } } } } function addDuplicateDeclarationErrorsForSymbols(target: Symbol, message: DiagnosticMessage, symbolName: string, source: Symbol) { forEach(target.declarations, node => { addDuplicateDeclarationError(node, message, symbolName, source.declarations); }); } function addDuplicateDeclarationError(node: Declaration, message: DiagnosticMessage, symbolName: string, relatedNodes: readonly Declaration[] | undefined) { const errorNode = (getExpandoInitializer(node, /*isPrototypeAssignment*/ false) ? getNameOfExpando(node) : getNameOfDeclaration(node)) || node; const err = lookupOrIssueError(errorNode, message, symbolName); for (const relatedNode of relatedNodes || emptyArray) { const adjustedNode = (getExpandoInitializer(relatedNode, /*isPrototypeAssignment*/ false) ? getNameOfExpando(relatedNode) : getNameOfDeclaration(relatedNode)) || relatedNode; if (adjustedNode === errorNode) continue; err.relatedInformation = err.relatedInformation || []; const leadingMessage = createDiagnosticForNode(adjustedNode, Diagnostics._0_was_also_declared_here, symbolName); const followOnMessage = createDiagnosticForNode(adjustedNode, Diagnostics.and_here); if (length(err.relatedInformation) >= 5 || some(err.relatedInformation, r => compareDiagnostics(r, followOnMessage) === Comparison.EqualTo || compareDiagnostics(r, leadingMessage) === Comparison.EqualTo)) continue; addRelatedInfo(err, !length(err.relatedInformation) ? leadingMessage : followOnMessage); } } function combineSymbolTables(first: SymbolTable | undefined, second: SymbolTable | undefined): SymbolTable | undefined { if (!first?.size) return second; if (!second?.size) return first; const combined = createSymbolTable(); mergeSymbolTable(combined, first); mergeSymbolTable(combined, second); return combined; } function mergeSymbolTable(target: SymbolTable, source: SymbolTable, unidirectional = false) { source.forEach((sourceSymbol, id) => { const targetSymbol = target.get(id); target.set(id, targetSymbol ? mergeSymbol(targetSymbol, sourceSymbol, unidirectional) : getMergedSymbol(sourceSymbol)); }); } function mergeModuleAugmentation(moduleName: StringLiteral | Identifier): void { const moduleAugmentation = moduleName.parent as ModuleDeclaration; 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) { // If we're merging an augmentation to a pattern ambient module, we want to // perform the merge unidirectionally from the augmentation ('a.foo') to // the pattern ('*.foo'), so that 'getMergedSymbol()' on a.foo gives you // all the exports both from the pattern and from the augmentation, but // 'getMergedSymbol()' on *.foo only gives you exports from *.foo. if (some(patternAmbientModules, module => mainModule === module.symbol)) { const merged = mergeSymbol(moduleAugmentation.symbol, mainModule, /*unidirectional*/ true); if (!patternAmbientModuleAugmentations) { patternAmbientModuleAugmentations = new Map(); } // moduleName will be a StringLiteral since this is not `declare global`. patternAmbientModuleAugmentations.set((moduleName as StringLiteral).text, merged); } else { if (mainModule.exports?.get(InternalSymbolName.ExportStar) && moduleAugmentation.symbol.exports?.size) { // We may need to merge the module augmentation's exports into the target symbols of the resolved exports const resolvedExports = getResolvedMembersOrExportsOfSymbol(mainModule, MembersOrExportsResolutionKind.resolvedExports); for (const [key, value] of arrayFrom(moduleAugmentation.symbol.exports.entries())) { if (resolvedExports.has(key) && !mainModule.exports.has(key)) { mergeSymbol(resolvedExports.get(key)!, value); } } } 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 (symbol as TransientSymbol).links; const id = getSymbolId(symbol); return symbolLinks[id] ??= new SymbolLinks(); } function getNodeLinks(node: Node): NodeLinks { const nodeId = getNodeId(node); return nodeLinks[nodeId] || (nodeLinks[nodeId] = new (NodeLinks as any)()); } function isGlobalSourceFile(node: Node) { return node.kind === SyntaxKind.SourceFile && !isExternalOrCommonJsModule(node as SourceFile); } function getSymbol(symbols: SymbolTable, name: __String, meaning: SymbolFlags): Symbol | undefined { if (meaning) { const symbol = getMergedSymbol(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 targetFlags = getAllSymbolFlags(symbol); // `targetFlags` will be `SymbolFlags.All` if an error occurred in alias resolution; this avoids cascading errors if (targetFlags & 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: ParameterPropertyDeclaration, 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); const declContainer = getEnclosingBlockScopeContainer(declaration); if (declarationFile !== useFile) { if ((moduleKind && (declarationFile.externalModuleIndicator || useFile.externalModuleIndicator)) || (!outFile(compilerOptions)) || 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 && !(isPropertyDeclaration(declaration) && isThisProperty(usage.parent) && !declaration.initializer && !declaration.exclamationToken)) { // 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); } else if (isPropertyDeclaration(declaration)) { // still might be illegal if a self-referencing property initializer (eg private x = this.x) return !isPropertyImmediatelyReferencedWithinDeclaration(declaration, usage, /*stopAtAnyPropertyDeclaration*/ false); } else if (isParameterPropertyDeclaration(declaration, declaration.parent)) { // foo = this.bar is illegal in esnext+useDefineForClassFields when bar is a parameter property return !(getEmitScriptTarget(compilerOptions) === ScriptTarget.ESNext && useDefineForClassFields && getContainingClass(declaration) === getContainingClass(usage) && isUsedInFunctionOrInstanceProperty(usage, 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 // (except when target: "esnext" and useDefineForClassFields: true and the reference is to a parameter 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; } if (!!(usage.flags & NodeFlags.JSDoc) || isInTypeQuery(usage) || isInAmbientOrTypeNode(usage)) { return true; } if (isUsedInFunctionOrInstanceProperty(usage, declaration)) { if (getEmitScriptTarget(compilerOptions) >= ScriptTarget.ES2022 && useDefineForClassFields && getContainingClass(declaration) && (isPropertyDeclaration(declaration) || isParameterPropertyDeclaration(declaration, declaration.parent))) { return !isPropertyImmediatelyReferencedWithinDeclaration(declaration, usage, /*stopAtAnyPropertyDeclaration*/ true); } else { return true; } } return false; function isImmediatelyUsedInInitializerOfBlockScopedVariable(declaration: VariableDeclaration, usage: Node): boolean { 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, declContainer)) { 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, declContainer); } function isUsedInFunctionOrInstanceProperty(usage: Node, declaration: Node): boolean { return !!findAncestor(usage, current => { if (current === declContainer) { return "quit"; } if (isFunctionLike(current)) { return true; } if (isClassStaticBlockDeclaration(current)) { return declaration.pos < usage.pos; } const propertyDeclaration = tryCast(current.parent, isPropertyDeclaration); if (propertyDeclaration) { const initializerOfProperty = propertyDeclaration.initializer === current; if (initializerOfProperty) { if (isStatic(current.parent)) { if (declaration.kind === SyntaxKind.MethodDeclaration) { return true; } if (isPropertyDeclaration(declaration) && getContainingClass(usage) === getContainingClass(declaration)) { const propName = declaration.name; if (isIdentifier(propName) || isPrivateIdentifier(propName)) { const type = getTypeOfSymbol(getSymbolOfDeclaration(declaration)); const staticBlocks = filter(declaration.parent.members, isClassStaticBlockDeclaration); if (isPropertyInitializedInStaticBlocks(propName, type, staticBlocks, declaration.parent.pos, current.pos)) { return true; } } } } else { const isDeclarationInstanceProperty = declaration.kind === SyntaxKind.PropertyDeclaration && !isStatic(declaration); if (!isDeclarationInstanceProperty || getContainingClass(usage) !== getContainingClass(declaration)) { return true; } } } } return false; }); } /** stopAtAnyPropertyDeclaration is used for detecting ES-standard class field use-before-def errors */ function isPropertyImmediatelyReferencedWithinDeclaration(declaration: PropertyDeclaration | ParameterPropertyDeclaration, usage: Node, stopAtAnyPropertyDeclaration: boolean) { // always legal if usage is after declaration if (usage.end > declaration.end) { return false; } // still might be legal if usage is deferred (e.g. x: any = () => this.x) // otherwise illegal if immediately referenced within the declaration (e.g. x: any = this.x) const ancestorChangingReferenceScope = findAncestor(usage, (node: Node) => { if (node === declaration) { return "quit"; } switch (node.kind) { case SyntaxKind.ArrowFunction: return true; case SyntaxKind.PropertyDeclaration: // even when stopping at any property declaration, they need to come from the same class return stopAtAnyPropertyDeclaration && (isPropertyDeclaration(declaration) && node.parent === declaration.parent || isParameterPropertyDeclaration(declaration, declaration.parent) && node.parent === declaration.parent.parent) ? "quit": true; case SyntaxKind.Block: switch (node.parent.kind) { case SyntaxKind.GetAccessor: case SyntaxKind.MethodDeclaration: case SyntaxKind.SetAccessor: return true; default: return false; } default: return false; } }); return ancestorChangingReferenceScope === undefined; } } function useOuterVariableScopeInParameter(result: Symbol, location: Node, lastLocation: Node) { const target = getEmitScriptTarget(compilerOptions); const functionLocation = location as FunctionLikeDeclaration; if (isParameter(lastLocation) && functionLocation.body && result.valueDeclaration && result.valueDeclaration.pos >= functionLocation.body.pos && result.valueDeclaration.end <= functionLocation.body.end) { // check for several cases where we introduce temporaries that require moving the name/initializer of the parameter to the body // - static field in a class expression // - optional chaining pre-es2020 // - nullish coalesce pre-es2020 // - spread assignment in binding pattern pre-es2017 if (target >= ScriptTarget.ES2015) { const links = getNodeLinks(functionLocation); if (links.declarationRequiresScopeChange === undefined) { links.declarationRequiresScopeChange = forEach(functionLocation.parameters, requiresScopeChange) || false; } return !links.declarationRequiresScopeChange; } } return false; function requiresScopeChange(node: ParameterDeclaration): boolean { return requiresScopeChangeWorker(node.name) || !!node.initializer && requiresScopeChangeWorker(node.initializer); } function requiresScopeChangeWorker(node: Node): boolean { switch (node.kind) { case SyntaxKind.ArrowFunction: case SyntaxKind.FunctionExpression: case SyntaxKind.FunctionDeclaration: case SyntaxKind.Constructor: // do not descend into these return false; case SyntaxKind.MethodDeclaration: case SyntaxKind.GetAccessor: case SyntaxKind.SetAccessor: case SyntaxKind.PropertyAssignment: return requiresScopeChangeWorker((node as MethodDeclaration | AccessorDeclaration | PropertyAssignment).name); case SyntaxKind.PropertyDeclaration: // static properties in classes introduce temporary variables if (hasStaticModifier(node)) { return target < ScriptTarget.ESNext || !useDefineForClassFields; } return requiresScopeChangeWorker((node as PropertyDeclaration).name); default: // null coalesce and optional chain pre-es2020 produce temporary variables if (isNullishCoalesce(node) || isOptionalChain(node)) { return target < ScriptTarget.ES2020; } if (isBindingElement(node) && node.dotDotDotToken && isObjectBindingPattern(node.parent)) { return target < ScriptTarget.ES2017; } if (isTypeNode(node)) return false; return forEachChild(node, requiresScopeChangeWorker) || false; } } } function isConstAssertion(location: Node) { return (isAssertionExpression(location) && isConstTypeReference(location.type)) || (isJSDocTypeTag(location) && isConstTypeReference(location.typeExpression)); } /** * 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 nameNotFoundMessage If defined, we will report errors found during resolve. * @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, getSpellingSuggestions = true): Symbol | undefined { return resolveNameHelper(location, name, meaning, nameNotFoundMessage, nameArg, isUse, excludeGlobals, getSpellingSuggestions, getSymbol); } function resolveNameHelper( location: Node | undefined, name: __String, meaning: SymbolFlags, nameNotFoundMessage: DiagnosticMessage | undefined, nameArg: __String | Identifier | undefined, isUse: boolean, excludeGlobals: boolean, getSpellingSuggestions: boolean, lookup: typeof getSymbol): 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: Declaration | undefined; let propertyWithInvalidInitializer: PropertyDeclaration | undefined; let associatedDeclarationForContainingInitializerOrBindingName: ParameterDeclaration | BindingElement | undefined; let withinDeferredContext = false; const errorLocation = location; let grandparent: Node; let isInExternalModule = false; loop: while (location) { if (name === "const" && isConstAssertion(location)) { // `const` in an `as const` has no symbol, but issues no error because there is no *actual* lookup of the type // (it refers to the constant type of the expression instead) return undefined; } if (isModuleDeclaration(location) && lastLocation && location.name === lastLocation) { // If this is the name of a namespace, skip the parent since it will have is own locals that could // conflict. lastLocation = location; location = location.parent; } // Locals of a source file are not in scope (because they get merged into the global symbol table) if (canHaveLocals(location) && location.locals && !isGlobalSourceFile(location)) { if (result = lookup(location.locals, name, meaning)) { let useResult = true; if (isFunctionLike(location) && lastLocation && lastLocation !== (location as FunctionLikeDeclaration).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.JSDoc) { useResult = result.flags & SymbolFlags.TypeParameter // type parameters are visible in parameter list, return type and type parameter list ? lastLocation === (location as FunctionLikeDeclaration).type || lastLocation.kind === SyntaxKind.Parameter || lastLocation.kind === SyntaxKind.JSDocParameterTag || lastLocation.kind === SyntaxKind.JSDocReturnTag || 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+ if (useOuterVariableScopeInParameter(result, location, lastLocation)) { 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 === (location as FunctionLikeDeclaration).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 === (location as ConditionalTypeNode).trueType; } if (useResult) { break loop; } else { result = undefined; } } } withinDeferredContext = withinDeferredContext || getIsDeferredContext(location, lastLocation); switch (location.kind) { case SyntaxKind.SourceFile: if (!isExternalOrCommonJsModule(location as SourceFile)) break; isInExternalModule = true; // falls through case SyntaxKind.ModuleDeclaration: const moduleExports = getSymbolOfDeclaration(location as SourceFile | ModuleDeclaration)?.exports || emptySymbols; if (location.kind === SyntaxKind.SourceFile || (isModuleDeclaration(location) && location.flags & NodeFlags.Ambient && !isGlobalScopeAugmentation(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) || getDeclarationOfKind(moduleExport, SyntaxKind.NamespaceExport))) { 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(getSymbolOfDeclaration(location as EnumDeclaration)?.exports || emptySymbols, name, meaning & SymbolFlags.EnumMember)) { if (nameNotFoundMessage && getIsolatedModules(compilerOptions) && !(location.flags & NodeFlags.Ambient) && getSourceFileOfNode(location) !== getSourceFileOfNode(result.valueDeclaration)) { error( errorLocation, Diagnostics.Cannot_access_0_from_another_file_without_qualification_when_1_is_enabled_Use_2_instead, unescapeLeadingUnderscores(name), isolatedModulesLikeFlagName, `${unescapeLeadingUnderscores(getSymbolOfNode(location)!.escapedName)}.${unescapeLeadingUnderscores(name)}`); } break loop; } break; case SyntaxKind.PropertyDeclaration: // 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 (!isStatic(location)) { const ctor = findConstructorDeclaration(location.parent as ClassLikeDeclaration); 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 Debug.assertNode(location, isPropertyDeclaration); 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(getSymbolOfDeclaration(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 && isStatic(lastLocation)) { // 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. if (nameNotFoundMessage) { error(errorLocation, Diagnostics.Static_members_cannot_reference_class_type_parameters); } return undefined; } break loop; } if (isClassExpression(location) && meaning & SymbolFlags.Class) { const className = 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 === (location as ExpressionWithTypeArguments).expression && (location.parent as HeritageClause).token === SyntaxKind.ExtendsKeyword) { const container = location.parent.parent; if (isClassLike(container) && (result = lookup(getSymbolOfDeclaration(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() { return '' } // class C { // <-- Class's own type parameter T // [foo()]() { } // <-- 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(getSymbolOfDeclaration(grandparent as ClassLikeDeclaration | InterfaceDeclaration).members!, name, meaning & SymbolFlags.Type)) { if (nameNotFoundMessage) { 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 (getEmitScriptTarget(compilerOptions) >= 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 = (location as FunctionExpression).name; if (functionName && name === functionName.escapedText) { result = (location as FunctionExpression).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. // } // // class Decorators are resolved outside of the class to avoid referencing type parameters of that class. // // type T = number; // declare function y(x: T): any; // @param(1 as T) // <-- T should resolve to the type alias outside of class C // class C {} if (location.parent && (isClassElement(location.parent) || location.parent.kind === SyntaxKind.ClassDeclaration)) { location = location.parent; } break; case SyntaxKind.JSDocTypedefTag: case SyntaxKind.JSDocCallbackTag: case SyntaxKind.JSDocEnumTag: // js type aliases do not resolve names from their host, so skip past it const root = getJSDocRoot(location); if (root) { location = root.parent; } break; case SyntaxKind.Parameter: if (lastLocation && ( lastLocation === (location as ParameterDeclaration).initializer || lastLocation === (location as ParameterDeclaration).name && isBindingPattern(lastLocation))) { if (!associatedDeclarationForContainingInitializerOrBindingName) { associatedDeclarationForContainingInitializerOrBindingName = location as ParameterDeclaration; } } break; case SyntaxKind.BindingElement: if (lastLocation && ( lastLocation === (location as BindingElement).initializer || lastLocation === (location as BindingElement).name && isBindingPattern(lastLocation))) { if (isParameterDeclaration(location as BindingElement) && !associatedDeclarationForContainingInitializerOrBindingName) { associatedDeclarationForContainingInitializerOrBindingName = location as BindingElement; } } break; case SyntaxKind.InferType: if (meaning & SymbolFlags.TypeParameter) { const parameterName = (location as InferTypeNode).typeParameter.name; if (parameterName && name === parameterName.escapedText) { result = (location as InferTypeNode).typeParameter.symbol; break loop; } } break; case SyntaxKind.ExportSpecifier: // External module export bindings shouldn't be resolved to local symbols. if (lastLocation && lastLocation === (location as ExportSpecifier).propertyName && (location as ExportSpecifier).parent.parent.moduleSpecifier) { location = location.parent.parent.parent; } break; } if (isSelfReferenceLocation(location)) { lastSelfReferenceLocation = location; } lastLocation = location; location = isJSDocTemplateTag(location) ? getEffectiveContainerForJSDocTemplateTag(location) || location.parent : isJSDocParameterTag(location) || isJSDocReturnTag(location) ? getHostSignatureFromJSDoc(location) || location.parent : 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.assertNode(lastLocation, isSourceFile); if (lastLocation.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, /*requireStringLiteralLikeArgument*/ false)) { return requireSymbol; } } } // The invalid initializer error is needed in two situation: // 1. When result is undefined, after checking for a missing "this." // 2. When result is defined function checkAndReportErrorForInvalidInitializer() { if (propertyWithInvalidInitializer && !(useDefineForClassFields && getEmitScriptTarget(compilerOptions) >= ScriptTarget.ES2022)) { // 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. Note that this is actually allowed // with ESNext+useDefineForClassFields because the scope semantics are different. error(errorLocation, errorLocation && propertyWithInvalidInitializer.type && textRangeContainsPositionInclusive(propertyWithInvalidInitializer.type, errorLocation.pos) ? Diagnostics.Type_of_instance_member_variable_0_cannot_reference_identifier_1_declared_in_the_constructor : Diagnostics.Initializer_of_instance_member_variable_0_cannot_reference_identifier_1_declared_in_the_constructor, declarationNameToString(propertyWithInvalidInitializer.name), diagnosticName(nameArg!)); return true; } return false; } if (!result) { if (nameNotFoundMessage) { addLazyDiagnostic(() => { if (!errorLocation || errorLocation.parent.kind !== SyntaxKind.JSDocLink && !checkAndReportErrorForMissingPrefix(errorLocation, name, nameArg!) && // TODO: GH#18217 !checkAndReportErrorForInvalidInitializer() && !checkAndReportErrorForExtendingInterface(errorLocation) && !checkAndReportErrorForUsingTypeAsNamespace(errorLocation, name, meaning) && !checkAndReportErrorForExportingPrimitiveType(errorLocation, name) && !checkAndReportErrorForUsingNamespaceAsTypeOrValue(errorLocation, name, meaning) && !checkAndReportErrorForUsingTypeAsValue(errorLocation, name, meaning) && !checkAndReportErrorForUsingValueAsType(errorLocation, name, meaning)) { let suggestion: Symbol | undefined; let suggestedLib: string | undefined; // Report missing lib first if (nameArg) { suggestedLib = getSuggestedLibForNonExistentName(nameArg); if (suggestedLib) { error(errorLocation, nameNotFoundMessage, diagnosticName(nameArg), suggestedLib); } } // then spelling suggestions if (!suggestedLib && getSpellingSuggestions && suggestionCount < maximumSuggestionCount) { suggestion = getSuggestedSymbolForNonexistentSymbol(originalLocation, name, meaning); const isGlobalScopeAugmentationDeclaration = suggestion?.valueDeclaration && isAmbientModule(suggestion.valueDeclaration) && isGlobalScopeAugmentation(suggestion.valueDeclaration); if (isGlobalScopeAugmentationDeclaration) { suggestion = undefined; } if (suggestion) { const suggestionName = symbolToString(suggestion); const isUncheckedJS = isUncheckedJSSuggestion(originalLocation, suggestion, /*excludeClasses*/ false); const message = meaning === SymbolFlags.Namespace || nameArg && typeof nameArg !== "string" && nodeIsSynthesized(nameArg) ? Diagnostics.Cannot_find_namespace_0_Did_you_mean_1 : isUncheckedJS ? Diagnostics.Could_not_find_name_0_Did_you_mean_1 : Diagnostics.Cannot_find_name_0_Did_you_mean_1; const diagnostic = createError(errorLocation, message, diagnosticName(nameArg!), suggestionName); addErrorOrSuggestion(!isUncheckedJS, diagnostic); if (suggestion.valueDeclaration) { addRelatedInfo( diagnostic, createDiagnosticForNode(suggestion.valueDeclaration, Diagnostics._0_is_declared_here, suggestionName) ); } } } // And then fall back to unspecified "not found" if (!suggestion && !suggestedLib && nameArg) { error(errorLocation, nameNotFoundMessage, diagnosticName(nameArg)); } suggestionCount++; } }); } return undefined; } else if (nameNotFoundMessage && checkAndReportErrorForInvalidInitializer()) { return undefined; } // Perform extra checks only if error reporting was requested if (nameNotFoundMessage) { addLazyDiagnostic(() => { // 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)) { errorOrSuggestion(!compilerOptions.allowUmdGlobalAccess, errorLocation!, Diagnostics._0_refers_to_a_UMD_global_but_the_current_file_is_a_module_Consider_adding_an_import_instead, unescapeLeadingUnderscores(name)); } } // If we're in a parameter initializer or binding name, we can't reference the values of the parameter whose initializer we're within or parameters to the right if (result && associatedDeclarationForContainingInitializerOrBindingName && !withinDeferredContext && (meaning & SymbolFlags.Value) === SymbolFlags.Value) { const candidate = getMergedSymbol(getLateBoundSymbol(result)); const root = (getRootDeclaration(associatedDeclarationForContainingInitializerOrBindingName) as ParameterDeclaration); // A parameter initializer or binding pattern initializer within a parameter cannot refer to itself if (candidate === getSymbolOfDeclaration(associatedDeclarationForContainingInitializerOrBindingName)) { error(errorLocation, Diagnostics.Parameter_0_cannot_reference_itself, declarationNameToString(associatedDeclarationForContainingInitializerOrBindingName.name)); } // And it cannot refer to any declarations which come after it else if (candidate.valueDeclaration && candidate.valueDeclaration.pos > associatedDeclarationForContainingInitializerOrBindingName.pos && root.parent.locals && lookup(root.parent.locals, candidate.escapedName, meaning) === candidate) { error(errorLocation, Diagnostics.Parameter_0_cannot_reference_identifier_1_declared_after_it, declarationNameToString(associatedDeclarationForContainingInitializerOrBindingName.name), declarationNameToString(errorLocation as Identifier)); } } if (result && errorLocation && meaning & SymbolFlags.Value && result.flags & SymbolFlags.Alias && !(result.flags & SymbolFlags.Value) && !isValidTypeOnlyAliasUseSite(errorLocation)) { const typeOnlyDeclaration = getTypeOnlyAliasDeclaration(result, SymbolFlags.Value); if (typeOnlyDeclaration) { const message = typeOnlyDeclaration.kind === SyntaxKind.ExportSpecifier || typeOnlyDeclaration.kind === SyntaxKind.ExportDeclaration || typeOnlyDeclaration.kind === SyntaxKind.NamespaceExport ? Diagnostics._0_cannot_be_used_as_a_value_because_it_was_exported_using_export_type : Diagnostics._0_cannot_be_used_as_a_value_because_it_was_imported_using_import_type; const unescapedName = unescapeLeadingUnderscores(name); addTypeOnlyDeclarationRelatedInfo( error(errorLocation, message, unescapedName), typeOnlyDeclaration, unescapedName); } } }); } return result; } function addTypeOnlyDeclarationRelatedInfo(diagnostic: Diagnostic, typeOnlyDeclaration: TypeOnlyCompatibleAliasDeclaration | undefined, unescapedName: string) { if (!typeOnlyDeclaration) return diagnostic; return addRelatedInfo( diagnostic, createDiagnosticForNode( typeOnlyDeclaration, typeOnlyDeclaration.kind === SyntaxKind.ExportSpecifier || typeOnlyDeclaration.kind === SyntaxKind.ExportDeclaration || typeOnlyDeclaration.kind === SyntaxKind.NamespaceExport ? Diagnostics._0_was_exported_here : Diagnostics._0_was_imported_here, unescapedName)); } function getIsDeferredContext(location: Node, lastLocation: Node | undefined): boolean { if (location.kind !== SyntaxKind.ArrowFunction && location.kind !== SyntaxKind.FunctionExpression) { // initializers in instance property declaration of class like entities are executed in constructor and thus deferred return isTypeQueryNode(location) || (( isFunctionLikeDeclaration(location) || (location.kind === SyntaxKind.PropertyDeclaration && !isStatic(location)) ) && (!lastLocation || lastLocation !== (location as SignatureDeclaration | PropertyDeclaration).name)); // A name is evaluated within the enclosing scope - so it shouldn't count as deferred } if (lastLocation && lastLocation === (location as FunctionExpression | ArrowFunction).name) { return false; } // generator functions and async functions are not inlined in control flow when immediately invoked if ((location as FunctionExpression | ArrowFunction).asteriskToken || hasSyntacticModifier(location, ModifierFlags.Async)) { return true; } return !getImmediatelyInvokedFunctionExpression(location); } type SelfReferenceLocation = | FunctionDeclaration | ClassDeclaration | InterfaceDeclaration | EnumDeclaration | TypeAliasDeclaration | ModuleDeclaration ; function isSelfReferenceLocation(node: Node): node is SelfReferenceLocation { 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 | PrivateIdentifier) { return isString(nameArg) ? unescapeLeadingUnderscores(nameArg as __String) : declarationNameToString(nameArg as Identifier); } function isTypeParameterSymbolDeclaredInContainer(symbol: Symbol, container: Node) { if (symbol.declarations) { 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)); } } } } 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, /*includeClassComputedPropertyName*/ false); let location: Node = container; while (location) { if (isClassLike(location.parent)) { const classSymbol = getSymbolOfDeclaration(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 && !isStatic(location)) { const instanceType = (getDeclaredTypeOfSymbol(classSymbol) as InterfaceType).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((node as ExpressionWithTypeArguments).expression)) { return (node as ExpressionWithTypeArguments).expression as EntityNameExpression; } // 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_Did_you_mean_typeof_0, unescapeLeadingUnderscores(name)); return true; } } return false; } function isPrimitiveTypeName(name: __String) { return name === "any" || name === "string" || name === "number" || name === "boolean" || name === "never" || name === "unknown"; } function checkAndReportErrorForExportingPrimitiveType(errorLocation: Node, name: __String): boolean { if (isPrimitiveTypeName(name) && errorLocation.parent.kind === SyntaxKind.ExportSpecifier) { error(errorLocation, Diagnostics.Cannot_export_0_Only_local_declarations_can_be_exported_from_a_module, name as string); return true; } return false; } function checkAndReportErrorForUsingTypeAsValue(errorLocation: Node, name: __String, meaning: SymbolFlags): boolean { if (meaning & SymbolFlags.Value) { if (isPrimitiveTypeName(name)) { if (isExtendedByInterface(errorLocation)) { error(errorLocation, Diagnostics.An_interface_cannot_extend_a_primitive_type_like_0_an_interface_can_only_extend_named_types_and_classes, unescapeLeadingUnderscores(name)); } else { 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)); const allFlags = symbol && getAllSymbolFlags(symbol); if (symbol && allFlags !== undefined && !(allFlags & SymbolFlags.Value)) { const rawName = unescapeLeadingUnderscores(name); if (isES2015OrLaterConstructorName(name)) { error(errorLocation, 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, rawName); } else if (maybeMappedType(errorLocation, symbol)) { error(errorLocation, Diagnostics._0_only_refers_to_a_type_but_is_being_used_as_a_value_here_Did_you_mean_to_use_1_in_0, rawName, rawName === "K" ? "P" : "K"); } else { error(errorLocation, Diagnostics._0_only_refers_to_a_type_but_is_being_used_as_a_value_here, rawName); } return true; } } return false; } function isExtendedByInterface(node: Node): boolean { const grandparent = node.parent.parent; const parentOfGrandparent = grandparent.parent; if(grandparent && parentOfGrandparent){ const isExtending = isHeritageClause(grandparent) && grandparent.token === SyntaxKind.ExtendsKeyword; const isInterface = isInterfaceDeclaration(parentOfGrandparent); return isExtending && isInterface; } return false; } function maybeMappedType(node: Node, symbol: Symbol) { const container = findAncestor(node.parent, n => isComputedPropertyName(n) || isPropertySignature(n) ? false : isTypeLiteralNode(n) || "quit") as TypeLiteralNode | undefined; if (container && container.members.length === 1) { const type = getDeclaredTypeOfSymbol(symbol); return !!(type.flags & TypeFlags.Union) && allTypesAssignableToKind(type, TypeFlags.StringOrNumberLiteral, /*strict*/ 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 checkAndReportErrorForUsingNamespaceAsTypeOrValue(errorLocation: Node, name: __String, meaning: SymbolFlags): boolean { if (meaning & (SymbolFlags.Value & ~SymbolFlags.Type)) { const symbol = resolveSymbol(resolveName(errorLocation, name, SymbolFlags.NamespaceModule, /*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.Value)) { const symbol = resolveSymbol(resolveName(errorLocation, name, SymbolFlags.Module, /*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)); if (result.flags & (SymbolFlags.Function | SymbolFlags.FunctionScopedVariable | SymbolFlags.Assignment) && result.flags & SymbolFlags.Class) { // constructor functions aren't block scoped return; } // Block-scoped variables cannot be used before their definition const declaration = result.declarations?.find( d => isBlockOrCatchScoped(d) || isClassLike(d) || (d.kind === SyntaxKind.EnumDeclaration)); if (declaration === undefined) return Debug.fail("checkResolvedBlockScopedVariable could not find block-scoped declaration"); 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); } 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. * If current node is an IIFE, continue walking up. * 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 === parent || (n === stopAt || isFunctionLike(n) && (!getImmediatelyInvokedFunctionExpression(n) || isAsyncFunction(n)) ? "quit" : false)); } 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 symbol.declarations && findLast(symbol.declarations, isAliasSymbolDeclaration); } /** * An alias symbol is created by one of the following declarations: * import = ... * import from ... * import * as from ... * import { x as } from ... * export { x as } from ... * export * as ns from ... * export = * export default * module.exports = * {} * {name: } * const { x } = require ... */ function isAliasSymbolDeclaration(node: Node): boolean { return node.kind === SyntaxKind.ImportEqualsDeclaration || node.kind === SyntaxKind.NamespaceExportDeclaration || node.kind === SyntaxKind.ImportClause && !!(node as ImportClause).name || node.kind === SyntaxKind.NamespaceImport || node.kind === SyntaxKind.NamespaceExport || node.kind === SyntaxKind.ImportSpecifier || node.kind === SyntaxKind.ExportSpecifier || node.kind === SyntaxKind.ExportAssignment && exportAssignmentIsAlias(node as ExportAssignment) || isBinaryExpression(node) && getAssignmentDeclarationKind(node) === AssignmentDeclarationKind.ModuleExports && exportAssignmentIsAlias(node) || isAccessExpression(node) && isBinaryExpression(node.parent) && node.parent.left === node && node.parent.operatorToken.kind === SyntaxKind.EqualsToken && isAliasableOrJsExpression(node.parent.right) || node.kind === SyntaxKind.ShorthandPropertyAssignment || node.kind === SyntaxKind.PropertyAssignment && isAliasableOrJsExpression((node as PropertyAssignment).initializer) || node.kind === SyntaxKind.VariableDeclaration && isVariableDeclarationInitializedToBareOrAccessedRequire(node) || node.kind === SyntaxKind.BindingElement && isVariableDeclarationInitializedToBareOrAccessedRequire(node.parent.parent); } function isAliasableOrJsExpression(e: Expression) { return isAliasableExpression(e) || isFunctionExpression(e) && isJSConstructor(e); } function getTargetOfImportEqualsDeclaration(node: ImportEqualsDeclaration | VariableDeclaration, dontResolveAlias: boolean): Symbol | undefined { const commonJSPropertyAccess = getCommonJSPropertyAccess(node); if (commonJSPropertyAccess) { const name = (getLeftmostAccessExpression(commonJSPropertyAccess.expression) as CallExpression).arguments[0] as StringLiteral; return isIdentifier(commonJSPropertyAccess.name) ? resolveSymbol(getPropertyOfType(resolveExternalModuleTypeByLiteral(name), commonJSPropertyAccess.name.escapedText)) : undefined; } if (isVariableDeclaration(node) || node.moduleReference.kind === SyntaxKind.ExternalModuleReference) { const immediate = resolveExternalModuleName( node, getExternalModuleRequireArgument(node) || getExternalModuleImportEqualsDeclarationExpression(node)); const resolved = resolveExternalModuleSymbol(immediate); markSymbolOfAliasDeclarationIfTypeOnly(node, immediate, resolved, /*overwriteEmpty*/ false); return resolved; } const resolved = getSymbolOfPartOfRightHandSideOfImportEquals(node.moduleReference, dontResolveAlias); checkAndReportErrorForResolvingImportAliasToTypeOnlySymbol(node, resolved); return resolved; } function checkAndReportErrorForResolvingImportAliasToTypeOnlySymbol(node: ImportEqualsDeclaration, resolved: Symbol | undefined) { if (markSymbolOfAliasDeclarationIfTypeOnly(node, /*immediateTarget*/ undefined, resolved, /*overwriteEmpty*/ false) && !node.isTypeOnly) { const typeOnlyDeclaration = getTypeOnlyAliasDeclaration(getSymbolOfDeclaration(node))!; const isExport = typeOnlyDeclaration.kind === SyntaxKind.ExportSpecifier || typeOnlyDeclaration.kind === SyntaxKind.ExportDeclaration; const message = isExport ? Diagnostics.An_import_alias_cannot_reference_a_declaration_that_was_exported_using_export_type : Diagnostics.An_import_alias_cannot_reference_a_declaration_that_was_imported_using_import_type; const relatedMessage = isExport ? Diagnostics._0_was_exported_here : Diagnostics._0_was_imported_here; // TODO: how to get name for export *? const name = typeOnlyDeclaration.kind === SyntaxKind.ExportDeclaration ? "*" : unescapeLeadingUnderscores(typeOnlyDeclaration.name.escapedText); addRelatedInfo(error(node.moduleReference, message), createDiagnosticForNode(typeOnlyDeclaration, relatedMessage, name)); } } function resolveExportByName(moduleSymbol: Symbol, name: __String, sourceNode: TypeOnlyCompatibleAliasDeclaration | undefined, dontResolveAlias: boolean) { const exportValue = moduleSymbol.exports!.get(InternalSymbolName.ExportEquals); const exportSymbol = exportValue ? getPropertyOfType(getTypeOfSymbol(exportValue), name, /*skipObjectFunctionPropertyAugment*/ true) : moduleSymbol.exports!.get(name); const resolved = resolveSymbol(exportSymbol, dontResolveAlias); markSymbolOfAliasDeclarationIfTypeOnly(sourceNode, exportSymbol, resolved, /*overwriteEmpty*/ false); return resolved; } function isSyntacticDefault(node: Node) { return ((isExportAssignment(node) && !node.isExportEquals) || hasSyntacticModifier(node, ModifierFlags.Default) || isExportSpecifier(node)); } function getUsageModeForExpression(usage: Expression) { return isStringLiteralLike(usage) ? getModeForUsageLocation(getSourceFileOfNode(usage), usage) : undefined; } function isESMFormatImportImportingCommonjsFormatFile(usageMode: ResolutionMode, targetMode: ResolutionMode) { return usageMode === ModuleKind.ESNext && targetMode === ModuleKind.CommonJS; } function isOnlyImportedAsDefault(usage: Expression) { const usageMode = getUsageModeForExpression(usage); return usageMode === ModuleKind.ESNext && endsWith((usage as StringLiteralLike).text, Extension.Json); } function canHaveSyntheticDefault(file: SourceFile | undefined, moduleSymbol: Symbol, dontResolveAlias: boolean, usage: Expression) { const usageMode = file && getUsageModeForExpression(usage); if (file && usageMode !== undefined) { const result = isESMFormatImportImportingCommonjsFormatFile(usageMode, file.impliedNodeFormat); if (usageMode === ModuleKind.ESNext || result) { return result; } // fallthrough on cjs usages so we imply defaults for interop'd imports, too } 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, /*sourceNode*/ undefined, /*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"), /*sourceNode*/ undefined, 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 typeof file.externalModuleIndicator !== "object" && !resolveExportByName(moduleSymbol, escapeLeadingUnderscores("__esModule"), /*sourceNode*/ undefined, dontResolveAlias); } function getTargetOfImportClause(node: ImportClause, dontResolveAlias: boolean): Symbol | undefined { const moduleSymbol = resolveExternalModuleName(node, node.parent.moduleSpecifier); if (moduleSymbol) { return getTargetofModuleDefault(moduleSymbol, node, dontResolveAlias); } } function getTargetofModuleDefault(moduleSymbol: Symbol, node: ImportClause | ImportOrExportSpecifier, dontResolveAlias: boolean) { let exportDefaultSymbol: Symbol | undefined; if (isShorthandAmbientModuleSymbol(moduleSymbol)) { exportDefaultSymbol = moduleSymbol; } else { exportDefaultSymbol = resolveExportByName(moduleSymbol, InternalSymbolName.Default, node, dontResolveAlias); } const file = moduleSymbol.declarations?.find(isSourceFile); const specifier = getModuleSpecifierForImportOrExport(node); if (!specifier) { return exportDefaultSymbol; } const hasDefaultOnly = isOnlyImportedAsDefault(specifier); const hasSyntheticDefault = canHaveSyntheticDefault(file, moduleSymbol, dontResolveAlias, specifier); if (!exportDefaultSymbol && !hasSyntheticDefault && !hasDefaultOnly) { if (hasExportAssignmentSymbol(moduleSymbol) && !allowSyntheticDefaultImports) { const compilerOptionName = moduleKind >= ModuleKind.ES2015 ? "allowSyntheticDefaultImports" : "esModuleInterop"; const exportEqualsSymbol = moduleSymbol.exports!.get(InternalSymbolName.ExportEquals); const exportAssignment = exportEqualsSymbol!.valueDeclaration; const err = error(node.name, Diagnostics.Module_0_can_only_be_default_imported_using_the_1_flag, symbolToString(moduleSymbol), compilerOptionName); if (exportAssignment) { addRelatedInfo(err, createDiagnosticForNode( exportAssignment, Diagnostics.This_module_is_declared_with_export_and_can_only_be_used_with_a_default_import_when_using_the_0_flag, compilerOptionName )); } } else if (isImportClause(node)) { reportNonDefaultExport(moduleSymbol, node); } else { errorNoModuleMemberSymbol(moduleSymbol, moduleSymbol, node, isImportOrExportSpecifier(node) && node.propertyName || node.name); } } else if (hasSyntheticDefault || hasDefaultOnly) { // per emit behavior, a synthetic default overrides a "real" .default member if `__esModule` is not present const resolved = resolveExternalModuleSymbol(moduleSymbol, dontResolveAlias) || resolveSymbol(moduleSymbol, dontResolveAlias); markSymbolOfAliasDeclarationIfTypeOnly(node, moduleSymbol, resolved, /*overwriteEmpty*/ false); return resolved; } markSymbolOfAliasDeclarationIfTypeOnly(node, exportDefaultSymbol, /*finalTarget*/ undefined, /*overwriteEmpty*/ false); return exportDefaultSymbol; } function getModuleSpecifierForImportOrExport(node: ImportEqualsDeclaration | ImportClause | NamespaceImport | ImportOrExportSpecifier): Expression | undefined { switch (node.kind) { case SyntaxKind.ImportClause: return node.parent.moduleSpecifier; case SyntaxKind.ImportEqualsDeclaration: return isExternalModuleReference(node.moduleReference) ? node.moduleReference.expression : undefined; case SyntaxKind.NamespaceImport: return node.parent.parent.moduleSpecifier; case SyntaxKind.ImportSpecifier: return node.parent.parent.parent.moduleSpecifier; case SyntaxKind.ExportSpecifier: return node.parent.parent.moduleSpecifier; default: return Debug.assertNever(node); } } function reportNonDefaultExport(moduleSymbol: Symbol, node: ImportClause) { if (moduleSymbol.exports?.has(node.symbol.escapedName)) { error( node.name, Diagnostics.Module_0_has_no_default_export_Did_you_mean_to_use_import_1_from_0_instead, symbolToString(moduleSymbol), symbolToString(node.symbol), ); } else { const diagnostic = error(node.name, Diagnostics.Module_0_has_no_default_export, symbolToString(moduleSymbol)); const exportStar = moduleSymbol.exports?.get(InternalSymbolName.ExportStar); if (exportStar) { const defaultExport = exportStar.declarations?.find(decl => !!( isExportDeclaration(decl) && decl.moduleSpecifier && resolveExternalModuleName(decl, decl.moduleSpecifier)?.exports?.has(InternalSymbolName.Default) )); if (defaultExport) { addRelatedInfo(diagnostic, createDiagnosticForNode(defaultExport, Diagnostics.export_Asterisk_does_not_re_export_a_default)); } } } } function getTargetOfNamespaceImport(node: NamespaceImport, dontResolveAlias: boolean): Symbol | undefined { const moduleSpecifier = node.parent.parent.moduleSpecifier; const immediate = resolveExternalModuleName(node, moduleSpecifier); const resolved = resolveESModuleSymbol(immediate, moduleSpecifier, dontResolveAlias, /*suppressInteropError*/ false); markSymbolOfAliasDeclarationIfTypeOnly(node, immediate, resolved, /*overwriteEmpty*/ false); return resolved; } function getTargetOfNamespaceExport(node: NamespaceExport, dontResolveAlias: boolean): Symbol | undefined { const moduleSpecifier = node.parent.moduleSpecifier; const immediate = moduleSpecifier && resolveExternalModuleName(node, moduleSpecifier); const resolved = moduleSpecifier && resolveESModuleSymbol(immediate, moduleSpecifier, dontResolveAlias, /*suppressInteropError*/ false); markSymbolOfAliasDeclarationIfTypeOnly(node, immediate, resolved, /*overwriteEmpty*/ false); return resolved; } // 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); Debug.assert(valueSymbol.declarations || typeSymbol.declarations); 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 = new Map(typeSymbol.members); if (valueSymbol.exports) result.exports = new Map(valueSymbol.exports); return result; } function getExportOfModule(symbol: Symbol, name: Identifier, specifier: Declaration, dontResolveAlias: boolean): Symbol | undefined { if (symbol.flags & SymbolFlags.Module) { const exportSymbol = getExportsOfSymbol(symbol).get(name.escapedText); const resolved = resolveSymbol(exportSymbol, dontResolveAlias); const exportStarDeclaration = getSymbolLinks(symbol).typeOnlyExportStarMap?.get(name.escapedText); markSymbolOfAliasDeclarationIfTypeOnly(specifier, exportSymbol, resolved, /*overwriteEmpty*/ false, exportStarDeclaration, name.escapedText); return resolved; } } function getPropertyOfVariable(symbol: Symbol, name: __String): Symbol | undefined { if (symbol.flags & SymbolFlags.Variable) { const typeAnnotation = (symbol.valueDeclaration as VariableDeclaration).type; if (typeAnnotation) { return resolveSymbol(getPropertyOfType(getTypeFromTypeNode(typeAnnotation), name)); } } } function getExternalModuleMember(node: ImportDeclaration | ExportDeclaration | VariableDeclaration, specifier: ImportOrExportSpecifier | BindingElement | PropertyAccessExpression, dontResolveAlias = false): Symbol | undefined { const moduleSpecifier = getExternalModuleRequireArgument(node) || (node as ImportDeclaration | ExportDeclaration).moduleSpecifier!; const moduleSymbol = resolveExternalModuleName(node, moduleSpecifier)!; // TODO: GH#18217 const name = !isPropertyAccessExpression(specifier) && specifier.propertyName || specifier.name; if (!isIdentifier(name)) { return undefined; } const suppressInteropError = name.escapedText === InternalSymbolName.Default && allowSyntheticDefaultImports; const targetSymbol = resolveESModuleSymbol(moduleSymbol, moduleSpecifier, /*dontResolveAlias*/ false, suppressInteropError); if (targetSymbol) { 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, /*skipObjectFunctionPropertyAugment*/ true); } else { symbolFromVariable = getPropertyOfVariable(targetSymbol, name.escapedText); } // if symbolFromVariable is export - get its final target symbolFromVariable = resolveSymbol(symbolFromVariable, dontResolveAlias); let symbolFromModule = getExportOfModule(targetSymbol, name, specifier, dontResolveAlias); if (symbolFromModule === undefined && name.escapedText === InternalSymbolName.Default) { const file = moduleSymbol.declarations?.find(isSourceFile); if (isOnlyImportedAsDefault(moduleSpecifier) || canHaveSyntheticDefault(file, moduleSymbol, dontResolveAlias, moduleSpecifier)) { symbolFromModule = resolveExternalModuleSymbol(moduleSymbol, dontResolveAlias) || resolveSymbol(moduleSymbol, dontResolveAlias); } } const symbol = symbolFromModule && symbolFromVariable && symbolFromModule !== symbolFromVariable ? combineValueAndTypeSymbols(symbolFromVariable, symbolFromModule) : symbolFromModule || symbolFromVariable; if (!symbol) { errorNoModuleMemberSymbol(moduleSymbol, targetSymbol, node, name); } return symbol; } } } function errorNoModuleMemberSymbol(moduleSymbol: Symbol, targetSymbol: Symbol, node: Node, name: Identifier) { 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._0_has_no_exported_member_named_1_Did_you_mean_2, moduleName, declarationName, suggestionName); if (suggestion.valueDeclaration) { addRelatedInfo(diagnostic, createDiagnosticForNode(suggestion.valueDeclaration, Diagnostics._0_is_declared_here, suggestionName) ); } } else { if (moduleSymbol.exports?.has(InternalSymbolName.Default)) { error( name, Diagnostics.Module_0_has_no_exported_member_1_Did_you_mean_to_use_import_1_from_0_instead, moduleName, declarationName ); } else { reportNonExportedMember(node, name, declarationName, moduleSymbol, moduleName); } } } function reportNonExportedMember(node: Node, name: Identifier, declarationName: string, moduleSymbol: Symbol, moduleName: string): void { const localSymbol = tryCast(moduleSymbol.valueDeclaration, canHaveLocals)?.locals?.get(name.escapedText); const exports = moduleSymbol.exports; if (localSymbol) { const exportedEqualsSymbol = exports?.get(InternalSymbolName.ExportEquals); if (exportedEqualsSymbol) { getSymbolIfSameReference(exportedEqualsSymbol, localSymbol) ? reportInvalidImportEqualsExportMember(node, name, declarationName, moduleName) : error(name, Diagnostics.Module_0_has_no_exported_member_1, moduleName, declarationName); } else { const exportedSymbol = exports ? find(symbolsToArray(exports), symbol => !!getSymbolIfSameReference(symbol, localSymbol)) : undefined; const diagnostic = exportedSymbol ? error(name, Diagnostics.Module_0_declares_1_locally_but_it_is_exported_as_2, moduleName, declarationName, symbolToString(exportedSymbol)) : error(name, Diagnostics.Module_0_declares_1_locally_but_it_is_not_exported, moduleName, declarationName); if (localSymbol.declarations) { addRelatedInfo(diagnostic, ...map(localSymbol.declarations, (decl, index) => createDiagnosticForNode(decl, index === 0 ? Diagnostics._0_is_declared_here : Diagnostics.and_here, declarationName))); } } } else { error(name, Diagnostics.Module_0_has_no_exported_member_1, moduleName, declarationName); } } function reportInvalidImportEqualsExportMember(node: Node, name: Identifier, declarationName: string, moduleName: string) { if (moduleKind >= ModuleKind.ES2015) { const message = getESModuleInterop(compilerOptions) ? Diagnostics._0_can_only_be_imported_by_using_a_default_import : Diagnostics._0_can_only_be_imported_by_turning_on_the_esModuleInterop_flag_and_using_a_default_import; error(name, message, declarationName); } else { if (isInJSFile(node)) { const message = getESModuleInterop(compilerOptions) ? Diagnostics._0_can_only_be_imported_by_using_a_require_call_or_by_using_a_default_import : Diagnostics._0_can_only_be_imported_by_using_a_require_call_or_by_turning_on_the_esModuleInterop_flag_and_using_a_default_import; error(name, message, declarationName); } else { const message = getESModuleInterop(compilerOptions) ? Diagnostics._0_can_only_be_imported_by_using_import_1_require_2_or_a_default_import : Diagnostics._0_can_only_be_imported_by_using_import_1_require_2_or_by_turning_on_the_esModuleInterop_flag_and_using_a_default_import; error(name, message, declarationName, declarationName, moduleName); } } } function getTargetOfImportSpecifier(node: ImportSpecifier | BindingElement, dontResolveAlias: boolean): Symbol | undefined { if (isImportSpecifier(node) && idText(node.propertyName || node.name) === InternalSymbolName.Default) { const specifier = getModuleSpecifierForImportOrExport(node); const moduleSymbol = specifier && resolveExternalModuleName(node, specifier); if (moduleSymbol) { return getTargetofModuleDefault(moduleSymbol, node, dontResolveAlias); } } const root = isBindingElement(node) ? getRootDeclaration(node) as VariableDeclaration : node.parent.parent.parent; const commonJSPropertyAccess = getCommonJSPropertyAccess(root); const resolved = getExternalModuleMember(root, commonJSPropertyAccess || node, dontResolveAlias); const name = node.propertyName || node.name; if (commonJSPropertyAccess && resolved && isIdentifier(name)) { return resolveSymbol(getPropertyOfType(getTypeOfSymbol(resolved), name.escapedText), dontResolveAlias); } markSymbolOfAliasDeclarationIfTypeOnly(node, /*immediateTarget*/ undefined, resolved, /*overwriteEmpty*/ false); return resolved; } function getCommonJSPropertyAccess(node: Node) { if (isVariableDeclaration(node) && node.initializer && isPropertyAccessExpression(node.initializer)) { return node.initializer; } } function getTargetOfNamespaceExportDeclaration(node: NamespaceExportDeclaration, dontResolveAlias: boolean): Symbol | undefined { if (canHaveSymbol(node.parent)) { const resolved = resolveExternalModuleSymbol(node.parent.symbol, dontResolveAlias); markSymbolOfAliasDeclarationIfTypeOnly(node, /*immediateTarget*/ undefined, resolved, /*overwriteEmpty*/ false); return resolved; } } function getTargetOfExportSpecifier(node: ExportSpecifier, meaning: SymbolFlags, dontResolveAlias?: boolean) { if (idText(node.propertyName || node.name) === InternalSymbolName.Default) { const specifier = getModuleSpecifierForImportOrExport(node); const moduleSymbol = specifier && resolveExternalModuleName(node, specifier); if (moduleSymbol) { return getTargetofModuleDefault(moduleSymbol, node, !!dontResolveAlias); } } const resolved = node.parent.parent.moduleSpecifier ? getExternalModuleMember(node.parent.parent, node, dontResolveAlias) : resolveEntityName(node.propertyName || node.name, meaning, /*ignoreErrors*/ false, dontResolveAlias); markSymbolOfAliasDeclarationIfTypeOnly(node, /*immediateTarget*/ undefined, resolved, /*overwriteEmpty*/ false); return resolved; } function getTargetOfExportAssignment(node: ExportAssignment | BinaryExpression, dontResolveAlias: boolean): Symbol | undefined { const expression = isExportAssignment(node) ? node.expression : node.right; const resolved = getTargetOfAliasLikeExpression(expression, dontResolveAlias); markSymbolOfAliasDeclarationIfTypeOnly(node, /*immediateTarget*/ undefined, resolved, /*overwriteEmpty*/ false); return resolved; } function getTargetOfAliasLikeExpression(expression: Expression, dontResolveAlias: boolean) { if (isClassExpression(expression)) { return checkExpressionCached(expression).symbol; } if (!isEntityName(expression) && !isEntityNameExpression(expression)) { return undefined; } const aliasLike = resolveEntityName(expression, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace, /*ignoreErrors*/ true, dontResolveAlias); if (aliasLike) { return aliasLike; } checkExpressionCached(expression); return getNodeLinks(expression).resolvedSymbol; } function getTargetOfAccessExpression(node: AccessExpression, dontRecursivelyResolve: boolean): Symbol | undefined { if (!(isBinaryExpression(node.parent) && node.parent.left === node && node.parent.operatorToken.kind === SyntaxKind.EqualsToken)) { return undefined; } return getTargetOfAliasLikeExpression(node.parent.right, dontRecursivelyResolve); } function getTargetOfAliasDeclaration(node: Declaration, dontRecursivelyResolve = false): Symbol | undefined { switch (node.kind) { case SyntaxKind.ImportEqualsDeclaration: case SyntaxKind.VariableDeclaration: return getTargetOfImportEqualsDeclaration(node as ImportEqualsDeclaration | VariableDeclaration, dontRecursivelyResolve); case SyntaxKind.ImportClause: return getTargetOfImportClause(node as ImportClause, dontRecursivelyResolve); case SyntaxKind.NamespaceImport: return getTargetOfNamespaceImport(node as NamespaceImport, dontRecursivelyResolve); case SyntaxKind.NamespaceExport: return getTargetOfNamespaceExport(node as NamespaceExport, dontRecursivelyResolve); case SyntaxKind.ImportSpecifier: case SyntaxKind.BindingElement: return getTargetOfImportSpecifier(node as ImportSpecifier | BindingElement, dontRecursivelyResolve); case SyntaxKind.ExportSpecifier: return getTargetOfExportSpecifier(node as ExportSpecifier, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace, dontRecursivelyResolve); case SyntaxKind.ExportAssignment: case SyntaxKind.BinaryExpression: return getTargetOfExportAssignment((node as ExportAssignment | BinaryExpression), dontRecursivelyResolve); case SyntaxKind.NamespaceExportDeclaration: return getTargetOfNamespaceExportDeclaration(node as NamespaceExportDeclaration, dontRecursivelyResolve); case SyntaxKind.ShorthandPropertyAssignment: return resolveEntityName((node as ShorthandPropertyAssignment).name, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace, /*ignoreErrors*/ true, dontRecursivelyResolve); case SyntaxKind.PropertyAssignment: return getTargetOfAliasLikeExpression((node as PropertyAssignment).initializer, dontRecursivelyResolve); case SyntaxKind.ElementAccessExpression: case SyntaxKind.PropertyAccessExpression: return getTargetOfAccessExpression(node as AccessExpression, 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.aliasTarget) { links.aliasTarget = resolvingSymbol; const node = getDeclarationOfAliasSymbol(symbol); if (!node) return Debug.fail(); const target = getTargetOfAliasDeclaration(node); if (links.aliasTarget === resolvingSymbol) { links.aliasTarget = target || unknownSymbol; } else { error(node, Diagnostics.Circular_definition_of_import_alias_0, symbolToString(symbol)); } } else if (links.aliasTarget === resolvingSymbol) { links.aliasTarget = unknownSymbol; } return links.aliasTarget; } function tryResolveAlias(symbol: Symbol): Symbol | undefined { const links = getSymbolLinks(symbol); if (links.aliasTarget !== resolvingSymbol) { return resolveAlias(symbol); } return undefined; } /** * Gets combined flags of a `symbol` and all alias targets it resolves to. `resolveAlias` * is typically recursive over chains of aliases, but stops mid-chain if an alias is merged * with another exported symbol, e.g. * ```ts * // a.ts * export const a = 0; * // b.ts * export { a } from "./a"; * export type a = number; * // c.ts * import { a } from "./b"; * ``` * Calling `resolveAlias` on the `a` in c.ts would stop at the merged symbol exported * from b.ts, even though there is still more alias to resolve. Consequently, if we were * trying to determine if the `a` in c.ts has a value meaning, looking at the flags on * the local symbol and on the symbol returned by `resolveAlias` is not enough. * @returns SymbolFlags.All if `symbol` is an alias that ultimately resolves to `unknown`; * combined flags of all alias targets otherwise. */ function getAllSymbolFlags(symbol: Symbol): SymbolFlags { let flags = symbol.flags; let seenSymbols; while (symbol.flags & SymbolFlags.Alias) { const target = resolveAlias(symbol); if (target === unknownSymbol) { return SymbolFlags.All; } // Optimizations - try to avoid creating or adding to // `seenSymbols` if possible if (target === symbol || seenSymbols?.has(target)) { break; } if (target.flags & SymbolFlags.Alias) { if (seenSymbols) { seenSymbols.add(target); } else { seenSymbols = new Set([symbol, target]); } } flags |= target.flags; symbol = target; } return flags; } /** * Marks a symbol as type-only if its declaration is syntactically type-only. * If it is not itself marked type-only, but resolves to a type-only alias * somewhere in its resolution chain, save a reference to the type-only alias declaration * so the alias _not_ marked type-only can be identified as _transitively_ type-only. * * This function is called on each alias declaration that could be type-only or resolve to * another type-only alias during `resolveAlias`, so that later, when an alias is used in a * JS-emitting expression, we can quickly determine if that symbol is effectively type-only * and issue an error if so. * * @param aliasDeclaration The alias declaration not marked as type-only * @param immediateTarget The symbol to which the alias declaration immediately resolves * @param finalTarget The symbol to which the alias declaration ultimately resolves * @param overwriteEmpty Checks `resolvesToSymbol` for type-only declarations even if `aliasDeclaration` * has already been marked as not resolving to a type-only alias. Used when recursively resolving qualified * names of import aliases, e.g. `import C = a.b.C`. If namespace `a` is not found to be type-only, the * import declaration will initially be marked as not resolving to a type-only symbol. But, namespace `b` * must still be checked for a type-only marker, overwriting the previous negative result if found. */ function markSymbolOfAliasDeclarationIfTypeOnly( aliasDeclaration: Declaration | undefined, immediateTarget: Symbol | undefined, finalTarget: Symbol | undefined, overwriteEmpty: boolean, exportStarDeclaration?: ExportDeclaration & { readonly isTypeOnly: true }, exportStarName?: __String, ): boolean { if (!aliasDeclaration || isPropertyAccessExpression(aliasDeclaration)) return false; // If the declaration itself is type-only, mark it and return. // No need to check what it resolves to. const sourceSymbol = getSymbolOfDeclaration(aliasDeclaration); if (isTypeOnlyImportOrExportDeclaration(aliasDeclaration)) { const links = getSymbolLinks(sourceSymbol); links.typeOnlyDeclaration = aliasDeclaration; return true; } if (exportStarDeclaration) { const links = getSymbolLinks(sourceSymbol); links.typeOnlyDeclaration = exportStarDeclaration; if (sourceSymbol.escapedName !== exportStarName) { links.typeOnlyExportStarName = exportStarName; } return true; } const links = getSymbolLinks(sourceSymbol); return markSymbolOfAliasDeclarationIfTypeOnlyWorker(links, immediateTarget, overwriteEmpty) || markSymbolOfAliasDeclarationIfTypeOnlyWorker(links, finalTarget, overwriteEmpty); } function markSymbolOfAliasDeclarationIfTypeOnlyWorker(aliasDeclarationLinks: SymbolLinks, target: Symbol | undefined, overwriteEmpty: boolean): boolean { if (target && (aliasDeclarationLinks.typeOnlyDeclaration === undefined || overwriteEmpty && aliasDeclarationLinks.typeOnlyDeclaration === false)) { const exportSymbol = target.exports?.get(InternalSymbolName.ExportEquals) ?? target; const typeOnly = exportSymbol.declarations && find(exportSymbol.declarations, isTypeOnlyImportOrExportDeclaration); aliasDeclarationLinks.typeOnlyDeclaration = typeOnly ?? getSymbolLinks(exportSymbol).typeOnlyDeclaration ?? false; } return !!aliasDeclarationLinks.typeOnlyDeclaration; } /** Indicates that a symbol directly or indirectly resolves to a type-only import or export. */ function getTypeOnlyAliasDeclaration(symbol: Symbol, include?: SymbolFlags): TypeOnlyAliasDeclaration | undefined { if (!(symbol.flags & SymbolFlags.Alias)) { return undefined; } const links = getSymbolLinks(symbol); if (include === undefined) { return links.typeOnlyDeclaration || undefined; } if (links.typeOnlyDeclaration) { const resolved = links.typeOnlyDeclaration.kind === SyntaxKind.ExportDeclaration ? resolveSymbol(getExportsOfModule(links.typeOnlyDeclaration.symbol.parent!).get(links.typeOnlyExportStarName || symbol.escapedName))! : resolveAlias(links.typeOnlyDeclaration.symbol); return getAllSymbolFlags(resolved) & include ? links.typeOnlyDeclaration : undefined; } return undefined; } function markExportAsReferenced(node: ImportEqualsDeclaration | ExportSpecifier) { if (!canCollectSymbolAliasAccessabilityData) { return; } const symbol = getSymbolOfDeclaration(node); const target = resolveAlias(symbol); if (target) { const markAlias = target === unknownSymbol || ((getAllSymbolFlags(target) & SymbolFlags.Value) && !isConstEnumOrConstEnumOnlyModule(target) && !getTypeOnlyAliasDeclaration(symbol, SymbolFlags.Value)); 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) { Debug.assert(canCollectSymbolAliasAccessabilityData); const links = getSymbolLinks(symbol); if (!links.referenced) { links.referenced = true; const node = getDeclarationOfAliasSymbol(symbol); if (!node) return Debug.fail(); // We defer checking of the reference of an `import =` until the import itself is referenced, // This way a chain of imports can be elided if ultimately the final input is only used in a type // position. if (isInternalModuleImportEqualsDeclaration(node)) { if (getAllSymbolFlags(resolveSymbol(symbol)) & SymbolFlags.Value) { // import foo = checkExpressionCached(node.moduleReference as Expression); } } } } // Aliases that resolve to const enums are not marked as referenced because they are not emitted, // but their usage in value positions must be tracked to determine if the import can be type-only. function markConstEnumAliasAsReferenced(symbol: Symbol) { const links = getSymbolLinks(symbol); if (!links.constEnumReferenced) { links.constEnumReferenced = true; } } // 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 = entityName.parent as QualifiedName; } // 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); } function getContainingQualifiedNameNode(node: QualifiedName) { while (isQualifiedName(node.parent)) { node = node.parent; } return node; } function tryGetQualifiedNameAsValue(node: QualifiedName) { let left: Identifier | QualifiedName = getFirstIdentifier(node); let symbol = resolveName(left, left.escapedText, SymbolFlags.Value, /*nameNotFoundMessage*/ undefined, left, /*isUse*/ true); if (!symbol) { return undefined; } while (isQualifiedName(left.parent)) { const type = getTypeOfSymbol(symbol); symbol = getPropertyOfType(type, left.parent.right.escapedText); if (!symbol) { return undefined; } left = left.parent; } return symbol; } /** * 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 || nodeIsSynthesized(name) ? Diagnostics.Cannot_find_namespace_0 : getCannotFindNameDiagnosticForName(getFirstIdentifier(name)); const symbolFromJSPrototype = isInJSFile(name) && !nodeIsSynthesized(name) ? resolveEntityNameFromAssignmentDeclaration(name, meaning) : undefined; symbol = getMergedSymbol(resolveName(location || name, name.escapedText, meaning, ignoreErrors || symbolFromJSPrototype ? undefined : message, name, /*isUse*/ true, /*excludeGlobals*/ false)); if (!symbol) { return getMergedSymbol(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 ( namespace.valueDeclaration && isInJSFile(namespace.valueDeclaration) && getEmitModuleResolutionKind(compilerOptions) !== ModuleResolutionKind.Bundler && 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 = getMergedSymbol(getSymbol(getExportsOfSymbol(namespace), right.escapedText, meaning)); if (!symbol && (namespace.flags & SymbolFlags.Alias)) { // `namespace` can be resolved further if there was a symbol merge with a re-export symbol = getMergedSymbol(getSymbol(getExportsOfSymbol(resolveAlias(namespace)), right.escapedText, meaning)); } if (!symbol) { if (!ignoreErrors) { const namespaceName = getFullyQualifiedName(namespace); const declarationName = declarationNameToString(right); const suggestionForNonexistentModule = getSuggestedSymbolForNonexistentModule(right, namespace); if (suggestionForNonexistentModule) { error(right, Diagnostics._0_has_no_exported_member_named_1_Did_you_mean_2, namespaceName, declarationName, symbolToString(suggestionForNonexistentModule)); return undefined; } const containingQualifiedName = isQualifiedName(name) && getContainingQualifiedNameNode(name); const canSuggestTypeof = globalObjectType // <-- can't pull on types if global types aren't initialized yet && (meaning & SymbolFlags.Type) && containingQualifiedName && !isTypeOfExpression(containingQualifiedName.parent) && tryGetQualifiedNameAsValue(containingQualifiedName); if (canSuggestTypeof) { error( containingQualifiedName, Diagnostics._0_refers_to_a_value_but_is_being_used_as_a_type_here_Did_you_mean_typeof_0, entityNameToString(containingQualifiedName) ); return undefined; } if (meaning & SymbolFlags.Namespace && isQualifiedName(name.parent)) { const exportedTypeSymbol = getMergedSymbol(getSymbol(getExportsOfSymbol(namespace), right.escapedText, SymbolFlags.Type)); if (exportedTypeSymbol) { error( name.parent.right, 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, symbolToString(exportedTypeSymbol), unescapeLeadingUnderscores(name.parent.right.escapedText) ); return undefined; } } error(right, Diagnostics.Namespace_0_has_no_exported_member_1, namespaceName, declarationName); } return undefined; } } else { Debug.assertNever(name, "Unknown entity name kind."); } Debug.assert((getCheckFlags(symbol) & CheckFlags.Instantiated) === 0, "Should never get an instantiated symbol here."); if (!nodeIsSynthesized(name) && isEntityName(name) && (symbol.flags & SymbolFlags.Alias || name.parent.kind === SyntaxKind.ExportAssignment)) { markSymbolOfAliasDeclarationIfTypeOnly(getAliasDeclarationFromName(name), symbol, /*finalTarget*/ undefined, /*overwriteEmpty*/ true); } 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 (host && isExpressionStatement(host) && isPrototypePropertyAssignment(host.expression)) { // /** @param {K} p */ X.prototype.m = function () { } <-- look for K on X's declaration const symbol = getSymbolOfDeclaration(host.expression.left); if (symbol) { return getDeclarationOfJSPrototypeContainer(symbol); } } if (host && isFunctionExpression(host) && isPrototypePropertyAssignment(host.parent) && isExpressionStatement(host.parent.parent)) { // X.prototype.m = /** @param {K} p */ function () { } <-- look for K on X's declaration const symbol = getSymbolOfDeclaration(host.parent.left); if (symbol) { return getDeclarationOfJSPrototypeContainer(symbol); } } if (host && (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 = getSymbolOfDeclaration(host.parent.parent.left as BindableStaticNameExpression); if (symbol) { return getDeclarationOfJSPrototypeContainer(symbol); } } const sig = getEffectiveJSDocHost(node); if (sig && isFunctionLike(sig)) { const symbol = getSymbolOfDeclaration(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; } /** * Get the real symbol of a declaration with an expando initializer. * * Normally, declarations have an associated symbol, but when a declaration has an expando * initializer, the expando's symbol is the one that has all the members merged into it. */ function getExpandoSymbol(symbol: Symbol): Symbol | undefined { const decl = symbol.valueDeclaration; if (!decl || !isInJSFile(decl) || symbol.flags & SymbolFlags.TypeAlias || getExpandoInitializer(decl, /*isPrototypeAssignment*/ false)) { return undefined; } const init = isVariableDeclaration(decl) ? getDeclaredExpandoInitializer(decl) : getAssignedExpandoInitializer(decl); if (init) { const initSymbol = getSymbolOfNode(init); if (initSymbol) { return mergeJSSymbols(initSymbol, symbol); } } } function resolveExternalModuleName(location: Node, moduleReferenceExpression: Expression, ignoreErrors?: boolean): Symbol | undefined { const isClassic = getEmitModuleResolutionKind(compilerOptions) === ModuleResolutionKind.Classic; const errorMessage = isClassic? Diagnostics.Cannot_find_module_0_Did_you_mean_to_set_the_moduleResolution_option_to_nodenext_or_to_add_aliases_to_the_paths_option : Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations; return resolveExternalModuleNameWorker(location, moduleReferenceExpression, ignoreErrors ? undefined : errorMessage); } 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 (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 contextSpecifier = isStringLiteralLike(location) ? location : findAncestor(location, isImportCall)?.arguments[0] || findAncestor(location, isImportDeclaration)?.moduleSpecifier || findAncestor(location, isExternalModuleImportEqualsDeclaration)?.moduleReference.expression || findAncestor(location, isExportDeclaration)?.moduleSpecifier || (isModuleDeclaration(location) ? location : location.parent && isModuleDeclaration(location.parent) && location.parent.name === location ? location.parent : undefined)?.name || (isLiteralImportTypeNode(location) ? location : undefined)?.argument.literal; const mode = contextSpecifier && isStringLiteralLike(contextSpecifier) ? getModeForUsageLocation(currentSourceFile, contextSpecifier) : currentSourceFile.impliedNodeFormat; const moduleResolutionKind = getEmitModuleResolutionKind(compilerOptions); const resolvedModule = getResolvedModule(currentSourceFile, moduleReference, mode); const resolutionDiagnostic = resolvedModule && getResolutionDiagnostic(compilerOptions, resolvedModule, currentSourceFile); const sourceFile = resolvedModule && (!resolutionDiagnostic || resolutionDiagnostic === Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set) && host.getSourceFile(resolvedModule.resolvedFileName); if (sourceFile) { // If there's a resolutionDiagnostic we need to report it even if a sourceFile is found. if (resolutionDiagnostic) { error(errorNode, resolutionDiagnostic, moduleReference, resolvedModule.resolvedFileName); } if (resolvedModule.resolvedUsingTsExtension && isDeclarationFileName(moduleReference)) { const importOrExport = findAncestor(location, isImportDeclaration)?.importClause || findAncestor(location, or(isImportEqualsDeclaration, isExportDeclaration)); if (importOrExport && !importOrExport.isTypeOnly || findAncestor(location, isImportCall)) { error( errorNode, Diagnostics.A_declaration_file_cannot_be_imported_without_import_type_Did_you_mean_to_import_an_implementation_file_0_instead, getSuggestedImportSource(Debug.checkDefined(tryExtractTSExtension(moduleReference)))); } } else if (resolvedModule.resolvedUsingTsExtension && !shouldAllowImportingTsExtension(compilerOptions, currentSourceFile.fileName)) { const tsExtension = Debug.checkDefined(tryExtractTSExtension(moduleReference)); error(errorNode, Diagnostics.An_import_path_can_only_end_with_a_0_extension_when_allowImportingTsExtensions_is_enabled, tsExtension); } if (sourceFile.symbol) { if (resolvedModule.isExternalLibraryImport && !resolutionExtensionIsTSOrJson(resolvedModule.extension)) { errorOnImplicitAnyModule(/*isError*/ false, errorNode, currentSourceFile, mode, resolvedModule, moduleReference); } if (moduleResolutionKind === ModuleResolutionKind.Node16 || moduleResolutionKind === ModuleResolutionKind.NodeNext) { const isSyncImport = (currentSourceFile.impliedNodeFormat === ModuleKind.CommonJS && !findAncestor(location, isImportCall)) || !!findAncestor(location, isImportEqualsDeclaration); const overrideClauseHost = findAncestor(location, l => isImportTypeNode(l) || isExportDeclaration(l) || isImportDeclaration(l)) as ImportTypeNode | ImportDeclaration | ExportDeclaration | undefined; const overrideClause = overrideClauseHost && isImportTypeNode(overrideClauseHost) ? overrideClauseHost.assertions?.assertClause : overrideClauseHost?.assertClause; // An override clause will take effect for type-only imports and import types, and allows importing the types across formats, regardless of // normal mode restrictions if (isSyncImport && sourceFile.impliedNodeFormat === ModuleKind.ESNext && !getResolutionModeOverrideForClause(overrideClause)) { if (findAncestor(location, isImportEqualsDeclaration)) { // ImportEquals in a ESM file resolving to another ESM file error(errorNode, Diagnostics.Module_0_cannot_be_imported_using_this_construct_The_specifier_only_resolves_to_an_ES_module_which_cannot_be_imported_with_require_Use_an_ECMAScript_import_instead, moduleReference); } else { // CJS file resolving to an ESM file let diagnosticDetails; const ext = tryGetExtensionFromPath(currentSourceFile.fileName); if (ext === Extension.Ts || ext === Extension.Js || ext === Extension.Tsx || ext === Extension.Jsx) { const scope = currentSourceFile.packageJsonScope; const targetExt = ext === Extension.Ts ? Extension.Mts : ext === Extension.Js ? Extension.Mjs : undefined; if (scope && !scope.contents.packageJsonContent.type) { if (targetExt) { diagnosticDetails = chainDiagnosticMessages( /*details*/ undefined, Diagnostics.To_convert_this_file_to_an_ECMAScript_module_change_its_file_extension_to_0_or_add_the_field_type_Colon_module_to_1, targetExt, combinePaths(scope.packageDirectory, "package.json")); } else { diagnosticDetails = chainDiagnosticMessages( /*details*/ undefined, Diagnostics.To_convert_this_file_to_an_ECMAScript_module_add_the_field_type_Colon_module_to_0, combinePaths(scope.packageDirectory, "package.json")); } } else { if (targetExt) { diagnosticDetails = chainDiagnosticMessages( /*details*/ undefined, Diagnostics.To_convert_this_file_to_an_ECMAScript_module_change_its_file_extension_to_0_or_create_a_local_package_json_file_with_type_Colon_module, targetExt); } else { diagnosticDetails = chainDiagnosticMessages( /*details*/ undefined, Diagnostics.To_convert_this_file_to_an_ECMAScript_module_create_a_local_package_json_file_with_type_Colon_module); } } } diagnostics.add(createDiagnosticForNodeFromMessageChain(getSourceFileOfNode(errorNode), errorNode, chainDiagnosticMessages( diagnosticDetails, Diagnostics.The_current_file_is_a_CommonJS_module_whose_imports_will_produce_require_calls_however_the_referenced_file_is_an_ECMAScript_module_and_cannot_be_imported_with_require_Consider_writing_a_dynamic_import_0_call_instead, 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) { // If the module reference matched a pattern ambient module ('*.foo') but there's also a // module augmentation by the specific name requested ('a.foo'), we store the merged symbol // by the augmentation name ('a.foo'), because asking for *.foo should not give you exports // from a.foo. const augmentation = patternAmbientModuleAugmentations && patternAmbientModuleAugmentations.get(moduleReference); if (augmentation) { return getMergedSymbol(augmentation); } 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, currentSourceFile, mode, 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) { // See if this was possibly a projectReference redirect if (resolvedModule) { const redirect = host.getProjectReferenceRedirect(resolvedModule.resolvedFileName); if (redirect) { error(errorNode, Diagnostics.Output_file_0_has_not_been_built_from_source_file_1, redirect, resolvedModule.resolvedFileName); return undefined; } } if (resolutionDiagnostic) { error(errorNode, resolutionDiagnostic, moduleReference, resolvedModule.resolvedFileName); } else { const isExtensionlessRelativePathImport = pathIsRelative(moduleReference) && !hasExtension(moduleReference); const resolutionIsNode16OrNext = moduleResolutionKind === ModuleResolutionKind.Node16 || moduleResolutionKind === ModuleResolutionKind.NodeNext; if (!getResolveJsonModule(compilerOptions) && fileExtensionIs(moduleReference, Extension.Json) && moduleResolutionKind !== ModuleResolutionKind.Classic && hasJsonModuleEmitEnabled(compilerOptions)) { error(errorNode, Diagnostics.Cannot_find_module_0_Consider_using_resolveJsonModule_to_import_module_with_json_extension, moduleReference); } else if (mode === ModuleKind.ESNext && resolutionIsNode16OrNext && isExtensionlessRelativePathImport) { const absoluteRef = getNormalizedAbsolutePath(moduleReference, getDirectoryPath(currentSourceFile.path)); const suggestedExt = suggestedExtensions.find(([actualExt, _importExt]) => host.fileExists(absoluteRef + actualExt))?.[1]; if (suggestedExt) { error(errorNode, Diagnostics.Relative_import_paths_need_explicit_file_extensions_in_EcmaScript_imports_when_moduleResolution_is_node16_or_nodenext_Did_you_mean_0, moduleReference + suggestedExt); } else { error(errorNode, Diagnostics.Relative_import_paths_need_explicit_file_extensions_in_EcmaScript_imports_when_moduleResolution_is_node16_or_nodenext_Consider_adding_an_extension_to_the_import_path); } } else { error(errorNode, moduleNotFoundError, moduleReference); } } } return undefined; function getSuggestedImportSource(tsExtension: string) { const importSourceWithoutExtension = removeExtension(moduleReference, tsExtension); /** * Direct users to import source with .js extension if outputting an ES module. * @see https://github.com/microsoft/TypeScript/issues/42151 */ if (emitModuleKindIsNonNodeESM(moduleKind) || mode === ModuleKind.ESNext) { const preferTs = isDeclarationFileName(moduleReference) && shouldAllowImportingTsExtension(compilerOptions); const ext = tsExtension === Extension.Mts || tsExtension === Extension.Dmts ? preferTs ? ".mts" : ".mjs" : tsExtension === Extension.Cts || tsExtension === Extension.Dmts ? preferTs ? ".cts" : ".cjs" : preferTs ? ".ts" : ".js"; return importSourceWithoutExtension + ext; } return importSourceWithoutExtension; } } function errorOnImplicitAnyModule(isError: boolean, errorNode: Node, sourceFile: SourceFile, mode: ResolutionMode, { packageId, resolvedFileName }: ResolvedModuleFull, moduleReference: string): void { let errorInfo: DiagnosticMessageChain | undefined; if (!isExternalModuleNameRelative(moduleReference) && packageId) { errorInfo = createModuleNotFoundChain(sourceFile, host, moduleReference, mode, packageId.name); } errorOrSuggestion(isError, errorNode, chainDiagnosticMessages( errorInfo, Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type, moduleReference, resolvedFileName)); } function resolveExternalModuleSymbol(moduleSymbol: Symbol, dontResolveAlias?: boolean): Symbol; function resolveExternalModuleSymbol(moduleSymbol: Symbol | undefined, dontResolveAlias?: boolean): Symbol | undefined; function resolveExternalModuleSymbol(moduleSymbol: Symbol | undefined, dontResolveAlias?: boolean): Symbol | undefined { if (moduleSymbol?.exports) { const exportEquals = resolveSymbol(moduleSymbol.exports.get(InternalSymbolName.ExportEquals), dontResolveAlias); const exported = getCommonJsExportEquals(getMergedSymbol(exportEquals), getMergedSymbol(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 links = getSymbolLinks(exported); if (links.cjsExportMerged) { return links.cjsExportMerged; } const merged = exported.flags & SymbolFlags.Transient ? exported : cloneSymbol(exported); merged.flags = merged.flags | SymbolFlags.ValueModule; if (merged.exports === undefined) { 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); }); if (merged === exported) { // We just mutated a symbol, reset any cached links we may have already set // (Notably required to make late bound members appear) getSymbolLinks(merged).resolvedExports = undefined; getSymbolLinks(merged).resolvedMembers = undefined; } getSymbolLinks(merged).cjsExportMerged = merged; return links.cjsExportMerged = 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, suppressInteropError: boolean): Symbol | undefined { const symbol = resolveExternalModuleSymbol(moduleSymbol, dontResolveAlias); if (!dontResolveAlias && symbol) { if (!suppressInteropError && !(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; } const referenceParent = referencingLocation.parent; if ( (isImportDeclaration(referenceParent) && getNamespaceDeclarationNode(referenceParent)) || isImportCall(referenceParent) ) { const reference = isImportCall(referenceParent) ? referenceParent.arguments[0] : referenceParent.moduleSpecifier; const type = getTypeOfSymbol(symbol); const defaultOnlyType = getTypeWithSyntheticDefaultOnly(type, symbol, moduleSymbol!, reference); if (defaultOnlyType) { return cloneTypeAsModuleType(symbol, defaultOnlyType, referenceParent); } const targetFile = moduleSymbol?.declarations?.find(isSourceFile); const isEsmCjsRef = targetFile && isESMFormatImportImportingCommonjsFormatFile(getUsageModeForExpression(reference), targetFile.impliedNodeFormat); if (getESModuleInterop(compilerOptions) || isEsmCjsRef) { let sigs = getSignaturesOfStructuredType(type, SignatureKind.Call); if (!sigs || !sigs.length) { sigs = getSignaturesOfStructuredType(type, SignatureKind.Construct); } if ( (sigs && sigs.length) || getPropertyOfType(type, InternalSymbolName.Default, /*skipObjectFunctionPropertyAugment*/ true) || isEsmCjsRef ) { const moduleType = type.flags & TypeFlags.StructuredType ? getTypeWithSyntheticDefaultImportType(type, symbol, moduleSymbol!, reference) : createDefaultPropertyWrapperForModule(symbol, symbol.parent); return cloneTypeAsModuleType(symbol, moduleType, referenceParent); } } } } return symbol; } /** * Create a new symbol which has the module's type less the call and construct signatures */ function cloneTypeAsModuleType(symbol: Symbol, moduleType: Type, referenceParent: ImportDeclaration | ImportCall) { const result = createSymbol(symbol.flags, symbol.escapedName); result.declarations = symbol.declarations ? symbol.declarations.slice() : []; result.parent = symbol.parent; result.links.target = symbol; result.links.originatingImport = referenceParent; if (symbol.valueDeclaration) result.valueDeclaration = symbol.valueDeclaration; if (symbol.constEnumOnlyModule) result.constEnumOnlyModule = true; if (symbol.members) result.members = new Map(symbol.members); if (symbol.exports) result.exports = new Map(symbol.exports); const resolvedModuleType = resolveStructuredTypeMembers(moduleType as StructuredType); // Should already be resolved from the signature checks above result.links.type = createAnonymousType(result, resolvedModuleType.members, emptyArray, emptyArray, resolvedModuleType.indexInfos); return result; } 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) { const type = getTypeOfSymbol(exportEquals); if (shouldTreatPropertiesOfExternalModuleAsExports(type)) { addRange(exports, getPropertiesOfType(type)); } } return exports; } function forEachExportAndPropertyOfModule(moduleSymbol: Symbol, cb: (symbol: Symbol, key: __String) => void): void { const exports = getExportsOfModule(moduleSymbol); exports.forEach((symbol, key) => { if (!isReservedMemberName(key)) { cb(symbol, key); } }); const exportEquals = resolveExternalModuleSymbol(moduleSymbol); if (exportEquals !== moduleSymbol) { const type = getTypeOfSymbol(exportEquals); if (shouldTreatPropertiesOfExternalModuleAsExports(type)) { forEachPropertyOfType(type, (symbol, escapedName) => { cb(symbol, escapedName); }); } } } 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 shouldTreatPropertiesOfExternalModuleAsExports(type) ? getPropertyOfType(type, memberName) : undefined; } function shouldTreatPropertiesOfExternalModuleAsExports(resolvedExternalModuleType: Type) { return !(resolvedExternalModuleType.flags & TypeFlags.Primitive || getObjectFlags(resolvedExternalModuleType) & ObjectFlags.Class || // `isArrayOrTupleLikeType` is too expensive to use in this auto-imports hot path isArrayType(resolvedExternalModuleType) || isTupleType(resolvedExternalModuleType)); } function getExportsOfSymbol(symbol: Symbol): SymbolTable { return symbol.flags & SymbolFlags.LateBindingContainer ? getResolvedMembersOrExportsOfSymbol(symbol, MembersOrExportsResolutionKind.resolvedExports) : symbol.flags & SymbolFlags.Module ? getExportsOfModule(symbol) : symbol.exports || emptySymbols; } function getExportsOfModule(moduleSymbol: Symbol): SymbolTable { const links = getSymbolLinks(moduleSymbol); if (!links.resolvedExports) { const { exports, typeOnlyExportStarMap } = getExportsOfModuleWorker(moduleSymbol); links.resolvedExports = exports; links.typeOnlyExportStarMap = typeOnlyExportStarMap; } return links.resolvedExports; } interface ExportCollisionTracker { specifierText: string; exportsWithDuplicate?: ExportDeclaration[]; } type ExportCollisionTrackerTable = Map<__String, 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!) }); } } 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) { const visitedSymbols: Symbol[] = []; let typeOnlyExportStarMap: Map<__String, ExportDeclaration & { readonly isTypeOnly: true }> | undefined; const nonTypeOnlyNames = new Set<__String>(); // A module defined by an 'export=' consists of one export that needs to be resolved moduleSymbol = resolveExternalModuleSymbol(moduleSymbol); const exports = visit(moduleSymbol) || emptySymbols; if (typeOnlyExportStarMap) { nonTypeOnlyNames.forEach(name => typeOnlyExportStarMap!.delete(name)); } return { exports, typeOnlyExportStarMap, }; // 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, exportStar?: ExportDeclaration, isTypeOnly?: boolean): SymbolTable | undefined { if (!isTypeOnly && symbol?.exports) { // Add non-type-only names before checking if we've visited this module, // because we might have visited it via an 'export type *', and visiting // again with 'export *' will override the type-onlyness of its exports. symbol.exports.forEach((_, name) => nonTypeOnlyNames.add(name)); } if (!(symbol && symbol.exports && pushIfUnique(visitedSymbols, symbol))) { return; } const symbols = new Map(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: ExportCollisionTrackerTable = new Map(); if (exportStars.declarations) { for (const node of exportStars.declarations) { const resolvedModule = resolveExternalModuleName(node, (node as ExportDeclaration).moduleSpecifier!); const exportedSymbols = visit(resolvedModule, node as ExportDeclaration, isTypeOnly || (node as ExportDeclaration).isTypeOnly); 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); } if (exportStar?.isTypeOnly) { typeOnlyExportStarMap ??= new Map(); symbols.forEach((_, escapedName) => typeOnlyExportStarMap!.set( escapedName, exportStar as ExportDeclaration & { readonly isTypeOnly: true })); } 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 getSymbolOfDeclaration(node: Declaration): Symbol { return getMergedSymbol(node.symbol && getLateBoundSymbol(node.symbol)); } /** * Get the merged symbol for a node. If you know the node is a `Declaration`, it is faster and more type safe to * use use `getSymbolOfDeclaration` instead. */ function getSymbolOfNode(node: Node): Symbol | undefined { return canHaveSymbol(node) ? getSymbolOfDeclaration(node) : undefined; } 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 = new Map())).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 = getSymbolOfDeclaration(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, meaning: SymbolFlags): Symbol[] | undefined { const container = getParentOfSymbol(symbol); // Type parameters end up in the `members` lists but are not externally visible if (container && !(symbol.flags & SymbolFlags.TypeParameter)) { const additionalContainers = mapDefined(container.declarations, fileSymbolIfFileSymbolExportEqualsContainer); const reexportContainers = enclosingDeclaration && getAlternativeContainingModules(symbol, enclosingDeclaration); const objectLiteralContainer = getVariableDeclarationOfObjectLiteral(container, meaning); if ( enclosingDeclaration && container.flags & getQualifiedLeftMeaning(meaning) && getAccessibleSymbolChain(container, enclosingDeclaration, SymbolFlags.Namespace, /*useOnlyExternalAliasing*/ false) ) { return append(concatenate(concatenate([container], additionalContainers), reexportContainers), objectLiteralContainer); // This order expresses a preference for the real container if it is in scope } // we potentially have a symbol which is a member of the instance side of something - look for a variable in scope with the container's type // which may be acting like a namespace (eg, `Symbol` acts like a namespace when looking up `Symbol.toStringTag`) const firstVariableMatch = !(container.flags & getQualifiedLeftMeaning(meaning)) && container.flags & SymbolFlags.Type && getDeclaredTypeOfSymbol(container).flags & TypeFlags.Object && meaning === SymbolFlags.Value ? forEachSymbolTableInScope(enclosingDeclaration, t => { return forEachEntry(t, s => { if (s.flags & getQualifiedLeftMeaning(meaning) && getTypeOfSymbol(s) === getDeclaredTypeOfSymbol(container)) { return s; } }); }) : undefined; let res = firstVariableMatch ? [firstVariableMatch, ...additionalContainers, container] : [...additionalContainers, container]; res = append(res, objectLiteralContainer); res = addRange(res, reexportContainers); return res; } const candidates = mapDefined(symbol.declarations, d => { if (!isAmbientModule(d) && d.parent){ // direct children of a module if (hasNonGlobalAugmentationExternalModuleSymbol(d.parent)) { return getSymbolOfDeclaration(d.parent as Declaration); } // export ='d member of an ambient module if (isModuleBlock(d.parent) && d.parent.parent && resolveExternalModuleSymbol(getSymbolOfDeclaration(d.parent.parent)) === symbol) { return getSymbolOfDeclaration(d.parent.parent); } } if (isClassExpression(d) && isBinaryExpression(d.parent) && d.parent.operatorToken.kind === SyntaxKind.EqualsToken && isAccessExpression(d.parent.left) && isEntityNameExpression(d.parent.left.expression)) { if (isModuleExportsAccessExpression(d.parent.left) || isExportsIdentifier(d.parent.left.expression)) { return getSymbolOfDeclaration(getSourceFileOfNode(d)); } checkExpressionCached(d.parent.left.expression); return getNodeLinks(d.parent.left.expression).resolvedSymbol; } }); if (!length(candidates)) { return undefined; } return mapDefined(candidates, candidate => getAliasForSymbolInContainer(candidate, symbol) ? candidate : undefined); function fileSymbolIfFileSymbolExportEqualsContainer(d: Declaration) { return container && getFileSymbolIfFileSymbolExportEqualsContainer(d, container); } } function getVariableDeclarationOfObjectLiteral(symbol: Symbol, meaning: SymbolFlags) { // 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 declaration's visibility, and therefore the literal. const firstDecl: Node | false = !!length(symbol.declarations) && first(symbol.declarations!); if (meaning & SymbolFlags.Value && firstDecl && firstDecl.parent && isVariableDeclaration(firstDecl.parent)) { if (isObjectLiteralExpression(firstDecl) && firstDecl === firstDecl.parent.initializer || isTypeLiteralNode(firstDecl) && firstDecl === firstDecl.parent.type) { return getSymbolOfDeclaration(firstDecl.parent); } } } function getFileSymbolIfFileSymbolExportEqualsContainer(d: Declaration, container: Symbol) { const fileSymbol = getExternalModuleContainer(d); const exported = fileSymbol && fileSymbol.exports && fileSymbol.exports.get(InternalSymbolName.ExportEquals); return exported && getSymbolIfSameReference(exported, 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; } // Check if container is a thing with an `export=` which points directly at `symbol`, and if so, return // the container itself as the alias for the symbol const exportEquals = container.exports && container.exports.get(InternalSymbolName.ExportEquals); if (exportEquals && getSymbolIfSameReference(exportEquals, symbol)) { return container; } const exports = getExportsOfSymbol(container); const quick = exports.get(symbol.escapedName); if (quick && getSymbolIfSameReference(quick, symbol)) { return quick; } return forEachEntry(exports, exported => { if (getSymbolIfSameReference(exported, symbol)) { return exported; } }); } /** * Checks if two symbols, through aliasing and/or merging, refer to the same thing */ function getSymbolIfSameReference(s1: Symbol, s2: Symbol) { if (getMergedSymbol(resolveSymbol(getMergedSymbol(s1))) === getMergedSymbol(resolveSymbol(getMergedSymbol(s2)))) { return s1; } } 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, includeTypeOnlyMembers?: boolean): boolean { return !!( symbol.flags & SymbolFlags.Value || symbol.flags & SymbolFlags.Alias && getAllSymbolFlags(symbol) & SymbolFlags.Value && (includeTypeOnlyMembers || !getTypeOnlyAliasDeclaration(symbol))); } function findConstructorDeclaration(node: ClassLikeDeclaration): ConstructorDeclaration | undefined { const members = node.members; for (const member of members) { if (member.kind === SyntaxKind.Constructor && nodeIsPresent((member as ConstructorDeclaration).body)) { return member as ConstructorDeclaration; } } } function createType(flags: TypeFlags): Type { const result = new Type(checker, flags); typeCount++; result.id = typeCount; tracing?.recordType(result); return result; } function createTypeWithSymbol(flags: TypeFlags, symbol: Symbol): Type { const result = createType(flags); result.symbol = symbol; return result; } function createOriginType(flags: TypeFlags): Type { return new Type(checker, flags); } function createIntrinsicType(kind: TypeFlags, intrinsicName: string, objectFlags = ObjectFlags.None): IntrinsicType { const type = createType(kind) as IntrinsicType; type.intrinsicName = intrinsicName; type.objectFlags = objectFlags; return type; } function createObjectType(objectFlags: ObjectFlags, symbol?: Symbol): ObjectType { const type = createTypeWithSymbol(TypeFlags.Object, symbol!) as ObjectType; type.objectFlags = objectFlags; type.members = undefined; type.properties = undefined; type.callSignatures = undefined; type.constructSignatures = undefined; type.indexInfos = undefined; return type; } function createTypeofType() { return getUnionType(arrayFrom(typeofNEFacts.keys(), getStringLiteralType)); } function createTypeParameter(symbol?: Symbol) { return createTypeWithSymbol(TypeFlags.TypeParameter, symbol!) as TypeParameter; } // A reserved member name starts with two underscores, but the third character cannot be an underscore, // @, or #. A third underscore indicates an escaped form of an identifier that started // with at least two underscores. The @ character indicates that the name is denoted by a well known ES // Symbol instance and the # character indicates that the name is a PrivateIdentifier. 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 && (name as string).charCodeAt(2) !== CharacterCodes.hash; } function getNamedMembers(members: SymbolTable): Symbol[] { let result: Symbol[] | undefined; members.forEach((symbol, id) => { if (isNamedMember(symbol, id)) { (result || (result = [])).push(symbol); } }); return result || emptyArray; } function isNamedMember(member: Symbol, escapedName: __String) { return !isReservedMemberName(escapedName) && symbolIsValue(member); } function getNamedOrIndexSignatureMembers(members: SymbolTable): Symbol[] { const result = getNamedMembers(members); const index = getIndexSymbolFromSymbolTable(members); return index ? concatenate(result, [index]) : result; } function setStructuredTypeMembers(type: StructuredType, members: SymbolTable, callSignatures: readonly Signature[], constructSignatures: readonly Signature[], indexInfos: readonly IndexInfo[]): ResolvedType { const resolved = type as ResolvedType; resolved.members = members; resolved.properties = emptyArray; resolved.callSignatures = callSignatures; resolved.constructSignatures = constructSignatures; resolved.indexInfos = indexInfos; // This can loop back to getPropertyOfType() which would crash if `callSignatures` & `constructSignatures` are not initialized. if (members !== emptySymbols) resolved.properties = getNamedMembers(members); return resolved; } function createAnonymousType(symbol: Symbol | undefined, members: SymbolTable, callSignatures: readonly Signature[], constructSignatures: readonly Signature[], indexInfos: readonly IndexInfo[]): ResolvedType { return setStructuredTypeMembers(createObjectType(ObjectFlags.Anonymous, symbol), members, callSignatures, constructSignatures, indexInfos); } function getResolvedTypeWithoutAbstractConstructSignatures(type: ResolvedType) { if (type.constructSignatures.length === 0) return type; if (type.objectTypeWithoutAbstractConstructSignatures) return type.objectTypeWithoutAbstractConstructSignatures; const constructSignatures = filter(type.constructSignatures, signature => !(signature.flags & SignatureFlags.Abstract)); if (type.constructSignatures === constructSignatures) return type; const typeCopy = createAnonymousType( type.symbol, type.members, type.callSignatures, some(constructSignatures) ? constructSignatures : emptyArray, type.indexInfos); type.objectTypeWithoutAbstractConstructSignatures = typeCopy; typeCopy.objectTypeWithoutAbstractConstructSignatures = typeCopy; return typeCopy; } function forEachSymbolTableInScope(enclosingDeclaration: Node | undefined, callback: (symbolTable: SymbolTable, ignoreQualification?: boolean, isLocalNameLookup?: boolean, scopeNode?: Node) => 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 (canHaveLocals(location) && location.locals && !isGlobalSourceFile(location)) { if (result = callback(location.locals, /*ignoreQualification*/ undefined, /*isLocalNameLookup*/ true, location)) { return result; } } switch (location.kind) { case SyntaxKind.SourceFile: if (!isExternalOrCommonJsModule(location as SourceFile)) { break; } // falls through case SyntaxKind.ModuleDeclaration: const sym = getSymbolOfDeclaration(location as ModuleDeclaration); // `sym` may not have exports if this module declaration is backed by the symbol for a `const` that's being rewritten // into a namespace - in such cases, it's best to just let the namespace appear empty (the const members couldn't have referred // to one another anyway) if (result = callback(sym?.exports || emptySymbols, /*ignoreQualification*/ undefined, /*isLocalNameLookup*/ true, location)) { return result; } break; case SyntaxKind.ClassDeclaration: case SyntaxKind.ClassExpression: case SyntaxKind.InterfaceDeclaration: // Type parameters are bound into `members` lists so they can merge across declarations // This is troublesome, since in all other respects, they behave like locals :cries: // TODO: the below is shared with similar code in `resolveName` - in fact, rephrasing all this symbol // lookup logic in terms of `resolveName` would be nice // 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! let table: Map<__String, Symbol> | undefined; // TODO: Should this filtered table be cached in some way? (getSymbolOfDeclaration(location as ClassLikeDeclaration | InterfaceDeclaration).members || emptySymbols).forEach((memberSymbol, key) => { if (memberSymbol.flags & (SymbolFlags.Type & ~SymbolFlags.Assignment)) { (table || (table = createSymbolTable())).set(key, memberSymbol); } }); if (table && (result = callback(table, /*ignoreQualification*/ undefined, /*isLocalNameLookup*/ false, location))) { return result; } break; } } return callback(globals, /*ignoreQualification*/ undefined, /*isLocalNameLookup*/ true); } 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 = new Map()): Symbol[] | undefined { if (!(symbol && !isPropertyOrMethodDeclarationSymbol(symbol))) { return undefined; } const links = getSymbolLinks(symbol); const cache = (links.accessibleChainCache ||= new Map()); // Go from enclosingDeclaration to the first scope we check, so the cache is keyed off the scope and thus shared more const firstRelevantLocation = forEachSymbolTableInScope(enclosingDeclaration, (_, __, ___, node) => node); const key = `${useOnlyExternalAliasing ? 0 : 1}|${firstRelevantLocation && getNodeId(firstRelevantLocation)}|${meaning}`; if (cache.has(key)) { return cache.get(key); } const id = getSymbolId(symbol); let visitedSymbolTables = visitedSymbolTablesMap.get(id); if (!visitedSymbolTables) { visitedSymbolTablesMap.set(id, visitedSymbolTables = []); } const result = forEachSymbolTableInScope(enclosingDeclaration, getAccessibleSymbolChainFromSymbolTable); cache.set(key, result); return result; /** * @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, isLocalNameLookup?: boolean): Symbol[] | undefined { if (!pushIfUnique(visitedSymbolTables!, symbols)) { return undefined; } const result = trySymbolTable(symbols, ignoreQualification, isLocalNameLookup); 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) || getMergedSymbol(symbol) === getMergedSymbol(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(getMergedSymbol(symbolFromSymbolTable), meaning)); } function trySymbolTable(symbols: SymbolTable, ignoreQualification: boolean | undefined, isLocalNameLookup: 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 aliases in scope const result = 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)) // If we're looking up a local name to reference directly, omit namespace reexports, otherwise when we're trawling through an export list to make a dotted name, we can keep it && (isLocalNameLookup ? !some(symbolFromSymbolTable.declarations, isNamespaceReexportDeclaration) : true) // 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); const candidate = getCandidateListForSymbol(symbolFromSymbolTable, resolvedImportedSymbol, ignoreQualification); if (candidate) { return candidate; } } if (symbolFromSymbolTable.escapedName === symbol!.escapedName && symbolFromSymbolTable.exportSymbol) { if (isAccessible(getMergedSymbol(symbolFromSymbolTable.exportSymbol), /*resolvedAliasSymbol*/ undefined, ignoreQualification)) { return [symbol!]; } } }); // If there's no result and we're looking at the global symbol table, treat `globalThis` like an alias and try to lookup thru that return result || (symbols === globals ? getCandidateListForSymbol(globalThisSymbol, globalThisSymbol, ignoreQualification) : undefined); } function getCandidateListForSymbol(symbolFromSymbolTable: Symbol, resolvedImportedSymbol: Symbol, ignoreQualification: boolean | undefined) { 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); } } } 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 const shouldResolveAlias = (symbolFromSymbolTable.flags & SymbolFlags.Alias && !getDeclarationOfKind(symbolFromSymbolTable, SyntaxKind.ExportSpecifier)); symbolFromSymbolTable = shouldResolveAlias ? resolveAlias(symbolFromSymbolTable) : symbolFromSymbolTable; const flags = shouldResolveAlias ? getAllSymbolFlags(symbolFromSymbolTable) : symbolFromSymbolTable.flags; if (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 = isSymbolAccessibleWorker(typeSymbol, enclosingDeclaration, SymbolFlags.Type, /*shouldComputeAliasesToMakeVisible*/ false, /*allowModules*/ true); return access.accessibility === SymbolAccessibility.Accessible; } function isValueSymbolAccessible(typeSymbol: Symbol, enclosingDeclaration: Node | undefined): boolean { const access = isSymbolAccessibleWorker(typeSymbol, enclosingDeclaration, SymbolFlags.Value, /*shouldComputeAliasesToMakeVisible*/ false, /*allowModules*/ true); return access.accessibility === SymbolAccessibility.Accessible; } function isSymbolAccessibleByFlags(typeSymbol: Symbol, enclosingDeclaration: Node | undefined, flags: SymbolFlags): boolean { const access = isSymbolAccessibleWorker(typeSymbol, enclosingDeclaration, flags, /*shouldComputeAliasesToMakeVisible*/ false, /*allowModules*/ false); return access.accessibility === SymbolAccessibility.Accessible; } function isAnySymbolAccessible(symbols: Symbol[] | undefined, enclosingDeclaration: Node | undefined, initialSymbol: Symbol, meaning: SymbolFlags, shouldComputeAliasesToMakeVisible: boolean, allowModules: boolean): SymbolAccessibilityResult | undefined { if (!length(symbols)) return; let hadAccessibleChain: Symbol | undefined; let earlyModuleBail = false; 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; } } if (allowModules) { if (some(symbol.declarations, hasNonGlobalAugmentationExternalModuleSymbol)) { if (shouldComputeAliasesToMakeVisible) { earlyModuleBail = true; // Generally speaking, we want to use the aliases that already exist to refer to a module, if present // In order to do so, we need to find those aliases in order to retain them in declaration emit; so // if we are in declaration emit, we cannot use the fast path for module visibility until we've exhausted // all other visibility options (in order to capture the possible aliases used to reference the module) continue; } // 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 const containers = getContainersOfSymbol(symbol, enclosingDeclaration, meaning); const parentResult = isAnySymbolAccessible(containers, enclosingDeclaration, initialSymbol, initialSymbol === symbol ? getQualifiedLeftMeaning(meaning) : meaning, shouldComputeAliasesToMakeVisible, allowModules); if (parentResult) { return parentResult; } } if (earlyModuleBail) { return { accessibility: SymbolAccessibility.Accessible }; } 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 { return isSymbolAccessibleWorker(symbol, enclosingDeclaration, meaning, shouldComputeAliasesToMakeVisible, /*allowModules*/ true); } function isSymbolAccessibleWorker(symbol: Symbol | undefined, enclosingDeclaration: Node | undefined, meaning: SymbolFlags, shouldComputeAliasesToMakeVisible: boolean, allowModules: boolean): SymbolAccessibilityResult { if (symbol && enclosingDeclaration) { const result = isAnySymbolAccessible([symbol], enclosingDeclaration, symbol, meaning, shouldComputeAliasesToMakeVisible, allowModules); 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), errorNode: isInJSFile(enclosingDeclaration) ? enclosingDeclaration : undefined, }; } } // 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 && getSymbolOfDeclaration(node as AmbientModuleDeclaration | SourceFile); } function hasExternalModuleSymbol(declaration: Node) { return isAmbientModule(declaration) || (declaration.kind === SyntaxKind.SourceFile && isExternalOrCommonJsModule(declaration as SourceFile)); } function hasNonGlobalAugmentationExternalModuleSymbol(declaration: Node) { return isModuleWithStringLiteralName(declaration) || (declaration.kind === SyntaxKind.SourceFile && isExternalOrCommonJsModule(declaration as SourceFile)); } function hasVisibleDeclarations(symbol: Symbol, shouldComputeAliasToMakeVisible: boolean): SymbolVisibilityResult | undefined { let aliasesToMakeVisible: LateVisibilityPaintedStatement[] | undefined; if (!every(filter(symbol.declarations, d => d.kind !== SyntaxKind.Identifier), 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 && !hasSyntacticModifier(anyImportSyntax, ModifierFlags.Export) && // import clause without export isDeclarationVisible(anyImportSyntax.parent)) { return addVisibleAlias(declaration, anyImportSyntax); } else if (isVariableDeclaration(declaration) && isVariableStatement(declaration.parent.parent) && !hasSyntacticModifier(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 && !hasSyntacticModifier(declaration, ModifierFlags.Export) && isDeclarationVisible(declaration.parent)) { return addVisibleAlias(declaration, declaration); } else if (isBindingElement(declaration)) { if (symbol.flags & SymbolFlags.Alias && isInJSFile(declaration) && declaration.parent?.parent // exported import-like top-level JS require statement && isVariableDeclaration(declaration.parent.parent) && declaration.parent.parent.parent?.parent && isVariableStatement(declaration.parent.parent.parent.parent) && !hasSyntacticModifier(declaration.parent.parent.parent.parent, ModifierFlags.Export) && declaration.parent.parent.parent.parent.parent // check if the thing containing the variable statement is visible (ie, the file) && isDeclarationVisible(declaration.parent.parent.parent.parent.parent)) { return addVisibleAlias(declaration, declaration.parent.parent.parent.parent); } else if (symbol.flags & SymbolFlags.BlockScopedVariable) { const variableStatement = findAncestor(declaration, isVariableStatement)!; if (hasSyntacticModifier(variableStatement, ModifierFlags.Export)) { return true; } if (!isDeclarationVisible(variableStatement.parent)) { return false; } return addVisibleAlias(declaration, variableStatement); } } // 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 || entityName.parent.kind === SyntaxKind.ExpressionWithTypeArguments && !isPartOfTypeNode(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, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ false); if (symbol && symbol.flags & SymbolFlags.TypeParameter && meaning & SymbolFlags.Type) { return { accessibility: SymbolAccessibility.Accessible }; } if (!symbol && isThisIdentifier(firstIdentifier) && isSymbolAccessible(getSymbolOfDeclaration(getThisContainer(firstIdentifier, /*includeArrowFunctions*/ false, /*includeClassComputedPropertyName*/ false)), firstIdentifier, meaning, /*shouldComputeAliasesToMakeVisible*/ false).accessibility === SymbolAccessibility.Accessible) { return { accessibility: SymbolAccessibility.Accessible }; } // 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; } if (flags & SymbolFormatFlags.WriteComputedProps) { nodeFlags |= NodeBuilderFlags.WriteComputedProps; } const builder = flags & SymbolFormatFlags.AllowAnyNodeKind ? nodeBuilder.symbolToNode : nodeBuilder.symbolToEntityName; return writer ? symbolToStringWorker(writer).getText() : usingSingleLineStringWriter(symbolToStringWorker); function symbolToStringWorker(writer: EmitTextWriter) { const entity = builder(symbol, meaning!, enclosingDeclaration, nodeFlags)!; // TODO: GH#18217 // add neverAsciiEscape for GH#39027 const printer = enclosingDeclaration?.kind === SyntaxKind.SourceFile ? createPrinterWithRemoveCommentsNeverAsciiEscape() : createPrinterWithRemoveComments(); 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 = createPrinterWithRemoveCommentsOmitTrailingSemicolon(); const sourceFile = enclosingDeclaration && getSourceFileOfNode(enclosingDeclaration); printer.writeNode(EmitHint.Unspecified, sig!, /*sourceFile*/ sourceFile, getTrailingSemicolonDeferringWriter(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)); if (typeNode === undefined) return Debug.fail("should always get typenode"); // The unresolved type gets a synthesized comment on `any` to hint to users that it's not a plain `any`. // Otherwise, we always strip comments out. const printer = type !== unresolvedType ? createPrinterWithRemoveComments() : createPrinterWithDefaults(); const sourceFile = enclosingDeclaration && getSourceFileOfNode(enclosingDeclaration); printer.writeNode(EmitHint.Unspecified, typeNode, /*sourceFile*/ sourceFile, writer); const result = writer.getText(); const maxLength = noTruncation ? noTruncationMaximumTruncationLength * 2 : defaultMaximumTruncationLength * 2; if (maxLength && result && result.length >= maxLength) { return result.substr(0, maxLength - "...".length) + "..."; } return result; } function getTypeNamesForErrorDisplay(left: Type, right: Type): [string, string] { let leftStr = symbolValueDeclarationIsContextSensitive(left.symbol) ? typeToString(left, left.symbol.valueDeclaration) : typeToString(left); let rightStr = symbolValueDeclarationIsContextSensitive(right.symbol) ? typeToString(right, right.symbol.valueDeclaration) : typeToString(right); if (leftStr === rightStr) { leftStr = getTypeNameForErrorDisplay(left); rightStr = getTypeNameForErrorDisplay(right); } return [leftStr, rightStr]; } function getTypeNameForErrorDisplay(type: Type) { return typeToString(type, /*enclosingDeclaration*/ undefined, TypeFormatFlags.UseFullyQualifiedType); } function symbolValueDeclarationIsContextSensitive(symbol: Symbol): boolean { return symbol && !!symbol.valueDeclaration && isExpression(symbol.valueDeclaration) && !isContextSensitive(symbol.valueDeclaration); } function toNodeBuilderFlags(flags = TypeFormatFlags.None): NodeBuilderFlags { return flags & TypeFormatFlags.NodeBuilderFlagsMask; } function isClassInstanceSide(type: Type) { return !!type.symbol && !!(type.symbol.flags & SymbolFlags.Class) && (type === getDeclaredTypeOfClassOrInterface(type.symbol) || (!!(type.flags & TypeFlags.Object) && !!(getObjectFlags(type) & ObjectFlags.IsClassInstanceClone))); } function createNodeBuilder() { return { typeToTypeNode: (type: Type, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker) => withContext(enclosingDeclaration, flags, tracker, context => typeToTypeNodeHelper(type, context)), indexInfoToIndexSignatureDeclaration: (indexInfo: IndexInfo, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker) => withContext(enclosingDeclaration, flags, tracker, context => indexInfoToIndexSignatureDeclarationHelper(indexInfo, context, /*typeNode*/ undefined)), signatureToSignatureDeclaration: (signature: Signature, kind: SignatureDeclaration["kind"], 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)), symbolTableToDeclarationStatements: (symbolTable: SymbolTable, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker, bundled?: boolean) => withContext(enclosingDeclaration, flags, tracker, context => symbolTableToDeclarationStatements(symbolTable, context, bundled)), symbolToNode: (symbol: Symbol, meaning: SymbolFlags, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker) => withContext(enclosingDeclaration, flags, tracker, context => symbolToNode(symbol, context, meaning)), }; function symbolToNode(symbol: Symbol, context: NodeBuilderContext, meaning: SymbolFlags) { if (context.flags & NodeBuilderFlags.WriteComputedProps) { if (symbol.valueDeclaration) { const name = getNameOfDeclaration(symbol.valueDeclaration); if (name && isComputedPropertyName(name)) return name; } const nameType = getSymbolLinks(symbol).nameType; if (nameType && nameType.flags & (TypeFlags.EnumLiteral | TypeFlags.UniqueESSymbol)) { context.enclosingDeclaration = nameType.symbol.valueDeclaration; return factory.createComputedPropertyName(symbolToExpression(nameType.symbol, context, meaning)); } } return symbolToExpression(symbol, context, meaning); } function withContext(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 moduleResolverHost = tracker?.trackSymbol ? tracker.moduleResolverHost : flags! & NodeBuilderFlags.DoNotIncludeSymbolChain ? createBasicNodeBuilderModuleSpecifierResolutionHost(host) : undefined; const context: NodeBuilderContext = { enclosingDeclaration, flags: flags || NodeBuilderFlags.None, tracker: undefined!, encounteredError: false, reportedDiagnostic: false, visitedTypes: undefined, symbolDepth: undefined, inferTypeParameters: undefined, approximateLength: 0 }; context.tracker = new SymbolTrackerImpl(context, tracker, moduleResolverHost); const resultingNode = cb(context); if (context.truncating && context.flags & NodeBuilderFlags.NoTruncation) { context.tracker.reportTruncationError(); } return context.encounteredError ? undefined : resultingNode; } function checkTruncationLength(context: NodeBuilderContext): boolean { if (context.truncating) return context.truncating; return context.truncating = context.approximateLength > ((context.flags & NodeBuilderFlags.NoTruncation) ? noTruncationMaximumTruncationLength : defaultMaximumTruncationLength); } function typeToTypeNodeHelper(type: Type, context: NodeBuilderContext): TypeNode { const savedFlags = context.flags; const typeNode = typeToTypeNodeWorker(type, context); context.flags = savedFlags; return typeNode; } function typeToTypeNodeWorker(type: Type, context: NodeBuilderContext): TypeNode { if (cancellationToken && cancellationToken.throwIfCancellationRequested) { cancellationToken.throwIfCancellationRequested(); } const inTypeAlias = context.flags & NodeBuilderFlags.InTypeAlias; context.flags &= ~NodeBuilderFlags.InTypeAlias; if (!type) { if (!(context.flags & NodeBuilderFlags.AllowEmptyUnionOrIntersection)) { context.encounteredError = true; return undefined!; // TODO: GH#18217 } context.approximateLength += 3; return factory.createKeywordTypeNode(SyntaxKind.AnyKeyword); } if (!(context.flags & NodeBuilderFlags.NoTypeReduction)) { type = getReducedType(type); } if (type.flags & TypeFlags.Any) { if (type.aliasSymbol) { return factory.createTypeReferenceNode(symbolToEntityNameNode(type.aliasSymbol), mapToTypeNodes(type.aliasTypeArguments, context)); } if (type === unresolvedType) { return addSyntheticLeadingComment(factory.createKeywordTypeNode(SyntaxKind.AnyKeyword), SyntaxKind.MultiLineCommentTrivia, "unresolved"); } context.approximateLength += 3; return factory.createKeywordTypeNode(type === intrinsicMarkerType ? SyntaxKind.IntrinsicKeyword : SyntaxKind.AnyKeyword); } if (type.flags & TypeFlags.Unknown) { return factory.createKeywordTypeNode(SyntaxKind.UnknownKeyword); } if (type.flags & TypeFlags.String) { context.approximateLength += 6; return factory.createKeywordTypeNode(SyntaxKind.StringKeyword); } if (type.flags & TypeFlags.Number) { context.approximateLength += 6; return factory.createKeywordTypeNode(SyntaxKind.NumberKeyword); } if (type.flags & TypeFlags.BigInt) { context.approximateLength += 6; return factory.createKeywordTypeNode(SyntaxKind.BigIntKeyword); } if (type.flags & TypeFlags.Boolean && !type.aliasSymbol) { context.approximateLength += 7; return factory.createKeywordTypeNode(SyntaxKind.BooleanKeyword); } if (type.flags & TypeFlags.EnumLike) { if (type.symbol.flags & SymbolFlags.EnumMember) { const parentSymbol = getParentOfSymbol(type.symbol)!; const parentName = symbolToTypeNode(parentSymbol, context, SymbolFlags.Type); if (getDeclaredTypeOfSymbol(parentSymbol) === type) { return parentName; } const memberName = symbolName(type.symbol); if (isIdentifierText(memberName, ScriptTarget.ES3)) { return appendReferenceToType( parentName as TypeReferenceNode | ImportTypeNode, factory.createTypeReferenceNode(memberName, /*typeArguments*/ undefined) ); } if (isImportTypeNode(parentName)) { (parentName as any).isTypeOf = true; // mutably update, node is freshly manufactured anyhow return factory.createIndexedAccessTypeNode(parentName, factory.createLiteralTypeNode(factory.createStringLiteral(memberName))); } else if (isTypeReferenceNode(parentName)) { return factory.createIndexedAccessTypeNode(factory.createTypeQueryNode(parentName.typeName), factory.createLiteralTypeNode(factory.createStringLiteral(memberName))); } else { return Debug.fail("Unhandled type node kind returned from `symbolToTypeNode`."); } } return symbolToTypeNode(type.symbol, context, SymbolFlags.Type); } if (type.flags & TypeFlags.StringLiteral) { context.approximateLength += ((type as StringLiteralType).value.length + 2); return factory.createLiteralTypeNode(setEmitFlags(factory.createStringLiteral((type as StringLiteralType).value, !!(context.flags & NodeBuilderFlags.UseSingleQuotesForStringLiteralType)), EmitFlags.NoAsciiEscaping)); } if (type.flags & TypeFlags.NumberLiteral) { const value = (type as NumberLiteralType).value; context.approximateLength += ("" + value).length; return factory.createLiteralTypeNode(value < 0 ? factory.createPrefixUnaryExpression(SyntaxKind.MinusToken, factory.createNumericLiteral(-value)) : factory.createNumericLiteral(value)); } if (type.flags & TypeFlags.BigIntLiteral) { context.approximateLength += (pseudoBigIntToString((type as BigIntLiteralType).value).length) + 1; return factory.createLiteralTypeNode((factory.createBigIntLiteral((type as BigIntLiteralType).value))); } if (type.flags & TypeFlags.BooleanLiteral) { context.approximateLength += (type as IntrinsicType).intrinsicName.length; return factory.createLiteralTypeNode((type as IntrinsicType).intrinsicName === "true" ? factory.createTrue() : factory.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 factory.createTypeOperatorNode(SyntaxKind.UniqueKeyword, factory.createKeywordTypeNode(SyntaxKind.SymbolKeyword)); } if (type.flags & TypeFlags.Void) { context.approximateLength += 4; return factory.createKeywordTypeNode(SyntaxKind.VoidKeyword); } if (type.flags & TypeFlags.Undefined) { context.approximateLength += 9; return factory.createKeywordTypeNode(SyntaxKind.UndefinedKeyword); } if (type.flags & TypeFlags.Null) { context.approximateLength += 4; return factory.createLiteralTypeNode(factory.createNull()); } if (type.flags & TypeFlags.Never) { context.approximateLength += 5; return factory.createKeywordTypeNode(SyntaxKind.NeverKeyword); } if (type.flags & TypeFlags.ESSymbol) { context.approximateLength += 6; return factory.createKeywordTypeNode(SyntaxKind.SymbolKeyword); } if (type.flags & TypeFlags.NonPrimitive) { context.approximateLength += 6; return factory.createKeywordTypeNode(SyntaxKind.ObjectKeyword); } if (isThisTypeParameter(type)) { if (context.flags & NodeBuilderFlags.InObjectTypeLiteral) { if (!context.encounteredError && !(context.flags & NodeBuilderFlags.AllowThisInObjectLiteral)) { context.encounteredError = true; } context.tracker.reportInaccessibleThisError?.(); } context.approximateLength += 4; return factory.createThisTypeNode(); } 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 factory.createTypeReferenceNode(factory.createIdentifier(""), typeArgumentNodes); if (length(typeArgumentNodes) === 1 && type.aliasSymbol === globalArrayType.symbol) { return factory.createArrayTypeNode(typeArgumentNodes![0]); } return symbolToTypeNode(type.aliasSymbol, context, SymbolFlags.Type, typeArgumentNodes); } const objectFlags = getObjectFlags(type); if (objectFlags & ObjectFlags.Reference) { Debug.assert(!!(type.flags & TypeFlags.Object)); return (type as TypeReference).node ? visitAndTransformType(type as TypeReference, typeReferenceToTypeNode) : typeReferenceToTypeNode(type as TypeReference); } if (type.flags & TypeFlags.TypeParameter || objectFlags & ObjectFlags.ClassOrInterface) { if (type.flags & TypeFlags.TypeParameter && contains(context.inferTypeParameters, type)) { context.approximateLength += (symbolName(type.symbol).length + 6); let constraintNode: TypeNode | undefined; const constraint = getConstraintOfTypeParameter(type as TypeParameter); if (constraint) { // If the infer type has a constraint that is not the same as the constraint // we would have normally inferred based on context, we emit the constraint // using `infer T extends ?`. We omit inferred constraints from type references // as they may be elided. const inferredConstraint = getInferredTypeParameterConstraint(type as TypeParameter, /*omitTypeReferences*/ true); if (!(inferredConstraint && isTypeIdenticalTo(constraint, inferredConstraint))) { context.approximateLength += 9; constraintNode = constraint && typeToTypeNodeHelper(constraint, context); } } return factory.createInferTypeNode(typeParameterToDeclarationWithConstraint(type as TypeParameter, context, constraintNode)); } if (context.flags & NodeBuilderFlags.GenerateNamesForShadowedTypeParams && type.flags & TypeFlags.TypeParameter && !isTypeSymbolAccessible(type.symbol, context.enclosingDeclaration)) { const name = typeParameterToName(type, context); context.approximateLength += idText(name).length; return factory.createTypeReferenceNode(factory.createIdentifier(idText(name)), /*typeArguments*/ undefined); } // Ignore constraint/default when creating a usage (as opposed to declaration) of a type parameter. if (type.symbol) { return symbolToTypeNode(type.symbol, context, SymbolFlags.Type); } const name = (type === markerSuperTypeForCheck || type === markerSubTypeForCheck) && varianceTypeParameter && varianceTypeParameter.symbol ? (type === markerSubTypeForCheck ? "sub-" : "super-") + symbolName(varianceTypeParameter.symbol) : "?"; return factory.createTypeReferenceNode(factory.createIdentifier(name), /*typeArguments*/ undefined); } if (type.flags & TypeFlags.Union && (type as UnionType).origin) { type = (type as UnionType).origin!; } if (type.flags & (TypeFlags.Union | TypeFlags.Intersection)) { const types = type.flags & TypeFlags.Union ? formatUnionTypes((type as UnionType).types) : (type as IntersectionType).types; if (length(types) === 1) { return typeToTypeNodeHelper(types[0], context); } const typeNodes = mapToTypeNodes(types, context, /*isBareList*/ true); if (typeNodes && typeNodes.length > 0) { return type.flags & TypeFlags.Union ? factory.createUnionTypeNode(typeNodes) : factory.createIntersectionTypeNode(typeNodes); } 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(type as ObjectType); } if (type.flags & TypeFlags.Index) { const indexedType = (type as IndexType).type; context.approximateLength += 6; const indexTypeNode = typeToTypeNodeHelper(indexedType, context); return factory.createTypeOperatorNode(SyntaxKind.KeyOfKeyword, indexTypeNode); } if (type.flags & TypeFlags.TemplateLiteral) { const texts = (type as TemplateLiteralType).texts; const types = (type as TemplateLiteralType).types; const templateHead = factory.createTemplateHead(texts[0]); const templateSpans = factory.createNodeArray( map(types, (t, i) => factory.createTemplateLiteralTypeSpan( typeToTypeNodeHelper(t, context), (i < types.length - 1 ? factory.createTemplateMiddle : factory.createTemplateTail)(texts[i + 1])))); context.approximateLength += 2; return factory.createTemplateLiteralType(templateHead, templateSpans); } if (type.flags & TypeFlags.StringMapping) { const typeNode = typeToTypeNodeHelper((type as StringMappingType).type, context); return symbolToTypeNode((type as StringMappingType).symbol, context, SymbolFlags.Type, [typeNode]); } if (type.flags & TypeFlags.IndexedAccess) { const objectTypeNode = typeToTypeNodeHelper((type as IndexedAccessType).objectType, context); const indexTypeNode = typeToTypeNodeHelper((type as IndexedAccessType).indexType, context); context.approximateLength += 2; return factory.createIndexedAccessTypeNode(objectTypeNode, indexTypeNode); } if (type.flags & TypeFlags.Conditional) { return visitAndTransformType(type, type => conditionalTypeToTypeNode(type as ConditionalType)); } if (type.flags & TypeFlags.Substitution) { return typeToTypeNodeHelper((type as SubstitutionType).baseType, context); } return Debug.fail("Should be unreachable."); function conditionalTypeToTypeNode(type: ConditionalType) { const checkTypeNode = typeToTypeNodeHelper(type.checkType, context); context.approximateLength += 15; if (context.flags & NodeBuilderFlags.GenerateNamesForShadowedTypeParams && type.root.isDistributive && !(type.checkType.flags & TypeFlags.TypeParameter)) { const newParam = createTypeParameter(createSymbol(SymbolFlags.TypeParameter, "T" as __String)); const name = typeParameterToName(newParam, context); const newTypeVariable = factory.createTypeReferenceNode(name); context.approximateLength += 37; // 15 each for two added conditionals, 7 for an added infer type const newMapper = prependTypeMapping(type.root.checkType, newParam, type.mapper); const saveInferTypeParameters = context.inferTypeParameters; context.inferTypeParameters = type.root.inferTypeParameters; const extendsTypeNode = typeToTypeNodeHelper(instantiateType(type.root.extendsType, newMapper), context); context.inferTypeParameters = saveInferTypeParameters; const trueTypeNode = typeToTypeNodeOrCircularityElision(instantiateType(getTypeFromTypeNode(type.root.node.trueType), newMapper)); const falseTypeNode = typeToTypeNodeOrCircularityElision(instantiateType(getTypeFromTypeNode(type.root.node.falseType), newMapper)); // outermost conditional makes `T` a type parameter, allowing the inner conditionals to be distributive // second conditional makes `T` have `T & checkType` substitution, so it is correctly usable as the checkType // inner conditional runs the check the user provided on the check type (distributively) and returns the result // checkType extends infer T ? T extends checkType ? T extends extendsType ? trueType : falseType : never : never; // this is potentially simplifiable to // checkType extends infer T ? T extends checkType & extendsType ? trueType : falseType : never; // but that may confuse users who read the output more. // On the other hand, // checkType extends infer T extends checkType ? T extends extendsType ? trueType : falseType : never; // may also work with `infer ... extends ...` in, but would produce declarations only compatible with the latest TS. return factory.createConditionalTypeNode( checkTypeNode, factory.createInferTypeNode(factory.createTypeParameterDeclaration(/*modifiers*/ undefined, factory.cloneNode(newTypeVariable.typeName) as Identifier)), factory.createConditionalTypeNode( factory.createTypeReferenceNode(factory.cloneNode(name)), typeToTypeNodeHelper(type.checkType, context), factory.createConditionalTypeNode(newTypeVariable, extendsTypeNode, trueTypeNode, falseTypeNode), factory.createKeywordTypeNode(SyntaxKind.NeverKeyword) ), factory.createKeywordTypeNode(SyntaxKind.NeverKeyword) ); } const saveInferTypeParameters = context.inferTypeParameters; context.inferTypeParameters = type.root.inferTypeParameters; const extendsTypeNode = typeToTypeNodeHelper(type.extendsType, context); context.inferTypeParameters = saveInferTypeParameters; const trueTypeNode = typeToTypeNodeOrCircularityElision(getTrueTypeFromConditionalType(type)); const falseTypeNode = typeToTypeNodeOrCircularityElision(getFalseTypeFromConditionalType(type)); return factory.createConditionalTypeNode(checkTypeNode, extendsTypeNode, trueTypeNode, falseTypeNode); } function typeToTypeNodeOrCircularityElision(type: Type) { if (type.flags & TypeFlags.Union) { if (context.visitedTypes?.has(getTypeId(type))) { if (!(context.flags & NodeBuilderFlags.AllowAnonymousIdentifier)) { context.encounteredError = true; context.tracker?.reportCyclicStructureError?.(); } return createElidedInformationPlaceholder(context); } return visitAndTransformType(type, type => typeToTypeNodeHelper(type, context)); } return typeToTypeNodeHelper(type, context); } function isMappedTypeHomomorphic(type: MappedType) { return !!getHomomorphicTypeVariable(type); } function isHomomorphicMappedTypeWithNonHomomorphicInstantiation(type: MappedType) { return !!type.target && isMappedTypeHomomorphic(type.target as MappedType) && !isMappedTypeHomomorphic(type); } function createMappedTypeNodeFromType(type: MappedType) { Debug.assert(!!(type.flags & TypeFlags.Object)); const readonlyToken = type.declaration.readonlyToken ? factory.createToken(type.declaration.readonlyToken.kind) as ReadonlyKeyword | PlusToken | MinusToken : undefined; const questionToken = type.declaration.questionToken ? factory.createToken(type.declaration.questionToken.kind) as QuestionToken | PlusToken | MinusToken : undefined; let appropriateConstraintTypeNode: TypeNode; let newTypeVariable: TypeReferenceNode | undefined; 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` if (isHomomorphicMappedTypeWithNonHomomorphicInstantiation(type) && context.flags & NodeBuilderFlags.GenerateNamesForShadowedTypeParams) { const newParam = createTypeParameter(createSymbol(SymbolFlags.TypeParameter, "T" as __String)); const name = typeParameterToName(newParam, context); newTypeVariable = factory.createTypeReferenceNode(name); } appropriateConstraintTypeNode = factory.createTypeOperatorNode(SyntaxKind.KeyOfKeyword, newTypeVariable || typeToTypeNodeHelper(getModifiersTypeFromMappedType(type), context)); } else { appropriateConstraintTypeNode = typeToTypeNodeHelper(getConstraintTypeFromMappedType(type), context); } const typeParameterNode = typeParameterToDeclarationWithConstraint(getTypeParameterFromMappedType(type), context, appropriateConstraintTypeNode); const nameTypeNode = type.declaration.nameType ? typeToTypeNodeHelper(getNameTypeFromMappedType(type)!, context) : undefined; const templateTypeNode = typeToTypeNodeHelper(removeMissingType(getTemplateTypeFromMappedType(type), !!(getMappedTypeModifiers(type) & MappedTypeModifiers.IncludeOptional)), context); const mappedTypeNode = factory.createMappedTypeNode(readonlyToken, typeParameterNode, nameTypeNode, questionToken, templateTypeNode, /*members*/ undefined); context.approximateLength += 10; const result = setEmitFlags(mappedTypeNode, EmitFlags.SingleLine); if (isHomomorphicMappedTypeWithNonHomomorphicInstantiation(type) && context.flags & NodeBuilderFlags.GenerateNamesForShadowedTypeParams) { // homomorphic mapped type with a non-homomorphic naive inlining // wrap it with a conditional like `SomeModifiersType extends infer U ? {..the mapped type...} : never` to ensure the resulting // type stays homomorphic const originalConstraint = instantiateType(getConstraintOfTypeParameter(getTypeFromTypeNode((type.declaration.typeParameter.constraint! as TypeOperatorNode).type) as TypeParameter) || unknownType, type.mapper); return factory.createConditionalTypeNode( typeToTypeNodeHelper(getModifiersTypeFromMappedType(type), context), factory.createInferTypeNode(factory.createTypeParameterDeclaration(/*modifiers*/ undefined, factory.cloneNode(newTypeVariable!.typeName) as Identifier, originalConstraint.flags & TypeFlags.Unknown ? undefined : typeToTypeNodeHelper(originalConstraint, context))), result, factory.createKeywordTypeNode(SyntaxKind.NeverKeyword) ); } return result; } function createAnonymousTypeNode(type: ObjectType): TypeNode { const typeId = type.id; const symbol = type.symbol; if (symbol) { const isInstanceType = isClassInstanceSide(type) ? SymbolFlags.Type : SymbolFlags.Value; if (isJSConstructor(symbol.valueDeclaration)) { // Instance and static types share the same symbol; only add 'typeof' for the static side. 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 && isClassLike(symbol.valueDeclaration) && context.flags & NodeBuilderFlags.WriteClassExpressionAsTypeLiteral && (!isClassDeclaration(symbol.valueDeclaration) || isSymbolAccessible(symbol, context.enclosingDeclaration, isInstanceType, /*shouldComputeAliasesToMakeVisible*/ false).accessibility !== SymbolAccessibility.Accessible)) || symbol.flags & (SymbolFlags.Enum | SymbolFlags.ValueModule) || shouldWriteTypeOfFunctionSymbol()) { return symbolToTypeNode(symbol, context, isInstanceType); } else if (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 { return visitAndTransformType(type, createTypeNodeFromObjectType); } } else { const isInstantiationExpressionType = !!(getObjectFlags(type) & ObjectFlags.InstantiationExpressionType); if (isInstantiationExpressionType) { const instantiationExpressionType = type as InstantiationExpressionType; if (isTypeQueryNode(instantiationExpressionType.node)) { const typeNode = serializeExistingTypeNode(context, instantiationExpressionType.node); if (typeNode) { return typeNode; } } if (context.visitedTypes?.has(typeId)) { return createElidedInformationPlaceholder(context); } return visitAndTransformType(type, createTypeNodeFromObjectType); } // 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 => isStatic(declaration)); 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?.has(typeId))) && // it is type of the symbol uses itself recursively (!(context.flags & NodeBuilderFlags.UseStructuralFallback) || isValueSymbolAccessible(symbol, context.enclosingDeclaration)); // And the build is going to succeed without visibility error or there is no structural fallback allowed } } } function visitAndTransformType(type: T, transform: (type: T) => TypeNode) { const typeId = type.id; const isConstructorObject = getObjectFlags(type) & ObjectFlags.Anonymous && type.symbol && type.symbol.flags & SymbolFlags.Class; const id = getObjectFlags(type) & ObjectFlags.Reference && (type as TypeReference & T).node ? "N" + getNodeId((type as TypeReference & T).node!) : type.flags & TypeFlags.Conditional ? "N" + getNodeId((type as ConditionalType & T).root.node) : type.symbol ? (isConstructorObject ? "+" : "") + getSymbolId(type.symbol) : undefined; // 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 = new Set(); } if (id && !context.symbolDepth) { context.symbolDepth = new Map(); } const links = context.enclosingDeclaration && getNodeLinks(context.enclosingDeclaration); const key = `${getTypeId(type)}|${context.flags}`; if (links) { links.serializedTypes ||= new Map(); } const cachedResult = links?.serializedTypes?.get(key); if (cachedResult) { if (cachedResult.truncating) { context.truncating = true; } context.approximateLength += cachedResult.addedLength; return deepCloneOrReuseNode(cachedResult.node); } let depth: number | undefined; if (id) { depth = context.symbolDepth!.get(id) || 0; if (depth > 10) { return createElidedInformationPlaceholder(context); } context.symbolDepth!.set(id, depth + 1); } context.visitedTypes.add(typeId); const startLength = context.approximateLength; const result = transform(type); const addedLength = context.approximateLength - startLength; if (!context.reportedDiagnostic && !context.encounteredError) { links?.serializedTypes?.set(key, { node: result, truncating: context.truncating, addedLength }); } context.visitedTypes.delete(typeId); if (id) { context.symbolDepth!.set(id, depth!); } return result; function deepCloneOrReuseNode(node: T): T { if (!nodeIsSynthesized(node) && getParseTreeNode(node) === node) { return node; } return setTextRange(factory.cloneNode(visitEachChild(node, deepCloneOrReuseNode, nullTransformationContext, deepCloneOrReuseNodes)), node); } function deepCloneOrReuseNodes( nodes: NodeArray | undefined, visitor: Visitor, test?: (node: Node) => boolean, start?: number, count?: number, ): NodeArray | undefined { if (nodes && nodes.length === 0) { // Ensure we explicitly make a copy of an empty array; visitNodes will not do this unless the array has elements, // which can lead to us reusing the same empty NodeArray more than once within the same AST during type noding. return setTextRange(factory.createNodeArray(/*elements*/ undefined, nodes.hasTrailingComma), nodes); } return visitNodes(nodes, visitor, test, start, count); } } function createTypeNodeFromObjectType(type: ObjectType): TypeNode { if (isGenericMappedType(type) || (type as MappedType).containsError) { return createMappedTypeNodeFromType(type as MappedType); } const resolved = resolveStructuredTypeMembers(type); if (!resolved.properties.length && !resolved.indexInfos.length) { if (!resolved.callSignatures.length && !resolved.constructSignatures.length) { context.approximateLength += 2; return setEmitFlags(factory.createTypeLiteralNode(/*members*/ undefined), EmitFlags.SingleLine); } if (resolved.callSignatures.length === 1 && !resolved.constructSignatures.length) { const signature = resolved.callSignatures[0]; const signatureNode = signatureToSignatureDeclarationHelper(signature, SyntaxKind.FunctionType, context) as FunctionTypeNode; return signatureNode; } if (resolved.constructSignatures.length === 1 && !resolved.callSignatures.length) { const signature = resolved.constructSignatures[0]; const signatureNode = signatureToSignatureDeclarationHelper(signature, SyntaxKind.ConstructorType, context) as ConstructorTypeNode; return signatureNode; } } const abstractSignatures = filter(resolved.constructSignatures, signature => !!(signature.flags & SignatureFlags.Abstract)); if (some(abstractSignatures)) { const types = map(abstractSignatures, getOrCreateTypeFromSignature); // count the number of type elements excluding abstract constructors const typeElementCount = resolved.callSignatures.length + (resolved.constructSignatures.length - abstractSignatures.length) + resolved.indexInfos.length + // exclude `prototype` when writing a class expression as a type literal, as per // the logic in `createTypeNodesFromResolvedType`. (context.flags & NodeBuilderFlags.WriteClassExpressionAsTypeLiteral ? countWhere(resolved.properties, p => !(p.flags & SymbolFlags.Prototype)) : length(resolved.properties)); // don't include an empty object literal if there were no other static-side // properties to write, i.e. `abstract class C { }` becomes `abstract new () => {}` // and not `(abstract new () => {}) & {}` if (typeElementCount) { // create a copy of the object type without any abstract construct signatures. types.push(getResolvedTypeWithoutAbstractConstructSignatures(resolved)); } return typeToTypeNodeHelper(getIntersectionType(types), context); } const savedFlags = context.flags; context.flags |= NodeBuilderFlags.InObjectTypeLiteral; const members = createTypeNodesFromResolvedType(resolved); context.flags = savedFlags; const typeLiteralNode = factory.createTypeLiteralNode(members); context.approximateLength += 2; setEmitFlags(typeLiteralNode, (context.flags & NodeBuilderFlags.MultilineObjectLiterals) ? 0 : EmitFlags.SingleLine); return typeLiteralNode; } function typeReferenceToTypeNode(type: TypeReference) { let typeArguments: readonly Type[] = getTypeArguments(type); if (type.target === globalArrayType || type.target === globalReadonlyArrayType) { if (context.flags & NodeBuilderFlags.WriteArrayAsGenericType) { const typeArgumentNode = typeToTypeNodeHelper(typeArguments[0], context); return factory.createTypeReferenceNode(type.target === globalArrayType ? "Array" : "ReadonlyArray", [typeArgumentNode]); } const elementType = typeToTypeNodeHelper(typeArguments[0], context); const arrayType = factory.createArrayTypeNode(elementType); return type.target === globalArrayType ? arrayType : factory.createTypeOperatorNode(SyntaxKind.ReadonlyKeyword, arrayType); } else if (type.target.objectFlags & ObjectFlags.Tuple) { typeArguments = sameMap(typeArguments, (t, i) => removeMissingType(t, !!((type.target as TupleType).elementFlags[i] & ElementFlags.Optional))); if (typeArguments.length > 0) { const arity = getTypeReferenceArity(type); const tupleConstituentNodes = mapToTypeNodes(typeArguments.slice(0, arity), context); if (tupleConstituentNodes) { if ((type.target as TupleType).labeledElementDeclarations) { for (let i = 0; i < tupleConstituentNodes.length; i++) { const flags = (type.target as TupleType).elementFlags[i]; tupleConstituentNodes[i] = factory.createNamedTupleMember( flags & ElementFlags.Variable ? factory.createToken(SyntaxKind.DotDotDotToken) : undefined, factory.createIdentifier(unescapeLeadingUnderscores(getTupleElementLabel((type.target as TupleType).labeledElementDeclarations![i]))), flags & ElementFlags.Optional ? factory.createToken(SyntaxKind.QuestionToken) : undefined, flags & ElementFlags.Rest ? factory.createArrayTypeNode(tupleConstituentNodes[i]) : tupleConstituentNodes[i] ); } } else { for (let i = 0; i < Math.min(arity, tupleConstituentNodes.length); i++) { const flags = (type.target as TupleType).elementFlags[i]; tupleConstituentNodes[i] = flags & ElementFlags.Variable ? factory.createRestTypeNode(flags & ElementFlags.Rest ? factory.createArrayTypeNode(tupleConstituentNodes[i]) : tupleConstituentNodes[i]) : flags & ElementFlags.Optional ? factory.createOptionalTypeNode(tupleConstituentNodes[i]) : tupleConstituentNodes[i]; } } const tupleTypeNode = setEmitFlags(factory.createTupleTypeNode(tupleConstituentNodes), EmitFlags.SingleLine); return (type.target as TupleType).readonly ? factory.createTypeOperatorNode(SyntaxKind.ReadonlyKeyword, tupleTypeNode) : tupleTypeNode; } } if (context.encounteredError || (context.flags & NodeBuilderFlags.AllowEmptyTuple)) { const tupleTypeNode = setEmitFlags(factory.createTupleTypeNode([]), EmitFlags.SingleLine); return (type.target as TupleType).readonly ? factory.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: readonly 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 let typeArguments = root.typeArguments; let qualifier = root.qualifier; if (qualifier) { if (isIdentifier(qualifier)) { if (typeArguments !== getIdentifierTypeArguments(qualifier)) { qualifier = setIdentifierTypeArguments(factory.cloneNode(qualifier), typeArguments); } } else { if (typeArguments !== getIdentifierTypeArguments(qualifier.right)) { qualifier = factory.updateQualifiedName(qualifier, qualifier.left, setIdentifierTypeArguments(factory.cloneNode(qualifier.right), typeArguments)); } } } typeArguments = ref.typeArguments; // then move qualifiers const ids = getAccessStack(ref); for (const id of ids) { qualifier = qualifier ? factory.createQualifiedName(qualifier, id) : id; } return factory.updateImportTypeNode( root, root.argument, root.assertions, qualifier, typeArguments, root.isTypeOf); } else { // first shift type arguments let typeArguments = root.typeArguments; let typeName = root.typeName; if (isIdentifier(typeName)) { if (typeArguments !== getIdentifierTypeArguments(typeName)) { typeName = setIdentifierTypeArguments(factory.cloneNode(typeName), typeArguments); } } else { if (typeArguments !== getIdentifierTypeArguments(typeName.right)) { typeName = factory.updateQualifiedName(typeName, typeName.left, setIdentifierTypeArguments(factory.cloneNode(typeName.right), typeArguments)); } } typeArguments = ref.typeArguments; // then move qualifiers const ids = getAccessStack(ref); for (const id of ids) { typeName = factory.createQualifiedName(typeName, id); } return factory.updateTypeReferenceNode( root, typeName, typeArguments); } } 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 [factory.createPropertySignature(/*modifiers*/ undefined, "...", /*questionToken*/ undefined, /*type*/ undefined)]; } const typeElements: TypeElement[] = []; for (const signature of resolvedType.callSignatures) { typeElements.push(signatureToSignatureDeclarationHelper(signature, SyntaxKind.CallSignature, context) as CallSignatureDeclaration); } for (const signature of resolvedType.constructSignatures) { if (signature.flags & SignatureFlags.Abstract) continue; typeElements.push(signatureToSignatureDeclarationHelper(signature, SyntaxKind.ConstructSignature, context) as ConstructSignatureDeclaration); } for (const info of resolvedType.indexInfos) { typeElements.push(indexInfoToIndexSignatureDeclarationHelper(info, context, resolvedType.objectFlags & ObjectFlags.ReverseMapped ? createElidedInformationPlaceholder(context) : undefined)); } 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(factory.createPropertySignature(/*modifiers*/ undefined, `... ${properties.length - i} more ...`, /*questionToken*/ undefined, /*type*/ 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 factory.createTypeReferenceNode(factory.createIdentifier("..."), /*typeArguments*/ undefined); } return factory.createKeywordTypeNode(SyntaxKind.AnyKeyword); } function shouldUsePlaceholderForProperty(propertySymbol: Symbol, context: NodeBuilderContext) { // Use placeholders for reverse mapped types we've either already descended into, or which // are nested reverse mappings within a mapping over a non-anonymous type. The later is a restriction mostly just to // reduce the blowup in printback size from doing, eg, a deep reverse mapping over `Window`. // Since anonymous types usually come from expressions, this allows us to preserve the output // for deep mappings which likely come from expressions, while truncating those parts which // come from mappings over library functions. return !!(getCheckFlags(propertySymbol) & CheckFlags.ReverseMapped) && ( contains(context.reverseMappedStack, propertySymbol as ReverseMappedSymbol) || ( context.reverseMappedStack?.[0] && !(getObjectFlags(last(context.reverseMappedStack).links.propertyType) & ObjectFlags.Anonymous) ) ); } function addPropertyToElementList(propertySymbol: Symbol, context: NodeBuilderContext, typeElements: TypeElement[]) { const propertyIsReverseMapped = !!(getCheckFlags(propertySymbol) & CheckFlags.ReverseMapped); const propertyType = shouldUsePlaceholderForProperty(propertySymbol, context) ? anyType : getNonMissingTypeOfSymbol(propertySymbol); const saveEnclosingDeclaration = context.enclosingDeclaration; context.enclosingDeclaration = undefined; if (context.tracker.canTrackSymbol && isLateBoundName(propertySymbol.escapedName)) { if (propertySymbol.declarations) { const decl = first(propertySymbol.declarations); if (hasLateBindableName(decl)) { if (isBinaryExpression(decl)) { const name = getNameOfDeclaration(decl); if (name && isElementAccessExpression(name) && isPropertyAccessEntityNameExpression(name.argumentExpression)) { trackComputedName(name.argumentExpression, saveEnclosingDeclaration, context); } } else { trackComputedName(decl.name.expression, saveEnclosingDeclaration, context); } } } else { context.tracker.reportNonSerializableProperty(symbolToString(propertySymbol)); } } context.enclosingDeclaration = propertySymbol.valueDeclaration || propertySymbol.declarations?.[0] || saveEnclosingDeclaration; const propertyName = getPropertyNameNodeForSymbol(propertySymbol, context); context.enclosingDeclaration = saveEnclosingDeclaration; context.approximateLength += (symbolName(propertySymbol).length + 1); const optionalToken = propertySymbol.flags & SymbolFlags.Optional ? factory.createToken(SyntaxKind.QuestionToken) : undefined; if (propertySymbol.flags & (SymbolFlags.Function | SymbolFlags.Method) && !getPropertiesOfObjectType(propertyType).length && !isReadonlySymbol(propertySymbol)) { const signatures = getSignaturesOfType(filterType(propertyType, t => !(t.flags & TypeFlags.Undefined)), SignatureKind.Call); for (const signature of signatures) { const methodDeclaration = signatureToSignatureDeclarationHelper(signature, SyntaxKind.MethodSignature, context, { name: propertyName, questionToken: optionalToken }) as MethodSignature; typeElements.push(preserveCommentsOn(methodDeclaration)); } if (signatures.length || !optionalToken) { return; } } let propertyTypeNode: TypeNode; if (shouldUsePlaceholderForProperty(propertySymbol, context)) { propertyTypeNode = createElidedInformationPlaceholder(context); } else { if (propertyIsReverseMapped) { context.reverseMappedStack ||= []; context.reverseMappedStack.push(propertySymbol as ReverseMappedSymbol); } propertyTypeNode = propertyType ? serializeTypeForDeclaration(context, propertyType, propertySymbol, saveEnclosingDeclaration) : factory.createKeywordTypeNode(SyntaxKind.AnyKeyword); if (propertyIsReverseMapped) { context.reverseMappedStack!.pop(); } } const modifiers = isReadonlySymbol(propertySymbol) ? [factory.createToken(SyntaxKind.ReadonlyKeyword)] : undefined; if (modifiers) { context.approximateLength += 9; } const propertySignature = factory.createPropertySignature( modifiers, propertyName, optionalToken, propertyTypeNode); typeElements.push(preserveCommentsOn(propertySignature)); function preserveCommentsOn(node: T) { if (some(propertySymbol.declarations, d => d.kind === SyntaxKind.JSDocPropertyTag)) { const d = propertySymbol.declarations?.find(d => d.kind === SyntaxKind.JSDocPropertyTag)! as JSDocPropertyTag; const commentText = getTextOfJSDocComment(d.comment); if (commentText) { setSyntheticLeadingComments(node, [{ kind: SyntaxKind.MultiLineCommentTrivia, text: "*\n * " + commentText.replace(/\n/g, "\n * ") + "\n ", pos: -1, end: -1, hasTrailingNewLine: true }]); } } else if (propertySymbol.valueDeclaration) { // Copy comments to node for declaration emit setCommentRange(node, propertySymbol.valueDeclaration); } return node; } } function mapToTypeNodes(types: readonly Type[] | undefined, context: NodeBuilderContext, isBareList?: boolean): TypeNode[] | undefined { if (some(types)) { if (checkTruncationLength(context)) { if (!isBareList) { return [factory.createTypeReferenceNode("...", /*typeArguments*/ undefined)]; } else if (types.length > 2) { return [ typeToTypeNodeHelper(types[0], context), factory.createTypeReferenceNode(`... ${types.length - 2} more ...`, /*typeArguments*/ undefined), typeToTypeNodeHelper(types[types.length - 1], context) ]; } } const mayHaveNameCollisions = !(context.flags & NodeBuilderFlags.UseFullyQualifiedType); /** Map from type reference identifier text to [type, index in `result` where the type node is] */ const seenNames = mayHaveNameCollisions ? createMultiMap<__String, [Type, number]>() : undefined; const result: TypeNode[] = []; let i = 0; for (const type of types) { i++; if (checkTruncationLength(context) && (i + 2 < types.length - 1)) { result.push(factory.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); if (seenNames && isIdentifierTypeReference(typeNode)) { seenNames.add(typeNode.typeName.escapedText, [type, result.length - 1]); } } } if (seenNames) { // To avoid printing types like `[Foo, Foo]` or `Bar & Bar` where // occurrences of the same name actually come from different // namespaces, go through the single-identifier type reference nodes // we just generated, and see if any names were generated more than // once while referring to different types. If so, regenerate the // type node for each entry by that name with the // `UseFullyQualifiedType` flag enabled. const saveContextFlags = context.flags; context.flags |= NodeBuilderFlags.UseFullyQualifiedType; seenNames.forEach(types => { if (!arrayIsHomogeneous(types, ([a], [b]) => typesAreSameReference(a, b))) { for (const [type, resultIndex] of types) { result[resultIndex] = typeToTypeNodeHelper(type, context); } } }); context.flags = saveContextFlags; } return result; } } function typesAreSameReference(a: Type, b: Type): boolean { return a === b || !!a.symbol && a.symbol === b.symbol || !!a.aliasSymbol && a.aliasSymbol === b.aliasSymbol; } function indexInfoToIndexSignatureDeclarationHelper(indexInfo: IndexInfo, context: NodeBuilderContext, typeNode: TypeNode | undefined): IndexSignatureDeclaration { const name = getNameFromIndexInfo(indexInfo) || "x"; const indexerTypeNode = typeToTypeNodeHelper(indexInfo.keyType, context); const indexingParameter = factory.createParameterDeclaration( /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, name, /*questionToken*/ undefined, indexerTypeNode, /*initializer*/ undefined); if (!typeNode) { typeNode = typeToTypeNodeHelper(indexInfo.type || anyType, context); } if (!indexInfo.type && !(context.flags & NodeBuilderFlags.AllowEmptyIndexInfoType)) { context.encounteredError = true; } context.approximateLength += (name.length + 4); return factory.createIndexSignature( indexInfo.isReadonly ? [factory.createToken(SyntaxKind.ReadonlyKeyword)] : undefined, [indexingParameter], typeNode); } interface SignatureToSignatureDeclarationOptions { modifiers?: readonly Modifier[]; name?: PropertyName; questionToken?: QuestionToken; privateSymbolVisitor?: (s: Symbol) => void; bundledImports?: boolean; } function signatureToSignatureDeclarationHelper(signature: Signature, kind: SignatureDeclaration["kind"], context: NodeBuilderContext, options?: SignatureToSignatureDeclarationOptions): SignatureDeclaration { const suppressAny = context.flags & NodeBuilderFlags.SuppressAnyReturnType; if (suppressAny) context.flags &= ~NodeBuilderFlags.SuppressAnyReturnType; // suppress only toplevel `any`s context.approximateLength += 3; // Usually a signature contributes a few more characters than this, but 3 is the minimum 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 expandedParams = getExpandedParameters(signature, /*skipUnionExpanding*/ true)[0]; // For regular function/method declarations, the enclosing declaration will already be signature.declaration, // so this is a no-op, but for arrow functions and function expressions, the enclosing declaration will be // the declaration that the arrow function / function expression is assigned to. // // If the parameters or return type include "typeof globalThis.paramName", using the wrong scope will lead // us to believe that we can emit "typeof paramName" instead, even though that would refer to the parameter, // not the global. Make sure we are in the right scope by changing the enclosingDeclaration to the function. // // We can't use the declaration directly; it may be in another file and so we may lose access to symbols // accessible to the current enclosing declaration, or gain access to symbols not accessible to the current // enclosing declaration. To keep this chain accurate, insert a fake scope into the chain which makes the // function's parameters visible. // // If the declaration is in a JS file, then we don't need to do this at all, as there are no annotations besides // JSDoc, which are always outside the function declaration, so are not in the parameter scope. let cleanup: (() => void) | undefined; if ( context.enclosingDeclaration && signature.declaration && signature.declaration !== context.enclosingDeclaration && !isInJSFile(signature.declaration) && some(expandedParams) ) { // As a performance optimization, reuse the same fake scope within this chain. // This is especially needed when we are working on an excessively deep type; // if we don't do this, then we spend all of our time adding more and more // scopes that need to be searched in isSymbolAccessible later. Since all we // really want to do is to mark certain names as unavailable, we can just keep // all of the names we're introducing in one large table and push/pop from it as // needed; isSymbolAccessible will walk upward and find the closest "fake" scope, // which will conveniently report on any and all faked scopes in the chain. // // It'd likely be better to store this somewhere else for isSymbolAccessible, but // since that API _only_ uses the enclosing declaration (and its parents), this is // seems like the best way to inject names into that search process. // // Note that we only check the most immediate enclosingDeclaration; the only place we // could potentially add another fake scope into the chain is right here, so we don't // traverse all ancestors. const existingFakeScope = getNodeLinks(context.enclosingDeclaration).fakeScopeForSignatureDeclaration ? context.enclosingDeclaration : undefined; Debug.assertOptionalNode(existingFakeScope, isBlock); const locals = existingFakeScope?.locals ?? createSymbolTable(); let newLocals: __String[] | undefined; for (const param of expandedParams) { if (!locals.has(param.escapedName)) { newLocals = append(newLocals, param.escapedName); locals.set(param.escapedName, param); } } if (newLocals) { function removeNewLocals() { forEach(newLocals, s => locals.delete(s)); } if (existingFakeScope) { cleanup = removeNewLocals; } else { // Use a Block for this; the type of the node doesn't matter so long as it // has locals, and this is cheaper/easier than using a function-ish Node. const fakeScope = parseNodeFactory.createBlock(emptyArray); getNodeLinks(fakeScope).fakeScopeForSignatureDeclaration = true; fakeScope.locals = locals; const saveEnclosingDeclaration = context.enclosingDeclaration; setParent(fakeScope, saveEnclosingDeclaration); context.enclosingDeclaration = fakeScope; cleanup = () => { context.enclosingDeclaration = saveEnclosingDeclaration; removeNewLocals(); }; } } } // If the expanded parameter list had a variadic in a non-trailing position, don't expand it const parameters = (some(expandedParams, p => p !== expandedParams[expandedParams.length - 1] && !!(getCheckFlags(p) & CheckFlags.RestParameter)) ? signature.parameters : expandedParams).map(parameter => symbolToParameterDeclaration(parameter, context, kind === SyntaxKind.Constructor, options?.privateSymbolVisitor, options?.bundledImports)); const thisParameter = context.flags & NodeBuilderFlags.OmitThisParameter ? undefined : tryGetThisParameterDeclaration(signature, context); if (thisParameter) { parameters.unshift(thisParameter); } let returnTypeNode: TypeNode | undefined; const typePredicate = getTypePredicateOfSignature(signature); if (typePredicate) { const assertsModifier = typePredicate.kind === TypePredicateKind.AssertsThis || typePredicate.kind === TypePredicateKind.AssertsIdentifier ? factory.createToken(SyntaxKind.AssertsKeyword) : undefined; const parameterName = typePredicate.kind === TypePredicateKind.Identifier || typePredicate.kind === TypePredicateKind.AssertsIdentifier ? setEmitFlags(factory.createIdentifier(typePredicate.parameterName), EmitFlags.NoAsciiEscaping) : factory.createThisTypeNode(); const typeNode = typePredicate.type && typeToTypeNodeHelper(typePredicate.type, context); returnTypeNode = factory.createTypePredicateNode(assertsModifier, parameterName, typeNode); } else { const returnType = getReturnTypeOfSignature(signature); if (returnType && !(suppressAny && isTypeAny(returnType))) { returnTypeNode = serializeReturnTypeForSignature(context, returnType, signature, options?.privateSymbolVisitor, options?.bundledImports); } else if (!suppressAny) { returnTypeNode = factory.createKeywordTypeNode(SyntaxKind.AnyKeyword); } } let modifiers = options?.modifiers; if ((kind === SyntaxKind.ConstructorType) && signature.flags & SignatureFlags.Abstract) { const flags = modifiersToFlags(modifiers); modifiers = factory.createModifiersFromModifierFlags(flags | ModifierFlags.Abstract); } const node = kind === SyntaxKind.CallSignature ? factory.createCallSignature(typeParameters, parameters, returnTypeNode) : kind === SyntaxKind.ConstructSignature ? factory.createConstructSignature(typeParameters, parameters, returnTypeNode) : kind === SyntaxKind.MethodSignature ? factory.createMethodSignature(modifiers, options?.name ?? factory.createIdentifier(""), options?.questionToken, typeParameters, parameters, returnTypeNode) : kind === SyntaxKind.MethodDeclaration ? factory.createMethodDeclaration(modifiers, /*asteriskToken*/ undefined, options?.name ?? factory.createIdentifier(""), /*questionToken*/ undefined, typeParameters, parameters, returnTypeNode, /*body*/ undefined) : kind === SyntaxKind.Constructor ? factory.createConstructorDeclaration(modifiers, parameters, /*body*/ undefined) : kind === SyntaxKind.GetAccessor ? factory.createGetAccessorDeclaration(modifiers, options?.name ?? factory.createIdentifier(""), parameters, returnTypeNode, /*body*/ undefined) : kind === SyntaxKind.SetAccessor ? factory.createSetAccessorDeclaration(modifiers, options?.name ?? factory.createIdentifier(""), parameters, /*body*/ undefined) : kind === SyntaxKind.IndexSignature ? factory.createIndexSignature(modifiers, parameters, returnTypeNode) : kind === SyntaxKind.JSDocFunctionType ? factory.createJSDocFunctionType(parameters, returnTypeNode) : kind === SyntaxKind.FunctionType ? factory.createFunctionTypeNode(typeParameters, parameters, returnTypeNode ?? factory.createTypeReferenceNode(factory.createIdentifier(""))) : kind === SyntaxKind.ConstructorType ? factory.createConstructorTypeNode(modifiers, typeParameters, parameters, returnTypeNode ?? factory.createTypeReferenceNode(factory.createIdentifier(""))) : kind === SyntaxKind.FunctionDeclaration ? factory.createFunctionDeclaration(modifiers, /*asteriskToken*/ undefined, options?.name ? cast(options.name, isIdentifier) : factory.createIdentifier(""), typeParameters, parameters, returnTypeNode, /*body*/ undefined) : kind === SyntaxKind.FunctionExpression ? factory.createFunctionExpression(modifiers, /*asteriskToken*/ undefined, options?.name ? cast(options.name, isIdentifier) : factory.createIdentifier(""), typeParameters, parameters, returnTypeNode, factory.createBlock([])) : kind === SyntaxKind.ArrowFunction ? factory.createArrowFunction(modifiers, typeParameters, parameters, returnTypeNode, /*equalsGreaterThanToken*/ undefined, factory.createBlock([])) : Debug.assertNever(kind); if (typeArguments) { node.typeArguments = factory.createNodeArray(typeArguments); } cleanup?.(); return node; } function tryGetThisParameterDeclaration(signature: Signature, context: NodeBuilderContext) { if (signature.thisParameter) { return symbolToParameterDeclaration(signature.thisParameter, context); } if (signature.declaration && isInJSFile(signature.declaration)) { const thisTag = getJSDocThisTag(signature.declaration); if (thisTag && thisTag.typeExpression) { return factory.createParameterDeclaration( /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "this", /*questionToken*/ undefined, typeToTypeNodeHelper(getTypeFromTypeNode(thisTag.typeExpression), context) ); } } } 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 modifiers = factory.createModifiersFromModifierFlags(getTypeParameterModifiers(type)); const name = typeParameterToName(type, context); const defaultParameter = getDefaultFromTypeParameter(type); const defaultParameterNode = defaultParameter && typeToTypeNodeHelper(defaultParameter, context); context.flags = savedContextFlags; return factory.createTypeParameterDeclaration(modifiers, 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, privateSymbolVisitor?: (s: Symbol) => void, bundledImports?: boolean): ParameterDeclaration { let parameterDeclaration: ParameterDeclaration | JSDocParameterTag | undefined = getDeclarationOfKind(parameterSymbol, SyntaxKind.Parameter); if (!parameterDeclaration && !isTransientSymbol(parameterSymbol)) { parameterDeclaration = getDeclarationOfKind(parameterSymbol, SyntaxKind.JSDocParameterTag); } let parameterType = getTypeOfSymbol(parameterSymbol); if (parameterDeclaration && isRequiredInitializedParameter(parameterDeclaration)) { parameterType = getOptionalType(parameterType); } const parameterTypeNode = serializeTypeForDeclaration(context, parameterType, parameterSymbol, context.enclosingDeclaration, privateSymbolVisitor, bundledImports); const modifiers = !(context.flags & NodeBuilderFlags.OmitParameterModifiers) && preserveModifierFlags && parameterDeclaration && canHaveModifiers(parameterDeclaration) ? map(getModifiers(parameterDeclaration), factory.cloneNode) : undefined; const isRest = parameterDeclaration && isRestParameter(parameterDeclaration) || getCheckFlags(parameterSymbol) & CheckFlags.RestParameter; const dotDotDotToken = isRest ? factory.createToken(SyntaxKind.DotDotDotToken) : undefined; const name = parameterDeclaration ? parameterDeclaration.name ? parameterDeclaration.name.kind === SyntaxKind.Identifier ? setEmitFlags(factory.cloneNode(parameterDeclaration.name), EmitFlags.NoAsciiEscaping) : parameterDeclaration.name.kind === SyntaxKind.QualifiedName ? setEmitFlags(factory.cloneNode(parameterDeclaration.name.right), EmitFlags.NoAsciiEscaping) : cloneBindingName(parameterDeclaration.name) : symbolName(parameterSymbol) : symbolName(parameterSymbol); const isOptional = parameterDeclaration && isOptionalParameter(parameterDeclaration) || getCheckFlags(parameterSymbol) & CheckFlags.OptionalParameter; const questionToken = isOptional ? factory.createToken(SyntaxKind.QuestionToken) : undefined; const parameterNode = factory.createParameterDeclaration( modifiers, dotDotDotToken, name, questionToken, parameterTypeNode, /*initializer*/ undefined); context.approximateLength += symbolName(parameterSymbol).length + 3; return parameterNode; function cloneBindingName(node: BindingName): BindingName { return elideInitializerAndSetEmitFlags(node) as BindingName; function elideInitializerAndSetEmitFlags(node: Node): Node { if (context.tracker.canTrackSymbol && isComputedPropertyName(node) && isLateBindableName(node)) { trackComputedName(node.expression, context.enclosingDeclaration, context); } let visited = visitEachChild(node, elideInitializerAndSetEmitFlags, nullTransformationContext, /*nodesVisitor*/ undefined, elideInitializerAndSetEmitFlags)!; if (isBindingElement(visited)) { visited = factory.updateBindingElement( visited, visited.dotDotDotToken, visited.propertyName, visited.name, /*initializer*/ undefined); } if (!nodeIsSynthesized(visited)) { visited = factory.cloneNode(visited); } return setEmitFlags(visited, EmitFlags.SingleLine | EmitFlags.NoAsciiEscaping); } } } function trackComputedName(accessExpression: EntityNameOrEntityNameExpression, enclosingDeclaration: Node | undefined, context: NodeBuilderContext) { if (!context.tracker.canTrackSymbol) return; // get symbol of the first identifier of the entityName const firstIdentifier = getFirstIdentifier(accessExpression); const name = resolveName(firstIdentifier, firstIdentifier.escapedText, SymbolFlags.Value | SymbolFlags.ExportValue, /*nameNotFoundMessage*/ 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); return lookupSymbolChainWorker(symbol, context, meaning, yieldModuleSymbol); } function lookupSymbolChainWorker(symbol: Symbol, context: NodeBuilderContext, meaning: SymbolFlags, yieldModuleSymbol?: boolean) { // 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.checkDefined(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, meaning); 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) { if (parent.exports && parent.exports.get(InternalSymbolName.ExportEquals) && getSymbolIfSameReference(parent.exports.get(InternalSymbolName.ExportEquals)!, symbol)) { // parentChain root _is_ symbol - symbol is a module export=, so it kinda looks like it's own parent // No need to lookup an alias for the symbol in itself accessibleSymbolChain = parentChain; break; } 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 | undefined; const targetSymbol = getTargetSymbol(symbol); if (targetSymbol.flags & (SymbolFlags.Class | SymbolFlags.Interface | SymbolFlags.TypeAlias)) { typeParameterNodes = factory.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]; const symbolId = getSymbolId(symbol); if (context.typeParameterSymbolList?.has(symbolId)) { return undefined; } (context.typeParameterSymbolList || (context.typeParameterSymbolList = new Set())).add(symbolId); let typeParameterNodes: readonly TypeNode[] | readonly 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 ); // NOTE: cast to TransientSymbol should be safe because only TransientSymbol can have CheckFlags.Instantiated typeParameterNodes = mapToTypeNodes(map(params, t => getMappedType(t, (nextSymbol as TransientSymbol).links.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, overrideImportMode?: ResolutionMode) { let file = getDeclarationOfKind(symbol, SyntaxKind.SourceFile); if (!file) { const equivalentFileSymbol = firstDefined(symbol.declarations, d => getFileSymbolIfFileSymbolExportEqualsContainer(d, symbol)); if (equivalentFileSymbol) { file = getDeclarationOfKind(equivalentFileSymbol, 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 resolutionMode = overrideImportMode || contextFile?.impliedNodeFormat; const cacheKey = createModeAwareCacheKey(contextFile.path, resolutionMode); const links = getSymbolLinks(symbol); let specifier = links.specifierCache && links.specifierCache.get(cacheKey); if (!specifier) { const isBundle = !!outFile(compilerOptions); // 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, checker, specifierCompilerOptions, contextFile, moduleResolverHost, { importModuleSpecifierPreference: isBundle ? "non-relative" : "project-relative", importModuleSpecifierEnding: isBundle ? "minimal" : resolutionMode === ModuleKind.ESNext ? "js" : undefined, }, { overrideImportMode } )); links.specifierCache ??= new Map(); links.specifierCache.set(cacheKey, specifier); } return specifier; } function symbolToEntityNameNode(symbol: Symbol): EntityName { const identifier = factory.createIdentifier(unescapeLeadingUnderscores(symbol.escapedName)); return symbol.parent ? factory.createQualifiedName(symbolToEntityNameNode(symbol.parent), identifier) : identifier; } function symbolToTypeNode(symbol: Symbol, context: NodeBuilderContext, meaning: SymbolFlags, overrideTypeArguments?: readonly 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 contextFile = getSourceFileOfNode(getOriginalNode(context.enclosingDeclaration)); const targetFile = getSourceFileOfModule(chain[0]); let specifier: string | undefined; let assertion: ImportTypeAssertionContainer | undefined; if (getEmitModuleResolutionKind(compilerOptions) === ModuleResolutionKind.Node16 || getEmitModuleResolutionKind(compilerOptions) === ModuleResolutionKind.NodeNext) { // An `import` type directed at an esm format file is only going to resolve in esm mode - set the esm mode assertion if (targetFile?.impliedNodeFormat === ModuleKind.ESNext && targetFile.impliedNodeFormat !== contextFile?.impliedNodeFormat) { specifier = getSpecifierForModuleSymbol(chain[0], context, ModuleKind.ESNext); assertion = factory.createImportTypeAssertionContainer(factory.createAssertClause(factory.createNodeArray([ factory.createAssertEntry( factory.createStringLiteral("resolution-mode"), factory.createStringLiteral("import") ) ]))); context.tracker.reportImportTypeNodeResolutionModeOverride?.(); } } if (!specifier) { specifier = getSpecifierForModuleSymbol(chain[0], context); } if (!(context.flags & NodeBuilderFlags.AllowNodeModulesRelativePaths) && getEmitModuleResolutionKind(compilerOptions) !== ModuleResolutionKind.Classic && specifier.indexOf("/node_modules/") >= 0) { const oldSpecifier = specifier; if (getEmitModuleResolutionKind(compilerOptions) === ModuleResolutionKind.Node16 || getEmitModuleResolutionKind(compilerOptions) === ModuleResolutionKind.NodeNext) { // We might be able to write a portable import type using a mode override; try specifier generation again, but with a different mode set const swappedMode = contextFile?.impliedNodeFormat === ModuleKind.ESNext ? ModuleKind.CommonJS : ModuleKind.ESNext; specifier = getSpecifierForModuleSymbol(chain[0], context, swappedMode); if (specifier.indexOf("/node_modules/") >= 0) { // Still unreachable :( specifier = oldSpecifier; } else { assertion = factory.createImportTypeAssertionContainer(factory.createAssertClause(factory.createNodeArray([ factory.createAssertEntry( factory.createStringLiteral("resolution-mode"), factory.createStringLiteral(swappedMode === ModuleKind.ESNext ? "import" : "require") ) ]))); context.tracker.reportImportTypeNodeResolutionModeOverride?.(); } } if (!assertion) { // 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(oldSpecifier); } } } const lit = factory.createLiteralTypeNode(factory.createStringLiteral(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; setIdentifierTypeArguments(lastId, /*typeArguments*/ undefined); } return factory.createImportTypeNode(lit, assertion, nonRootParts as EntityName, typeParameterNodes as readonly TypeNode[], isTypeOf); } else { const splitNode = getTopmostIndexedAccessType(nonRootParts); const qualifier = (splitNode.objectType as TypeReferenceNode).typeName; return factory.createIndexedAccessTypeNode(factory.createImportTypeNode(lit, assertion, qualifier, typeParameterNodes as readonly 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 factory.createTypeQueryNode(entityName); } else { const lastId = isIdentifier(entityName) ? entityName : entityName.right; const lastTypeArgs = getIdentifierTypeArguments(lastId); setIdentifierTypeArguments(lastId, /*typeArguments*/ undefined); return factory.createTypeReferenceNode(entityName, lastTypeArgs as NodeArray); } 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]; const parent = chain[index - 1]; let symbolName: string | undefined; if (index === 0) { context.flags |= NodeBuilderFlags.InInitialEntityName; symbolName = getNameOfSymbolAsWritten(symbol, context); context.approximateLength += (symbolName ? symbolName.length : 0) + 1; context.flags ^= NodeBuilderFlags.InInitialEntityName; } else { if (parent && getExportsOfSymbol(parent)) { const exports = getExportsOfSymbol(parent); forEachEntry(exports, (ex, name) => { if (getSymbolIfSameReference(ex, symbol) && !isLateBoundName(name) && name !== InternalSymbolName.ExportEquals) { symbolName = unescapeLeadingUnderscores(name); return true; } }); } } if (symbolName === undefined) { const name = firstDefined(symbol.declarations, getNameOfDeclaration); if (name && isComputedPropertyName(name) && isEntityName(name.expression)) { const LHS = createAccessFromSymbolChain(chain, index - 1, stopper); if (isEntityName(LHS)) { return factory.createIndexedAccessTypeNode(factory.createParenthesizedType(factory.createTypeQueryNode(LHS)), factory.createTypeQueryNode(name.expression)); } return LHS; } symbolName = getNameOfSymbolAsWritten(symbol, context); } context.approximateLength += symbolName.length + 1; if (!(context.flags & NodeBuilderFlags.ForbidIndexedAccessSymbolReferences) && parent && getMembersOfSymbol(parent) && getMembersOfSymbol(parent).get(symbol.escapedName) && getSymbolIfSameReference(getMembersOfSymbol(parent).get(symbol.escapedName)!, symbol)) { // Should use an indexed access const LHS = createAccessFromSymbolChain(chain, index - 1, stopper); if (isIndexedAccessTypeNode(LHS)) { return factory.createIndexedAccessTypeNode(LHS, factory.createLiteralTypeNode(factory.createStringLiteral(symbolName))); } else { return factory.createIndexedAccessTypeNode(factory.createTypeReferenceNode(LHS, typeParameterNodes as readonly TypeNode[]), factory.createLiteralTypeNode(factory.createStringLiteral(symbolName))); } } const identifier = setEmitFlags(factory.createIdentifier(symbolName), EmitFlags.NoAsciiEscaping); if (typeParameterNodes) setIdentifierTypeArguments(identifier, factory.createNodeArray(typeParameterNodes)); 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 factory.createQualifiedName(LHS, identifier); } return identifier; } } function typeParameterShadowsNameInScope(escapedName: __String, context: NodeBuilderContext, type: TypeParameter) { const result = resolveName(context.enclosingDeclaration, escapedName, SymbolFlags.Type, /*nameNotFoundMessage*/ undefined, escapedName, /*isUse*/ false); if (result) { if (result.flags & SymbolFlags.TypeParameter && result === type.symbol) { return false; } return true; } return false; } function typeParameterToName(type: TypeParameter, context: NodeBuilderContext) { if (context.flags & NodeBuilderFlags.GenerateNamesForShadowedTypeParams && context.typeParameterNames) { const cached = context.typeParameterNames.get(getTypeId(type)); if (cached) { return cached; } } let result = symbolToName(type.symbol, context, SymbolFlags.Type, /*expectsIdentifier*/ true); if (!(result.kind & SyntaxKind.Identifier)) { return factory.createIdentifier("(Missing type parameter)"); } if (context.flags & NodeBuilderFlags.GenerateNamesForShadowedTypeParams) { const rawtext = result.escapedText as string; let i = context.typeParameterNamesByTextNextNameCount?.get(rawtext) || 0; let text = rawtext; while (context.typeParameterNamesByText?.has(text) || typeParameterShadowsNameInScope(text as __String, context, type)) { i++; text = `${rawtext}_${i}`; } if (text !== rawtext) { const typeArguments = getIdentifierTypeArguments(result); result = factory.createIdentifier(text); setIdentifierTypeArguments(result, typeArguments); } // avoiding iterations of the above loop turns out to be worth it when `i` starts to get large, so we cache the max // `i` we've used thus far, to save work later (context.typeParameterNamesByTextNextNameCount ||= new Map()).set(rawtext, i); (context.typeParameterNames ||= new Map()).set(getTypeId(type), result); (context.typeParameterNamesByText ||= new Set()).add(rawtext); } return result; } 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.AllowQualifiedNameInPlaceOfIdentifier)) { 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(factory.createIdentifier(symbolName), EmitFlags.NoAsciiEscaping); if (typeParameterNodes) setIdentifierTypeArguments(identifier, factory.createNodeArray(typeParameterNodes)); identifier.symbol = symbol; return index > 0 ? factory.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 (index === 0) { context.flags |= NodeBuilderFlags.InInitialEntityName; } let symbolName = getNameOfSymbolAsWritten(symbol, context); if (index === 0) { context.flags ^= NodeBuilderFlags.InInitialEntityName; } let firstChar = symbolName.charCodeAt(0); if (isSingleOrDoubleQuote(firstChar) && some(symbol.declarations, hasNonGlobalAugmentationExternalModuleSymbol)) { return factory.createStringLiteral(getSpecifierForModuleSymbol(symbol, context)); } if (index === 0 || canUsePropertyAccess(symbolName, languageVersion)) { const identifier = setEmitFlags(factory.createIdentifier(symbolName), EmitFlags.NoAsciiEscaping); if (typeParameterNodes) setIdentifierTypeArguments(identifier, factory.createNodeArray(typeParameterNodes)); identifier.symbol = symbol; return index > 0 ? factory.createPropertyAccessExpression(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) && !(symbol.flags & SymbolFlags.EnumMember)) { expression = factory.createStringLiteral(stripQuotes(symbolName).replace(/\\./g, s => s.substring(1)), firstChar === CharacterCodes.singleQuote); } else if (("" + +symbolName) === symbolName) { expression = factory.createNumericLiteral(+symbolName); } if (!expression) { const identifier = setEmitFlags(factory.createIdentifier(symbolName), EmitFlags.NoAsciiEscaping); if (typeParameterNodes) setIdentifierTypeArguments(identifier, factory.createNodeArray(typeParameterNodes)); identifier.symbol = symbol; expression = identifier; } return factory.createElementAccessExpression(createExpressionFromSymbolChain(chain, index - 1), expression); } } } function isStringNamed(d: Declaration) { const name = getNameOfDeclaration(d); return !!name && isStringLiteral(name); } function isSingleQuotedStringNamed(d: Declaration) { const name = getNameOfDeclaration(d); return !!(name && isStringLiteral(name) && (name.singleQuote || !nodeIsSynthesized(name) && startsWith(getTextOfNode(name, /*includeTrivia*/ false), "'"))); } function getPropertyNameNodeForSymbol(symbol: Symbol, context: NodeBuilderContext) { const stringNamed = !!length(symbol.declarations) && every(symbol.declarations, isStringNamed); const singleQuote = !!length(symbol.declarations) && every(symbol.declarations, isSingleQuotedStringNamed); const fromNameType = getPropertyNameNodeForSymbolFromNameType(symbol, context, singleQuote, stringNamed); if (fromNameType) { return fromNameType; } const rawName = unescapeLeadingUnderscores(symbol.escapedName); return createPropertyNameNodeForIdentifierOrLiteral(rawName, getEmitScriptTarget(compilerOptions), singleQuote, stringNamed); } // See getNameForSymbolFromNameType for a stringy equivalent function getPropertyNameNodeForSymbolFromNameType(symbol: Symbol, context: NodeBuilderContext, singleQuote?: boolean, stringNamed?: boolean) { const nameType = getSymbolLinks(symbol).nameType; if (nameType) { if (nameType.flags & TypeFlags.StringOrNumberLiteral) { const name = "" + (nameType as StringLiteralType | NumberLiteralType).value; if (!isIdentifierText(name, getEmitScriptTarget(compilerOptions)) && (stringNamed || !isNumericLiteralName(name))) { return factory.createStringLiteral(name, !!singleQuote); } if (isNumericLiteralName(name) && startsWith(name, "-")) { return factory.createComputedPropertyName(factory.createNumericLiteral(+name)); } return createPropertyNameNodeForIdentifierOrLiteral(name, getEmitScriptTarget(compilerOptions)); } if (nameType.flags & TypeFlags.UniqueESSymbol) { return factory.createComputedPropertyName(symbolToExpression((nameType as UniqueESSymbolType).symbol, context, SymbolFlags.Value)); } } } function cloneNodeBuilderContext(context: NodeBuilderContext): NodeBuilderContext { const initial: NodeBuilderContext = { ...context }; // Make type parameters created within this context not consume the name outside this context // The symbol serializer ends up creating many sibling scopes that all need "separate" contexts when // it comes to naming things - within a normal `typeToTypeNode` call, the node builder only ever descends // through the type tree, so the only cases where we could have used distinct sibling scopes was when there // were multiple generic overloads with similar generated type parameter names // The effect: // When we write out // export const x: (x: T) => T // export const y: (x: T) => T // we write it out like that, rather than as // export const x: (x: T) => T // export const y: (x: T_1) => T_1 if (initial.typeParameterNames) { initial.typeParameterNames = new Map(initial.typeParameterNames); } if (initial.typeParameterNamesByText) { initial.typeParameterNamesByText = new Set(initial.typeParameterNamesByText); } if (initial.typeParameterSymbolList) { initial.typeParameterSymbolList = new Set(initial.typeParameterSymbolList); } initial.tracker = new SymbolTrackerImpl(initial, initial.tracker.inner, initial.tracker.moduleResolverHost); return initial; } function getDeclarationWithTypeAnnotation(symbol: Symbol, enclosingDeclaration: Node | undefined) { return symbol.declarations && find(symbol.declarations, s => !!getEffectiveTypeAnnotationNode(s) && (!enclosingDeclaration || !!findAncestor(s, n => n === enclosingDeclaration))); } function existingTypeNodeIsNotReferenceOrIsReferenceWithCompatibleTypeArgumentCount(existing: TypeNode, type: Type) { return !(getObjectFlags(type) & ObjectFlags.Reference) || !isTypeReferenceNode(existing) || length(existing.typeArguments) >= getMinTypeArgumentCount((type as TypeReference).target.typeParameters); } function getEnclosingDeclarationIgnoringFakeScope(enclosingDeclaration: Node) { return getNodeLinks(enclosingDeclaration).fakeScopeForSignatureDeclaration ? enclosingDeclaration.parent : enclosingDeclaration; } /** * Unlike `typeToTypeNodeHelper`, this handles setting up the `AllowUniqueESSymbolType` flag * so a `unique symbol` is returned when appropriate for the input symbol, rather than `typeof sym` */ function serializeTypeForDeclaration(context: NodeBuilderContext, type: Type, symbol: Symbol, enclosingDeclaration: Node | undefined, includePrivateSymbol?: (s: Symbol) => void, bundled?: boolean) { if (!isErrorType(type) && enclosingDeclaration) { const declWithExistingAnnotation = getDeclarationWithTypeAnnotation(symbol, getEnclosingDeclarationIgnoringFakeScope(enclosingDeclaration)); if (declWithExistingAnnotation && !isFunctionLikeDeclaration(declWithExistingAnnotation) && !isGetAccessorDeclaration(declWithExistingAnnotation)) { // try to reuse the existing annotation const existing = getEffectiveTypeAnnotationNode(declWithExistingAnnotation)!; if (typeNodeIsEquivalentToType(existing, declWithExistingAnnotation, type) && existingTypeNodeIsNotReferenceOrIsReferenceWithCompatibleTypeArgumentCount(existing, type)) { const result = serializeExistingTypeNode(context, existing, includePrivateSymbol, bundled); if (result) { return result; } } } } const oldFlags = context.flags; if (type.flags & TypeFlags.UniqueESSymbol && type.symbol === symbol && (!context.enclosingDeclaration || some(symbol.declarations, d => getSourceFileOfNode(d) === getSourceFileOfNode(context.enclosingDeclaration!)))) { context.flags |= NodeBuilderFlags.AllowUniqueESSymbolType; } const result = typeToTypeNodeHelper(type, context); context.flags = oldFlags; return result; } function typeNodeIsEquivalentToType(typeNode: TypeNode, annotatedDeclaration: Declaration, type: Type) { const typeFromTypeNode = getTypeFromTypeNode(typeNode); if (typeFromTypeNode === type) { return true; } if (isParameter(annotatedDeclaration) && annotatedDeclaration.questionToken) { return getTypeWithFacts(type, TypeFacts.NEUndefined) === typeFromTypeNode; } return false; } function serializeReturnTypeForSignature(context: NodeBuilderContext, type: Type, signature: Signature, includePrivateSymbol?: (s: Symbol) => void, bundled?: boolean) { if (!isErrorType(type) && context.enclosingDeclaration) { const annotation = signature.declaration && getEffectiveReturnTypeNode(signature.declaration); const enclosingDeclarationIgnoringFakeScope = getEnclosingDeclarationIgnoringFakeScope(context.enclosingDeclaration); if (!!findAncestor(annotation, n => n === enclosingDeclarationIgnoringFakeScope) && annotation) { const annotated = getTypeFromTypeNode(annotation); const thisInstantiated = annotated.flags & TypeFlags.TypeParameter && (annotated as TypeParameter).isThisType ? instantiateType(annotated, signature.mapper) : annotated; if (thisInstantiated === type && existingTypeNodeIsNotReferenceOrIsReferenceWithCompatibleTypeArgumentCount(annotation, type)) { const result = serializeExistingTypeNode(context, annotation, includePrivateSymbol, bundled); if (result) { return result; } } } } return typeToTypeNodeHelper(type, context); } function trackExistingEntityName(node: T, context: NodeBuilderContext, includePrivateSymbol?: (s: Symbol) => void) { let introducesError = false; const leftmost = getFirstIdentifier(node); if (isInJSFile(node) && (isExportsIdentifier(leftmost) || isModuleExportsAccessExpression(leftmost.parent) || (isQualifiedName(leftmost.parent) && isModuleIdentifier(leftmost.parent.left) && isExportsIdentifier(leftmost.parent.right)))) { introducesError = true; return { introducesError, node }; } const sym = resolveEntityName(leftmost, SymbolFlags.All, /*ignoreErrors*/ true, /*dontResolveAlias*/ true); if (sym) { if (isSymbolAccessible(sym, context.enclosingDeclaration, SymbolFlags.All, /*shouldComputeAliasesToMakeVisible*/ false).accessibility !== SymbolAccessibility.Accessible) { introducesError = true; } else { context.tracker.trackSymbol(sym, context.enclosingDeclaration, SymbolFlags.All); includePrivateSymbol?.(sym); } if (isIdentifier(node)) { const type = getDeclaredTypeOfSymbol(sym); const name = sym.flags & SymbolFlags.TypeParameter && !isTypeSymbolAccessible(type.symbol, context.enclosingDeclaration) ? typeParameterToName(type, context) : factory.cloneNode(node); name.symbol = sym; // for quickinfo, which uses identifier symbol information return { introducesError, node: setEmitFlags(setOriginalNode(name, node), EmitFlags.NoAsciiEscaping) }; } } return { introducesError, node }; } function serializeExistingTypeNode(context: NodeBuilderContext, existing: TypeNode, includePrivateSymbol?: (s: Symbol) => void, bundled?: boolean) { if (cancellationToken && cancellationToken.throwIfCancellationRequested) { cancellationToken.throwIfCancellationRequested(); } let hadError = false; const file = getSourceFileOfNode(existing); const transformed = visitNode(existing, visitExistingNodeTreeSymbols, isTypeNode); if (hadError) { return undefined; } return transformed === existing ? setTextRange(factory.cloneNode(existing), existing) : transformed; function visitExistingNodeTreeSymbols(node: Node): Node { // We don't _actually_ support jsdoc namepath types, emit `any` instead if (isJSDocAllType(node) || node.kind === SyntaxKind.JSDocNamepathType) { return factory.createKeywordTypeNode(SyntaxKind.AnyKeyword); } if (isJSDocUnknownType(node)) { return factory.createKeywordTypeNode(SyntaxKind.UnknownKeyword); } if (isJSDocNullableType(node)) { return factory.createUnionTypeNode([visitNode(node.type, visitExistingNodeTreeSymbols, isTypeNode), factory.createLiteralTypeNode(factory.createNull())]); } if (isJSDocOptionalType(node)) { return factory.createUnionTypeNode([visitNode(node.type, visitExistingNodeTreeSymbols, isTypeNode), factory.createKeywordTypeNode(SyntaxKind.UndefinedKeyword)]); } if (isJSDocNonNullableType(node)) { return visitNode(node.type, visitExistingNodeTreeSymbols); } if (isJSDocVariadicType(node)) { return factory.createArrayTypeNode(visitNode(node.type, visitExistingNodeTreeSymbols, isTypeNode)); } if (isJSDocTypeLiteral(node)) { return factory.createTypeLiteralNode(map(node.jsDocPropertyTags, t => { const name = isIdentifier(t.name) ? t.name : t.name.right; const typeViaParent = getTypeOfPropertyOfType(getTypeFromTypeNode(node), name.escapedText); const overrideTypeNode = typeViaParent && t.typeExpression && getTypeFromTypeNode(t.typeExpression.type) !== typeViaParent ? typeToTypeNodeHelper(typeViaParent, context) : undefined; return factory.createPropertySignature( /*modifiers*/ undefined, name, t.isBracketed || t.typeExpression && isJSDocOptionalType(t.typeExpression.type) ? factory.createToken(SyntaxKind.QuestionToken) : undefined, overrideTypeNode || (t.typeExpression && visitNode(t.typeExpression.type, visitExistingNodeTreeSymbols, isTypeNode)) || factory.createKeywordTypeNode(SyntaxKind.AnyKeyword) ); })); } if (isTypeReferenceNode(node) && isIdentifier(node.typeName) && node.typeName.escapedText === "") { return setOriginalNode(factory.createKeywordTypeNode(SyntaxKind.AnyKeyword), node); } if ((isExpressionWithTypeArguments(node) || isTypeReferenceNode(node)) && isJSDocIndexSignature(node)) { return factory.createTypeLiteralNode([factory.createIndexSignature( /*modifiers*/ undefined, [factory.createParameterDeclaration( /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "x", /*questionToken*/ undefined, visitNode(node.typeArguments![0], visitExistingNodeTreeSymbols, isTypeNode) )], visitNode(node.typeArguments![1], visitExistingNodeTreeSymbols, isTypeNode) )]); } if (isJSDocFunctionType(node)) { if (isJSDocConstructSignature(node)) { let newTypeNode: TypeNode | undefined; return factory.createConstructorTypeNode( /*modifiers*/ undefined, visitNodes(node.typeParameters, visitExistingNodeTreeSymbols, isTypeParameterDeclaration), mapDefined(node.parameters, (p, i) => p.name && isIdentifier(p.name) && p.name.escapedText === "new" ? (newTypeNode = p.type, undefined) : factory.createParameterDeclaration( /*modifiers*/ undefined, getEffectiveDotDotDotForParameter(p), getNameForJSDocFunctionParameter(p, i), p.questionToken, visitNode(p.type, visitExistingNodeTreeSymbols, isTypeNode), /*initializer*/ undefined )), visitNode(newTypeNode || node.type, visitExistingNodeTreeSymbols, isTypeNode) || factory.createKeywordTypeNode(SyntaxKind.AnyKeyword) ); } else { return factory.createFunctionTypeNode( visitNodes(node.typeParameters, visitExistingNodeTreeSymbols, isTypeParameterDeclaration), map(node.parameters, (p, i) => factory.createParameterDeclaration( /*modifiers*/ undefined, getEffectiveDotDotDotForParameter(p), getNameForJSDocFunctionParameter(p, i), p.questionToken, visitNode(p.type, visitExistingNodeTreeSymbols, isTypeNode), /*initializer*/ undefined )), visitNode(node.type, visitExistingNodeTreeSymbols, isTypeNode) || factory.createKeywordTypeNode(SyntaxKind.AnyKeyword) ); } } if (isTypeReferenceNode(node) && isInJSDoc(node) && (!existingTypeNodeIsNotReferenceOrIsReferenceWithCompatibleTypeArgumentCount(node, getTypeFromTypeNode(node)) || getIntendedTypeFromJSDocTypeReference(node) || unknownSymbol === resolveTypeReferenceName(node, SymbolFlags.Type, /*ignoreErrors*/ true))) { return setOriginalNode(typeToTypeNodeHelper(getTypeFromTypeNode(node), context), node); } if (isLiteralImportTypeNode(node)) { const nodeSymbol = getNodeLinks(node).resolvedSymbol; if (isInJSDoc(node) && nodeSymbol && ( // The import type resolved using jsdoc fallback logic (!node.isTypeOf && !(nodeSymbol.flags & SymbolFlags.Type)) || // The import type had type arguments autofilled by js fallback logic !(length(node.typeArguments) >= getMinTypeArgumentCount(getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(nodeSymbol))) ) ) { return setOriginalNode(typeToTypeNodeHelper(getTypeFromTypeNode(node), context), node); } return factory.updateImportTypeNode( node, factory.updateLiteralTypeNode(node.argument, rewriteModuleSpecifier(node, node.argument.literal)), node.assertions, node.qualifier, visitNodes(node.typeArguments, visitExistingNodeTreeSymbols, isTypeNode), node.isTypeOf ); } if (isEntityName(node) || isEntityNameExpression(node)) { const { introducesError, node: result } = trackExistingEntityName(node, context, includePrivateSymbol); hadError = hadError || introducesError; if (result !== node) { return result; } } if (file && isTupleTypeNode(node) && (getLineAndCharacterOfPosition(file, node.pos).line === getLineAndCharacterOfPosition(file, node.end).line)) { setEmitFlags(node, EmitFlags.SingleLine); } return visitEachChild(node, visitExistingNodeTreeSymbols, nullTransformationContext); function getEffectiveDotDotDotForParameter(p: ParameterDeclaration) { return p.dotDotDotToken || (p.type && isJSDocVariadicType(p.type) ? factory.createToken(SyntaxKind.DotDotDotToken) : undefined); } /** Note that `new:T` parameters are not handled, but should be before calling this function. */ function getNameForJSDocFunctionParameter(p: ParameterDeclaration, index: number) { return p.name && isIdentifier(p.name) && p.name.escapedText === "this" ? "this" : getEffectiveDotDotDotForParameter(p) ? `args` : `arg${index}`; } function rewriteModuleSpecifier(parent: ImportTypeNode, lit: StringLiteral) { if (bundled) { if (context.tracker && context.tracker.moduleResolverHost) { const targetFile = getExternalModuleFileFromDeclaration(parent); if (targetFile) { const getCanonicalFileName = createGetCanonicalFileName(!!host.useCaseSensitiveFileNames); const resolverHost = { getCanonicalFileName, getCurrentDirectory: () => context.tracker.moduleResolverHost!.getCurrentDirectory(), getCommonSourceDirectory: () => context.tracker.moduleResolverHost!.getCommonSourceDirectory() }; const newName = getResolvedExternalModuleName(resolverHost, targetFile); return factory.createStringLiteral(newName); } } } else { if (context.tracker && context.tracker.trackExternalModuleSymbolOfImportTypeNode) { const moduleSym = resolveExternalModuleNameWorker(lit, lit, /*moduleNotFoundError*/ undefined); if (moduleSym) { context.tracker.trackExternalModuleSymbolOfImportTypeNode(moduleSym); } } } return lit; } } } function symbolTableToDeclarationStatements(symbolTable: SymbolTable, context: NodeBuilderContext, bundled?: boolean): Statement[] { const serializePropertySymbolForClass = makeSerializePropertySymbol(factory.createPropertyDeclaration, SyntaxKind.MethodDeclaration, /*useAccessors*/ true); const serializePropertySymbolForInterfaceWorker = makeSerializePropertySymbol((mods, name, question, type) => factory.createPropertySignature(mods, name, question, type), SyntaxKind.MethodSignature, /*useAccessors*/ false); // TODO: Use `setOriginalNode` on original declaration names where possible so these declarations see some kind of // declaration mapping // We save the enclosing declaration off here so it's not adjusted by well-meaning declaration // emit codepaths which want to apply more specific contexts (so we can still refer to the root real declaration // we're trying to emit from later on) const enclosingDeclaration = context.enclosingDeclaration!; let results: Statement[] = []; const visitedSymbols = new Set(); const deferredPrivatesStack: Map[] = []; const oldcontext = context; context = { ...oldcontext, usedSymbolNames: new Set(oldcontext.usedSymbolNames), remappedSymbolNames: new Map(), tracker: undefined!, }; const tracker: SymbolTracker = { ...oldcontext.tracker.inner, trackSymbol: (sym, decl, meaning) => { const accessibleResult = isSymbolAccessible(sym, decl, meaning, /*shouldComputeAliasesToMakeVisible*/ false); if (accessibleResult.accessibility === SymbolAccessibility.Accessible) { // Lookup the root symbol of the chain of refs we'll use to access it and serialize it const chain = lookupSymbolChainWorker(sym, context, meaning); if (!(sym.flags & SymbolFlags.Property)) { includePrivateSymbol(chain[0]); } } else if (oldcontext.tracker.inner?.trackSymbol) { return oldcontext.tracker.inner.trackSymbol(sym, decl, meaning); } return false; }, }; context.tracker = new SymbolTrackerImpl(context, tracker, oldcontext.tracker.moduleResolverHost); forEachEntry(symbolTable, (symbol, name) => { const baseName = unescapeLeadingUnderscores(name); void getInternalSymbolName(symbol, baseName); // Called to cache values into `usedSymbolNames` and `remappedSymbolNames` }); let addingDeclare = !bundled; const exportEquals = symbolTable.get(InternalSymbolName.ExportEquals); if (exportEquals && symbolTable.size > 1 && exportEquals.flags & SymbolFlags.Alias) { symbolTable = createSymbolTable(); // Remove extraneous elements from root symbol table (they'll be mixed back in when the target of the `export=` is looked up) symbolTable.set(InternalSymbolName.ExportEquals, exportEquals); } visitSymbolTable(symbolTable); return mergeRedundantStatements(results); function isIdentifierAndNotUndefined(node: Node | undefined): node is Identifier { return !!node && node.kind === SyntaxKind.Identifier; } function getNamesOfDeclaration(statement: Statement): Identifier[] { if (isVariableStatement(statement)) { return filter(map(statement.declarationList.declarations, getNameOfDeclaration), isIdentifierAndNotUndefined); } return filter([getNameOfDeclaration(statement as DeclarationStatement)], isIdentifierAndNotUndefined); } function flattenExportAssignedNamespace(statements: Statement[]) { const exportAssignment = find(statements, isExportAssignment); const nsIndex = findIndex(statements, isModuleDeclaration); let ns = nsIndex !== -1 ? statements[nsIndex] as ModuleDeclaration : undefined; if (ns && exportAssignment && exportAssignment.isExportEquals && isIdentifier(exportAssignment.expression) && isIdentifier(ns.name) && idText(ns.name) === idText(exportAssignment.expression) && ns.body && isModuleBlock(ns.body)) { // Pass 0: Correct situations where a module has both an `export = ns` and multiple top-level exports by stripping the export modifiers from // the top-level exports and exporting them in the targeted ns, as can occur when a js file has both typedefs and `module.export` assignments const excessExports = filter(statements, s => !!(getEffectiveModifierFlags(s) & ModifierFlags.Export)); const name = ns.name; let body = ns.body; if (length(excessExports)) { ns = factory.updateModuleDeclaration( ns, ns.modifiers, ns.name, body = factory.updateModuleBlock( body, factory.createNodeArray([...ns.body.statements, factory.createExportDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, factory.createNamedExports(map(flatMap(excessExports, e => getNamesOfDeclaration(e)), id => factory.createExportSpecifier(/*isTypeOnly*/ false, /*propertyName*/ undefined, id))), /*moduleSpecifier*/ undefined )]) ) ); statements = [...statements.slice(0, nsIndex), ns, ...statements.slice(nsIndex + 1)]; } // Pass 1: Flatten `export namespace _exports {} export = _exports;` so long as the `export=` only points at a single namespace declaration if (!find(statements, s => s !== ns && nodeHasName(s, name))) { results = []; // If the namespace contains no export assignments or declarations, and no declarations flagged with `export`, then _everything_ is exported - // to respect this as the top level, we need to add an `export` modifier to everything const mixinExportFlag = !some(body.statements, s => hasSyntacticModifier(s, ModifierFlags.Export) || isExportAssignment(s) || isExportDeclaration(s)); forEach(body.statements, s => { addResult(s, mixinExportFlag ? ModifierFlags.Export : ModifierFlags.None); // Recalculates the ambient (and export, if applicable from above) flag }); statements = [...filter(statements, s => s !== ns && s !== exportAssignment), ...results]; } } return statements; } function mergeExportDeclarations(statements: Statement[]) { // Pass 2: Combine all `export {}` declarations const exports = filter(statements, d => isExportDeclaration(d) && !d.moduleSpecifier && !!d.exportClause && isNamedExports(d.exportClause)) as ExportDeclaration[]; if (length(exports) > 1) { const nonExports = filter(statements, d => !isExportDeclaration(d) || !!d.moduleSpecifier || !d.exportClause); statements = [...nonExports, factory.createExportDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, factory.createNamedExports(flatMap(exports, e => cast(e.exportClause, isNamedExports).elements)), /*moduleSpecifier*/ undefined )]; } // Pass 2b: Also combine all `export {} from "..."` declarations as needed const reexports = filter(statements, d => isExportDeclaration(d) && !!d.moduleSpecifier && !!d.exportClause && isNamedExports(d.exportClause)) as ExportDeclaration[]; if (length(reexports) > 1) { const groups = group(reexports, decl => isStringLiteral(decl.moduleSpecifier!) ? ">" + decl.moduleSpecifier.text : ">"); if (groups.length !== reexports.length) { for (const group of groups) { if (group.length > 1) { // remove group members from statements and then merge group members and add back to statements statements = [ ...filter(statements, s => group.indexOf(s as ExportDeclaration) === -1), factory.createExportDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, factory.createNamedExports(flatMap(group, e => cast(e.exportClause, isNamedExports).elements)), group[0].moduleSpecifier ) ]; } } } } return statements; } function inlineExportModifiers(statements: Statement[]) { // Pass 3: Move all `export {}`'s to `export` modifiers where possible const index = findIndex(statements, d => isExportDeclaration(d) && !d.moduleSpecifier && !d.assertClause && !!d.exportClause && isNamedExports(d.exportClause)); if (index >= 0) { const exportDecl = statements[index] as ExportDeclaration & { readonly exportClause: NamedExports }; const replacements = mapDefined(exportDecl.exportClause.elements, e => { if (!e.propertyName) { // export {name} - look thru `statements` for `name`, and if all results can take an `export` modifier, do so and filter it const indices = indicesOf(statements); const associatedIndices = filter(indices, i => nodeHasName(statements[i], e.name)); if (length(associatedIndices) && every(associatedIndices, i => canHaveExportModifier(statements[i]))) { for (const index of associatedIndices) { statements[index] = addExportModifier(statements[index] as Extract); } return undefined; } } return e; }); if (!length(replacements)) { // all clauses removed, remove the export declaration orderedRemoveItemAt(statements, index); } else { // some items filtered, others not - update the export declaration statements[index] = factory.updateExportDeclaration( exportDecl, exportDecl.modifiers, exportDecl.isTypeOnly, factory.updateNamedExports( exportDecl.exportClause, replacements ), exportDecl.moduleSpecifier, exportDecl.assertClause ); } } return statements; } function mergeRedundantStatements(statements: Statement[]) { statements = flattenExportAssignedNamespace(statements); statements = mergeExportDeclarations(statements); statements = inlineExportModifiers(statements); // Not a cleanup, but as a final step: If there is a mix of `export` and non-`export` declarations, but no `export =` or `export {}` add a `export {};` so // declaration privacy is respected. if (enclosingDeclaration && ((isSourceFile(enclosingDeclaration) && isExternalOrCommonJsModule(enclosingDeclaration)) || isModuleDeclaration(enclosingDeclaration)) && (!some(statements, isExternalModuleIndicator) || (!hasScopeMarker(statements) && some(statements, needsScopeMarker)))) { statements.push(createEmptyExports(factory)); } return statements; } function addExportModifier(node: Extract) { const flags = (getEffectiveModifierFlags(node) | ModifierFlags.Export) & ~ModifierFlags.Ambient; return factory.updateModifiers(node, flags); } function removeExportModifier(node: Extract) { const flags = getEffectiveModifierFlags(node) & ~ModifierFlags.Export; return factory.updateModifiers(node, flags); } function visitSymbolTable(symbolTable: SymbolTable, suppressNewPrivateContext?: boolean, propertyAsAlias?: boolean) { if (!suppressNewPrivateContext) { deferredPrivatesStack.push(new Map()); } symbolTable.forEach((symbol: Symbol) => { serializeSymbol(symbol, /*isPrivate*/ false, !!propertyAsAlias); }); if (!suppressNewPrivateContext) { // deferredPrivates will be filled up by visiting the symbol table // And will continue to iterate as elements are added while visited `deferredPrivates` // (As that's how a map iterator is defined to work) deferredPrivatesStack[deferredPrivatesStack.length - 1].forEach((symbol: Symbol) => { serializeSymbol(symbol, /*isPrivate*/ true, !!propertyAsAlias); }); deferredPrivatesStack.pop(); } } function serializeSymbol(symbol: Symbol, isPrivate: boolean, propertyAsAlias: boolean): void { // cache visited list based on merged symbol, since we want to use the unmerged top-level symbol, but // still skip reserializing it if we encounter the merged product later on const visitedSym = getMergedSymbol(symbol); if (visitedSymbols.has(getSymbolId(visitedSym))) { return; // Already printed } visitedSymbols.add(getSymbolId(visitedSym)); // Only actually serialize symbols within the correct enclosing declaration, otherwise do nothing with the out-of-context symbol const skipMembershipCheck = !isPrivate; // We only call this on exported symbols when we know they're in the correct scope if (skipMembershipCheck || (!!length(symbol.declarations) && some(symbol.declarations, d => !!findAncestor(d, n => n === enclosingDeclaration)))) { const oldContext = context; context = cloneNodeBuilderContext(context); serializeSymbolWorker(symbol, isPrivate, propertyAsAlias); if (context.reportedDiagnostic) { oldcontext.reportedDiagnostic = context.reportedDiagnostic; // hoist diagnostic result into outer context } context = oldContext; } } // Synthesize declarations for a symbol - might be an Interface, a Class, a Namespace, a Type, a Variable (const, let, or var), an Alias // or a merge of some number of those. // An interesting challenge is ensuring that when classes merge with namespaces and interfaces, is keeping // each symbol in only one of the representations // Also, synthesizing a default export of some kind // If it's an alias: emit `export default ref` // If it's a property: emit `export default _default` with a `_default` prop // If it's a class/interface/function: emit a class/interface/function with a `default` modifier // These forms can merge, eg (`export default 12; export default interface A {}`) function serializeSymbolWorker(symbol: Symbol, isPrivate: boolean, propertyAsAlias: boolean): void { const symbolName = unescapeLeadingUnderscores(symbol.escapedName); const isDefault = symbol.escapedName === InternalSymbolName.Default; if (isPrivate && !(context.flags & NodeBuilderFlags.AllowAnonymousIdentifier) && isStringANonContextualKeyword(symbolName) && !isDefault) { // Oh no. We cannot use this symbol's name as it's name... It's likely some jsdoc had an invalid name like `export` or `default` :( context.encounteredError = true; // TODO: Issue error via symbol tracker? return; // If we need to emit a private with a keyword name, we're done for, since something else will try to refer to it by that name } let needsPostExportDefault = isDefault && !!( symbol.flags & SymbolFlags.ExportDoesNotSupportDefaultModifier || (symbol.flags & SymbolFlags.Function && length(getPropertiesOfType(getTypeOfSymbol(symbol)))) ) && !(symbol.flags & SymbolFlags.Alias); // An alias symbol should preclude needing to make an alias ourselves let needsExportDeclaration = !needsPostExportDefault && !isPrivate && isStringANonContextualKeyword(symbolName) && !isDefault; // `serializeVariableOrProperty` will handle adding the export declaration if it is run (since `getInternalSymbolName` will create the name mapping), so we need to ensuer we unset `needsExportDeclaration` if it is if (needsPostExportDefault || needsExportDeclaration) { isPrivate = true; } const modifierFlags = (!isPrivate ? ModifierFlags.Export : 0) | (isDefault && !needsPostExportDefault ? ModifierFlags.Default : 0); const isConstMergedWithNS = symbol.flags & SymbolFlags.Module && symbol.flags & (SymbolFlags.BlockScopedVariable | SymbolFlags.FunctionScopedVariable | SymbolFlags.Property) && symbol.escapedName !== InternalSymbolName.ExportEquals; const isConstMergedWithNSPrintableAsSignatureMerge = isConstMergedWithNS && isTypeRepresentableAsFunctionNamespaceMerge(getTypeOfSymbol(symbol), symbol); if (symbol.flags & (SymbolFlags.Function | SymbolFlags.Method) || isConstMergedWithNSPrintableAsSignatureMerge) { serializeAsFunctionNamespaceMerge(getTypeOfSymbol(symbol), symbol, getInternalSymbolName(symbol, symbolName), modifierFlags); } if (symbol.flags & SymbolFlags.TypeAlias) { serializeTypeAlias(symbol, symbolName, modifierFlags); } // Need to skip over export= symbols below - json source files get a single `Property` flagged // symbol of name `export=` which needs to be handled like an alias. It's not great, but it is what it is. if (symbol.flags & (SymbolFlags.BlockScopedVariable | SymbolFlags.FunctionScopedVariable | SymbolFlags.Property | SymbolFlags.Accessor) && symbol.escapedName !== InternalSymbolName.ExportEquals && !(symbol.flags & SymbolFlags.Prototype) && !(symbol.flags & SymbolFlags.Class) && !(symbol.flags & SymbolFlags.Method) && !isConstMergedWithNSPrintableAsSignatureMerge) { if (propertyAsAlias) { const createdExport = serializeMaybeAliasAssignment(symbol); if (createdExport) { needsExportDeclaration = false; needsPostExportDefault = false; } } else { const type = getTypeOfSymbol(symbol); const localName = getInternalSymbolName(symbol, symbolName); if (!(symbol.flags & SymbolFlags.Function) && isTypeRepresentableAsFunctionNamespaceMerge(type, symbol)) { // If the type looks like a function declaration + ns could represent it, and it's type is sourced locally, rewrite it into a function declaration + ns serializeAsFunctionNamespaceMerge(type, symbol, localName, modifierFlags); } else { // A Class + Property merge is made for a `module.exports.Member = class {}`, and it doesn't serialize well as either a class _or_ a property symbol - in fact, _it behaves like an alias!_ // `var` is `FunctionScopedVariable`, `const` and `let` are `BlockScopedVariable`, and `module.exports.thing =` is `Property` const flags = !(symbol.flags & SymbolFlags.BlockScopedVariable) ? symbol.parent?.valueDeclaration && isSourceFile(symbol.parent?.valueDeclaration) ? NodeFlags.Const // exports are immutable in es6, which is what we emulate and check; so it's safe to mark all exports as `const` (there's no difference to consumers, but it allows unique symbol type declarations) : undefined : isConstVariable(symbol) ? NodeFlags.Const : NodeFlags.Let; const name = (needsPostExportDefault || !(symbol.flags & SymbolFlags.Property)) ? localName : getUnusedName(localName, symbol); let textRange: Node | undefined = symbol.declarations && find(symbol.declarations, d => isVariableDeclaration(d)); if (textRange && isVariableDeclarationList(textRange.parent) && textRange.parent.declarations.length === 1) { textRange = textRange.parent.parent; } const propertyAccessRequire = symbol.declarations?.find(isPropertyAccessExpression); if (propertyAccessRequire && isBinaryExpression(propertyAccessRequire.parent) && isIdentifier(propertyAccessRequire.parent.right) && type.symbol?.valueDeclaration && isSourceFile(type.symbol.valueDeclaration)) { const alias = localName === propertyAccessRequire.parent.right.escapedText ? undefined : propertyAccessRequire.parent.right; addResult( factory.createExportDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, factory.createNamedExports([factory.createExportSpecifier(/*isTypeOnly*/ false, alias, localName)]) ), ModifierFlags.None ); context.tracker.trackSymbol(type.symbol, context.enclosingDeclaration, SymbolFlags.Value); } else { const statement = setTextRange(factory.createVariableStatement(/*modifiers*/ undefined, factory.createVariableDeclarationList([ factory.createVariableDeclaration(name, /*exclamationToken*/ undefined, serializeTypeForDeclaration(context, type, symbol, enclosingDeclaration, includePrivateSymbol, bundled)) ], flags)), textRange); addResult(statement, name !== localName ? modifierFlags & ~ModifierFlags.Export : modifierFlags); if (name !== localName && !isPrivate) { // We rename the variable declaration we generate for Property symbols since they may have a name which // conflicts with a local declaration. For example, given input: // ``` // function g() {} // module.exports.g = g // ``` // In such a situation, we have a local variable named `g`, and a separate exported variable named `g`. // Naively, we would emit // ``` // function g() {} // export const g: typeof g; // ``` // That's obviously incorrect - the `g` in the type annotation needs to refer to the local `g`, but // the export declaration shadows it. // To work around that, we instead write // ``` // function g() {} // const g_1: typeof g; // export { g_1 as g }; // ``` // To create an export named `g` that does _not_ shadow the local `g` addResult( factory.createExportDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, factory.createNamedExports([factory.createExportSpecifier(/*isTypeOnly*/ false, name, localName)]) ), ModifierFlags.None ); needsExportDeclaration = false; needsPostExportDefault = false; } } } } } if (symbol.flags & SymbolFlags.Enum) { serializeEnum(symbol, symbolName, modifierFlags); } if (symbol.flags & SymbolFlags.Class) { if (symbol.flags & SymbolFlags.Property && symbol.valueDeclaration && isBinaryExpression(symbol.valueDeclaration.parent) && isClassExpression(symbol.valueDeclaration.parent.right)) { // Looks like a `module.exports.Sub = class {}` - if we serialize `symbol` as a class, the result will have no members, // since the classiness is actually from the target of the effective alias the symbol is. yes. A BlockScopedVariable|Class|Property // _really_ acts like an Alias, and none of a BlockScopedVariable, Class, or Property. This is the travesty of JS binding today. serializeAsAlias(symbol, getInternalSymbolName(symbol, symbolName), modifierFlags); } else { serializeAsClass(symbol, getInternalSymbolName(symbol, symbolName), modifierFlags); } } if ((symbol.flags & (SymbolFlags.ValueModule | SymbolFlags.NamespaceModule) && (!isConstMergedWithNS || isTypeOnlyNamespace(symbol))) || isConstMergedWithNSPrintableAsSignatureMerge) { serializeModule(symbol, symbolName, modifierFlags); } // The class meaning serialization should handle serializing all interface members if (symbol.flags & SymbolFlags.Interface && !(symbol.flags & SymbolFlags.Class)) { serializeInterface(symbol, symbolName, modifierFlags); } if (symbol.flags & SymbolFlags.Alias) { serializeAsAlias(symbol, getInternalSymbolName(symbol, symbolName), modifierFlags); } if (symbol.flags & SymbolFlags.Property && symbol.escapedName === InternalSymbolName.ExportEquals) { serializeMaybeAliasAssignment(symbol); } if (symbol.flags & SymbolFlags.ExportStar) { // synthesize export * from "moduleReference" // Straightforward - only one thing to do - make an export declaration if (symbol.declarations) { for (const node of symbol.declarations) { const resolvedModule = resolveExternalModuleName(node, (node as ExportDeclaration).moduleSpecifier!); if (!resolvedModule) continue; addResult(factory.createExportDeclaration(/*modifiers*/ undefined, /*isTypeOnly*/ (node as ExportDeclaration).isTypeOnly, /*exportClause*/ undefined, factory.createStringLiteral(getSpecifierForModuleSymbol(resolvedModule, context))), ModifierFlags.None); } } } if (needsPostExportDefault) { addResult(factory.createExportAssignment(/*modifiers*/ undefined, /*isExportEquals*/ false, factory.createIdentifier(getInternalSymbolName(symbol, symbolName))), ModifierFlags.None); } else if (needsExportDeclaration) { addResult(factory.createExportDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, factory.createNamedExports([factory.createExportSpecifier(/*isTypeOnly*/ false, getInternalSymbolName(symbol, symbolName), symbolName)]) ), ModifierFlags.None); } } function includePrivateSymbol(symbol: Symbol) { if (some(symbol.declarations, isParameterDeclaration)) return; Debug.assertIsDefined(deferredPrivatesStack[deferredPrivatesStack.length - 1]); getUnusedName(unescapeLeadingUnderscores(symbol.escapedName), symbol); // Call to cache unique name for symbol // Blanket moving (import) aliases into the root private context should work, since imports are not valid within namespaces // (so they must have been in the root to begin with if they were real imports) cjs `require` aliases (an upcoming feature) // will throw a wrench in this, since those may have been nested, but we'll need to synthesize them in the outer scope // anyway, as that's the only place the import they translate to is valid. In such a case, we might need to use a unique name // for the moved import; which hopefully the above `getUnusedName` call should produce. const isExternalImportAlias = !!(symbol.flags & SymbolFlags.Alias) && !some(symbol.declarations, d => !!findAncestor(d, isExportDeclaration) || isNamespaceExport(d) || (isImportEqualsDeclaration(d) && !isExternalModuleReference(d.moduleReference)) ); deferredPrivatesStack[isExternalImportAlias ? 0 : (deferredPrivatesStack.length - 1)].set(getSymbolId(symbol), symbol); } function isExportingScope(enclosingDeclaration: Node) { return ((isSourceFile(enclosingDeclaration) && (isExternalOrCommonJsModule(enclosingDeclaration) || isJsonSourceFile(enclosingDeclaration))) || (isAmbientModule(enclosingDeclaration) && !isGlobalScopeAugmentation(enclosingDeclaration))); } // Prepends a `declare` and/or `export` modifier if the context requires it, and then adds `node` to `result` and returns `node` function addResult(node: Statement, additionalModifierFlags: ModifierFlags) { if (canHaveModifiers(node)) { let newModifierFlags: ModifierFlags = ModifierFlags.None; const enclosingDeclaration = context.enclosingDeclaration && (isJSDocTypeAlias(context.enclosingDeclaration) ? getSourceFileOfNode(context.enclosingDeclaration) : context.enclosingDeclaration); if (additionalModifierFlags & ModifierFlags.Export && enclosingDeclaration && (isExportingScope(enclosingDeclaration) || isModuleDeclaration(enclosingDeclaration)) && canHaveExportModifier(node) ) { // Classes, namespaces, variables, functions, interfaces, and types should all be `export`ed in a module context if not private newModifierFlags |= ModifierFlags.Export; } if (addingDeclare && !(newModifierFlags & ModifierFlags.Export) && (!enclosingDeclaration || !(enclosingDeclaration.flags & NodeFlags.Ambient)) && (isEnumDeclaration(node) || isVariableStatement(node) || isFunctionDeclaration(node) || isClassDeclaration(node) || isModuleDeclaration(node))) { // Classes, namespaces, variables, enums, and functions all need `declare` modifiers to be valid in a declaration file top-level scope newModifierFlags |= ModifierFlags.Ambient; } if ((additionalModifierFlags & ModifierFlags.Default) && (isClassDeclaration(node) || isInterfaceDeclaration(node) || isFunctionDeclaration(node))) { newModifierFlags |= ModifierFlags.Default; } if (newModifierFlags) { node = factory.updateModifiers(node, newModifierFlags | getEffectiveModifierFlags(node)); } } results.push(node); } function serializeTypeAlias(symbol: Symbol, symbolName: string, modifierFlags: ModifierFlags) { const aliasType = getDeclaredTypeOfTypeAlias(symbol); const typeParams = getSymbolLinks(symbol).typeParameters; const typeParamDecls = map(typeParams, p => typeParameterToDeclaration(p, context)); const jsdocAliasDecl = symbol.declarations?.find(isJSDocTypeAlias); const commentText = getTextOfJSDocComment(jsdocAliasDecl ? jsdocAliasDecl.comment || jsdocAliasDecl.parent.comment : undefined); const oldFlags = context.flags; context.flags |= NodeBuilderFlags.InTypeAlias; const oldEnclosingDecl = context.enclosingDeclaration; context.enclosingDeclaration = jsdocAliasDecl; const typeNode = jsdocAliasDecl && jsdocAliasDecl.typeExpression && isJSDocTypeExpression(jsdocAliasDecl.typeExpression) && serializeExistingTypeNode(context, jsdocAliasDecl.typeExpression.type, includePrivateSymbol, bundled) || typeToTypeNodeHelper(aliasType, context); addResult(setSyntheticLeadingComments( factory.createTypeAliasDeclaration(/*modifiers*/ undefined, getInternalSymbolName(symbol, symbolName), typeParamDecls, typeNode), !commentText ? [] : [{ kind: SyntaxKind.MultiLineCommentTrivia, text: "*\n * " + commentText.replace(/\n/g, "\n * ") + "\n ", pos: -1, end: -1, hasTrailingNewLine: true }] ), modifierFlags); context.flags = oldFlags; context.enclosingDeclaration = oldEnclosingDecl; } function serializeInterface(symbol: Symbol, symbolName: string, modifierFlags: ModifierFlags) { const interfaceType = getDeclaredTypeOfClassOrInterface(symbol); const localParams = getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(symbol); const typeParamDecls = map(localParams, p => typeParameterToDeclaration(p, context)); const baseTypes = getBaseTypes(interfaceType); const baseType = length(baseTypes) ? getIntersectionType(baseTypes) : undefined; const members = flatMap(getPropertiesOfType(interfaceType), p => serializePropertySymbolForInterface(p, baseType)); const callSignatures = serializeSignatures(SignatureKind.Call, interfaceType, baseType, SyntaxKind.CallSignature) as CallSignatureDeclaration[]; const constructSignatures = serializeSignatures(SignatureKind.Construct, interfaceType, baseType, SyntaxKind.ConstructSignature) as ConstructSignatureDeclaration[]; const indexSignatures = serializeIndexSignatures(interfaceType, baseType); const heritageClauses = !length(baseTypes) ? undefined : [factory.createHeritageClause(SyntaxKind.ExtendsKeyword, mapDefined(baseTypes, b => trySerializeAsTypeReference(b, SymbolFlags.Value)))]; addResult(factory.createInterfaceDeclaration( /*modifiers*/ undefined, getInternalSymbolName(symbol, symbolName), typeParamDecls, heritageClauses, [...indexSignatures, ...constructSignatures, ...callSignatures, ...members] ), modifierFlags); } function getNamespaceMembersForSerialization(symbol: Symbol) { const exports = getExportsOfSymbol(symbol); return !exports ? [] : filter(arrayFrom(exports.values()), m => isNamespaceMember(m) && isIdentifierText(m.escapedName as string, ScriptTarget.ESNext)); } function isTypeOnlyNamespace(symbol: Symbol) { return every(getNamespaceMembersForSerialization(symbol), m => !(getAllSymbolFlags(resolveSymbol(m)) & SymbolFlags.Value)); } function serializeModule(symbol: Symbol, symbolName: string, modifierFlags: ModifierFlags) { const members = getNamespaceMembersForSerialization(symbol); // Split NS members up by declaration - members whose parent symbol is the ns symbol vs those whose is not (but were added in later via merging) const locationMap = arrayToMultiMap(members, m => m.parent && m.parent === symbol ? "real" : "merged"); const realMembers = locationMap.get("real") || emptyArray; const mergedMembers = locationMap.get("merged") || emptyArray; // TODO: `suppressNewPrivateContext` is questionable -we need to simply be emitting privates in whatever scope they were declared in, rather // than whatever scope we traverse to them in. That's a bit of a complex rewrite, since we're not _actually_ tracking privates at all in advance, // so we don't even have placeholders to fill in. if (length(realMembers)) { const localName = getInternalSymbolName(symbol, symbolName); serializeAsNamespaceDeclaration(realMembers, localName, modifierFlags, !!(symbol.flags & (SymbolFlags.Function | SymbolFlags.Assignment))); } if (length(mergedMembers)) { const containingFile = getSourceFileOfNode(context.enclosingDeclaration); const localName = getInternalSymbolName(symbol, symbolName); const nsBody = factory.createModuleBlock([factory.createExportDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, factory.createNamedExports(mapDefined(filter(mergedMembers, n => n.escapedName !== InternalSymbolName.ExportEquals), s => { const name = unescapeLeadingUnderscores(s.escapedName); const localName = getInternalSymbolName(s, name); const aliasDecl = s.declarations && getDeclarationOfAliasSymbol(s); if (containingFile && (aliasDecl ? containingFile !== getSourceFileOfNode(aliasDecl) : !some(s.declarations, d => getSourceFileOfNode(d) === containingFile))) { context.tracker?.reportNonlocalAugmentation?.(containingFile, symbol, s); return undefined; } const target = aliasDecl && getTargetOfAliasDeclaration(aliasDecl, /*dontRecursivelyResolve*/ true); includePrivateSymbol(target || s); const targetName = target ? getInternalSymbolName(target, unescapeLeadingUnderscores(target.escapedName)) : localName; return factory.createExportSpecifier(/*isTypeOnly*/ false, name === targetName ? undefined : targetName, name); })) )]); addResult(factory.createModuleDeclaration( /*modifiers*/ undefined, factory.createIdentifier(localName), nsBody, NodeFlags.Namespace ), ModifierFlags.None); } } function serializeEnum(symbol: Symbol, symbolName: string, modifierFlags: ModifierFlags) { addResult(factory.createEnumDeclaration( factory.createModifiersFromModifierFlags(isConstEnumSymbol(symbol) ? ModifierFlags.Const : 0), getInternalSymbolName(symbol, symbolName), map(filter(getPropertiesOfType(getTypeOfSymbol(symbol)), p => !!(p.flags & SymbolFlags.EnumMember)), p => { // TODO: Handle computed names // I hate that to get the initialized value we need to walk back to the declarations here; but there's no // other way to get the possible const value of an enum member that I'm aware of, as the value is cached // _on the declaration_, not on the declaration's symbol... const initializedValue = p.declarations && p.declarations[0] && isEnumMember(p.declarations[0]) ? getConstantValue(p.declarations[0]) : undefined; return factory.createEnumMember(unescapeLeadingUnderscores(p.escapedName), initializedValue === undefined ? undefined : typeof initializedValue === "string" ? factory.createStringLiteral(initializedValue) : factory.createNumericLiteral(initializedValue)); }) ), modifierFlags); } function serializeAsFunctionNamespaceMerge(type: Type, symbol: Symbol, localName: string, modifierFlags: ModifierFlags) { const signatures = getSignaturesOfType(type, SignatureKind.Call); for (const sig of signatures) { // Each overload becomes a separate function declaration, in order const decl = signatureToSignatureDeclarationHelper(sig, SyntaxKind.FunctionDeclaration, context, { name: factory.createIdentifier(localName), privateSymbolVisitor: includePrivateSymbol, bundledImports: bundled }) as FunctionDeclaration; addResult(setTextRange(decl, getSignatureTextRangeLocation(sig)), modifierFlags); } // Module symbol emit will take care of module-y members, provided it has exports if (!(symbol.flags & (SymbolFlags.ValueModule | SymbolFlags.NamespaceModule) && !!symbol.exports && !!symbol.exports.size)) { const props = filter(getPropertiesOfType(type), isNamespaceMember); serializeAsNamespaceDeclaration(props, localName, modifierFlags, /*suppressNewPrivateContext*/ true); } } function getSignatureTextRangeLocation(signature: Signature) { if (signature.declaration && signature.declaration.parent) { if (isBinaryExpression(signature.declaration.parent) && getAssignmentDeclarationKind(signature.declaration.parent) === AssignmentDeclarationKind.Property) { return signature.declaration.parent; } // for expressions assigned to `var`s, use the `var` as the text range if (isVariableDeclaration(signature.declaration.parent) && signature.declaration.parent.parent) { return signature.declaration.parent.parent; } } return signature.declaration; } function serializeAsNamespaceDeclaration(props: readonly Symbol[], localName: string, modifierFlags: ModifierFlags, suppressNewPrivateContext: boolean) { if (length(props)) { const localVsRemoteMap = arrayToMultiMap(props, p => !length(p.declarations) || some(p.declarations, d => getSourceFileOfNode(d) === getSourceFileOfNode(context.enclosingDeclaration!) ) ? "local" : "remote" ); const localProps = localVsRemoteMap.get("local") || emptyArray; // handle remote props first - we need to make an `import` declaration that points at the module containing each remote // prop in the outermost scope (TODO: a namespace within a namespace would need to be appropriately handled by this) // Example: // import Foo_1 = require("./exporter"); // export namespace ns { // import Foo = Foo_1.Foo; // export { Foo }; // export const c: number; // } // This is needed because in JS, statements like `const x = require("./f")` support both type and value lookup, even if they're // normally just value lookup (so it functions kinda like an alias even when it's not an alias) // _Usually_, we'll simply print the top-level as an alias instead of a `var` in such situations, however is is theoretically // possible to encounter a situation where a type has members from both the current file and other files - in those situations, // emit akin to the above would be needed. // Add a namespace // Create namespace as non-synthetic so it is usable as an enclosing declaration let fakespace = parseNodeFactory.createModuleDeclaration(/*modifiers*/ undefined, factory.createIdentifier(localName), factory.createModuleBlock([]), NodeFlags.Namespace); setParent(fakespace, enclosingDeclaration as SourceFile | NamespaceDeclaration); fakespace.locals = createSymbolTable(props); fakespace.symbol = props[0].parent!; const oldResults = results; results = []; const oldAddingDeclare = addingDeclare; addingDeclare = false; const subcontext = { ...context, enclosingDeclaration: fakespace }; const oldContext = context; context = subcontext; // TODO: implement handling for the localVsRemoteMap.get("remote") - should be difficult to trigger (see comment above), as only interesting cross-file js merges should make this possible visitSymbolTable(createSymbolTable(localProps), suppressNewPrivateContext, /*propertyAsAlias*/ true); context = oldContext; addingDeclare = oldAddingDeclare; const declarations = results; results = oldResults; // replace namespace with synthetic version const defaultReplaced = map(declarations, d => isExportAssignment(d) && !d.isExportEquals && isIdentifier(d.expression) ? factory.createExportDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, factory.createNamedExports([factory.createExportSpecifier(/*isTypeOnly*/ false, d.expression, factory.createIdentifier(InternalSymbolName.Default))]) ) : d); const exportModifierStripped = every(defaultReplaced, d => hasSyntacticModifier(d, ModifierFlags.Export)) ? map(defaultReplaced as Extract[], removeExportModifier) : defaultReplaced; fakespace = factory.updateModuleDeclaration( fakespace, fakespace.modifiers, fakespace.name, factory.createModuleBlock(exportModifierStripped)); addResult(fakespace, modifierFlags); // namespaces can never be default exported } } function isNamespaceMember(p: Symbol) { return !!(p.flags & (SymbolFlags.Type | SymbolFlags.Namespace | SymbolFlags.Alias)) || !(p.flags & SymbolFlags.Prototype || p.escapedName === "prototype" || p.valueDeclaration && isStatic(p.valueDeclaration) && isClassLike(p.valueDeclaration.parent)); } function sanitizeJSDocImplements(clauses: readonly ExpressionWithTypeArguments[]): ExpressionWithTypeArguments[] | undefined { const result = mapDefined(clauses, e => { const oldEnclosing = context.enclosingDeclaration; context.enclosingDeclaration = e; let expr = e.expression; if (isEntityNameExpression(expr)) { if (isIdentifier(expr) && idText(expr) === "") { return cleanup(/*result*/ undefined); // Empty heritage clause, should be an error, but prefer emitting no heritage clauses to reemitting the empty one } let introducesError: boolean; ({ introducesError, node: expr } = trackExistingEntityName(expr, context, includePrivateSymbol)); if (introducesError) { return cleanup(/*result*/ undefined); } } return cleanup(factory.createExpressionWithTypeArguments(expr, map(e.typeArguments, a => serializeExistingTypeNode(context, a, includePrivateSymbol, bundled) || typeToTypeNodeHelper(getTypeFromTypeNode(a), context) ) )); function cleanup(result: T): T { context.enclosingDeclaration = oldEnclosing; return result; } }); if (result.length === clauses.length) { return result; } return undefined; } function serializeAsClass(symbol: Symbol, localName: string, modifierFlags: ModifierFlags) { const originalDecl = symbol.declarations?.find(isClassLike); const oldEnclosing = context.enclosingDeclaration; context.enclosingDeclaration = originalDecl || oldEnclosing; const localParams = getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(symbol); const typeParamDecls = map(localParams, p => typeParameterToDeclaration(p, context)); const classType = getTypeWithThisArgument(getDeclaredTypeOfClassOrInterface(symbol)) as InterfaceType; const baseTypes = getBaseTypes(classType); const originalImplements = originalDecl && getEffectiveImplementsTypeNodes(originalDecl); const implementsExpressions = originalImplements && sanitizeJSDocImplements(originalImplements) || mapDefined(getImplementsTypes(classType), serializeImplementedType); const staticType = getTypeOfSymbol(symbol); const isClass = !!staticType.symbol?.valueDeclaration && isClassLike(staticType.symbol.valueDeclaration); const staticBaseType = isClass ? getBaseConstructorTypeOfClass(staticType as InterfaceType) : anyType; const heritageClauses = [ ...!length(baseTypes) ? [] : [factory.createHeritageClause(SyntaxKind.ExtendsKeyword, map(baseTypes, b => serializeBaseType(b, staticBaseType, localName)))], ...!length(implementsExpressions) ? [] : [factory.createHeritageClause(SyntaxKind.ImplementsKeyword, implementsExpressions)] ]; const symbolProps = getNonInheritedProperties(classType, baseTypes, getPropertiesOfType(classType)); const publicSymbolProps = filter(symbolProps, s => { // `valueDeclaration` could be undefined if inherited from // a union/intersection base type, but inherited properties // don't matter here. const valueDecl = s.valueDeclaration; return !!valueDecl && !(isNamedDeclaration(valueDecl) && isPrivateIdentifier(valueDecl.name)); }); const hasPrivateIdentifier = some(symbolProps, s => { // `valueDeclaration` could be undefined if inherited from // a union/intersection base type, but inherited properties // don't matter here. const valueDecl = s.valueDeclaration; return !!valueDecl && isNamedDeclaration(valueDecl) && isPrivateIdentifier(valueDecl.name); }); // Boil down all private properties into a single one. const privateProperties = hasPrivateIdentifier ? [factory.createPropertyDeclaration( /*modifiers*/ undefined, factory.createPrivateIdentifier("#private"), /*questionOrExclamationToken*/ undefined, /*type*/ undefined, /*initializer*/ undefined, )] : emptyArray; const publicProperties = flatMap(publicSymbolProps, p => serializePropertySymbolForClass(p, /*isStatic*/ false, baseTypes[0])); // Consider static members empty if symbol also has function or module meaning - function namespacey emit will handle statics const staticMembers = flatMap( filter(getPropertiesOfType(staticType), p => !(p.flags & SymbolFlags.Prototype) && p.escapedName !== "prototype" && !isNamespaceMember(p)), p => serializePropertySymbolForClass(p, /*isStatic*/ true, staticBaseType)); // When we encounter an `X.prototype.y` assignment in a JS file, we bind `X` as a class regardless as to whether // the value is ever initialized with a class or function-like value. For cases where `X` could never be // created via `new`, we will inject a `private constructor()` declaration to indicate it is not createable. const isNonConstructableClassLikeInJsFile = !isClass && !!symbol.valueDeclaration && isInJSFile(symbol.valueDeclaration) && !some(getSignaturesOfType(staticType, SignatureKind.Construct)); const constructors = isNonConstructableClassLikeInJsFile ? [factory.createConstructorDeclaration(factory.createModifiersFromModifierFlags(ModifierFlags.Private), [], /*body*/ undefined)] : serializeSignatures(SignatureKind.Construct, staticType, staticBaseType, SyntaxKind.Constructor) as ConstructorDeclaration[]; const indexSignatures = serializeIndexSignatures(classType, baseTypes[0]); context.enclosingDeclaration = oldEnclosing; addResult(setTextRange(factory.createClassDeclaration( /*modifiers*/ undefined, localName, typeParamDecls, heritageClauses, [...indexSignatures, ...staticMembers, ...constructors, ...publicProperties, ...privateProperties] ), symbol.declarations && filter(symbol.declarations, d => isClassDeclaration(d) || isClassExpression(d))[0]), modifierFlags); } function getSomeTargetNameFromDeclarations(declarations: Declaration[] | undefined) { return firstDefined(declarations, d => { if (isImportSpecifier(d) || isExportSpecifier(d)) { return idText(d.propertyName || d.name); } if (isBinaryExpression(d) || isExportAssignment(d)) { const expression = isExportAssignment(d) ? d.expression : d.right; if (isPropertyAccessExpression(expression)) { return idText(expression.name); } } if (isAliasSymbolDeclaration(d)) { // This is... heuristic, at best. But it's probably better than always printing the name of the shorthand ambient module. const name = getNameOfDeclaration(d); if (name && isIdentifier(name)) { return idText(name); } } return undefined; }); } function serializeAsAlias(symbol: Symbol, localName: string, modifierFlags: ModifierFlags) { // synthesize an alias, eg `export { symbolName as Name }` // need to mark the alias `symbol` points at // as something we need to serialize as a private declaration as well const node = getDeclarationOfAliasSymbol(symbol); if (!node) return Debug.fail(); const target = getMergedSymbol(getTargetOfAliasDeclaration(node, /*dontRecursivelyResolve*/ true)); if (!target) { return; } // If `target` refers to a shorthand module symbol, the name we're trying to pull out isn;t recoverable from the target symbol // In such a scenario, we must fall back to looking for an alias declaration on `symbol` and pulling the target name from that let verbatimTargetName = isShorthandAmbientModuleSymbol(target) && getSomeTargetNameFromDeclarations(symbol.declarations) || unescapeLeadingUnderscores(target.escapedName); if (verbatimTargetName === InternalSymbolName.ExportEquals && allowSyntheticDefaultImports) { // target refers to an `export=` symbol that was hoisted into a synthetic default - rename here to match verbatimTargetName = InternalSymbolName.Default; } const targetName = getInternalSymbolName(target, verbatimTargetName); includePrivateSymbol(target); // the target may be within the same scope - attempt to serialize it first switch (node.kind) { case SyntaxKind.BindingElement: if (node.parent?.parent?.kind === SyntaxKind.VariableDeclaration) { // const { SomeClass } = require('./lib'); const specifier = getSpecifierForModuleSymbol(target.parent || target, context); // './lib' const { propertyName } = node as BindingElement; addResult(factory.createImportDeclaration( /*modifiers*/ undefined, factory.createImportClause(/*isTypeOnly*/ false, /*name*/ undefined, factory.createNamedImports([factory.createImportSpecifier( /*isTypeOnly*/ false, propertyName && isIdentifier(propertyName) ? factory.createIdentifier(idText(propertyName)) : undefined, factory.createIdentifier(localName) )])), factory.createStringLiteral(specifier), /*assertClause*/ undefined ), ModifierFlags.None); break; } // We don't know how to serialize this (nested?) binding element Debug.failBadSyntaxKind(node.parent?.parent || node, "Unhandled binding element grandparent kind in declaration serialization"); break; case SyntaxKind.ShorthandPropertyAssignment: if (node.parent?.parent?.kind === SyntaxKind.BinaryExpression) { // module.exports = { SomeClass } serializeExportSpecifier( unescapeLeadingUnderscores(symbol.escapedName), targetName ); } break; case SyntaxKind.VariableDeclaration: // commonjs require: const x = require('y') if (isPropertyAccessExpression((node as VariableDeclaration).initializer!)) { // const x = require('y').z const initializer = (node as VariableDeclaration).initializer! as PropertyAccessExpression; // require('y').z const uniqueName = factory.createUniqueName(localName); // _x const specifier = getSpecifierForModuleSymbol(target.parent || target, context); // 'y' // import _x = require('y'); addResult(factory.createImportEqualsDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, uniqueName, factory.createExternalModuleReference(factory.createStringLiteral(specifier)) ), ModifierFlags.None); // import x = _x.z addResult(factory.createImportEqualsDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, factory.createIdentifier(localName), factory.createQualifiedName(uniqueName, initializer.name as Identifier), ), modifierFlags); break; } // else fall through and treat commonjs require just like import= case SyntaxKind.ImportEqualsDeclaration: // This _specifically_ only exists to handle json declarations - where we make aliases, but since // we emit no declarations for the json document, must not refer to it in the declarations if (target.escapedName === InternalSymbolName.ExportEquals && some(target.declarations, d => isSourceFile(d) && isJsonSourceFile(d))) { serializeMaybeAliasAssignment(symbol); break; } // Could be a local `import localName = ns.member` or // an external `import localName = require("whatever")` const isLocalImport = !(target.flags & SymbolFlags.ValueModule) && !isVariableDeclaration(node); addResult(factory.createImportEqualsDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, factory.createIdentifier(localName), isLocalImport ? symbolToName(target, context, SymbolFlags.All, /*expectsIdentifier*/ false) : factory.createExternalModuleReference(factory.createStringLiteral(getSpecifierForModuleSymbol(target, context))) ), isLocalImport ? modifierFlags : ModifierFlags.None); break; case SyntaxKind.NamespaceExportDeclaration: // export as namespace foo // TODO: Not part of a file's local or export symbol tables // Is bound into file.symbol.globalExports instead, which we don't currently traverse addResult(factory.createNamespaceExportDeclaration(idText((node as NamespaceExportDeclaration).name)), ModifierFlags.None); break; case SyntaxKind.ImportClause: { const generatedSpecifier = getSpecifierForModuleSymbol(target.parent || target, context); // generate specifier (even though we're reusing and existing one) for ambient module reference include side effects const specifier = bundled ? factory.createStringLiteral(generatedSpecifier) : (node as ImportClause).parent.moduleSpecifier; addResult(factory.createImportDeclaration( /*modifiers*/ undefined, factory.createImportClause(/*isTypeOnly*/ false, factory.createIdentifier(localName), /*namedBindings*/ undefined), specifier, (node as ImportClause).parent.assertClause ), ModifierFlags.None); break; } case SyntaxKind.NamespaceImport: { const generatedSpecifier = getSpecifierForModuleSymbol(target.parent || target, context); // generate specifier (even though we're reusing and existing one) for ambient module reference include side effects const specifier = bundled ? factory.createStringLiteral(generatedSpecifier) : (node as NamespaceImport).parent.parent.moduleSpecifier; addResult(factory.createImportDeclaration( /*modifiers*/ undefined, factory.createImportClause(/*isTypeOnly*/ false, /*name*/ undefined, factory.createNamespaceImport(factory.createIdentifier(localName))), specifier, (node as NamespaceImport).parent.parent.assertClause ), ModifierFlags.None); break; } case SyntaxKind.NamespaceExport: addResult(factory.createExportDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, factory.createNamespaceExport(factory.createIdentifier(localName)), factory.createStringLiteral(getSpecifierForModuleSymbol(target, context)) ), ModifierFlags.None); break; case SyntaxKind.ImportSpecifier: { const generatedSpecifier = getSpecifierForModuleSymbol(target.parent || target, context); // generate specifier (even though we're reusing and existing one) for ambient module reference include side effects const specifier = bundled ? factory.createStringLiteral(generatedSpecifier) : (node as ImportSpecifier).parent.parent.parent.moduleSpecifier; addResult(factory.createImportDeclaration( /*modifiers*/ undefined, factory.createImportClause( /*isTypeOnly*/ false, /*name*/ undefined, factory.createNamedImports([ factory.createImportSpecifier( /*isTypeOnly*/ false, localName !== verbatimTargetName ? factory.createIdentifier(verbatimTargetName) : undefined, factory.createIdentifier(localName) ) ])), specifier, (node as ImportSpecifier).parent.parent.parent.assertClause, ), ModifierFlags.None); break; } case SyntaxKind.ExportSpecifier: // does not use localName because the symbol name in this case refers to the name in the exports table, // which we must exactly preserve const specifier = (node.parent.parent as ExportDeclaration).moduleSpecifier; // targetName is only used when the target is local, as otherwise the target is an alias that points at // another file serializeExportSpecifier( unescapeLeadingUnderscores(symbol.escapedName), specifier ? verbatimTargetName : targetName, specifier && isStringLiteralLike(specifier) ? factory.createStringLiteral(specifier.text) : undefined ); break; case SyntaxKind.ExportAssignment: serializeMaybeAliasAssignment(symbol); break; case SyntaxKind.BinaryExpression: case SyntaxKind.PropertyAccessExpression: case SyntaxKind.ElementAccessExpression: // Could be best encoded as though an export specifier or as though an export assignment // If name is default or export=, do an export assignment // Otherwise do an export specifier if (symbol.escapedName === InternalSymbolName.Default || symbol.escapedName === InternalSymbolName.ExportEquals) { serializeMaybeAliasAssignment(symbol); } else { serializeExportSpecifier(localName, targetName); } break; default: return Debug.failBadSyntaxKind(node, "Unhandled alias declaration kind in symbol serializer!"); } } function serializeExportSpecifier(localName: string, targetName: string, specifier?: Expression) { addResult(factory.createExportDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, factory.createNamedExports([factory.createExportSpecifier(/*isTypeOnly*/ false, localName !== targetName ? targetName : undefined, localName)]), specifier ), ModifierFlags.None); } /** * Returns `true` if an export assignment or declaration was produced for the symbol */ function serializeMaybeAliasAssignment(symbol: Symbol): boolean { if (symbol.flags & SymbolFlags.Prototype) { return false; } const name = unescapeLeadingUnderscores(symbol.escapedName); const isExportEquals = name === InternalSymbolName.ExportEquals; const isDefault = name === InternalSymbolName.Default; const isExportAssignmentCompatibleSymbolName = isExportEquals || isDefault; // synthesize export = ref // ref should refer to either be a locally scoped symbol which we need to emit, or // a reference to another namespace/module which we may need to emit an `import` statement for const aliasDecl = symbol.declarations && getDeclarationOfAliasSymbol(symbol); // serialize what the alias points to, preserve the declaration's initializer const target = aliasDecl && getTargetOfAliasDeclaration(aliasDecl, /*dontRecursivelyResolve*/ true); // If the target resolves and resolves to a thing defined in this file, emit as an alias, otherwise emit as a const if (target && length(target.declarations) && some(target.declarations, d => getSourceFileOfNode(d) === getSourceFileOfNode(enclosingDeclaration))) { // In case `target` refers to a namespace member, look at the declaration and serialize the leftmost symbol in it // eg, `namespace A { export class B {} }; exports = A.B;` // Technically, this is all that's required in the case where the assignment is an entity name expression const expr = aliasDecl && ((isExportAssignment(aliasDecl) || isBinaryExpression(aliasDecl)) ? getExportAssignmentExpression(aliasDecl) : getPropertyAssignmentAliasLikeExpression(aliasDecl as ShorthandPropertyAssignment | PropertyAssignment | PropertyAccessExpression)); const first = expr && isEntityNameExpression(expr) ? getFirstNonModuleExportsIdentifier(expr) : undefined; const referenced = first && resolveEntityName(first, SymbolFlags.All, /*ignoreErrors*/ true, /*dontResolveAlias*/ true, enclosingDeclaration); if (referenced || target) { includePrivateSymbol(referenced || target); } // We disable the context's symbol tracker for the duration of this name serialization // as, by virtue of being here, the name is required to print something, and we don't want to // issue a visibility error on it. Only anonymous classes that an alias points at _would_ issue // a visibility error here (as they're not visible within any scope), but we want to hoist them // into the containing scope anyway, so we want to skip the visibility checks. const prevDisableTrackSymbol = context.tracker.disableTrackSymbol; context.tracker.disableTrackSymbol = true; if (isExportAssignmentCompatibleSymbolName) { results.push(factory.createExportAssignment( /*modifiers*/ undefined, isExportEquals, symbolToExpression(target, context, SymbolFlags.All) )); } else { if (first === expr && first) { // serialize as `export {target as name}` serializeExportSpecifier(name, idText(first)); } else if (expr && isClassExpression(expr)) { serializeExportSpecifier(name, getInternalSymbolName(target, symbolName(target))); } else { // serialize as `import _Ref = t.arg.et; export { _Ref as name }` const varName = getUnusedName(name, symbol); addResult(factory.createImportEqualsDeclaration( /*modifiers*/ undefined, /*isTypeOnly*/ false, factory.createIdentifier(varName), symbolToName(target, context, SymbolFlags.All, /*expectsIdentifier*/ false) ), ModifierFlags.None); serializeExportSpecifier(name, varName); } } context.tracker.disableTrackSymbol = prevDisableTrackSymbol; return true; } else { // serialize as an anonymous property declaration const varName = getUnusedName(name, symbol); // We have to use `getWidenedType` here since the object within a json file is unwidened within the file // (Unwidened types can only exist in expression contexts and should never be serialized) const typeToSerialize = getWidenedType(getTypeOfSymbol(getMergedSymbol(symbol))); if (isTypeRepresentableAsFunctionNamespaceMerge(typeToSerialize, symbol)) { // If there are no index signatures and `typeToSerialize` is an object type, emit as a namespace instead of a const serializeAsFunctionNamespaceMerge(typeToSerialize, symbol, varName, isExportAssignmentCompatibleSymbolName ? ModifierFlags.None : ModifierFlags.Export); } else { const statement = factory.createVariableStatement(/*modifiers*/ undefined, factory.createVariableDeclarationList([ factory.createVariableDeclaration(varName, /*exclamationToken*/ undefined, serializeTypeForDeclaration(context, typeToSerialize, symbol, enclosingDeclaration, includePrivateSymbol, bundled)) ], context.enclosingDeclaration?.kind === SyntaxKind.ModuleDeclaration ? NodeFlags.Let : NodeFlags.Const)); // Inlined JSON types exported with [module.]exports= will already emit an export=, so should use `declare`. // Otherwise, the type itself should be exported. addResult(statement, target && target.flags & SymbolFlags.Property && target.escapedName === InternalSymbolName.ExportEquals ? ModifierFlags.Ambient : name === varName ? ModifierFlags.Export : ModifierFlags.None); } if (isExportAssignmentCompatibleSymbolName) { results.push(factory.createExportAssignment( /*modifiers*/ undefined, isExportEquals, factory.createIdentifier(varName) )); return true; } else if (name !== varName) { serializeExportSpecifier(name, varName); return true; } return false; } } function isTypeRepresentableAsFunctionNamespaceMerge(typeToSerialize: Type, hostSymbol: Symbol) { // Only object types which are not constructable, or indexable, whose members all come from the // context source file, and whose property names are all valid identifiers and not late-bound, _and_ // whose input is not type annotated (if the input symbol has an annotation we can reuse, we should prefer it) const ctxSrc = getSourceFileOfNode(context.enclosingDeclaration); return getObjectFlags(typeToSerialize) & (ObjectFlags.Anonymous | ObjectFlags.Mapped) && !length(getIndexInfosOfType(typeToSerialize)) && !isClassInstanceSide(typeToSerialize) && // While a class instance is potentially representable as a NS, prefer printing a reference to the instance type and serializing the class !!(length(filter(getPropertiesOfType(typeToSerialize), isNamespaceMember)) || length(getSignaturesOfType(typeToSerialize, SignatureKind.Call))) && !length(getSignaturesOfType(typeToSerialize, SignatureKind.Construct)) && // TODO: could probably serialize as function + ns + class, now that that's OK !getDeclarationWithTypeAnnotation(hostSymbol, enclosingDeclaration) && !(typeToSerialize.symbol && some(typeToSerialize.symbol.declarations, d => getSourceFileOfNode(d) !== ctxSrc)) && !some(getPropertiesOfType(typeToSerialize), p => isLateBoundName(p.escapedName)) && !some(getPropertiesOfType(typeToSerialize), p => some(p.declarations, d => getSourceFileOfNode(d) !== ctxSrc)) && every(getPropertiesOfType(typeToSerialize), p => isIdentifierText(symbolName(p), languageVersion)); } function makeSerializePropertySymbol(createProperty: ( modifiers: readonly Modifier[] | undefined, name: string | PropertyName, questionOrExclamationToken: QuestionToken | undefined, type: TypeNode | undefined, initializer: Expression | undefined ) => T, methodKind: SignatureDeclaration["kind"], useAccessors: true): (p: Symbol, isStatic: boolean, baseType: Type | undefined) => (T | AccessorDeclaration | (T | AccessorDeclaration)[]); function makeSerializePropertySymbol(createProperty: ( modifiers: readonly Modifier[] | undefined, name: string | PropertyName, questionOrExclamationToken: QuestionToken | undefined, type: TypeNode | undefined, initializer: Expression | undefined ) => T, methodKind: SignatureDeclaration["kind"], useAccessors: false): (p: Symbol, isStatic: boolean, baseType: Type | undefined) => (T | T[]); function makeSerializePropertySymbol(createProperty: ( modifiers: readonly Modifier[] | undefined, name: string | PropertyName, questionOrExclamationToken: QuestionToken | undefined, type: TypeNode | undefined, initializer: Expression | undefined ) => T, methodKind: SignatureDeclaration["kind"], useAccessors: boolean): (p: Symbol, isStatic: boolean, baseType: Type | undefined) => (T | AccessorDeclaration | (T | AccessorDeclaration)[]) { return function serializePropertySymbol(p: Symbol, isStatic: boolean, baseType: Type | undefined): (T | AccessorDeclaration | (T | AccessorDeclaration)[]) { const modifierFlags = getDeclarationModifierFlagsFromSymbol(p); const isPrivate = !!(modifierFlags & ModifierFlags.Private); if (isStatic && (p.flags & (SymbolFlags.Type | SymbolFlags.Namespace | SymbolFlags.Alias))) { // Only value-only-meaning symbols can be correctly encoded as class statics, type/namespace/alias meaning symbols // need to be merged namespace members return []; } if (p.flags & SymbolFlags.Prototype || p.escapedName === "constructor" || (baseType && getPropertyOfType(baseType, p.escapedName) && isReadonlySymbol(getPropertyOfType(baseType, p.escapedName)!) === isReadonlySymbol(p) && (p.flags & SymbolFlags.Optional) === (getPropertyOfType(baseType, p.escapedName)!.flags & SymbolFlags.Optional) && isTypeIdenticalTo(getTypeOfSymbol(p), getTypeOfPropertyOfType(baseType, p.escapedName)!))) { return []; } const flag = (modifierFlags & ~ModifierFlags.Async) | (isStatic ? ModifierFlags.Static : 0); const name = getPropertyNameNodeForSymbol(p, context); const firstPropertyLikeDecl = p.declarations?.find(or(isPropertyDeclaration, isAccessor, isVariableDeclaration, isPropertySignature, isBinaryExpression, isPropertyAccessExpression)); if (p.flags & SymbolFlags.Accessor && useAccessors) { const result: AccessorDeclaration[] = []; if (p.flags & SymbolFlags.SetAccessor) { result.push(setTextRange(factory.createSetAccessorDeclaration( factory.createModifiersFromModifierFlags(flag), name, [factory.createParameterDeclaration( /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "arg", /*questionToken*/ undefined, isPrivate ? undefined : serializeTypeForDeclaration(context, getTypeOfSymbol(p), p, enclosingDeclaration, includePrivateSymbol, bundled) )], /*body*/ undefined ), p.declarations?.find(isSetAccessor) || firstPropertyLikeDecl)); } if (p.flags & SymbolFlags.GetAccessor) { const isPrivate = modifierFlags & ModifierFlags.Private; result.push(setTextRange(factory.createGetAccessorDeclaration( factory.createModifiersFromModifierFlags(flag), name, [], isPrivate ? undefined : serializeTypeForDeclaration(context, getTypeOfSymbol(p), p, enclosingDeclaration, includePrivateSymbol, bundled), /*body*/ undefined ), p.declarations?.find(isGetAccessor) || firstPropertyLikeDecl)); } return result; } // This is an else/if as accessors and properties can't merge in TS, but might in JS // If this happens, we assume the accessor takes priority, as it imposes more constraints else if (p.flags & (SymbolFlags.Property | SymbolFlags.Variable | SymbolFlags.Accessor)) { return setTextRange(createProperty( factory.createModifiersFromModifierFlags((isReadonlySymbol(p) ? ModifierFlags.Readonly : 0) | flag), name, p.flags & SymbolFlags.Optional ? factory.createToken(SyntaxKind.QuestionToken) : undefined, isPrivate ? undefined : serializeTypeForDeclaration(context, getWriteTypeOfSymbol(p), p, enclosingDeclaration, includePrivateSymbol, bundled), // TODO: https://github.com/microsoft/TypeScript/pull/32372#discussion_r328386357 // interface members can't have initializers, however class members _can_ /*initializer*/ undefined ), p.declarations?.find(or(isPropertyDeclaration, isVariableDeclaration)) || firstPropertyLikeDecl); } if (p.flags & (SymbolFlags.Method | SymbolFlags.Function)) { const type = getTypeOfSymbol(p); const signatures = getSignaturesOfType(type, SignatureKind.Call); if (flag & ModifierFlags.Private) { return setTextRange(createProperty( factory.createModifiersFromModifierFlags((isReadonlySymbol(p) ? ModifierFlags.Readonly : 0) | flag), name, p.flags & SymbolFlags.Optional ? factory.createToken(SyntaxKind.QuestionToken) : undefined, /*type*/ undefined, /*initializer*/ undefined ), p.declarations?.find(isFunctionLikeDeclaration) || signatures[0] && signatures[0].declaration || p.declarations && p.declarations[0]); } const results = []; for (const sig of signatures) { // Each overload becomes a separate method declaration, in order const decl = signatureToSignatureDeclarationHelper( sig, methodKind, context, { name, questionToken: p.flags & SymbolFlags.Optional ? factory.createToken(SyntaxKind.QuestionToken) : undefined, modifiers: flag ? factory.createModifiersFromModifierFlags(flag) : undefined } ); const location = sig.declaration && isPrototypePropertyAssignment(sig.declaration.parent) ? sig.declaration.parent : sig.declaration; results.push(setTextRange(decl, location)); } return results as unknown as T[]; } // The `Constructor`'s symbol isn't in the class's properties lists, obviously, since it's a signature on the static return Debug.fail(`Unhandled class member kind! ${(p as any).__debugFlags || p.flags}`); }; } function serializePropertySymbolForInterface(p: Symbol, baseType: Type | undefined) { return serializePropertySymbolForInterfaceWorker(p, /*isStatic*/ false, baseType); } function serializeSignatures(kind: SignatureKind, input: Type, baseType: Type | undefined, outputKind: SignatureDeclaration["kind"]) { const signatures = getSignaturesOfType(input, kind); if (kind === SignatureKind.Construct) { if (!baseType && every(signatures, s => length(s.parameters) === 0)) { return []; // No base type, every constructor is empty - elide the extraneous `constructor()` } if (baseType) { // If there is a base type, if every signature in the class is identical to a signature in the baseType, elide all the declarations const baseSigs = getSignaturesOfType(baseType, SignatureKind.Construct); if (!length(baseSigs) && every(signatures, s => length(s.parameters) === 0)) { return []; // Base had no explicit signatures, if all our signatures are also implicit, return an empty list } if (baseSigs.length === signatures.length) { let failed = false; for (let i = 0; i < baseSigs.length; i++) { if (!compareSignaturesIdentical(signatures[i], baseSigs[i], /*partialMatch*/ false, /*ignoreThisTypes*/ false, /*ignoreReturnTypes*/ true, compareTypesIdentical)) { failed = true; break; } } if (!failed) { return []; // Every signature was identical - elide constructor list as it is inherited } } } let privateProtected: ModifierFlags = 0; for (const s of signatures) { if (s.declaration) { privateProtected |= getSelectedEffectiveModifierFlags(s.declaration, ModifierFlags.Private | ModifierFlags.Protected); } } if (privateProtected) { return [setTextRange(factory.createConstructorDeclaration( factory.createModifiersFromModifierFlags(privateProtected), /*parameters*/ [], /*body*/ undefined, ), signatures[0].declaration)]; } } const results = []; for (const sig of signatures) { // Each overload becomes a separate constructor declaration, in order const decl = signatureToSignatureDeclarationHelper(sig, outputKind, context); results.push(setTextRange(decl, sig.declaration)); } return results; } function serializeIndexSignatures(input: Type, baseType: Type | undefined) { const results: IndexSignatureDeclaration[] = []; for (const info of getIndexInfosOfType(input)) { if (baseType) { const baseInfo = getIndexInfoOfType(baseType, info.keyType); if (baseInfo) { if (isTypeIdenticalTo(info.type, baseInfo.type)) { continue; // elide identical index signatures } } } results.push(indexInfoToIndexSignatureDeclarationHelper(info, context, /*typeNode*/ undefined)); } return results; } function serializeBaseType(t: Type, staticType: Type, rootName: string) { const ref = trySerializeAsTypeReference(t, SymbolFlags.Value); if (ref) { return ref; } const tempName = getUnusedName(`${rootName}_base`); const statement = factory.createVariableStatement(/*modifiers*/ undefined, factory.createVariableDeclarationList([ factory.createVariableDeclaration(tempName, /*exclamationToken*/ undefined, typeToTypeNodeHelper(staticType, context)) ], NodeFlags.Const)); addResult(statement, ModifierFlags.None); return factory.createExpressionWithTypeArguments(factory.createIdentifier(tempName), /*typeArguments*/ undefined); } function trySerializeAsTypeReference(t: Type, flags: SymbolFlags) { let typeArgs: TypeNode[] | undefined; let reference: Expression | undefined; // We don't use `isValueSymbolAccessible` below. since that considers alternative containers (like modules) // which we can't write out in a syntactically valid way as an expression if ((t as TypeReference).target && isSymbolAccessibleByFlags((t as TypeReference).target.symbol, enclosingDeclaration, flags)) { typeArgs = map(getTypeArguments(t as TypeReference), t => typeToTypeNodeHelper(t, context)); reference = symbolToExpression((t as TypeReference).target.symbol, context, SymbolFlags.Type); } else if (t.symbol && isSymbolAccessibleByFlags(t.symbol, enclosingDeclaration, flags)) { reference = symbolToExpression(t.symbol, context, SymbolFlags.Type); } if (reference) { return factory.createExpressionWithTypeArguments(reference, typeArgs); } } function serializeImplementedType(t: Type) { const ref = trySerializeAsTypeReference(t, SymbolFlags.Type); if (ref) { return ref; } if (t.symbol) { return factory.createExpressionWithTypeArguments(symbolToExpression(t.symbol, context, SymbolFlags.Type), /*typeArguments*/ undefined); } } function getUnusedName(input: string, symbol?: Symbol): string { const id = symbol ? getSymbolId(symbol) : undefined; if (id) { if (context.remappedSymbolNames!.has(id)) { return context.remappedSymbolNames!.get(id)!; } } if (symbol) { input = getNameCandidateWorker(symbol, input); } let i = 0; const original = input; while (context.usedSymbolNames?.has(input)) { i++; input = `${original}_${i}`; } context.usedSymbolNames?.add(input); if (id) { context.remappedSymbolNames!.set(id, input); } return input; } function getNameCandidateWorker(symbol: Symbol, localName: string) { if (localName === InternalSymbolName.Default || localName === InternalSymbolName.Class || localName === InternalSymbolName.Function) { const flags = context.flags; context.flags |= NodeBuilderFlags.InInitialEntityName; const nameCandidate = getNameOfSymbolAsWritten(symbol, context); context.flags = flags; localName = nameCandidate.length > 0 && isSingleOrDoubleQuote(nameCandidate.charCodeAt(0)) ? stripQuotes(nameCandidate) : nameCandidate; } if (localName === InternalSymbolName.Default) { localName = "_default"; } else if (localName === InternalSymbolName.ExportEquals) { localName = "_exports"; } localName = isIdentifierText(localName, languageVersion) && !isStringANonContextualKeyword(localName) ? localName : "_" + localName.replace(/[^a-zA-Z0-9]/g, "_"); return localName; } function getInternalSymbolName(symbol: Symbol, localName: string) { const id = getSymbolId(symbol); if (context.remappedSymbolNames!.has(id)) { return context.remappedSymbolNames!.get(id)!; } localName = getNameCandidateWorker(symbol, localName); // The result of this is going to be used as the symbol's name - lock it in, so `getUnusedName` will also pick it up context.remappedSymbolNames!.set(id, localName); return localName; } } } 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 = factory.createTypePredicateNode( typePredicate.kind === TypePredicateKind.AssertsThis || typePredicate.kind === TypePredicateKind.AssertsIdentifier ? factory.createToken(SyntaxKind.AssertsKeyword) : undefined, typePredicate.kind === TypePredicateKind.Identifier || typePredicate.kind === TypePredicateKind.AssertsIdentifier ? factory.createIdentifier(typePredicate.parameterName) : factory.createThisTypeNode(), typePredicate.type && nodeBuilder.typeToTypeNode(typePredicate.type, enclosingDeclaration, toNodeBuilderFlags(flags) | NodeBuilderFlags.IgnoreErrors | NodeBuilderFlags.WriteTypeParametersInQualifiedName)! // TODO: GH#18217 ); const printer = createPrinterWithRemoveComments(); const sourceFile = enclosingDeclaration && getSourceFileOfNode(enclosingDeclaration); printer.writeNode(EmitHint.Unspecified, predicate, /*sourceFile*/ sourceFile, writer); return writer; } } function formatUnionTypes(types: readonly Type[]): Type[] { const result: Type[] = []; let flags = 0 as TypeFlags; 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.EnumLike)) { const baseType = t.flags & TypeFlags.BooleanLiteral ? booleanType : getBaseTypeOfEnumLikeType(t as LiteralType); if (baseType.flags & TypeFlags.Union) { const count = (baseType as UnionType).types.length; if (i + count <= types.length && getRegularTypeOfLiteralType(types[i + count - 1]) === getRegularTypeOfLiteralType((baseType as UnionType).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 { 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 && type.symbol.declarations) { const node = walkUpParenthesizedTypes(type.symbol.declarations[0].parent); if (isTypeAliasDeclaration(node)) { return getSymbolOfDeclaration(node); } } return undefined; } function isTopLevelInExternalModuleAugmentation(node: Node): boolean { return node && node.parent && node.parent.kind === SyntaxKind.ModuleBlock && isExternalModuleAugmentation(node.parent.parent); } function isDefaultBindingContext(location: Node) { return location.kind === SyntaxKind.SourceFile || isAmbientModule(location); } function getNameOfSymbolFromNameType(symbol: Symbol, context?: NodeBuilderContext) { const nameType = getSymbolLinks(symbol).nameType; if (nameType) { if (nameType.flags & TypeFlags.StringOrNumberLiteral) { const name = "" + (nameType as StringLiteralType | NumberLiteralType).value; if (!isIdentifierText(name, getEmitScriptTarget(compilerOptions)) && !isNumericLiteralName(name)) { return `"${escapeString(name, CharacterCodes.doubleQuote)}"`; } if (isNumericLiteralName(name) && startsWith(name, "-")) { return `[${name}]`; } return name; } if (nameType.flags & TypeFlags.UniqueESSymbol) { return `[${getNameOfSymbolAsWritten((nameType as UniqueESSymbolType).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) { let declaration = firstDefined(symbol.declarations, d => getNameOfDeclaration(d) ? d : undefined); // Try using a declaration with a name, first const name = declaration && getNameOfDeclaration(declaration); if (declaration && name) { if (isCallExpression(declaration) && isBindableObjectDefinePropertyCall(declaration)) { return symbolName(symbol); } if (isComputedPropertyName(name) && !(getCheckFlags(symbol) & CheckFlags.Late)) { const nameType = getSymbolLinks(symbol).nameType; if (nameType && 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) { declaration = symbol.declarations[0]; // Declaration may be nameless, but we'll try anyway } if (declaration.parent && declaration.parent.kind === SyntaxKind.VariableDeclaration) { return declarationNameToString((declaration.parent as VariableDeclaration).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: case SyntaxKind.JSDocEnumTag: // 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 (hasEffectiveModifier(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: case SyntaxKind.NamedTupleMember: 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 // falls through 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(node.parent as ExportSpecifier, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace | SymbolFlags.Alias); } let result: Node[] | undefined; let visited: Set | undefined; if (exportSymbol) { visited = new Set(); visited.add(getSymbolId(exportSymbol)); buildVisibleNodeList(exportSymbol.declarations); } return result; function buildVisibleNodeList(declarations: Declaration[] | undefined) { 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 = declaration.moduleReference as Identifier | QualifiedName; const firstIdentifier = getFirstIdentifier(internalModuleReference); const importSymbol = resolveName(declaration, firstIdentifier.escapedText, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ false); if (importSymbol && visited) { if (tryAddToSet(visited, getSymbolId(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 >= resolutionStart; i--) { if (resolutionTargetHasProperty(resolutionTargets[i], resolutionPropertyNames[i])) { return -1; } if (resolutionTargets[i] === target && resolutionPropertyNames[i] === propertyName) { return i; } } return -1; } function resolutionTargetHasProperty(target: TypeSystemEntity, propertyName: TypeSystemPropertyName): boolean { switch (propertyName) { case TypeSystemPropertyName.Type: return !!getSymbolLinks(target as Symbol).type; case TypeSystemPropertyName.EnumTagType: return !!(getNodeLinks(target as JSDocEnumTag).resolvedEnumType); case TypeSystemPropertyName.DeclaredType: return !!getSymbolLinks(target as Symbol).declaredType; case TypeSystemPropertyName.ResolvedBaseConstructorType: return !!(target as InterfaceType).resolvedBaseConstructorType; case TypeSystemPropertyName.ResolvedReturnType: return !!(target as Signature).resolvedReturnType; case TypeSystemPropertyName.ImmediateBaseConstraint: return !!(target as Type).immediateBaseConstraint; case TypeSystemPropertyName.ResolvedTypeArguments: return !!(target as TypeReference).resolvedTypeArguments; case TypeSystemPropertyName.ResolvedBaseTypes: return !!(target as InterfaceType).baseTypesResolved; case TypeSystemPropertyName.WriteType: return !!getSymbolLinks(target as Symbol).writeType; case TypeSystemPropertyName.ParameterInitializerContainsUndefined: return getNodeLinks(target as ParameterDeclaration).parameterInitializerContainsUndefined !== undefined; } 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 = getDeclaredTypeOfSymbol(getParentOfSymbol(prototype)!) as InterfaceType; return classType.typeParameters ? createTypeReference(classType as GenericType, 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) || getApplicableIndexInfoForName(type, name)?.type || unknownType; } function isTypeAny(type: Type | undefined) { return type && (type.flags & TypeFlags.Any) !== 0; } function isErrorType(type: Type) { // The only 'any' types that have alias symbols are those manufactured by getTypeFromTypeAliasReference for // a reference to an unresolved symbol. We want those to behave like the errorType. return type === errorType || !!(type.flags & TypeFlags.Any && type.aliasSymbol); } // 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, checkMode: CheckMode) { if (checkMode !== CheckMode.Normal) { return getTypeForVariableLikeDeclaration(node, /*includeOptionality*/ false, checkMode); } const symbol = getSymbolOfDeclaration(node); return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node, /*includeOptionality*/ false, checkMode); } 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)); } let omitKeyType = getUnionType(map(properties, getLiteralTypeFromPropertyName)); const spreadableProperties: Symbol[] = []; const unspreadableToRestKeys: Type[] = []; for (const prop of getPropertiesOfType(source)) { const literalTypeFromProperty = getLiteralTypeFromProperty(prop, TypeFlags.StringOrNumberLiteralOrUnique); if (!isTypeAssignableTo(literalTypeFromProperty, omitKeyType) && !(getDeclarationModifierFlagsFromSymbol(prop) & (ModifierFlags.Private | ModifierFlags.Protected)) && isSpreadableProperty(prop)) { spreadableProperties.push(prop); } else { unspreadableToRestKeys.push(literalTypeFromProperty); } } if (isGenericObjectType(source) || isGenericIndexType(omitKeyType)) { if (unspreadableToRestKeys.length) { // If the type we're spreading from has properties that cannot // be spread into the rest type (e.g. getters, methods), ensure // they are explicitly omitted, as they would in the non-generic case. omitKeyType = getUnionType([omitKeyType, ...unspreadableToRestKeys]); } if (omitKeyType.flags & TypeFlags.Never) { return source; } const omitTypeAlias = getGlobalOmitSymbol(); if (!omitTypeAlias) { return errorType; } return getTypeAliasInstantiation(omitTypeAlias, [source, omitKeyType]); } const members = createSymbolTable(); for (const prop of spreadableProperties) { members.set(prop.escapedName, getSpreadSymbol(prop, /*readonly*/ false)); } const result = createAnonymousType(symbol, members, emptyArray, emptyArray, getIndexInfosOfType(source)); result.objectFlags |= ObjectFlags.ObjectRestType; return result; } function isGenericTypeWithUndefinedConstraint(type: Type) { return !!(type.flags & TypeFlags.Instantiable) && maybeTypeOfKind(getBaseConstraintOfType(type) || unknownType, TypeFlags.Undefined); } function getNonUndefinedType(type: Type) { const typeOrConstraint = someType(type, isGenericTypeWithUndefinedConstraint) ? mapType(type, t => t.flags & TypeFlags.Instantiable ? getBaseConstraintOrType(t) : t) : type; return getTypeWithFacts(typeOrConstraint, TypeFacts.NEUndefined); } // 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 && canHaveFlowNode(parentAccess) && parentAccess.flowNode) { const propName = getDestructuringPropertyName(node); if (propName) { const literal = setTextRange(parseNodeFactory.createStringLiteral(propName), node); const lhsExpr = isLeftHandSideExpression(parentAccess) ? parentAccess : parseNodeFactory.createParenthesizedExpression(parentAccess); const result = setTextRange(parseNodeFactory.createElementAccessExpression(lhsExpr, literal), node); setParent(literal, result); setParent(result, node); if (lhsExpr !== parentAccess) { setParent(lhsExpr, result); } 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(ancestor as BindingElement | PropertyAssignment); case SyntaxKind.ArrayLiteralExpression: return getSyntheticElementAccess(node.parent as Expression); case SyntaxKind.VariableDeclaration: return (ancestor as VariableDeclaration).initializer; case SyntaxKind.BinaryExpression: return (ancestor as BinaryExpression).right; } } function getDestructuringPropertyName(node: BindingElement | PropertyAssignment | ShorthandPropertyAssignment | Expression) { const parent = node.parent; if (node.kind === SyntaxKind.BindingElement && parent.kind === SyntaxKind.ObjectBindingPattern) { return getLiteralPropertyNameText((node as BindingElement).propertyName || (node as BindingElement).name as Identifier); } if (node.kind === SyntaxKind.PropertyAssignment || node.kind === SyntaxKind.ShorthandPropertyAssignment) { return getLiteralPropertyNameText((node as PropertyAssignment | ShorthandPropertyAssignment).name); } return "" + ((parent as BindingPattern | ArrayLiteralExpression).elements as NodeArray).indexOf(node); } function getLiteralPropertyNameText(name: PropertyName) { const type = getLiteralTypeFromPropertyName(name); return type.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral) ? "" + (type as StringLiteralType | NumberLiteralType).value : undefined; } /** Return the inferred type for a binding element */ function getTypeForBindingElement(declaration: BindingElement): Type | undefined { const checkMode = declaration.dotDotDotToken ? CheckMode.RestBindingElement : CheckMode.Normal; const parentType = getTypeForBindingElementParent(declaration.parent.parent, checkMode); return parentType && getBindingElementTypeFromParentType(declaration, parentType); } function getBindingElementTypeFromParentType(declaration: BindingElement, parentType: Type): Type { // If an any type was inferred for parent, infer that for the binding element if (isTypeAny(parentType)) { return parentType; } const pattern = declaration.parent; // 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); } // Filter `undefined` from the type we check against if the parent has an initializer and that initializer is not possibly `undefined` else if (strictNullChecks && pattern.parent.initializer && !(getTypeFacts(getTypeOfInitializer(pattern.parent.initializer)) & TypeFacts.EQUndefined)) { parentType = getTypeWithFacts(parentType, TypeFacts.NEUndefined); } let type: Type | undefined; if (pattern.kind === SyntaxKind.ObjectBindingPattern) { if (declaration.dotDotDotToken) { parentType = getReducedType(parentType); 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 || declaration.name as Identifier; const indexType = getLiteralTypeFromPropertyName(name); const declaredType = getIndexedAccessType(parentType, indexType, AccessFlags.ExpressionPosition, 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(IterationUse.Destructuring | (declaration.dotDotDotToken ? 0 : IterationUse.PossiblyOutOfBounds), parentType, undefinedType, pattern); 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. const baseConstraint = mapType(parentType, t => t.flags & TypeFlags.InstantiableNonPrimitive ? getBaseConstraintOrType(t) : t); type = everyType(baseConstraint, isTupleType) ? mapType(baseConstraint, t => sliceTupleType(t as TupleTypeReference, index)) : createArrayType(elementType); } else if (isArrayLikeType(parentType)) { const indexType = getNumberLiteralType(index); const accessFlags = AccessFlags.ExpressionPosition | (hasDefaultValue(declaration) ? AccessFlags.NoTupleBoundsCheck : 0); const declaredType = getIndexedAccessTypeOrUndefined(parentType, indexType, accessFlags, declaration.name) || errorType; type = getFlowTypeOfDestructuring(declaration, declaredType); } else { type = elementType; } } if (!declaration.initializer) { return type; } if (getEffectiveTypeAnnotationNode(walkUpBindingElementsAndPatterns(declaration))) { // In strict null checking mode, if a default value of a non-undefined type is specified, remove // undefined from the final type. return strictNullChecks && !(getTypeFacts(checkDeclarationInitializer(declaration, CheckMode.Normal)) & TypeFacts.IsUndefined) ? getNonUndefinedType(type) : type; } return widenTypeInferredFromInitializer(declaration, getUnionType([getNonUndefinedType(type), checkDeclarationInitializer(declaration, CheckMode.Normal)], UnionReduction.Subtype)); } function getTypeForDeclarationFromJSDocComment(declaration: Node) { const jsdocType = getJSDocType(declaration); if (jsdocType) { return getTypeFromTypeNode(jsdocType); } return undefined; } function isNullOrUndefined(node: Expression) { const expr = skipParentheses(node, /*excludeJSDocTypeAssertions*/ true); return expr.kind === SyntaxKind.NullKeyword || expr.kind === SyntaxKind.Identifier && getResolvedSymbol(expr as Identifier) === undefinedSymbol; } function isEmptyArrayLiteral(node: Expression) { const expr = skipParentheses(node, /*excludeJSDocTypeAssertions*/ true); return expr.kind === SyntaxKind.ArrayLiteralExpression && (expr as ArrayLiteralExpression).elements.length === 0; } function addOptionality(type: Type, isProperty = false, isOptional = true): Type { return strictNullChecks && isOptional ? getOptionalType(type, isProperty) : type; } // Return the inferred type for a variable, parameter, or property declaration function getTypeForVariableLikeDeclaration( declaration: ParameterDeclaration | PropertyDeclaration | PropertySignature | VariableDeclaration | BindingElement | JSDocPropertyLikeTag, includeOptionality: boolean, checkMode: CheckMode, ): 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, /*checkMode*/ checkMode))); 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) || anyType; } if (isBindingPattern(declaration.parent)) { return getTypeForBindingElement(declaration as BindingElement); } const isProperty = (isPropertyDeclaration(declaration) && !hasAccessorModifier(declaration)) || isPropertySignature(declaration) || isJSDocPropertyTag(declaration); const isOptional = includeOptionality && isOptionalDeclaration(declaration); // Use type from type annotation if one is present const declaredType = tryGetTypeFromEffectiveTypeNode(declaration); if (isCatchClauseVariableDeclarationOrBindingElement(declaration)) { if (declaredType) { // If the catch clause is explicitly annotated with any or unknown, accept it, otherwise error. return isTypeAny(declaredType) || declaredType === unknownType ? declaredType : errorType; } // If the catch clause is not explicitly annotated, treat it as though it were explicitly // annotated with unknown or any, depending on useUnknownInCatchVariables. return useUnknownInCatchVariables ? unknownType : anyType; } if (declaredType) { return addOptionality(declaredType, isProperty, isOptional); } if ((noImplicitAny || isInJSFile(declaration)) && isVariableDeclaration(declaration) && !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 (isParameter(declaration)) { const func = declaration.parent as FunctionLikeDeclaration; // For a parameter of a set accessor, use the type of the get accessor if one is present if (func.kind === SyntaxKind.SetAccessor && hasBindableName(func)) { const getter = getDeclarationOfKind(getSymbolOfDeclaration(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); } } const parameterTypeOfTypeTag = getParameterTypeOfTypeTag(func, declaration); if (parameterTypeOfTypeTag) return parameterTypeOfTypeTag; // Use contextual parameter type if one is available const type = declaration.symbol.escapedName === InternalSymbolName.This ? getContextualThisParameterType(func) : getContextuallyTypedParameterType(declaration); if (type) { return addOptionality(type, /*isProperty*/ false, isOptional); } } // Use the type of the initializer expression if one is present and the declaration is // not a parameter of a contextually typed function if (hasOnlyExpressionInitializer(declaration) && !!declaration.initializer) { if (isInJSFile(declaration) && !isParameter(declaration)) { const containerObjectType = getJSContainerObjectType(declaration, getSymbolOfDeclaration(declaration), getDeclaredExpandoInitializer(declaration)); if (containerObjectType) { return containerObjectType; } } const type = widenTypeInferredFromInitializer(declaration, checkDeclarationInitializer(declaration, checkMode)); return addOptionality(type, isProperty, isOptional); } if (isPropertyDeclaration(declaration) && (noImplicitAny || isInJSFile(declaration))) { // We have a property declaration with no type annotation or initializer, in noImplicitAny mode or a .js file. // Use control flow analysis of this.xxx assignments in the constructor or static block to determine the type of the property. if (!hasStaticModifier(declaration)) { const constructor = findConstructorDeclaration(declaration.parent); const type = constructor ? getFlowTypeInConstructor(declaration.symbol, constructor) : getEffectiveModifierFlags(declaration) & ModifierFlags.Ambient ? getTypeOfPropertyInBaseClass(declaration.symbol) : undefined; return type && addOptionality(type, /*isProperty*/ true, isOptional); } else { const staticBlocks = filter(declaration.parent.members, isClassStaticBlockDeclaration); const type = staticBlocks.length ? getFlowTypeInStaticBlocks(declaration.symbol, staticBlocks) : getEffectiveModifierFlags(declaration) & ModifierFlags.Ambient ? getTypeOfPropertyInBaseClass(declaration.symbol) : undefined; return type && addOptionality(type, /*isProperty*/ true, isOptional); } } if (isJsxAttribute(declaration)) { // if JSX attribute doesn't have initializer, by default the attribute will have boolean value of true. // I.e is sugar for 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)) { return getTypeFromBindingPattern(declaration.name, /*includePatternInType*/ false, /*reportErrors*/ true); } // No type specified and nothing can be inferred return undefined; } function isConstructorDeclaredProperty(symbol: Symbol) { // A property is considered a constructor declared property when all declaration sites are this.xxx assignments, // when no declaration sites have JSDoc type annotations, and when at least one declaration site is in the body of // a class constructor. if (symbol.valueDeclaration && isBinaryExpression(symbol.valueDeclaration)) { const links = getSymbolLinks(symbol); if (links.isConstructorDeclaredProperty === undefined) { links.isConstructorDeclaredProperty = false; links.isConstructorDeclaredProperty = !!getDeclaringConstructor(symbol) && every(symbol.declarations, declaration => isBinaryExpression(declaration) && isPossiblyAliasedThisProperty(declaration) && (declaration.left.kind !== SyntaxKind.ElementAccessExpression || isStringOrNumericLiteralLike((declaration.left as ElementAccessExpression).argumentExpression)) && !getAnnotatedTypeForAssignmentDeclaration(/*declaredType*/ undefined, declaration, symbol, declaration)); } return links.isConstructorDeclaredProperty; } return false; } function isAutoTypedProperty(symbol: Symbol) { // A property is auto-typed when its declaration has no type annotation or initializer and we're in // noImplicitAny mode or a .js file. const declaration = symbol.valueDeclaration; return declaration && isPropertyDeclaration(declaration) && !getEffectiveTypeAnnotationNode(declaration) && !declaration.initializer && (noImplicitAny || isInJSFile(declaration)); } function getDeclaringConstructor(symbol: Symbol) { if (!symbol.declarations) { return; } for (const declaration of symbol.declarations) { const container = getThisContainer(declaration, /*includeArrowFunctions*/ false, /*includeClassComputedPropertyName*/ false); if (container && (container.kind === SyntaxKind.Constructor || isJSConstructor(container))) { return container as ConstructorDeclaration; } } } /** Create a synthetic property access flow node after the last statement of the file */ function getFlowTypeFromCommonJSExport(symbol: Symbol) { const file = getSourceFileOfNode(symbol.declarations![0]); const accessName = unescapeLeadingUnderscores(symbol.escapedName); const areAllModuleExports = symbol.declarations!.every(d => isInJSFile(d) && isAccessExpression(d) && isModuleExportsAccessExpression(d.expression)); const reference = areAllModuleExports ? factory.createPropertyAccessExpression(factory.createPropertyAccessExpression(factory.createIdentifier("module"), factory.createIdentifier("exports")), accessName) : factory.createPropertyAccessExpression(factory.createIdentifier("exports"), accessName); if (areAllModuleExports) { setParent((reference.expression as PropertyAccessExpression).expression, reference.expression); } setParent(reference.expression, reference); setParent(reference, file); reference.flowNode = file.endFlowNode; return getFlowTypeOfReference(reference, autoType, undefinedType); } function getFlowTypeInStaticBlocks(symbol: Symbol, staticBlocks: readonly ClassStaticBlockDeclaration[]) { const accessName = startsWith(symbol.escapedName as string, "__#") ? factory.createPrivateIdentifier((symbol.escapedName as string).split("@")[1]) : unescapeLeadingUnderscores(symbol.escapedName); for (const staticBlock of staticBlocks) { const reference = factory.createPropertyAccessExpression(factory.createThis(), accessName); setParent(reference.expression, reference); setParent(reference, staticBlock); reference.flowNode = staticBlock.returnFlowNode; const flowType = getFlowTypeOfProperty(reference, symbol); if (noImplicitAny && (flowType === autoType || flowType === autoArrayType)) { error(symbol.valueDeclaration, Diagnostics.Member_0_implicitly_has_an_1_type, symbolToString(symbol), typeToString(flowType)); } // We don't infer a type if assignments are only null or undefined. if (everyType(flowType, isNullableType)) { continue; } return convertAutoToAny(flowType); } } function getFlowTypeInConstructor(symbol: Symbol, constructor: ConstructorDeclaration) { const accessName = startsWith(symbol.escapedName as string, "__#") ? factory.createPrivateIdentifier((symbol.escapedName as string).split("@")[1]) : unescapeLeadingUnderscores(symbol.escapedName); const reference = factory.createPropertyAccessExpression(factory.createThis(), accessName); setParent(reference.expression, reference); setParent(reference, constructor); reference.flowNode = constructor.returnFlowNode; const flowType = getFlowTypeOfProperty(reference, symbol); if (noImplicitAny && (flowType === autoType || flowType === autoArrayType)) { error(symbol.valueDeclaration, Diagnostics.Member_0_implicitly_has_an_1_type, symbolToString(symbol), typeToString(flowType)); } // We don't infer a type if assignments are only null or undefined. return everyType(flowType, isNullableType) ? undefined : convertAutoToAny(flowType); } function getFlowTypeOfProperty(reference: Node, prop: Symbol | undefined) { const initialType = prop?.valueDeclaration && (!isAutoTypedProperty(prop) || getEffectiveModifierFlags(prop.valueDeclaration) & ModifierFlags.Ambient) && getTypeOfPropertyInBaseClass(prop) || undefinedType; return getFlowTypeOfReference(reference, autoType, initialType); } function getWidenedTypeForAssignmentDeclaration(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 = isInJSFile(container) ? getJSDocTypeTag(container) : undefined; if (tag && tag.typeExpression) { return getTypeFromTypeNode(tag.typeExpression); } const containerObjectType = symbol.valueDeclaration && getJSContainerObjectType(symbol.valueDeclaration, symbol, container); return containerObjectType || getWidenedLiteralType(checkExpressionCached(container)); } let type; let definedInConstructor = false; let definedInMethod = false; // We use control flow analysis to determine the type of the property if the property qualifies as a constructor // declared property and the resulting control flow type isn't just undefined or null. if (isConstructorDeclaredProperty(symbol)) { type = getFlowTypeInConstructor(symbol, getDeclaringConstructor(symbol)!); } if (!type) { let types: Type[] | undefined; if (symbol.declarations) { let jsdocType: Type | undefined; for (const declaration of symbol.declarations) { const expression = (isBinaryExpression(declaration) || isCallExpression(declaration)) ? declaration : isAccessExpression(declaration) ? isBinaryExpression(declaration.parent) ? declaration.parent : declaration : undefined; if (!expression) { continue; // Non-assignment declaration merged in (eg, an Identifier to mark the thing as a namespace) - skip over it and pull type info from elsewhere } const kind = isAccessExpression(expression) ? getAssignmentDeclarationPropertyAccessKind(expression) : getAssignmentDeclarationKind(expression); if (kind === AssignmentDeclarationKind.ThisProperty || isBinaryExpression(expression) && isPossiblyAliasedThisProperty(expression, kind)) { if (isDeclarationInConstructor(expression)) { definedInConstructor = true; } else { definedInMethod = true; } } if (!isCallExpression(expression)) { jsdocType = getAnnotatedTypeForAssignmentDeclaration(jsdocType, expression, symbol, declaration); } if (!jsdocType) { (types || (types = [])).push((isBinaryExpression(expression) || isCallExpression(expression)) ? getInitializerTypeFromAssignmentDeclaration(symbol, resolvedSymbol, expression, kind) : neverType); } } type = jsdocType; } if (!type) { if (!length(types)) { return errorType; // No types from any declarations :( } let constructorTypes = definedInConstructor && symbol.declarations ? getConstructorDefinedThisAssignmentTypes(types!, symbol.declarations) : undefined; // use only the constructor types unless they were only assigned null | undefined (including widening variants) if (definedInMethod) { const propType = getTypeOfPropertyInBaseClass(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!); } } const widened = getWidenedType(addOptionality(type, /*isProperty*/ false, definedInMethod && !definedInConstructor)); if (symbol.valueDeclaration && 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?.exports?.size) { mergeSymbolTable(exports, s.exports); } decl = isBinaryExpression(decl) ? decl.parent : decl.parent.parent; } const s = getSymbolOfNode(decl); if (s?.exports?.size) { mergeSymbolTable(exports, s.exports); } const type = createAnonymousType(symbol, exports, emptyArray, emptyArray, emptyArray); type.objectFlags |= ObjectFlags.JSLiteral; return type; } function getAnnotatedTypeForAssignmentDeclaration(declaredType: Type | undefined, expression: Expression, symbol: Symbol, declaration: Declaration) { const typeNode = getEffectiveTypeAnnotationNode(expression.parent); if (typeNode) { const type = getWidenedType(getTypeFromTypeNode(typeNode)); if (!declaredType) { return type; } else if (!isErrorType(declaredType) && !isErrorType(type) && !isTypeIdenticalTo(declaredType, type)) { errorNextVariableOrPropertyDeclarationMustHaveSameType(/*firstDeclaration*/ undefined, declaredType, declaration, type); } } if (symbol.parent?.valueDeclaration) { const typeNode = getEffectiveTypeAnnotationNode(symbol.parent.valueDeclaration); if (typeNode) { const annotationSymbol = getPropertyOfType(getTypeFromTypeNode(typeNode), symbol.escapedName); if (annotationSymbol) { return getNonMissingTypeOfSymbol(annotationSymbol); } } } 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; } if (containsSameNamedThisProperty(expression.left, expression.right)) { return anyType; } const isDirectExport = kind === AssignmentDeclarationKind.ExportsProperty && (isPropertyAccessExpression(expression.left) || isElementAccessExpression(expression.left)) && (isModuleExportsAccessExpression(expression.left.expression) || (isIdentifier(expression.left.expression) && isExportsIdentifier(expression.left.expression))); const type = resolvedSymbol ? getTypeOfSymbol(resolvedSymbol) : isDirectExport ? getRegularTypeOfLiteralType(checkExpressionCached(expression.right)) : 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); const initialSize = members.size; if (resolvedSymbol && !resolvedSymbol.exports) { resolvedSymbol.exports = createSymbolTable(); } (resolvedSymbol || symbol).exports!.forEach((s, name) => { const exportedMember = members.get(name)!; if (exportedMember && exportedMember !== s && !(s.flags & SymbolFlags.Alias)) { if (s.flags & SymbolFlags.Value && exportedMember.flags & SymbolFlags.Value) { // If the member has an additional value-like declaration, union the types from the two declarations, // but issue an error if they occurred in two different files. The purpose is to support a JS file with // a pattern like: // // module.exports = { a: true }; // module.exports.a = 3; // // but we may have a JS file with `module.exports = { a: true }` along with a TypeScript module augmentation // declaring an `export const a: number`. In that case, we issue a duplicate identifier error, because // it's unclear what that's supposed to mean, so it's probably a mistake. if (s.valueDeclaration && exportedMember.valueDeclaration && getSourceFileOfNode(s.valueDeclaration) !== getSourceFileOfNode(exportedMember.valueDeclaration)) { const unescapedName = unescapeLeadingUnderscores(s.escapedName); const exportedMemberName = tryCast(exportedMember.valueDeclaration, isNamedDeclaration)?.name || exportedMember.valueDeclaration; addRelatedInfo( error(s.valueDeclaration, Diagnostics.Duplicate_identifier_0, unescapedName), createDiagnosticForNode(exportedMemberName, Diagnostics._0_was_also_declared_here, unescapedName)); addRelatedInfo( error(exportedMemberName, Diagnostics.Duplicate_identifier_0, unescapedName), createDiagnosticForNode(s.valueDeclaration, Diagnostics._0_was_also_declared_here, unescapedName)); } const union = createSymbol(s.flags | exportedMember.flags, name); union.links.type = getUnionType([getTypeOfSymbol(s), getTypeOfSymbol(exportedMember)]); union.valueDeclaration = exportedMember.valueDeclaration; union.declarations = concatenate(exportedMember.declarations, s.declarations); members.set(name, union); } else { members.set(name, mergeSymbol(s, exportedMember)); } } else { members.set(name, s); } }); const result = createAnonymousType( initialSize !== members.size ? undefined : exportedType.symbol, // Only set the type's symbol if it looks to be the same as the original type members, exportedType.callSignatures, exportedType.constructSignatures, exportedType.indexInfos); if (initialSize === members.size) { if (type.aliasSymbol) { result.aliasSymbol = type.aliasSymbol; result.aliasTypeArguments = type.aliasTypeArguments; } if (getObjectFlags(type) & ObjectFlags.Reference) { result.aliasSymbol = (type as TypeReference).symbol; const args = getTypeArguments(type as TypeReference); result.aliasTypeArguments = length(args) ? args : undefined; } } result.objectFlags |= (getObjectFlags(type) & ObjectFlags.JSLiteral); // Propagate JSLiteral flag if (result.symbol && result.symbol.flags & SymbolFlags.Class && type === getDeclaredTypeOfClassOrInterface(result.symbol)) { result.objectFlags |= ObjectFlags.IsClassInstanceClone; // Propagate the knowledge that this type is equivalent to the symbol's class instance type } return result; } if (isEmptyArrayLiteralType(type)) { reportImplicitAny(expression, anyArrayType); return anyArrayType; } return type; } function containsSameNamedThisProperty(thisProperty: Expression, expression: Expression) { return isPropertyAccessExpression(thisProperty) && thisProperty.expression.kind === SyntaxKind.ThisKeyword && forEachChildRecursively(expression, n => isMatchingReference(thisProperty, n)); } function isDeclarationInConstructor(expression: Expression) { const thisContainer = getThisContainer(expression, /*includeArrowFunctions*/ false, /*includeClassComputedPropertyName*/ 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); }); } // 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) { // The type implied by a binding pattern is independent of context, so we check the initializer with no // contextual type or, if the element itself is a binding pattern, with the type implied by that binding // pattern. const contextualType = isBindingPattern(element.name) ? getTypeFromBindingPattern(element.name, /*includePatternInType*/ true, /*reportErrors*/ false) : unknownType; return addOptionality(widenTypeInferredFromInitializer(element, checkDeclarationInitializer(element, CheckMode.Normal, contextualType))); } if (isBindingPattern(element.name)) { return getTypeFromBindingPattern(element.name, includePatternInType, reportErrors); } if (reportErrors && !declarationBelongsToPrivateAmbientMember(element)) { reportImplicitAny(element, anyType); } // When we're including the pattern in the type (an indication we're obtaining a contextual type), we // use a non-inferrable any type. Inference will never directly infer this type, but it is possible // to infer a type that contains it, e.g. for a binding pattern like [foo] or { foo }. In such cases, // widening of the binding pattern type substitutes a regular any for the non-inferrable any. return includePatternInType ? nonInferrableAnyType : 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.ContainsObjectOrArrayLiteral; forEach(pattern.elements, e => { const name = e.propertyName || e.name as Identifier; if (e.dotDotDotToken) { stringIndexInfo = createIndexInfo(stringType, 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.links.type = getTypeFromBindingElement(e, includePatternInType, reportErrors); symbol.links.bindingElement = e; members.set(symbol.escapedName, symbol); }); const result = createAnonymousType(/*symbol*/ undefined, members, emptyArray, emptyArray, stringIndexInfo ? [stringIndexInfo] : emptyArray); result.objectFlags |= objectFlags; if (includePatternInType) { result.pattern = pattern; result.objectFlags |= ObjectFlags.ContainsObjectOrArrayLiteral; } 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 restElement = lastElement && lastElement.kind === SyntaxKind.BindingElement && lastElement.dotDotDotToken ? lastElement : undefined; if (elements.length === 0 || elements.length === 1 && restElement) { return languageVersion >= ScriptTarget.ES2015 ? createIterableType(anyType) : anyArrayType; } const elementTypes = map(elements, e => isOmittedExpression(e) ? anyType : getTypeFromBindingElement(e, includePatternInType, reportErrors)); const minLength = findLastIndex(elements, e => !(e === restElement || isOmittedExpression(e) || hasDefaultValue(e)), elements.length - 1) + 1; const elementFlags = map(elements, (e, i) => e === restElement ? ElementFlags.Rest : i >= minLength ? ElementFlags.Optional : ElementFlags.Required); let result = createTupleType(elementTypes, elementFlags) as TypeReference; if (includePatternInType) { result = cloneTypeReference(result); result.pattern = pattern; result.objectFlags |= ObjectFlags.ContainsObjectOrArrayLiteral; } 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 | JSDocPropertyLikeTag, reportErrors?: boolean): Type { return widenTypeForVariableLikeDeclaration(getTypeForVariableLikeDeclaration(declaration, /*includeOptionality*/ true, CheckMode.Normal), declaration, reportErrors); } function isGlobalSymbolConstructor(node: Node) { const symbol = getSymbolOfNode(node); const globalSymbol = getGlobalESSymbolConstructorTypeSymbol(/*reportErrors*/ false); return globalSymbol && symbol && symbol === globalSymbol; } function widenTypeForVariableLikeDeclaration(type: Type | undefined, declaration: any, reportErrors?: boolean) { if (type) { // TODO: If back compat with pre-3.0/4.0 libs isn't required, remove the following SymbolConstructor special case transforming `symbol` into `unique symbol` if (type.flags & TypeFlags.ESSymbol && isGlobalSymbolConstructor(declaration.parent)) { type = getESSymbolLikeTypeForNode(declaration); } 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 !== getSymbolOfDeclaration(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(node: Node) { const typeNode = getEffectiveTypeAnnotationNode(node); if (typeNode) { return getTypeFromTypeNode(typeNode); } } function isParameterOfContextSensitiveSignature(symbol: Symbol) { let decl = symbol.valueDeclaration; if (!decl) { return false; } if (isBindingElement(decl)) { decl = walkUpBindingElementsAndPatterns(decl); } if (isParameter(decl)) { return isContextSensitiveFunctionOrObjectLiteralMethod(decl.parent); } return false; } 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. In fact, we need to _prefer_ that type, but it won't // be assigned until contextual typing is complete, so we need to defer in // cases where contextual typing may take place. if (!links.type && !isParameterOfContextSensitiveSignature(symbol)) { links.type = type; } return type; } return links.type; } function getTypeOfVariableOrParameterOrPropertyWorker(symbol: Symbol): Type { // 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 && symbol.valueDeclaration) { const fileSymbol = getSymbolOfDeclaration(getSourceFileOfNode(symbol.valueDeclaration)); const result = createSymbol(fileSymbol.flags, "exports" as __String); result.declarations = fileSymbol.declarations ? fileSymbol.declarations.slice() : []; result.parent = symbol; result.links.target = fileSymbol; if (fileSymbol.valueDeclaration) result.valueDeclaration = fileSymbol.valueDeclaration; if (fileSymbol.members) result.members = new Map(fileSymbol.members); if (fileSymbol.exports) result.exports = new Map(fileSymbol.exports); const members = createSymbolTable(); members.set("exports" as __String, result); return createAnonymousType(symbol, members, emptyArray, emptyArray, emptyArray); } Debug.assertIsDefined(symbol.valueDeclaration); const declaration = symbol.valueDeclaration; // Handle export default expressions if (isSourceFile(declaration) && isJsonSourceFile(declaration)) { if (!declaration.statements.length) { return emptyObjectType; } return getWidenedType(getWidenedLiteralType(checkExpression(declaration.statements[0].expression))); } if (isAccessor(declaration)) { // Binding of certain patterns in JS code will occasionally mark symbols as both properties // and accessors. Here we dispatch to accessor resolution if needed. return getTypeOfAccessors(symbol); } // 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 && !(symbol.flags & SymbolFlags.Assignment)) { return getTypeOfFuncClassEnumModule(symbol); } return reportCircularityError(symbol); } let type: Type; if (declaration.kind === SyntaxKind.ExportAssignment) { type = widenTypeForVariableLikeDeclaration(tryGetTypeFromEffectiveTypeNode(declaration) || checkExpressionCached((declaration as ExportAssignment).expression), declaration); } else if ( isBinaryExpression(declaration) || (isInJSFile(declaration) && (isCallExpression(declaration) || (isPropertyAccessExpression(declaration) || isBindableStaticElementAccessExpression(declaration)) && isBinaryExpression(declaration.parent)))) { type = getWidenedTypeForAssignmentDeclaration(symbol); } else if (isPropertyAccessExpression(declaration) || isElementAccessExpression(declaration) || isIdentifier(declaration) || isStringLiteralLike(declaration) || isNumericLiteral(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) ? getWidenedTypeForAssignmentDeclaration(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) || isJSDocPropertyLikeTag(declaration)) { type = getWidenedTypeForVariableLikeDeclaration(declaration, /*reportErrors*/ 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.formatSyntaxKind(declaration.kind) + " for " + Debug.formatSymbol(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 && !(symbol.flags & SymbolFlags.Assignment)) { return getTypeOfFuncClassEnumModule(symbol); } return reportCircularityError(symbol); } return type; } function getAnnotatedAccessorTypeNode(accessor: AccessorDeclaration | PropertyDeclaration | undefined): TypeNode | undefined { if (accessor) { switch (accessor.kind) { case SyntaxKind.GetAccessor: const getterTypeAnnotation = getEffectiveReturnTypeNode(accessor); return getterTypeAnnotation; case SyntaxKind.SetAccessor: const setterTypeAnnotation = getEffectiveSetAccessorTypeAnnotationNode(accessor); return setterTypeAnnotation; case SyntaxKind.PropertyDeclaration: Debug.assert(hasAccessorModifier(accessor)); const accessorTypeAnnotation = getEffectiveTypeAnnotationNode(accessor); return accessorTypeAnnotation; } } return undefined; } function getAnnotatedAccessorType(accessor: AccessorDeclaration | PropertyDeclaration | 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); if (!links.type) { if (!pushTypeResolution(symbol, TypeSystemPropertyName.Type)) { return errorType; } const getter = getDeclarationOfKind(symbol, SyntaxKind.GetAccessor); const setter = getDeclarationOfKind(symbol, SyntaxKind.SetAccessor); const accessor = tryCast(getDeclarationOfKind(symbol, SyntaxKind.PropertyDeclaration), isAutoAccessorPropertyDeclaration); // We try to resolve a getter type annotation, a setter type annotation, or a getter function // body return type inference, in that order. let type = getter && isInJSFile(getter) && getTypeForDeclarationFromJSDocComment(getter) || getAnnotatedAccessorType(getter) || getAnnotatedAccessorType(setter) || getAnnotatedAccessorType(accessor) || getter && getter.body && getReturnTypeFromBody(getter) || accessor && accessor.initializer && getWidenedTypeForVariableLikeDeclaration(accessor, /*reportErrors*/ true); if (!type) { if (setter && !isPrivateWithinAmbient(setter)) { errorOrSuggestion(noImplicitAny, setter, Diagnostics.Property_0_implicitly_has_type_any_because_its_set_accessor_lacks_a_parameter_type_annotation, symbolToString(symbol)); } else if (getter && !isPrivateWithinAmbient(getter)) { errorOrSuggestion(noImplicitAny, getter, Diagnostics.Property_0_implicitly_has_type_any_because_its_get_accessor_lacks_a_return_type_annotation, symbolToString(symbol)); } else if (accessor && !isPrivateWithinAmbient(accessor)) { errorOrSuggestion(noImplicitAny, accessor, Diagnostics.Member_0_implicitly_has_an_1_type, symbolToString(symbol), "any"); } type = anyType; } if (!popTypeResolution()) { if (getAnnotatedAccessorTypeNode(getter)) { error(getter, Diagnostics._0_is_referenced_directly_or_indirectly_in_its_own_type_annotation, symbolToString(symbol)); } else if (getAnnotatedAccessorTypeNode(setter)) { error(setter, Diagnostics._0_is_referenced_directly_or_indirectly_in_its_own_type_annotation, symbolToString(symbol)); } else if (getAnnotatedAccessorTypeNode(accessor)) { error(setter, Diagnostics._0_is_referenced_directly_or_indirectly_in_its_own_type_annotation, symbolToString(symbol)); } else if (getter && noImplicitAny) { 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)); } type = anyType; } links.type = type; } return links.type; } function getWriteTypeOfAccessors(symbol: Symbol): Type { const links = getSymbolLinks(symbol); if (!links.writeType) { if (!pushTypeResolution(symbol, TypeSystemPropertyName.WriteType)) { return errorType; } const setter = getDeclarationOfKind(symbol, SyntaxKind.SetAccessor) ?? tryCast(getDeclarationOfKind(symbol, SyntaxKind.PropertyDeclaration), isAutoAccessorPropertyDeclaration); let writeType = getAnnotatedAccessorType(setter); if (!popTypeResolution()) { if (getAnnotatedAccessorTypeNode(setter)) { error(setter, Diagnostics._0_is_referenced_directly_or_indirectly_in_its_own_type_annotation, symbolToString(symbol)); } writeType = anyType; } // Absent an explicit setter type annotation we use the read type of the accessor. links.writeType = writeType || getTypeOfAccessors(symbol); } return links.writeType; } function getBaseTypeVariableOfClass(symbol: Symbol) { const baseConstructorType = getBaseConstructorTypeOfClass(getDeclaredTypeOfClassOrInterface(symbol)); return baseConstructorType.flags & TypeFlags.TypeVariable ? baseConstructorType : baseConstructorType.flags & TypeFlags.Intersection ? find((baseConstructorType as IntersectionType).types, t => !!(t.flags & TypeFlags.TypeVariable)) : undefined; } function getTypeOfFuncClassEnumModule(symbol: Symbol): Type { let links = getSymbolLinks(symbol); const originalLinks = links; if (!links.type) { const expando = symbol.valueDeclaration && getSymbolOfExpando(symbol.valueDeclaration, /*allowDeclaration*/ false); if (expando) { const merged = mergeJSSymbols(symbol, expando); if (merged) { // note:we overwrite links because we just cloned the symbol symbol = merged; links = merged.links; } } 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 && (declaration.kind === SyntaxKind.BinaryExpression || isAccessExpression(declaration) && declaration.parent.kind === SyntaxKind.BinaryExpression)) { return getWidenedTypeForAssignmentDeclaration(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 = getWidenedTypeForAssignmentDeclaration(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, /*isProperty*/ true) : 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); const exportSymbol = symbol.declarations && getTargetOfAliasDeclaration(getDeclarationOfAliasSymbol(symbol)!, /*dontRecursivelyResolve*/ true); const declaredType = firstDefined(exportSymbol?.declarations, d => isExportAssignment(d) ? tryGetTypeFromEffectiveTypeNode(d) : undefined); // 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 = exportSymbol?.declarations && isDuplicatedCommonJSExport(exportSymbol.declarations) && symbol.declarations!.length ? getFlowTypeFromCommonJSExport(exportSymbol) : isDuplicatedCommonJSExport(symbol.declarations) ? autoType : declaredType ? declaredType : getAllSymbolFlags(targetSymbol) & SymbolFlags.Value ? getTypeOfSymbol(targetSymbol) : errorType; } return links.type; } function getTypeOfInstantiatedSymbol(symbol: Symbol): Type { const links = getSymbolLinks(symbol); return links.type || (links.type = instantiateType(getTypeOfSymbol(links.target!), links.mapper)); } function getWriteTypeOfInstantiatedSymbol(symbol: Symbol): Type { const links = getSymbolLinks(symbol); return links.writeType || (links.writeType = instantiateType(getWriteTypeOfSymbol(links.target!), links.mapper)); } function reportCircularityError(symbol: Symbol) { const declaration = symbol.valueDeclaration as VariableLikeDeclaration; // 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 || (declaration as HasInitializer).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 getTypeOfSymbolWithDeferredType(symbol: Symbol) { const links = getSymbolLinks(symbol); if (!links.type) { Debug.assertIsDefined(links.deferralParent); Debug.assertIsDefined(links.deferralConstituents); links.type = links.deferralParent.flags & TypeFlags.Union ? getUnionType(links.deferralConstituents) : getIntersectionType(links.deferralConstituents); } return links.type; } function getWriteTypeOfSymbolWithDeferredType(symbol: Symbol): Type | undefined { const links = getSymbolLinks(symbol); if (!links.writeType && links.deferralWriteConstituents) { Debug.assertIsDefined(links.deferralParent); Debug.assertIsDefined(links.deferralConstituents); links.writeType = links.deferralParent.flags & TypeFlags.Union ? getUnionType(links.deferralWriteConstituents) : getIntersectionType(links.deferralWriteConstituents); } return links.writeType; } /** * Distinct write types come only from set accessors, but synthetic union and intersection * properties deriving from set accessors will either pre-compute or defer the union or * intersection of the writeTypes of their constituents. */ function getWriteTypeOfSymbol(symbol: Symbol): Type { const checkFlags = getCheckFlags(symbol); if (symbol.flags & SymbolFlags.Property) { return checkFlags & CheckFlags.SyntheticProperty ? checkFlags & CheckFlags.DeferredType ? getWriteTypeOfSymbolWithDeferredType(symbol) || getTypeOfSymbolWithDeferredType(symbol) : // NOTE: cast to TransientSymbol should be safe because only TransientSymbols can have CheckFlags.SyntheticProperty (symbol as TransientSymbol).links.writeType || (symbol as TransientSymbol).links.type! : getTypeOfSymbol(symbol); } if (symbol.flags & SymbolFlags.Accessor) { return checkFlags & CheckFlags.Instantiated ? getWriteTypeOfInstantiatedSymbol(symbol) : getWriteTypeOfAccessors(symbol); } return getTypeOfSymbol(symbol); } function getTypeOfSymbol(symbol: Symbol): Type { const checkFlags = getCheckFlags(symbol); if (checkFlags & CheckFlags.DeferredType) { return getTypeOfSymbolWithDeferredType(symbol); } if (checkFlags & CheckFlags.Instantiated) { return getTypeOfInstantiatedSymbol(symbol); } if (checkFlags & CheckFlags.Mapped) { return getTypeOfMappedSymbol(symbol as MappedSymbol); } if (checkFlags & 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 getNonMissingTypeOfSymbol(symbol: Symbol) { return removeMissingType(getTypeOfSymbol(symbol), !!(symbol.flags & SymbolFlags.Optional)); } function isReferenceToType(type: Type, target: Type) { return type !== undefined && target !== undefined && (getObjectFlags(type) & ObjectFlags.Reference) !== 0 && (type as TypeReference).target === target; } function getTargetType(type: Type): Type { return getObjectFlags(type) & ObjectFlags.Reference ? (type as TypeReference).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 = getTargetType(type) as InterfaceType; return target === checkBase || some(getBaseTypes(target), check); } else if (type.flags & TypeFlags.Intersection) { return some((type as IntersectionType).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: readonly TypeParameterDeclaration[]): TypeParameter[] | undefined { for (const declaration of declarations) { typeParameters = appendIfUnique(typeParameters, getDeclaredTypeOfTypeParameter(getSymbolOfDeclaration(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 && isBinaryExpression(node)) { // prototype assignments get the outer type parameters of their constructor function const assignmentKind = getAssignmentDeclarationKind(node); if (assignmentKind === AssignmentDeclarationKind.Prototype || assignmentKind === AssignmentDeclarationKind.PrototypeProperty) { const symbol = getSymbolOfDeclaration(node.left as BindableStaticNameExpression | PropertyAssignment); if (symbol && symbol.parent && !findAncestor(symbol.parent.valueDeclaration, d => node === d)) { node = symbol.parent.valueDeclaration!; } } } 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.JSDocEnumTag: case SyntaxKind.JSDocCallbackTag: case SyntaxKind.MappedType: case SyntaxKind.ConditionalType: { const outerTypeParameters = getOuterTypeParameters(node, includeThisTypes); if (node.kind === SyntaxKind.MappedType) { return append(outerTypeParameters, getDeclaredTypeOfTypeParameter(getSymbolOfDeclaration((node as MappedTypeNode).typeParameter))); } else if (node.kind === SyntaxKind.ConditionalType) { return concatenate(outerTypeParameters, getInferTypeParameters(node as ConditionalTypeNode)); } const outerAndOwnTypeParameters = appendTypeParameters(outerTypeParameters, getEffectiveTypeParameterDeclarations(node as DeclarationWithTypeParameters)); const thisType = includeThisTypes && (node.kind === SyntaxKind.ClassDeclaration || node.kind === SyntaxKind.ClassExpression || node.kind === SyntaxKind.InterfaceDeclaration || isJSConstructor(node)) && getDeclaredTypeOfClassOrInterface(getSymbolOfDeclaration(node as ClassLikeDeclaration | InterfaceDeclaration)).thisType; return thisType ? append(outerAndOwnTypeParameters, thisType) : outerAndOwnTypeParameters; } case SyntaxKind.JSDocParameterTag: const paramSymbol = getParameterSymbolFromJSDoc(node as JSDocParameterTag); if (paramSymbol) { node = paramSymbol.valueDeclaration!; } break; case SyntaxKind.JSDoc: { const outerTypeParameters = getOuterTypeParameters(node, includeThisTypes); return (node as JSDoc).tags ? appendTypeParameters(outerTypeParameters, flatMap((node as JSDoc).tags, t => isJSDocTemplateTag(t) ? t.typeParameters : undefined)) : outerTypeParameters; } } } } // 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.flags & SymbolFlags.Function) ? symbol.valueDeclaration : symbol.declarations?.find(decl => { if (decl.kind === SyntaxKind.InterfaceDeclaration) { return true; } if (decl.kind !== SyntaxKind.VariableDeclaration) { return false; } const initializer = (decl as VariableDeclaration).initializer; return !!initializer && (initializer.kind === SyntaxKind.FunctionExpression || initializer.kind === SyntaxKind.ArrowFunction); })!; Debug.assert(!!declaration, "Class was missing valueDeclaration -OR- non-class had no interface declarations"); 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 { if (!symbol.declarations) { return; } let result: TypeParameter[] | undefined; for (const node of symbol.declarations) { if (node.kind === SyntaxKind.InterfaceDeclaration || node.kind === SyntaxKind.ClassDeclaration || node.kind === SyntaxKind.ClassExpression || isJSConstructor(node) || isTypeAlias(node)) { const declaration = node as InterfaceDeclaration | TypeAliasDeclaration | JSDocTypedefTag | JSDocCallbackTag; 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]; if (!s.typeParameters && s.parameters.length === 1 && signatureHasRestParameter(s)) { const paramType = getTypeOfParameter(s.parameters[0]); return isTypeAny(paramType) || getElementTypeOfArrayType(paramType) === anyType; } } return false; } function isConstructorType(type: Type): boolean { if (getSignaturesOfType(type, SignatureKind.Construct).length > 0) { return true; } if (type.flags & TypeFlags.TypeVariable) { const constraint = getBaseConstraintOfType(type); return !!constraint && isMixinConstructorType(constraint); } return false; } function getBaseTypeNodeOfClass(type: InterfaceType): ExpressionWithTypeArguments | undefined { const decl = getClassLikeDeclarationOfSymbol(type.symbol); return decl && getEffectiveBaseTypeNode(decl); } function getConstructorsForTypeArguments(type: Type, typeArgumentNodes: readonly TypeNode[] | undefined, location: Node): readonly 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: readonly TypeNode[] | undefined, location: Node): readonly Signature[] { const signatures = getConstructorsForTypeArguments(type, typeArgumentNodes, location); const typeArguments = map(typeArgumentNodes, getTypeFromTypeNode); return sameMap(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 = getClassLikeDeclarationOfSymbol(type.symbol); const extended = decl && 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(baseConstructorType as ObjectType); } 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]); } } if (baseConstructorType.symbol.declarations) { 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 getImplementsTypes(type: InterfaceType): BaseType[] { let resolvedImplementsTypes: BaseType[] = emptyArray; if (type.symbol.declarations) { for (const declaration of type.symbol.declarations) { const implementsTypeNodes = getEffectiveImplementsTypeNodes(declaration as ClassLikeDeclaration); if (!implementsTypeNodes) continue; for (const node of implementsTypeNodes) { const implementsType = getTypeFromTypeNode(node); if (!isErrorType(implementsType)) { if (resolvedImplementsTypes === emptyArray) { resolvedImplementsTypes = [implementsType as ObjectType]; } else { resolvedImplementsTypes.push(implementsType); } } } } } return resolvedImplementsTypes; } function reportCircularBaseType(node: Node, type: Type) { error(node, Diagnostics.Type_0_recursively_references_itself_as_a_base_type, typeToString(type, /*enclosingDeclaration*/ undefined, TypeFormatFlags.WriteArrayAsGenericType)); } function getBaseTypes(type: InterfaceType): BaseType[] { if (!type.baseTypesResolved) { if (pushTypeResolution(type, TypeSystemPropertyName.ResolvedBaseTypes)) { if (type.objectFlags & ObjectFlags.Tuple) { type.resolvedBaseTypes = [getTupleBaseType(type as TupleType)]; } 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"); } if (!popTypeResolution() && type.symbol.declarations) { for (const declaration of type.symbol.declarations) { if (declaration.kind === SyntaxKind.ClassDeclaration || declaration.kind === SyntaxKind.InterfaceDeclaration) { reportCircularBaseType(declaration, type); } } } } type.baseTypesResolved = true; } return type.resolvedBaseTypes; } function getTupleBaseType(type: TupleType) { const elementTypes = sameMap(type.typeParameters, (t, i) => type.elementFlags[i] & ElementFlags.Variadic ? getIndexedAccessType(t, numberType) : t); return createArrayType(getUnionType(elementTypes || emptyArray), type.readonly); } 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)!; let baseType: Type; const originalBaseType = 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); } else if (baseConstructorType.flags & TypeFlags.Any) { baseType = baseConstructorType; } 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 (isErrorType(baseType)) { return type.resolvedBaseTypes = emptyArray; } const reducedBaseType = getReducedType(baseType); if (!isValidBaseType(reducedBaseType)) { const elaboration = elaborateNeverIntersection(/*errorInfo*/ undefined, baseType); const diagnostic = chainDiagnosticMessages(elaboration, Diagnostics.Base_constructor_return_type_0_is_not_an_object_type_or_intersection_of_object_types_with_statically_known_members, typeToString(reducedBaseType)); diagnostics.add(createDiagnosticForNodeFromMessageChain(getSourceFileOfNode(baseTypeNode.expression), baseTypeNode.expression, diagnostic)); return type.resolvedBaseTypes = emptyArray; } if (type === reducedBaseType || hasBaseType(reducedBaseType, 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 = [reducedBaseType]; } 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 = (type as InterfaceType).outerTypeParameters; if (outerTypeParameters) { const last = outerTypeParameters.length - 1; const typeArguments = getTypeArguments(type as TypeReference); return outerTypeParameters[last].symbol !== typeArguments[last].symbol; } return true; } // A valid base type is `any`, an object type or intersection of object types. function isValidBaseType(type: Type): type is BaseType { if (type.flags & TypeFlags.TypeParameter) { const constraint = getBaseConstraintOfType(type); if (constraint) { return isValidBaseType(constraint); } } // TODO: Given that we allow type parmeters here now, is this `!isGenericMappedType(type)` check really needed? // There's no reason a `T` should be allowed while a `Readonly` should not. return !!(type.flags & (TypeFlags.Object | TypeFlags.NonPrimitive | TypeFlags.Any) && !isGenericMappedType(type) || type.flags & TypeFlags.Intersection && every((type as IntersectionType).types, isValidBaseType)); } function resolveBaseTypesOfInterface(type: InterfaceType): void { type.resolvedBaseTypes = type.resolvedBaseTypes || emptyArray; if (type.symbol.declarations) { for (const declaration of type.symbol.declarations) { if (declaration.kind === SyntaxKind.InterfaceDeclaration && getInterfaceBaseTypeNodes(declaration as InterfaceDeclaration)) { for (const node of getInterfaceBaseTypeNodes(declaration as InterfaceDeclaration)!) { const baseType = getReducedType(getTypeFromTypeNode(node)); if (!isErrorType(baseType)) { if (isValidBaseType(baseType)) { if (type !== baseType && !hasBaseType(baseType, type)) { if (type.resolvedBaseTypes === emptyArray) { type.resolvedBaseTypes = [baseType as ObjectType]; } else { type.resolvedBaseTypes.push(baseType); } } else { reportCircularBaseType(declaration, type); } } 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 { if (!symbol.declarations) { return true; } for (const declaration of symbol.declarations) { if (declaration.kind === SyntaxKind.InterfaceDeclaration) { if (declaration.flags & NodeFlags.ContainsThis) { return false; } const baseTypeNodes = getInterfaceBaseTypeNodes(declaration as InterfaceDeclaration); 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 { let links = getSymbolLinks(symbol); const originalLinks = links; if (!links.declaredType) { const kind = symbol.flags & SymbolFlags.Class ? ObjectFlags.Class : ObjectFlags.Interface; const merged = mergeJSSymbols(symbol, symbol.valueDeclaration && getAssignedClassSymbol(symbol.valueDeclaration)); if (merged) { // note:we overwrite links because we just cloned the symbol symbol = merged; links = merged.links; } const type = originalLinks.declaredType = links.declaredType = createObjectType(kind, symbol) as InterfaceType; 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; (type as GenericType).instantiations = new Map(); (type as GenericType).instantiations.set(getTypeListId(type.typeParameters), type as GenericType); (type as GenericType).target = type as GenericType; (type as GenericType).resolvedTypeArguments = type.typeParameters; type.thisType = createTypeParameter(symbol); type.thisType.isThisType = true; type.thisType.constraint = type; } } return links.declaredType as InterfaceType; } 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 = Debug.checkDefined(symbol.declarations?.find(isTypeAlias), "Type alias symbol with no valid declaration found"); 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 = new Map(); links.instantiations.set(getTypeListId(typeParameters), type); } } else { type = errorType; if (declaration.kind === SyntaxKind.JSDocEnumTag) { error(declaration.typeExpression.type, Diagnostics.Type_alias_0_circularly_references_itself, symbolToString(symbol)); } else { error(isNamedDeclaration(declaration) ? declaration.name || declaration : declaration, Diagnostics.Type_alias_0_circularly_references_itself, symbolToString(symbol)); } } links.declaredType = type; } return links.declaredType; } function getBaseTypeOfEnumLikeType(type: Type) { return type.flags & TypeFlags.EnumLike && type.symbol.flags & SymbolFlags.EnumMember ? getDeclaredTypeOfSymbol(getParentOfSymbol(type.symbol)!) : type; } function getDeclaredTypeOfEnum(symbol: Symbol): Type { const links = getSymbolLinks(symbol); if (!links.declaredType) { const memberTypeList: Type[] = []; if (symbol.declarations) { for (const declaration of symbol.declarations) { if (declaration.kind === SyntaxKind.EnumDeclaration) { for (const member of (declaration as EnumDeclaration).members) { if (hasBindableName(member)) { const memberSymbol = getSymbolOfDeclaration(member); const value = getEnumMemberValue(member); const memberType = getFreshTypeOfLiteralType(value !== undefined ? getEnumLiteralType(value, getSymbolId(symbol), memberSymbol) : createComputedEnumType(memberSymbol)); getSymbolLinks(memberSymbol).declaredType = memberType; memberTypeList.push(getRegularTypeOfLiteralType(memberType)); } } } } } const enumType = memberTypeList.length ? getUnionType(memberTypeList, UnionReduction.Literal, symbol, /*aliasTypeArguments*/ undefined) : createComputedEnumType(symbol); if (enumType.flags & TypeFlags.Union) { enumType.flags |= TypeFlags.EnumLiteral; enumType.symbol = symbol; } links.declaredType = enumType; } return links.declaredType; } function createComputedEnumType(symbol: Symbol) { const regularType = createTypeWithSymbol(TypeFlags.Enum, symbol) as EnumType; const freshType = createTypeWithSymbol(TypeFlags.Enum, symbol) as EnumType; regularType.regularType = regularType; regularType.freshType = freshType; freshType.regularType = regularType; freshType.freshType = freshType; return regularType; } 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.NeverKeyword: case SyntaxKind.LiteralType: return true; case SyntaxKind.ArrayType: return isThislessType((node as ArrayTypeNode).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(declaration as VariableLikeDeclaration); case SyntaxKind.MethodDeclaration: case SyntaxKind.MethodSignature: case SyntaxKind.Constructor: case SyntaxKind.GetAccessor: case SyntaxKind.SetAccessor: return isThislessFunctionLikeDeclaration(declaration as FunctionLikeDeclaration | AccessorDeclaration); } } } 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 base of baseSymbols) { if (isStaticPrivateIdentifierProperty(base)) { continue; } const derived = symbols.get(base.escapedName); if (!derived // non-constructor/static-block assignment declarations are ignored here; they're not treated as overrides || derived.valueDeclaration && isBinaryExpression(derived.valueDeclaration) && !isConstructorDeclaredProperty(derived) && !getContainingClassStaticBlock(derived.valueDeclaration)) { symbols.set(base.escapedName, base); symbols.set(base.escapedName, base); } } } function isStaticPrivateIdentifierProperty(s: Symbol): boolean { return !!s.valueDeclaration && isPrivateIdentifierClassElementDeclaration(s.valueDeclaration) && isStatic(s.valueDeclaration); } function resolveDeclaredMembers(type: InterfaceType): InterfaceTypeWithDeclaredMembers { if (!(type as InterfaceTypeWithDeclaredMembers).declaredProperties) { const symbol = type.symbol; const members = getMembersOfSymbol(symbol); (type as InterfaceTypeWithDeclaredMembers).declaredProperties = getNamedMembers(members); // Start with signatures at empty array in case of recursive types (type as InterfaceTypeWithDeclaredMembers).declaredCallSignatures = emptyArray; (type as InterfaceTypeWithDeclaredMembers).declaredConstructSignatures = emptyArray; (type as InterfaceTypeWithDeclaredMembers).declaredIndexInfos = emptyArray; (type as InterfaceTypeWithDeclaredMembers).declaredCallSignatures = getSignaturesOfSymbol(members.get(InternalSymbolName.Call)); (type as InterfaceTypeWithDeclaredMembers).declaredConstructSignatures = getSignaturesOfSymbol(members.get(InternalSymbolName.New)); (type as InterfaceTypeWithDeclaredMembers).declaredIndexInfos = getIndexInfosOfSymbol(symbol); } return type as InterfaceTypeWithDeclaredMembers; } /** * 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 { if (!isComputedPropertyName(node) && !isElementAccessExpression(node)) { return false; } const expr = isComputedPropertyName(node) ? node.expression : node.argumentExpression; return isEntityNameExpression(expr) && isTypeUsableAsPropertyName(isComputedPropertyName(node) ? checkComputedPropertyName(node) : checkExpressionCached(expr)); } 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 | LateBoundBinaryExpressionDeclaration { const name = getNameOfDeclaration(node); return !!name && isLateBindableName(name); } /** * Indicates whether a declaration has an early-bound name or a dynamic name that can be late-bound. */ function hasBindableName(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 (type as UniqueESSymbolType).escapedName; } if (type.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral)) { return escapeLeadingUnderscores("" + (type as StringLiteralType | NumberLiteralType).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 | BinaryExpression, 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 if(!member.symbol.isReplaceableByMethod) { 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: Map<__String, TransientSymbol>, decl: LateBoundDeclaration | LateBoundBinaryExpressionDeclaration) { 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 declName = isBinaryExpression(decl) ? decl.left : decl.name; const type = isElementAccessExpression(declName) ? checkExpressionCached(declName.argumentExpression) : checkComputedPropertyName(declName); 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(declName); forEach(declarations, declaration => error(getNameOfDeclaration(declaration) || declaration, Diagnostics.Property_0_was_also_declared_here, name)); error(declName || decl, Diagnostics.Duplicate_property_0, name); lateSymbol = createSymbol(SymbolFlags.None, memberName, CheckFlags.Late); } lateSymbol.links.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): Map<__String, Symbol> { const links = getSymbolLinks(symbol); if (!links[resolutionKind]) { const isStatic = resolutionKind === MembersOrExportsResolutionKind.resolvedExports; const earlySymbols = !isStatic ? symbol.members : symbol.flags & SymbolFlags.Module ? getExportsOfModuleWorker(symbol).exports : 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() as Map<__String, TransientSymbol>; for (const decl of symbol.declarations || emptyArray) { const members = getMembersOfDeclaration(decl); if (members) { for (const member of members) { if (isStatic === hasStaticModifier(member)) { if (hasLateBindableName(member)) { lateBindMember(symbol, earlySymbols, lateSymbols, member); } } } } } const assignments = symbol.assignmentDeclarationMembers; if (assignments) { const decls = arrayFrom(assignments.values()); for (const member of decls) { const assignmentKind = getAssignmentDeclarationKind(member as BinaryExpression | CallExpression); const isInstanceMember = assignmentKind === AssignmentDeclarationKind.PrototypeProperty || isBinaryExpression(member) && isPossiblyAliasedThisProperty(member, assignmentKind) || assignmentKind === AssignmentDeclarationKind.ObjectDefinePrototypeProperty || assignmentKind === AssignmentDeclarationKind.Prototype; // A straight `Prototype` assignment probably can never have a computed name if (isStatic === !isInstanceMember) { if (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 const parent = getMergedSymbol(symbol.parent)!; if (some(symbol.declarations, hasStaticModifier)) { getExportsOfSymbol(parent); } else { getMembersOfSymbol(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 = (type as TypeReference).target; const typeArguments = getTypeArguments(type as TypeReference); 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) { const types = sameMap((type as IntersectionType).types, t => getTypeWithThisArgument(t, thisArgument, needApparentType)); return types !== (type as IntersectionType).types ? getIntersectionType(types) : type; } return needApparentType ? getApparentType(type) : type; } function getThisArgument(type: Type) { return getObjectFlags(type) & ObjectFlags.Reference && length(getTypeArguments(type as TypeReference)) > getTypeReferenceArity(type as TypeReference) ? last(getTypeArguments(type as TypeReference)) : type; } function resolveObjectTypeMembers(type: ObjectType, source: InterfaceTypeWithDeclaredMembers, typeParameters: readonly TypeParameter[], typeArguments: readonly Type[]) { let mapper: TypeMapper | undefined; let members: SymbolTable; let callSignatures: readonly Signature[]; let constructSignatures: readonly Signature[]; let indexInfos: readonly IndexInfo[]; if (rangeEquals(typeParameters, typeArguments, 0, typeParameters.length)) { members = source.symbol ? getMembersOfSymbol(source.symbol) : createSymbolTable(source.declaredProperties); callSignatures = source.declaredCallSignatures; constructSignatures = source.declaredConstructSignatures; indexInfos = source.declaredIndexInfos; } else { mapper = createTypeMapper(typeParameters, typeArguments); members = createInstantiatedSymbolTable(source.declaredProperties, mapper, /*mappingThisOnly*/ typeParameters.length === 1); callSignatures = instantiateSignatures(source.declaredCallSignatures, mapper); constructSignatures = instantiateSignatures(source.declaredConstructSignatures, mapper); indexInfos = instantiateIndexInfos(source.declaredIndexInfos, mapper); } const baseTypes = getBaseTypes(source); if (baseTypes.length) { if (source.symbol && members === getMembersOfSymbol(source.symbol)) { members = createSymbolTable(source.declaredProperties); } setStructuredTypeMembers(type, members, callSignatures, constructSignatures, indexInfos); 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)); const inheritedIndexInfos = instantiatedBaseType !== anyType ? getIndexInfosOfType(instantiatedBaseType) : [createIndexInfo(stringType, anyType, /*isReadonly*/ false)]; indexInfos = concatenate(indexInfos, filter(inheritedIndexInfos, info => !findIndexInfo(indexInfos, info.keyType))); } } setStructuredTypeMembers(type, members, callSignatures, constructSignatures, indexInfos); } 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 = getTypeArguments(type); const paddedTypeArguments = typeArguments.length === typeParameters.length ? typeArguments : concatenate(typeArguments, [type]); resolveObjectTypeMembers(type, source, typeParameters, paddedTypeArguments); } function createSignature( declaration: SignatureDeclaration | JSDocSignature | undefined, typeParameters: readonly TypeParameter[] | undefined, thisParameter: Symbol | undefined, parameters: readonly Symbol[], resolvedReturnType: Type | undefined, resolvedTypePredicate: TypePredicate | undefined, minArgumentCount: number, flags: SignatureFlags ): Signature { const sig = new Signature(checker, flags); sig.declaration = declaration; sig.typeParameters = typeParameters; sig.parameters = parameters; sig.thisParameter = thisParameter; sig.resolvedReturnType = resolvedReturnType; sig.resolvedTypePredicate = resolvedTypePredicate; sig.minArgumentCount = minArgumentCount; sig.resolvedMinArgumentCount = undefined; sig.target = undefined; sig.mapper = undefined; sig.compositeSignatures = undefined; sig.compositeKind = undefined; return sig; } function cloneSignature(sig: Signature): Signature { const result = createSignature(sig.declaration, sig.typeParameters, sig.thisParameter, sig.parameters, /*resolvedReturnType*/ undefined, /*resolvedTypePredicate*/ undefined, sig.minArgumentCount, sig.flags & SignatureFlags.PropagatingFlags); result.target = sig.target; result.mapper = sig.mapper; result.compositeSignatures = sig.compositeSignatures; result.compositeKind = sig.compositeKind; return result; } function createUnionSignature(signature: Signature, unionSignatures: Signature[]) { const result = cloneSignature(signature); result.compositeSignatures = unionSignatures; result.compositeKind = TypeFlags.Union; result.target = undefined; result.mapper = undefined; return result; } function getOptionalCallSignature(signature: Signature, callChainFlags: SignatureFlags): Signature { if ((signature.flags & SignatureFlags.CallChainFlags) === callChainFlags) { return signature; } if (!signature.optionalCallSignatureCache) { signature.optionalCallSignatureCache = {}; } const key = callChainFlags === SignatureFlags.IsInnerCallChain ? "inner" : "outer"; return signature.optionalCallSignatureCache[key] || (signature.optionalCallSignatureCache[key] = createOptionalCallSignature(signature, callChainFlags)); } function createOptionalCallSignature(signature: Signature, callChainFlags: SignatureFlags) { Debug.assert(callChainFlags === SignatureFlags.IsInnerCallChain || callChainFlags === SignatureFlags.IsOuterCallChain, "An optional call signature can either be for an inner call chain or an outer call chain, but not both."); const result = cloneSignature(signature); result.flags |= callChainFlags; return result; } function getExpandedParameters(sig: Signature, skipUnionExpanding?: boolean): readonly (readonly Symbol[])[] { if (signatureHasRestParameter(sig)) { const restIndex = sig.parameters.length - 1; const restType = getTypeOfSymbol(sig.parameters[restIndex]); if (isTupleType(restType)) { return [expandSignatureParametersWithTupleMembers(restType, restIndex)]; } else if (!skipUnionExpanding && restType.flags & TypeFlags.Union && every((restType as UnionType).types, isTupleType)) { return map((restType as UnionType).types, t => expandSignatureParametersWithTupleMembers(t as TupleTypeReference, restIndex)); } } return [sig.parameters]; function expandSignatureParametersWithTupleMembers(restType: TupleTypeReference, restIndex: number) { const elementTypes = getElementTypes(restType); const associatedNames = getUniqAssociatedNamesFromTupleType(restType); const restParams = map(elementTypes, (t, i) => { // Lookup the label from the individual tuple passed in before falling back to the signature `rest` parameter name const name = associatedNames && associatedNames[i] ? associatedNames[i] : getParameterNameAtPosition(sig, restIndex + i, restType); const flags = restType.target.elementFlags[i]; const checkFlags = flags & ElementFlags.Variable ? CheckFlags.RestParameter : flags & ElementFlags.Optional ? CheckFlags.OptionalParameter : 0; const symbol = createSymbol(SymbolFlags.FunctionScopedVariable, name, checkFlags); symbol.links.type = flags & ElementFlags.Rest ? createArrayType(t) : t; return symbol; }); return concatenate(sig.parameters.slice(0, restIndex), restParams); } function getUniqAssociatedNamesFromTupleType(type: TupleTypeReference) { const associatedNamesMap = new Map<__String, number>(); return map(type.target.labeledElementDeclarations, labeledElement => { const name = getTupleElementLabel(labeledElement); const prevCounter = associatedNamesMap.get(name); if (prevCounter === undefined) { associatedNamesMap.set(name, 1); return name; } else { associatedNamesMap.set(name, prevCounter + 1); return `${name}_${prevCounter}` as __String; } }); } } function getDefaultConstructSignatures(classType: InterfaceType): Signature[] { const baseConstructorType = getBaseConstructorTypeOfClass(classType); const baseSignatures = getSignaturesOfType(baseConstructorType, SignatureKind.Construct); const declaration = getClassLikeDeclarationOfSymbol(classType.symbol); const isAbstract = !!declaration && hasSyntacticModifier(declaration, ModifierFlags.Abstract); if (baseSignatures.length === 0) { return [createSignature(/*declaration*/ undefined, classType.localTypeParameters, /*thisParameter*/ undefined, emptyArray, classType, /*resolvedTypePredicate*/ undefined, 0, isAbstract ? SignatureFlags.Abstract : SignatureFlags.None)]; } 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; sig.flags = isAbstract ? sig.flags | SignatureFlags.Abstract : sig.flags & ~SignatureFlags.Abstract; result.push(sig); } } return result; } function findMatchingSignature(signatureList: readonly 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: readonly (readonly 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. // Prefer matching this types if possible. const match = i === listIndex ? signature : findMatchingSignature(signatureLists[i], signature, /*partialMatch*/ true, /*ignoreThisTypes*/ false, /*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: readonly (readonly 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*/ false, /*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; const firstThisParameterOfUnionSignatures = forEach(unionSignatures, sig => sig.thisParameter); if (firstThisParameterOfUnionSignatures) { const thisType = getIntersectionType(mapDefined(unionSignatures, sig => sig.thisParameter && getTypeOfSymbol(sig.thisParameter))); thisParameter = createSymbolWithType(firstThisParameterOfUnionSignatures, thisType); } s = createUnionSignature(signature, unionSignatures); s.thisParameter = thisParameter; } (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 && !compareTypeParametersIdentical(signature.typeParameters, s.typeParameters)) ? undefined : map(results, sig => combineSignaturesOfUnionMembers(sig, signature)); if (!results) { break; } } } result = results; } return result || emptyArray; } function compareTypeParametersIdentical(sourceParams: readonly TypeParameter[] | undefined, targetParams: readonly TypeParameter[] | undefined): boolean { if (length(sourceParams) !== length(targetParams)) { return false; } if (!sourceParams || !targetParams) { return true; } const mapper = createTypeMapper(targetParams, sourceParams); for (let i = 0; i < sourceParams.length; i++) { const source = sourceParams[i]; const target = targetParams[i]; if (source === target) continue; // We instantiate the target type parameter constraints into the source types so we can recognize `` as the same as `` if (!isTypeIdenticalTo(getConstraintFromTypeParameter(source) || unknownType, instantiateType(getConstraintFromTypeParameter(target) || unknownType, mapper))) return false; // We don't compare defaults - we just use the type parameter defaults from the first signature that seems to match. // It might make sense to combine these defaults in the future, but doing so intelligently requires knowing // if the parameter is used covariantly or contravariantly (so we intersect if it's used like a parameter or union if used like a return type) // and, since it's just an inference _default_, just picking one arbitrarily works OK. } return true; } function combineUnionThisParam(left: Symbol | undefined, right: Symbol | undefined, mapper: TypeMapper | 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 intersect the `this` types just like we do for param types in union signatures. const thisType = getIntersectionType([getTypeOfSymbol(left), instantiateType(getTypeOfSymbol(right), mapper)]); return createSymbolWithType(left, thisType); } function combineUnionParameters(left: Signature, right: Signature, mapper: TypeMapper | undefined) { const leftCount = getParameterCount(left); const rightCount = getParameterCount(right); const longest = leftCount >= rightCount ? left : right; const shorter = longest === left ? right : left; const longestCount = longest === left ? leftCount : rightCount; const eitherHasEffectiveRest = (hasEffectiveRestParameter(left) || hasEffectiveRestParameter(right)); const needsExtraRestElement = eitherHasEffectiveRest && !hasEffectiveRestParameter(longest); const params = new Array(longestCount + (needsExtraRestElement ? 1 : 0)); for (let i = 0; i < longestCount; i++) { let longestParamType = tryGetTypeAtPosition(longest, i)!; if (longest === right) { longestParamType = instantiateType(longestParamType, mapper); } let shorterParamType = tryGetTypeAtPosition(shorter, i) || unknownType; if (shorter === right) { shorterParamType = instantiateType(shorterParamType, mapper); } const unionParamType = getIntersectionType([longestParamType, shorterParamType]); const isRestParam = eitherHasEffectiveRest && !needsExtraRestElement && i === (longestCount - 1); const isOptional = i >= getMinArgumentCount(longest) && i >= getMinArgumentCount(shorter); const leftName = i >= leftCount ? undefined : getParameterNameAtPosition(left, i); const rightName = i >= rightCount ? undefined : getParameterNameAtPosition(right, i); const paramName = leftName === rightName ? leftName : !leftName ? rightName : !rightName ? leftName : undefined; const paramSymbol = createSymbol( SymbolFlags.FunctionScopedVariable | (isOptional && !isRestParam ? SymbolFlags.Optional : 0), paramName || `arg${i}` as __String ); paramSymbol.links.type = isRestParam ? createArrayType(unionParamType) : unionParamType; params[i] = paramSymbol; } if (needsExtraRestElement) { const restParamSymbol = createSymbol(SymbolFlags.FunctionScopedVariable, "args" as __String); restParamSymbol.links.type = createArrayType(getTypeAtPosition(shorter, longestCount)); if (shorter === right) { restParamSymbol.links.type = instantiateType(restParamSymbol.links.type, mapper); } params[longestCount] = restParamSymbol; } return params; } function combineSignaturesOfUnionMembers(left: Signature, right: Signature): Signature { const typeParams = left.typeParameters || right.typeParameters; let paramMapper: TypeMapper | undefined; if (left.typeParameters && right.typeParameters) { paramMapper = createTypeMapper(right.typeParameters, left.typeParameters); // We just use the type parameter defaults from the first signature } const declaration = left.declaration; const params = combineUnionParameters(left, right, paramMapper); const thisParam = combineUnionThisParam(left.thisParameter, right.thisParameter, paramMapper); const minArgCount = Math.max(left.minArgumentCount, right.minArgumentCount); const result = createSignature( declaration, typeParams, thisParam, params, /*resolvedReturnType*/ undefined, /*resolvedTypePredicate*/ undefined, minArgCount, (left.flags | right.flags) & SignatureFlags.PropagatingFlags ); result.compositeKind = TypeFlags.Union; result.compositeSignatures = concatenate(left.compositeKind !== TypeFlags.Intersection && left.compositeSignatures || [left], [right]); if (paramMapper) { result.mapper = left.compositeKind !== TypeFlags.Intersection && left.mapper && left.compositeSignatures ? combineTypeMappers(left.mapper, paramMapper) : paramMapper; } return result; } function getUnionIndexInfos(types: readonly Type[]): IndexInfo[] { const sourceInfos = getIndexInfosOfType(types[0]); if (sourceInfos) { const result = []; for (const info of sourceInfos) { const indexType = info.keyType; if (every(types, t => !!getIndexInfoOfType(t, indexType))) { result.push(createIndexInfo(indexType, getUnionType(map(types, t => getIndexTypeOfType(t, indexType)!)), some(types, t => getIndexInfoOfType(t, indexType)!.isReadonly))); } } return result; } return emptyArray; } 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 indexInfos = getUnionIndexInfos(type.types); setStructuredTypeMembers(type, emptySymbols, callSignatures, constructSignatures, indexInfos); } 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 findMixins(types: readonly Type[]): readonly boolean[] { const constructorTypeCount = countWhere(types, (t) => getSignaturesOfType(t, SignatureKind.Construct).length > 0); const mixinFlags = map(types, isMixinConstructorType); if (constructorTypeCount > 0 && constructorTypeCount === countWhere(mixinFlags, (b) => b)) { const firstMixinIndex = mixinFlags.indexOf(/*searchElement*/ true); mixinFlags[firstMixinIndex] = false; } return mixinFlags; } function includeMixinType(type: Type, types: readonly Type[], mixinFlags: readonly boolean[], index: number): Type { const mixedTypes: Type[] = []; for (let i = 0; i < types.length; i++) { if (i === index) { mixedTypes.push(type); } else if (mixinFlags[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: Signature[] | undefined; let constructSignatures: Signature[] | undefined; let indexInfos: IndexInfo[] | undefined; const types = type.types; const mixinFlags = findMixins(types); const mixinCount = countWhere(mixinFlags, (b) => b); 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 (!mixinFlags[i]) { 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, mixinFlags, i); return clone; }); } constructSignatures = appendSignatures(constructSignatures, signatures); } callSignatures = appendSignatures(callSignatures, getSignaturesOfType(t, SignatureKind.Call)); indexInfos = reduceLeft(getIndexInfosOfType(t), (infos, newInfo) => appendIndexInfo(infos, newInfo, /*union*/ false), indexInfos); } setStructuredTypeMembers(type, emptySymbols, callSignatures || emptyArray, constructSignatures || emptyArray, indexInfos || emptyArray); } function appendSignatures(signatures: Signature[] | undefined, newSignatures: readonly Signature[]) { for (const sig of newSignatures) { if (!signatures || every(signatures, s => !compareSignaturesIdentical(s, sig, /*partialMatch*/ false, /*ignoreThisTypes*/ false, /*ignoreReturnTypes*/ false, compareTypesIdentical))) { signatures = append(signatures, sig); } } return signatures; } function appendIndexInfo(indexInfos: IndexInfo[] | undefined, newInfo: IndexInfo, union: boolean) { if (indexInfos) { for (let i = 0; i < indexInfos.length; i++) { const info = indexInfos[i]; if (info.keyType === newInfo.keyType) { indexInfos[i] = createIndexInfo(info.keyType, union ? getUnionType([info.type, newInfo.type]) : getIntersectionType([info.type, newInfo.type]), union ? info.isReadonly || newInfo.isReadonly : info.isReadonly && newInfo.isReadonly); return indexInfos; } } } return append(indexInfos, newInfo); } /** * Converts an AnonymousType to a ResolvedType. */ function resolveAnonymousTypeMembers(type: AnonymousType) { if (type.target) { setStructuredTypeMembers(type, emptySymbols, emptyArray, emptyArray, emptyArray); 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 indexInfos = instantiateIndexInfos(getIndexInfosOfType(type.target), type.mapper!); setStructuredTypeMembers(type, members, callSignatures, constructSignatures, indexInfos); return; } const symbol = getMergedSymbol(type.symbol); if (symbol.flags & SymbolFlags.TypeLiteral) { setStructuredTypeMembers(type, emptySymbols, emptyArray, emptyArray, emptyArray); const members = getMembersOfSymbol(symbol); const callSignatures = getSignaturesOfSymbol(members.get(InternalSymbolName.Call)); const constructSignatures = getSignaturesOfSymbol(members.get(InternalSymbolName.New)); const indexInfos = getIndexInfosOfSymbol(symbol); setStructuredTypeMembers(type, members, callSignatures, constructSignatures, indexInfos); return; } // Combinations of function, class, enum and module let members = emptySymbols; let indexInfos: IndexInfo[] | undefined; if (symbol.exports) { members = getExportsOfSymbol(symbol); if (symbol === globalThisSymbol) { const varsOnly = new Map<__String, Symbol>(); members.forEach(p => { if (!(p.flags & SymbolFlags.BlockScoped) && !(p.flags & SymbolFlags.ValueModule && p.declarations?.length && every(p.declarations, isAmbientModule))) { varsOnly.set(p.escapedName, p); } }); members = varsOnly; } } let baseConstructorIndexInfo: IndexInfo | undefined; setStructuredTypeMembers(type, members, emptyArray, emptyArray, emptyArray); if (symbol.flags & SymbolFlags.Class) { const classType = getDeclaredTypeOfClassOrInterface(symbol); const baseConstructorType = getBaseConstructorTypeOfClass(classType); if (baseConstructorType.flags & (TypeFlags.Object | TypeFlags.Intersection | TypeFlags.TypeVariable)) { members = createSymbolTable(getNamedOrIndexSignatureMembers(members)); addInheritedMembers(members, getPropertiesOfType(baseConstructorType)); } else if (baseConstructorType === anyType) { baseConstructorIndexInfo = createIndexInfo(stringType, anyType, /*isReadonly*/ false); } } const indexSymbol = getIndexSymbolFromSymbolTable(members); if (indexSymbol) { indexInfos = getIndexInfosOfIndexSymbol(indexSymbol); } else { if (baseConstructorIndexInfo) { indexInfos = append(indexInfos, baseConstructorIndexInfo); } if (symbol.flags & SymbolFlags.Enum && (getDeclaredTypeOfSymbol(symbol).flags & TypeFlags.Enum || some(type.properties, prop => !!(getTypeOfSymbol(prop).flags & TypeFlags.NumberLike)))) { indexInfos = append(indexInfos, enumNumberIndexInfo); } } setStructuredTypeMembers(type, members, emptyArray, emptyArray, indexInfos || emptyArray); // 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); } // And likewise for construct signatures for classes if (symbol.flags & SymbolFlags.Class) { const classType = getDeclaredTypeOfClassOrInterface(symbol); let constructSignatures = symbol.members ? getSignaturesOfSymbol(symbol.members.get(InternalSymbolName.Constructor)) : emptyArray; if (symbol.flags & SymbolFlags.Function) { constructSignatures = addRange(constructSignatures.slice(), mapDefined( type.callSignatures, sig => isJSConstructor(sig.declaration) ? createSignature(sig.declaration, sig.typeParameters, sig.thisParameter, sig.parameters, classType, /*resolvedTypePredicate*/ undefined, sig.minArgumentCount, sig.flags & SignatureFlags.PropagatingFlags) : undefined)); } if (!constructSignatures.length) { constructSignatures = getDefaultConstructSignatures(classType); } type.constructSignatures = constructSignatures; } } type ReplaceableIndexedAccessType = IndexedAccessType & { objectType: TypeParameter, indexType: TypeParameter }; function replaceIndexedAccess(instantiable: Type, type: ReplaceableIndexedAccessType, replacement: Type) { // map type.indexType to 0 // map type.objectType to `[TReplacement]` // thus making the indexed access `[TReplacement][0]` or `TReplacement` return instantiateType(instantiable, createTypeMapper([type.indexType, type.objectType], [getNumberLiteralType(0), createTupleType([replacement])])); } function resolveReverseMappedTypeMembers(type: ReverseMappedType) { const indexInfo = getIndexInfoOfType(type.source, stringType); const modifiers = getMappedTypeModifiers(type.mappedType); const readonlyMask = modifiers & MappedTypeModifiers.IncludeReadonly ? false : true; const optionalMask = modifiers & MappedTypeModifiers.IncludeOptional ? 0 : SymbolFlags.Optional; const indexInfos = indexInfo ? [createIndexInfo(stringType, inferReverseMappedType(indexInfo.type, type.mappedType, type.constraintType), readonlyMask && indexInfo.isReadonly)] : emptyArray; 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.links.nameType = getSymbolLinks(prop).nameType; inferredProp.links.propertyType = getTypeOfSymbol(prop); if (type.constraintType.type.flags & TypeFlags.IndexedAccess && (type.constraintType.type as IndexedAccessType).objectType.flags & TypeFlags.TypeParameter && (type.constraintType.type as IndexedAccessType).indexType.flags & TypeFlags.TypeParameter) { // A reverse mapping of `{[K in keyof T[K_1]]: T[K_1]}` is the same as that of `{[K in keyof T]: T}`, since all we care about is // inferring to the "type parameter" (or indexed access) shared by the constraint and template. So, to reduce the number of // type identities produced, we simplify such indexed access occurences const newTypeParam = (type.constraintType.type as IndexedAccessType).objectType; const newMappedType = replaceIndexedAccess(type.mappedType, type.constraintType.type as ReplaceableIndexedAccessType, newTypeParam); inferredProp.links.mappedType = newMappedType as MappedType; inferredProp.links.constraintType = getIndexType(newTypeParam) as IndexType; } else { inferredProp.links.mappedType = type.mappedType; inferredProp.links.constraintType = type.constraintType; } members.set(prop.escapedName, inferredProp); } setStructuredTypeMembers(type, members, emptyArray, emptyArray, indexInfos); } // 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.Index) { const t = getApparentType((type as IndexType).type); return isGenericTupleType(t) ? getKnownKeysOfTupleType(t) : getIndexType(t); } if (type.flags & TypeFlags.Conditional) { if ((type as ConditionalType).root.isDistributive) { const checkType = (type as ConditionalType).checkType; const constraint = getLowerBoundOfKeyType(checkType); if (constraint !== checkType) { return getConditionalTypeInstantiation(type as ConditionalType, prependTypeMapping((type as ConditionalType).root.checkType, constraint, (type as ConditionalType).mapper)); } } return type; } if (type.flags & TypeFlags.Union) { return mapType(type as UnionType, getLowerBoundOfKeyType, /*noReductions*/ true); } if (type.flags & TypeFlags.Intersection) { // Similarly to getTypeFromIntersectionTypeNode, we preserve the special string & {}, number & {}, // and bigint & {} intersections that are used to prevent subtype reduction in union types. const types = (type as IntersectionType).types; if (types.length === 2 && !!(types[0].flags & (TypeFlags.String | TypeFlags.Number | TypeFlags.BigInt)) && types[1] === emptyTypeLiteralType) { return type; } return getIntersectionType(sameMap((type as UnionType).types, getLowerBoundOfKeyType)); } return type; } function getIsLateCheckFlag(s: Symbol): CheckFlags { return getCheckFlags(s) & CheckFlags.Late; } function forEachMappedTypePropertyKeyTypeAndIndexSignatureKeyType(type: Type, include: TypeFlags, stringsOnly: boolean, cb: (keyType: Type) => void) { for (const prop of getPropertiesOfType(type)) { cb(getLiteralTypeFromProperty(prop, include)); } if (type.flags & TypeFlags.Any) { cb(stringType); } else { for (const info of getIndexInfosOfType(type)) { if (!stringsOnly || info.keyType.flags & (TypeFlags.String | TypeFlags.TemplateLiteral)) { cb(info.keyType); } } } } /** Resolve the members of a mapped type { [P in K]: T } */ function resolveMappedTypeMembers(type: MappedType) { const members: SymbolTable = createSymbolTable(); let indexInfos: IndexInfo[] | undefined; // Resolve upfront such that recursive references see an empty object type. setStructuredTypeMembers(type, emptySymbols, emptyArray, emptyArray, emptyArray); // 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 mappedType = (type.target as MappedType) || type; const nameType = getNameTypeFromMappedType(mappedType); const shouldLinkPropDeclarations = !nameType || isFilteringMappedType(mappedType); const templateType = getTemplateTypeFromMappedType(mappedType); 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 } forEachMappedTypePropertyKeyTypeAndIndexSignatureKeyType(modifiersType, include, keyofStringsOnly, addMemberForKeyType); } else { forEachType(getLowerBoundOfKeyType(constraintType), addMemberForKeyType); } setStructuredTypeMembers(type, members, emptyArray, emptyArray, indexInfos || emptyArray); function addMemberForKeyType(keyType: Type) { const propNameType = nameType ? instantiateType(nameType, appendTypeMapping(type.mapper, typeParameter, keyType)) : keyType; forEachType(propNameType, t => addMemberForKeyTypeWorker(keyType, t)); } function addMemberForKeyTypeWorker(keyType: Type, propNameType: Type) { // 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(propNameType)) { const propName = getPropertyNameFromType(propNameType); // String enum members from separate enums with identical values // are distinct types with the same property name. Make the resulting // property symbol's name type be the union of those enum member types. const existingProp = members.get(propName) as MappedSymbol | undefined; if (existingProp) { existingProp.links.nameType = getUnionType([existingProp.links.nameType!, propNameType]); existingProp.links.keyType = getUnionType([existingProp.links.keyType, keyType]); } else { const modifiersProp = isTypeUsableAsPropertyName(keyType) ? getPropertyOfType(modifiersType, getPropertyNameFromType(keyType)) : undefined; 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 stripOptional = strictNullChecks && !isOptional && modifiersProp && modifiersProp.flags & SymbolFlags.Optional; const lateFlag: CheckFlags = modifiersProp ? getIsLateCheckFlag(modifiersProp) : 0; const prop = createSymbol(SymbolFlags.Property | (isOptional ? SymbolFlags.Optional : 0), propName, lateFlag | CheckFlags.Mapped | (isReadonly ? CheckFlags.Readonly : 0) | (stripOptional ? CheckFlags.StripOptional : 0)) as MappedSymbol; prop.links.mappedType = type; prop.links.nameType = propNameType; prop.links.keyType = keyType; if (modifiersProp) { prop.links.syntheticOrigin = modifiersProp; prop.declarations = shouldLinkPropDeclarations ? modifiersProp.declarations : undefined; } members.set(propName, prop); } } else if (isValidIndexKeyType(propNameType) || propNameType.flags & (TypeFlags.Any | TypeFlags.Enum)) { const indexKeyType = propNameType.flags & (TypeFlags.Any | TypeFlags.String) ? stringType : propNameType.flags & (TypeFlags.Number | TypeFlags.Enum) ? numberType : propNameType; const propType = instantiateType(templateType, appendTypeMapping(type.mapper, typeParameter, keyType)); const indexInfo = createIndexInfo(indexKeyType, propType, !!(templateModifiers & MappedTypeModifiers.IncludeReadonly)); indexInfos = appendIndexInfo(indexInfos, indexInfo, /*union*/ true); } } } function getTypeOfMappedSymbol(symbol: MappedSymbol) { if (!symbol.links.type) { const mappedType = symbol.links.mappedType; if (!pushTypeResolution(symbol, TypeSystemPropertyName.Type)) { mappedType.containsError = true; return errorType; } const templateType = getTemplateTypeFromMappedType(mappedType.target as MappedType || mappedType); const mapper = appendTypeMapping(mappedType.mapper, getTypeParameterFromMappedType(mappedType), symbol.links.keyType); const propType = instantiateType(templateType, mapper); // 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. let type = strictNullChecks && symbol.flags & SymbolFlags.Optional && !maybeTypeOfKind(propType, TypeFlags.Undefined | TypeFlags.Void) ? getOptionalType(propType, /*isProperty*/ true) : symbol.links.checkFlags & CheckFlags.StripOptional ? removeMissingOrUndefinedType(propType) : propType; if (!popTypeResolution()) { error(currentNode, Diagnostics.Type_of_property_0_circularly_references_itself_in_mapped_type_1, symbolToString(symbol), typeToString(mappedType)); type = errorType; } symbol.links.type = type; } return symbol.links.type; } function getTypeParameterFromMappedType(type: MappedType) { return type.typeParameter || (type.typeParameter = getDeclaredTypeOfTypeParameter(getSymbolOfDeclaration(type.declaration.typeParameter))); } function getConstraintTypeFromMappedType(type: MappedType) { return type.constraintType || (type.constraintType = getConstraintOfTypeParameter(getTypeParameterFromMappedType(type)) || errorType); } function getNameTypeFromMappedType(type: MappedType) { return type.declaration.nameType ? type.nameType || (type.nameType = instantiateType(getTypeFromTypeNode(type.declaration.nameType), type.mapper)) : undefined; } function getTemplateTypeFromMappedType(type: MappedType) { return type.templateType || (type.templateType = type.declaration.type ? instantiateType(addOptionality(getTypeFromTypeNode(type.declaration.type), /*isProperty*/ true, !!(getMappedTypeModifiers(type) & MappedTypeModifiers.IncludeOptional)), type.mapper) : 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 && (constraintDeclaration as TypeOperatorNode).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((getConstraintDeclarationForMappedType(type) as TypeOperatorNode).type), type.mapper); } 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 unknown. const declaredType = getTypeFromMappedTypeNode(type.declaration) as MappedType; const constraint = getConstraintTypeFromMappedType(declaredType); const extendedConstraint = constraint && constraint.flags & TypeFlags.TypeParameter ? getConstraintOfTypeParameter(constraint as TypeParameter) : constraint; type.modifiersType = extendedConstraint && extendedConstraint.flags & TypeFlags.Index ? instantiateType((extendedConstraint as IndexType).type, type.mapper) : unknownType; } } 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(type as MappedType) & MappedTypeModifiers.IncludeOptional); } function isGenericMappedType(type: Type): type is MappedType { if (getObjectFlags(type) & ObjectFlags.Mapped) { const constraint = getConstraintTypeFromMappedType(type as MappedType); if (isGenericIndexType(constraint)) { return true; } // A mapped type is generic if the 'as' clause references generic types other than the iteration type. // To determine this, we substitute the constraint type (that we now know isn't generic) for the iteration // type and check whether the resulting type is generic. const nameType = getNameTypeFromMappedType(type as MappedType); if (nameType && isGenericIndexType(instantiateType(nameType, makeUnaryTypeMapper(getTypeParameterFromMappedType(type as MappedType), constraint)))) { return true; } } return false; } function isFilteringMappedType(type: MappedType): boolean { const nameType = getNameTypeFromMappedType(type); return !!nameType && isTypeAssignableTo(nameType, getTypeParameterFromMappedType(type)); } function resolveStructuredTypeMembers(type: StructuredType): ResolvedType { if (!(type as ResolvedType).members) { if (type.flags & TypeFlags.Object) { if ((type as ObjectType).objectFlags & ObjectFlags.Reference) { resolveTypeReferenceMembers(type as TypeReference); } else if ((type as ObjectType).objectFlags & ObjectFlags.ClassOrInterface) { resolveClassOrInterfaceMembers(type as InterfaceType); } else if ((type as ReverseMappedType).objectFlags & ObjectFlags.ReverseMapped) { resolveReverseMappedTypeMembers(type as ReverseMappedType); } else if ((type as ObjectType).objectFlags & ObjectFlags.Anonymous) { resolveAnonymousTypeMembers(type as AnonymousType); } else if ((type as MappedType).objectFlags & ObjectFlags.Mapped) { resolveMappedTypeMembers(type as MappedType); } else { Debug.fail("Unhandled object type " + Debug.formatObjectFlags(type.objectFlags)); } } else if (type.flags & TypeFlags.Union) { resolveUnionTypeMembers(type as UnionType); } else if (type.flags & TypeFlags.Intersection) { resolveIntersectionTypeMembers(type as IntersectionType); } else { Debug.fail("Unhandled type " + Debug.formatTypeFlags(type.flags)); } } return type as ResolvedType; } /** 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(type as ObjectType).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(type as ObjectType); 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 without index signature if (type.flags & TypeFlags.Union && getIndexInfosOfType(current).length === 0) { break; } } type.resolvedProperties = getNamedMembers(members); } return type.resolvedProperties; } function getPropertiesOfType(type: Type): Symbol[] { type = getReducedApparentType(type); return type.flags & TypeFlags.UnionOrIntersection ? getPropertiesOfUnionOrIntersectionType(type as UnionType) : getPropertiesOfObjectType(type); } function forEachPropertyOfType(type: Type, action: (symbol: Symbol, escapedName: __String) => void): void { type = getReducedApparentType(type); if (type.flags & TypeFlags.StructuredType) { resolveStructuredTypeMembers(type as StructuredType).members.forEach((symbol, escapedName) => { if (isNamedMember(symbol, escapedName)) { action(symbol, escapedName); } }); } } function isTypeInvalidDueToUnionDiscriminant(contextualType: Type, obj: ObjectLiteralExpression | JsxAttributes): boolean { const list = obj.properties as NodeArray; return list.some(property => { const nameType = property.name && (isJsxNamespacedName(property.name) ? getStringLiteralType(getTextOfJsxAttributeName(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: readonly 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(type as TypeParameter) : type.flags & TypeFlags.IndexedAccess ? getConstraintOfIndexedAccess(type as IndexedAccessType) : type.flags & TypeFlags.Conditional ? getConstraintOfConditionalType(type as ConditionalType) : getBaseConstraintOfType(type); } function getConstraintOfTypeParameter(typeParameter: TypeParameter): Type | undefined { return hasNonCircularBaseConstraint(typeParameter) ? getConstraintFromTypeParameter(typeParameter) : undefined; } function isConstTypeVariable(type: Type | undefined): boolean { return !!(type && ( type.flags & TypeFlags.TypeParameter && some((type as TypeParameter).symbol?.declarations, d => hasSyntacticModifier(d, ModifierFlags.Const)) || type.flags & TypeFlags.Union && some((type as UnionType).types, isConstTypeVariable) || type.flags & TypeFlags.IndexedAccess && isConstTypeVariable((type as IndexedAccessType).objectType) || type.flags & TypeFlags.Conditional && isConstTypeVariable(getConstraintOfConditionalType(type as ConditionalType)) || type.flags & TypeFlags.Substitution && isConstTypeVariable((type as SubstitutionType).baseType) || isGenericTupleType(type) && findIndex(getElementTypes(type), (t, i) => !!(type.target.elementFlags[i] & ElementFlags.Variadic) && isConstTypeVariable(t)) >= 0)); } function getConstraintOfIndexedAccess(type: IndexedAccessType) { return hasNonCircularBaseConstraint(type) ? getConstraintFromIndexedAccess(type) : undefined; } function getSimplifiedTypeOrConstraint(type: Type) { const simplified = getSimplifiedType(type, /*writing*/ false); return simplified !== type ? simplified : getConstraintOfType(type); } function getConstraintFromIndexedAccess(type: IndexedAccessType) { if (isMappedTypeGenericIndexedAccess(type) || isGenericMappedType(type.objectType)) { // For indexed access types of the form { [P in K]: E }[X], where K is non-generic and X is generic, // we substitute an instantiation of E where P is replaced with X. return substituteIndexedMappedType(type.objectType as MappedType, type.indexType); } const indexConstraint = getSimplifiedTypeOrConstraint(type.indexType); if (indexConstraint && indexConstraint !== type.indexType) { const indexedAccess = getIndexedAccessTypeOrUndefined(type.objectType, indexConstraint, type.accessFlags); if (indexedAccess) { return indexedAccess; } } const objectConstraint = getSimplifiedTypeOrConstraint(type.objectType); if (objectConstraint && objectConstraint !== type.objectType) { return getIndexedAccessTypeOrUndefined(objectConstraint, type.indexType, type.accessFlags); } return undefined; } function getDefaultConstraintOfConditionalType(type: ConditionalType) { if (!type.resolvedDefaultConstraint) { // An `any` branch of a conditional type would normally be viral - specifically, without special handling here, // a conditional type with a single branch of type `any` would be assignable to anything, since it's constraint would simplify to // just `any`. This result is _usually_ unwanted - so instead here we elide an `any` branch from the constraint type, // in effect treating `any` like `never` rather than `unknown` in this location. const trueConstraint = getInferredTrueTypeFromConditionalType(type); const falseConstraint = getFalseTypeFromConditionalType(type); type.resolvedDefaultConstraint = isTypeAny(trueConstraint) ? falseConstraint : isTypeAny(falseConstraint) ? trueConstraint : getUnionType([trueConstraint, falseConstraint]); } return type.resolvedDefaultConstraint; } function getConstraintOfDistributiveConditionalType(type: ConditionalType): Type | undefined { if (type.resolvedConstraintOfDistributive !== undefined) { return type.resolvedConstraintOfDistributive || 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. // We skip returning a distributive constraint for a restrictive instantiation of a conditional type // as the constraint for all type params (check type included) have been replace with `unknown`, which // is going to produce even more false positive/negative results than the distribute constraint already does. // Please note: the distributive constraint is a kludge for emulating what a negated type could to do filter // a union - once negated types exist and are applied to the conditional false branch, this "constraint" // likely doesn't need to exist. if (type.root.isDistributive && type.restrictiveInstantiation !== type) { const simplified = getSimplifiedType(type.checkType, /*writing*/ false); const constraint = simplified === type.checkType ? getConstraintOfType(simplified) : simplified; if (constraint && constraint !== type.checkType) { const instantiated = getConditionalTypeInstantiation(type, prependTypeMapping(type.root.checkType, constraint, type.mapper)); if (!(instantiated.flags & TypeFlags.Never)) { type.resolvedConstraintOfDistributive = instantiated; return instantiated; } } } type.resolvedConstraintOfDistributive = false; return undefined; } function getConstraintFromConditionalType(type: ConditionalType) { return getConstraintOfDistributiveConditionalType(type) || getDefaultConstraintOfConditionalType(type); } function getConstraintOfConditionalType(type: ConditionalType) { return hasNonCircularBaseConstraint(type) ? getConstraintFromConditionalType(type) : undefined; } function getEffectiveConstraintOfIntersection(types: readonly Type[], targetIsUnion: boolean) { let constraints: Type[] | undefined; let hasDisjointDomainType = false; for (const t of 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) { constraints = append(constraints, constraint); if (targetIsUnion) { constraints = append(constraints, t); } } } else if (t.flags & TypeFlags.DisjointDomains || isEmptyAnonymousObjectType(t)) { hasDisjointDomainType = true; } } // If the target is a union type or if we are intersecting with types belonging to one of the // disjoint domains, 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 domains because they might cause the final // intersection operation to reduce the union constraints. for (const t of types) { if (t.flags & TypeFlags.DisjointDomains || isEmptyAnonymousObjectType(t)) { constraints = append(constraints, t); } } } // The source types were normalized; ensure the result is normalized too. return getNormalizedType(getIntersectionType(constraints), /*writing*/ false); } return undefined; } function getBaseConstraintOfType(type: Type): Type | undefined { if (type.flags & (TypeFlags.InstantiableNonPrimitive | TypeFlags.UnionOrIntersection | TypeFlags.TemplateLiteral | TypeFlags.StringMapping) || isGenericTupleType(type)) { const constraint = getResolvedBaseConstraint(type as InstantiableType | UnionOrIntersectionType); 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 { if (type.resolvedBaseConstraint) { return type.resolvedBaseConstraint; } const stack: object[] = []; return type.resolvedBaseConstraint = getTypeWithThisArgument(getImmediateBaseConstraint(type), getThisArgument(type)); function getImmediateBaseConstraint(t: Type): Type { if (!t.immediateBaseConstraint) { if (!pushTypeResolution(t, TypeSystemPropertyName.ImmediateBaseConstraint)) { return circularConstraintType; } let result; // We always explore at least 10 levels of nested constraints. Thereafter, we continue to explore // up to 50 levels of nested constraints provided there are no "deeply nested" types on the stack // (i.e. no types for which five instantiations have been recorded on the stack). If we reach 50 // levels of nesting, we are presumably exploring a repeating pattern with a long cycle that hasn't // yet triggered the deeply nested limiter. We have no test cases that actually get to 50 levels of // nesting, so it is effectively just a safety stop. const identity = getRecursionIdentity(t); if (stack.length < 10 || stack.length < 50 && !contains(stack, identity)) { stack.push(identity); result = computeBaseConstraint(getSimplifiedType(t, /*writing*/ false)); stack.pop(); } if (!popTypeResolution()) { if (t.flags & TypeFlags.TypeParameter) { const errorNode = getConstraintDeclaration(t as TypeParameter); 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; } 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(t as TypeParameter); return (t as TypeParameter).isThisType || !constraint ? constraint : getBaseConstraint(constraint); } if (t.flags & TypeFlags.UnionOrIntersection) { const types = (t as UnionOrIntersectionType).types; const baseTypes: Type[] = []; let different = false; for (const type of types) { const baseType = getBaseConstraint(type); if (baseType) { if (baseType !== type) { different = true; } baseTypes.push(baseType); } else { different = true; } } if (!different) { return t; } 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.TemplateLiteral) { const types = (t as TemplateLiteralType).types; const constraints = mapDefined(types, getBaseConstraint); return constraints.length === types.length ? getTemplateLiteralType((t as TemplateLiteralType).texts, constraints) : stringType; } if (t.flags & TypeFlags.StringMapping) { const constraint = getBaseConstraint((t as StringMappingType).type); return constraint && constraint !== (t as StringMappingType).type ? getStringMappingType((t as StringMappingType).symbol, constraint) : stringType; } if (t.flags & TypeFlags.IndexedAccess) { if (isMappedTypeGenericIndexedAccess(t)) { // For indexed access types of the form { [P in K]: E }[X], where K is non-generic and X is generic, // we substitute an instantiation of E where P is replaced with X. return getBaseConstraint(substituteIndexedMappedType((t as IndexedAccessType).objectType as MappedType, (t as IndexedAccessType).indexType)); } const baseObjectType = getBaseConstraint((t as IndexedAccessType).objectType); const baseIndexType = getBaseConstraint((t as IndexedAccessType).indexType); const baseIndexedAccess = baseObjectType && baseIndexType && getIndexedAccessTypeOrUndefined(baseObjectType, baseIndexType, (t as IndexedAccessType).accessFlags); return baseIndexedAccess && getBaseConstraint(baseIndexedAccess); } if (t.flags & TypeFlags.Conditional) { const constraint = getConstraintFromConditionalType(t as ConditionalType); return constraint && getBaseConstraint(constraint); } if (t.flags & TypeFlags.Substitution) { return getBaseConstraint(getSubstitutionIntersection(t as SubstitutionType)); } if (isGenericTupleType(t)) { // We substitute constraints for variadic elements only when the constraints are array types or // non-variadic tuple types as we want to avoid further (possibly unbounded) recursion. const newElements = map(getElementTypes(t), (v, i) => { const constraint = t.target.elementFlags[i] & ElementFlags.Variadic && getBaseConstraint(v) || v; return constraint && everyType(constraint, c => isArrayOrTupleType(c) && !isGenericTupleType(c)) ? constraint : v; }); return createTupleType(newElements, t.target.elementFlags, t.target.readonly, t.target.labeledElementDeclarations); } return t; } } function getApparentTypeOfIntersectionType(type: IntersectionType) { return type.resolvedApparentType || (type.resolvedApparentType = getTypeWithThisArgument(type, type, /*needApparentType*/ 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 && !type.declaration.nameType) { const constraint = getConstraintOfTypeParameter(typeVariable); if (constraint && everyType(constraint, isArrayOrTupleType)) { return instantiateType(type, prependTypeMapping(typeVariable, constraint, type.mapper)); } } return type; } function isMappedTypeGenericIndexedAccess(type: Type) { let objectType; return !!(type.flags & TypeFlags.IndexedAccess && getObjectFlags(objectType = (type as IndexedAccessType).objectType) & ObjectFlags.Mapped && !isGenericMappedType(objectType) && isGenericIndexType((type as IndexedAccessType).indexType) && !(getMappedTypeModifiers(objectType as MappedType) & MappedTypeModifiers.ExcludeOptional) && !(objectType as MappedType).declaration.nameType); } /** * 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. */ function getApparentType(type: Type): Type { const t = !(type.flags & TypeFlags.Instantiable) ? type : getBaseConstraintOfType(type) || unknownType; return getObjectFlags(t) & ObjectFlags.Mapped ? getApparentTypeOfMappedType(t as MappedType) : t.flags & TypeFlags.Intersection ? getApparentTypeOfIntersectionType(t as IntersectionType) : t.flags & TypeFlags.StringLike ? globalStringType : t.flags & TypeFlags.NumberLike ? globalNumberType : t.flags & TypeFlags.BigIntLike ? getGlobalBigIntType() : t.flags & TypeFlags.BooleanLike ? globalBooleanType : t.flags & TypeFlags.ESSymbolLike ? getGlobalESSymbolType() : t.flags & TypeFlags.NonPrimitive ? emptyObjectType : t.flags & TypeFlags.Index ? keyofConstraintType : t.flags & TypeFlags.Unknown && !strictNullChecks ? emptyObjectType : t; } function getReducedApparentType(type: Type): Type { // Since getApparentType may return a non-reduced union or intersection type, we need to perform // type reduction both before and after obtaining the apparent type. For example, given a type parameter // 'T extends A | B', the type 'T & X' becomes 'A & X | B & X' after obtaining the apparent type, and // that type may need further reduction to remove empty intersections. return getReducedType(getApparentType(getReducedType(type))); } function createUnionOrIntersectionProperty(containingType: UnionOrIntersectionType, name: __String, skipObjectFunctionPropertyAugment?: boolean): Symbol | undefined { let singleProp: Symbol | undefined; let propSet: Map | undefined; let indexTypes: Type[] | undefined; const isUnion = containingType.flags & TypeFlags.Union; // Flags we want to propagate to the result if they exist in all source symbols let optionalFlag: SymbolFlags | undefined; let syntheticFlag = CheckFlags.SyntheticMethod; let checkFlags = isUnion ? 0 : CheckFlags.Readonly; let mergedInstantiations = false; for (const current of containingType.types) { const type = getApparentType(current); if (!(isErrorType(type) || type.flags & TypeFlags.Never)) { const prop = getPropertyOfType(type, name, skipObjectFunctionPropertyAugment); const modifiers = prop ? getDeclarationModifierFlagsFromSymbol(prop) : 0; if (prop) { if (prop.flags & SymbolFlags.ClassMember) { optionalFlag ??= isUnion ? SymbolFlags.None : SymbolFlags.Optional; if (isUnion) { optionalFlag |= (prop.flags & SymbolFlags.Optional); } else { optionalFlag &= prop.flags; } } if (!singleProp) { singleProp = prop; } else if (prop !== singleProp) { const isInstantiation = (getTargetSymbol(prop) || prop) === (getTargetSymbol(singleProp) || singleProp); // If the symbols are instances of one another with identical types - consider the symbols // equivalent and just use the first one, which thus allows us to avoid eliding private // members when intersecting a (this-)instantiations of a class with its raw base or another instance if (isInstantiation && compareProperties(singleProp, prop, (a, b) => a === b ? Ternary.True : Ternary.False) === Ternary.True) { // If we merged instantiations of a generic type, we replicate the symbol parent resetting behavior we used // to do when we recorded multiple distinct symbols so that we still get, eg, `Array.length` printed // back and not `Array.length` when we're looking at a `.length` access on a `string[] | number[]` mergedInstantiations = !!singleProp.parent && !!length(getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(singleProp.parent)); } else { if (!propSet) { propSet = new Map(); propSet.set(getSymbolId(singleProp), singleProp); } const id = getSymbolId(prop); if (!propSet.has(id)) { propSet.set(id, prop); } } } if (isUnion && isReadonlySymbol(prop)) { checkFlags |= CheckFlags.Readonly; } else if (!isUnion && !isReadonlySymbol(prop)) { checkFlags &= ~CheckFlags.Readonly; } checkFlags |= (!(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) && getApplicableIndexInfoForName(type, name); if (indexInfo) { checkFlags |= CheckFlags.WritePartial | (indexInfo.isReadonly ? CheckFlags.Readonly : 0); indexTypes = append(indexTypes, isTupleType(type) ? getRestTypeOfTupleType(type) || undefinedType : indexInfo.type); } else if (isObjectLiteralType(type) && !(getObjectFlags(type) & ObjectFlags.ContainsSpread)) { checkFlags |= CheckFlags.WritePartial; indexTypes = append(indexTypes, undefinedType); } else { checkFlags |= CheckFlags.ReadPartial; } } } } if (!singleProp || isUnion && (propSet || checkFlags & CheckFlags.Partial) && checkFlags & (CheckFlags.ContainsPrivate | CheckFlags.ContainsProtected) && !(propSet && getCommonDeclarationsOfSymbols(propSet.values())) ) { // No property was found, or, in a union, a property has a private or protected declaration in one // constituent, but is missing or has a different declaration in another constituent. return undefined; } if (!propSet && !(checkFlags & CheckFlags.ReadPartial) && !indexTypes) { if (mergedInstantiations) { // No symbol from a union/intersection should have a `.parent` set (since unions/intersections don't act as symbol parents) // Unless that parent is "reconstituted" from the "first value declaration" on the symbol (which is likely different than its instantiated parent!) // They also have a `.containingType` set, which affects some services endpoints behavior, like `getRootSymbol` const links = tryCast(singleProp, isTransientSymbol)?.links; const clone = createSymbolWithType(singleProp, links?.type); clone.parent = singleProp.valueDeclaration?.symbol?.parent; clone.links.containingType = containingType; clone.links.mapper = links?.mapper; return clone; } else { return singleProp; } } const props = propSet ? arrayFrom(propSet.values()) : [singleProp]; let declarations: Declaration[] | undefined; let firstType: Type | undefined; let nameType: Type | undefined; const propTypes: Type[] = []; let writeTypes: Type[] | undefined; let firstValueDeclaration: Declaration | undefined; let hasNonUniformValueDeclaration = false; for (const prop of props) { if (!firstValueDeclaration) { firstValueDeclaration = prop.valueDeclaration; } else if (prop.valueDeclaration && prop.valueDeclaration !== firstValueDeclaration) { hasNonUniformValueDeclaration = true; } declarations = addRange(declarations, prop.declarations); const type = getTypeOfSymbol(prop); if (!firstType) { firstType = type; nameType = getSymbolLinks(prop).nameType; } const writeType = getWriteTypeOfSymbol(prop); if (writeTypes || writeType !== type) { writeTypes = append(!writeTypes ? propTypes.slice() : writeTypes, writeType); } else if (type !== firstType) { checkFlags |= CheckFlags.HasNonUniformType; } if (isLiteralType(type) || isPatternLiteralType(type)) { checkFlags |= CheckFlags.HasLiteralType; } if (type.flags & TypeFlags.Never && type !== uniqueLiteralType) { checkFlags |= CheckFlags.HasNeverType; } propTypes.push(type); } addRange(propTypes, indexTypes); const result = createSymbol(SymbolFlags.Property | (optionalFlag ?? 0), name, syntheticFlag | checkFlags); result.links.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.links.nameType = nameType; if (propTypes.length > 2) { // When `propTypes` has the potential to explode in size when normalized, defer normalization until absolutely needed result.links.checkFlags |= CheckFlags.DeferredType; result.links.deferralParent = containingType; result.links.deferralConstituents = propTypes; result.links.deferralWriteConstituents = writeTypes; } else { result.links.type = isUnion ? getUnionType(propTypes) : getIntersectionType(propTypes); if (writeTypes) { result.links.writeType = isUnion ? getUnionType(writeTypes) : getIntersectionType(writeTypes); } } 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, skipObjectFunctionPropertyAugment?: boolean): Symbol | undefined { let property = type.propertyCacheWithoutObjectFunctionPropertyAugment?.get(name) || !skipObjectFunctionPropertyAugment ? type.propertyCache?.get(name) : undefined; if (!property) { property = createUnionOrIntersectionProperty(type, name, skipObjectFunctionPropertyAugment); if (property) { const properties = skipObjectFunctionPropertyAugment ? type.propertyCacheWithoutObjectFunctionPropertyAugment ||= createSymbolTable() : type.propertyCache ||= createSymbolTable(); properties.set(name, property); } } return property; } function getCommonDeclarationsOfSymbols(symbols: Iterable) { let commonDeclarations: Set | undefined; for (const symbol of symbols) { if (!symbol.declarations) { return undefined; } if (!commonDeclarations) { commonDeclarations = new Set(symbol.declarations); continue; } commonDeclarations.forEach(declaration => { if (!contains(symbol.declarations, declaration)) { commonDeclarations!.delete(declaration); } }); if (commonDeclarations.size === 0) { return undefined; } } return commonDeclarations; } function getPropertyOfUnionOrIntersectionType(type: UnionOrIntersectionType, name: __String, skipObjectFunctionPropertyAugment?: boolean): Symbol | undefined { const property = getUnionOrIntersectionProperty(type, name, skipObjectFunctionPropertyAugment); // We need to filter out partial properties in union types return property && !(getCheckFlags(property) & CheckFlags.ReadPartial) ? property : undefined; } /** * Return the reduced form of the given type. For a union type, it is a union of the normalized constituent types. * For an intersection of types containing one or more mututally exclusive discriminant properties, it is 'never'. * For all other types, it is simply the type itself. Discriminant properties are considered mutually exclusive when * no constituent property has type 'never', but the intersection of the constituent property types is 'never'. */ function getReducedType(type: Type): Type { if (type.flags & TypeFlags.Union && (type as UnionType).objectFlags & ObjectFlags.ContainsIntersections) { return (type as UnionType).resolvedReducedType || ((type as UnionType).resolvedReducedType = getReducedUnionType(type as UnionType)); } else if (type.flags & TypeFlags.Intersection) { if (!((type as IntersectionType).objectFlags & ObjectFlags.IsNeverIntersectionComputed)) { (type as IntersectionType).objectFlags |= ObjectFlags.IsNeverIntersectionComputed | (some(getPropertiesOfUnionOrIntersectionType(type as IntersectionType), isNeverReducedProperty) ? ObjectFlags.IsNeverIntersection : 0); } return (type as IntersectionType).objectFlags & ObjectFlags.IsNeverIntersection ? neverType : type; } return type; } function getReducedUnionType(unionType: UnionType) { const reducedTypes = sameMap(unionType.types, getReducedType); if (reducedTypes === unionType.types) { return unionType; } const reduced = getUnionType(reducedTypes); if (reduced.flags & TypeFlags.Union) { (reduced as UnionType).resolvedReducedType = reduced; } return reduced; } function isNeverReducedProperty(prop: Symbol) { return isDiscriminantWithNeverType(prop) || isConflictingPrivateProperty(prop); } function isDiscriminantWithNeverType(prop: Symbol) { // Return true for a synthetic non-optional property with non-uniform types, where at least one is // a literal type and none is never, that reduces to never. return !(prop.flags & SymbolFlags.Optional) && (getCheckFlags(prop) & (CheckFlags.Discriminant | CheckFlags.HasNeverType)) === CheckFlags.Discriminant && !!(getTypeOfSymbol(prop).flags & TypeFlags.Never); } function isConflictingPrivateProperty(prop: Symbol) { // Return true for a synthetic property with multiple declarations, at least one of which is private. return !prop.valueDeclaration && !!(getCheckFlags(prop) & CheckFlags.ContainsPrivate); } /** * A union type which is reducible upon instantiation (meaning some members are removed under certain instantiations) * must be kept generic, as that instantiation information needs to flow through the type system. By replacing all * type parameters in the union with a special never type that is treated as a literal in `getReducedType`, we can cause * the `getReducedType` logic to reduce the resulting type if possible (since only intersections with conflicting * literal-typed properties are reducible). */ function isGenericReducibleType(type: Type): boolean { return !!(type.flags & TypeFlags.Union && (type as UnionType).objectFlags & ObjectFlags.ContainsIntersections && some((type as UnionType).types, isGenericReducibleType) || type.flags & TypeFlags.Intersection && isReducibleIntersection(type as IntersectionType)); } function isReducibleIntersection(type: IntersectionType) { const uniqueFilled = type.uniqueLiteralFilledInstantiation || (type.uniqueLiteralFilledInstantiation = instantiateType(type, uniqueLiteralMapper)); return getReducedType(uniqueFilled) !== uniqueFilled; } function elaborateNeverIntersection(errorInfo: DiagnosticMessageChain | undefined, type: Type) { if (type.flags & TypeFlags.Intersection && getObjectFlags(type) & ObjectFlags.IsNeverIntersection) { const neverProp = find(getPropertiesOfUnionOrIntersectionType(type as IntersectionType), isDiscriminantWithNeverType); if (neverProp) { return chainDiagnosticMessages(errorInfo, Diagnostics.The_intersection_0_was_reduced_to_never_because_property_1_has_conflicting_types_in_some_constituents, typeToString(type, /*enclosingDeclaration*/ undefined, TypeFormatFlags.NoTypeReduction), symbolToString(neverProp)); } const privateProp = find(getPropertiesOfUnionOrIntersectionType(type as IntersectionType), isConflictingPrivateProperty); if (privateProp) { return chainDiagnosticMessages(errorInfo, Diagnostics.The_intersection_0_was_reduced_to_never_because_property_1_exists_in_multiple_constituents_and_is_private_in_some, typeToString(type, /*enclosingDeclaration*/ undefined, TypeFormatFlags.NoTypeReduction), symbolToString(privateProp)); } } return errorInfo; } /** * 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, skipObjectFunctionPropertyAugment?: boolean, includeTypeOnlyMembers?: boolean): Symbol | undefined { type = getReducedApparentType(type); if (type.flags & TypeFlags.Object) { const resolved = resolveStructuredTypeMembers(type as ObjectType); const symbol = resolved.members.get(name); if (symbol && symbolIsValue(symbol, includeTypeOnlyMembers)) { return symbol; } if (skipObjectFunctionPropertyAugment) return undefined; 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(type as UnionOrIntersectionType, name, skipObjectFunctionPropertyAugment); } return undefined; } function getSignaturesOfStructuredType(type: Type, kind: SignatureKind): readonly Signature[] { if (type.flags & TypeFlags.StructuredType) { const resolved = resolveStructuredTypeMembers(type as ObjectType); 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): readonly Signature[] { const result = getSignaturesOfStructuredType(getReducedApparentType(type), kind); if (kind === SignatureKind.Call && !length(result) && type.flags & TypeFlags.Union) { if ((type as UnionType).arrayFallbackSignatures) { return (type as UnionType).arrayFallbackSignatures!; } // If the union is all different instantiations of a member of the global array type... let memberName: __String; if (everyType(type, t => !!t.symbol?.parent && isArrayOrTupleSymbol(t.symbol.parent) && (!memberName ? (memberName = t.symbol.escapedName, true) : memberName === t.symbol.escapedName))) { // Transform the type from `(A[] | B[])["member"]` to `(A | B)[]["member"]` (since we pretend array is covariant anyway) const arrayArg = mapType(type, t => getMappedType((isReadonlyArraySymbol(t.symbol.parent) ? globalReadonlyArrayType : globalArrayType).typeParameters![0], (t as AnonymousType).mapper!)); const arrayType = createArrayType(arrayArg, someType(type, t => isReadonlyArraySymbol(t.symbol.parent))); return (type as UnionType).arrayFallbackSignatures = getSignaturesOfType(getTypeOfPropertyOfType(arrayType, memberName!)!, kind); } (type as UnionType).arrayFallbackSignatures = result; } return result; } function isArrayOrTupleSymbol(symbol: Symbol | undefined) { if (!symbol || !globalArrayType.symbol || !globalReadonlyArrayType.symbol) { return false; } return !!getSymbolIfSameReference(symbol, globalArrayType.symbol) || !!getSymbolIfSameReference(symbol, globalReadonlyArrayType.symbol); } function isReadonlyArraySymbol(symbol: Symbol | undefined) { if (!symbol || !globalReadonlyArrayType.symbol) { return false; } return !!getSymbolIfSameReference(symbol, globalReadonlyArrayType.symbol); } function findIndexInfo(indexInfos: readonly IndexInfo[], keyType: Type) { return find(indexInfos, info => info.keyType === keyType); } function findApplicableIndexInfo(indexInfos: readonly IndexInfo[], keyType: Type) { // Index signatures for type 'string' are considered only when no other index signatures apply. let stringIndexInfo: IndexInfo | undefined; let applicableInfo: IndexInfo | undefined; let applicableInfos: IndexInfo[] | undefined; for (const info of indexInfos) { if (info.keyType === stringType) { stringIndexInfo = info; } else if (isApplicableIndexType(keyType, info.keyType)) { if (!applicableInfo) { applicableInfo = info; } else { (applicableInfos || (applicableInfos = [applicableInfo])).push(info); } } } // When more than one index signature is applicable we create a synthetic IndexInfo. Instead of computing // the intersected key type, we just use unknownType for the key type as nothing actually depends on the // keyType property of the returned IndexInfo. return applicableInfos ? createIndexInfo(unknownType, getIntersectionType(map(applicableInfos, info => info.type)), reduceLeft(applicableInfos, (isReadonly, info) => isReadonly && info.isReadonly, /*initial*/ true)) : applicableInfo ? applicableInfo : stringIndexInfo && isApplicableIndexType(keyType, stringType) ? stringIndexInfo : undefined; } function isApplicableIndexType(source: Type, target: Type): boolean { // A 'string' index signature applies to types assignable to 'string' or 'number', and a 'number' index // signature applies to types assignable to 'number', `${number}` and numeric string literal types. return isTypeAssignableTo(source, target) || target === stringType && isTypeAssignableTo(source, numberType) || target === numberType && (source === numericStringType || !!(source.flags & TypeFlags.StringLiteral) && isNumericLiteralName((source as StringLiteralType).value)); } function getIndexInfosOfStructuredType(type: Type): readonly IndexInfo[] { if (type.flags & TypeFlags.StructuredType) { const resolved = resolveStructuredTypeMembers(type as ObjectType); return resolved.indexInfos; } return emptyArray; } function getIndexInfosOfType(type: Type): readonly IndexInfo[] { return getIndexInfosOfStructuredType(getReducedApparentType(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, keyType: Type): IndexInfo | undefined { return findIndexInfo(getIndexInfosOfType(type), keyType); } // 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, keyType: Type): Type | undefined { return getIndexInfoOfType(type, keyType)?.type; } function getApplicableIndexInfos(type: Type, keyType: Type): IndexInfo[] { return getIndexInfosOfType(type).filter(info => isApplicableIndexType(keyType, info.keyType)); } function getApplicableIndexInfo(type: Type, keyType: Type): IndexInfo | undefined { return findApplicableIndexInfo(getIndexInfosOfType(type), keyType); } function getApplicableIndexInfoForName(type: Type, name: __String): IndexInfo | undefined { return getApplicableIndexInfo(type, isLateBoundName(name) ? esSymbolType : getStringLiteralType(unescapeLeadingUnderscores(name))); } // Return list of type parameters with duplicates removed (duplicate identifier errors are generated in the actual // type checking functions). function getTypeParametersFromDeclaration(declaration: DeclarationWithTypeParameters): readonly TypeParameter[] | undefined { let result: TypeParameter[] | undefined; for (const node of getEffectiveTypeParameterDeclarations(declaration)) { result = appendIfUnique(result, getDeclaredTypeOfTypeParameter(node.symbol)); } return result?.length ? result : isFunctionDeclaration(declaration) ? getSignatureOfTypeTag(declaration)?.typeParameters : undefined; } function symbolsToArray(symbols: SymbolTable): Symbol[] { const result: Symbol[] = []; symbols.forEach((symbol, id) => { if (!isReservedMemberName(id)) { result.push(symbol); } }); return result; } 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 | JSDocPropertyTag) { if (hasQuestionToken(node) || isOptionalJSDocPropertyLikeTag(node) || isJSDocOptionalParameter(node)) { return true; } if (node.initializer) { const signature = getSignatureFromDeclaration(node.parent); const parameterIndex = node.parent.parameters.indexOf(node); Debug.assert(parameterIndex >= 0); // Only consider syntactic or instantiated parameters as optional, not `void` parameters as this function is used // in grammar checks and checking for `void` too early results in parameter types widening too early // and causes some noImplicitAny errors to be lost. return parameterIndex >= getMinArgumentCount(signature, MinArgumentCountFlags.StrongArityForUntypedJS | MinArgumentCountFlags.VoidIsNonOptional); } const iife = getImmediatelyInvokedFunctionExpression(node.parent); if (iife) { return !node.type && !node.dotDotDotToken && node.parent.parameters.indexOf(node) >= iife.arguments.length; } return false; } function isOptionalPropertyDeclaration(node: Declaration) { return isPropertyDeclaration(node) && !hasAccessorModifier(node) && node.questionToken; } function createTypePredicate(kind: TypePredicateKind, parameterName: string | undefined, parameterIndex: number | undefined, type: Type | undefined): TypePredicate { return { kind, parameterName, parameterIndex, type } as TypePredicate; } /** * Gets the minimum number of type arguments needed to satisfy all non-optional type * parameters. */ function getMinTypeArgumentCount(typeParameters: readonly 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: readonly Type[], typeParameters: readonly TypeParameter[] | undefined, minTypeArgumentCount: number, isJavaScriptImplicitAny: boolean): Type[]; function fillMissingTypeArguments(typeArguments: readonly Type[] | undefined, typeParameters: readonly TypeParameter[] | undefined, minTypeArgumentCount: number, isJavaScriptImplicitAny: boolean): Type[] | undefined; function fillMissingTypeArguments(typeArguments: readonly Type[] | undefined, typeParameters: readonly 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, unknownType) || 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 flags = SignatureFlags.None; 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 (isUntypedSignatureInJSFile) { flags |= SignatureFlags.IsUntypedSignatureInJSFile; } // 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, /*nameNotFoundMessage*/ undefined, /*nameArg*/ 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) { flags |= SignatureFlags.HasLiteralTypes; } // Record a new minimum argument count if this is not an optional parameter const isOptionalParameter = isOptionalJSDocPropertyLikeTag(param) || param.initializer || param.questionToken || isRestParameter(param) || iife && parameters.length > iife.arguments.length && !type || 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) && hasBindableName(declaration) && (!hasThisParameter || !thisParameter)) { const otherKind = declaration.kind === SyntaxKind.GetAccessor ? SyntaxKind.SetAccessor : SyntaxKind.GetAccessor; const other = getDeclarationOfKind(getSymbolOfDeclaration(declaration), otherKind); if (other) { thisParameter = getAnnotatedAccessorThisParameter(other); } } if (isInJSFile(declaration)) { const thisTag = getJSDocThisTag(declaration); if (thisTag && thisTag.typeExpression) { thisParameter = createSymbolWithType(createSymbol(SymbolFlags.FunctionScopedVariable, InternalSymbolName.This), getTypeFromTypeNode(thisTag.typeExpression)); } } const hostDeclaration = isJSDocSignature(declaration) ? getEffectiveJSDocHost(declaration) : declaration; const classType = hostDeclaration && isConstructorDeclaration(hostDeclaration) ? getDeclaredTypeOfClassOrInterface(getMergedSymbol((hostDeclaration.parent as ClassDeclaration).symbol)) : undefined; const typeParameters = classType ? classType.localTypeParameters : getTypeParametersFromDeclaration(declaration); if (hasRestParameter(declaration) || isInJSFile(declaration) && maybeAddJsSyntheticRestParameter(declaration, parameters)) { flags |= SignatureFlags.HasRestParameter; } if (isConstructorTypeNode(declaration) && hasSyntacticModifier(declaration, ModifierFlags.Abstract) || isConstructorDeclaration(declaration) && hasSyntacticModifier(declaration.parent, ModifierFlags.Abstract)) { flags |= SignatureFlags.Abstract; } links.resolvedSignature = createSignature(declaration, typeParameters, thisParameter, parameters, /*resolvedReturnType*/ undefined, /*resolvedTypePredicate*/ undefined, minArgumentCount, flags); } 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); if (lastParamVariadicType) { // Parameter has effective annotation, lock in type syntheticArgsSymbol.links.type = createArrayType(getTypeFromTypeNode(lastParamVariadicType.type)); } else { // Parameter has no annotation // By using a `DeferredType` symbol, we allow the type of this rest arg to be overriden by contextual type assignment so long as its type hasn't been // cached by `getTypeOfSymbol` yet. syntheticArgsSymbol.links.checkFlags |= CheckFlags.DeferredType; syntheticArgsSymbol.links.deferralParent = neverType; syntheticArgsSymbol.links.deferralConstituents = [anyArrayType]; syntheticArgsSymbol.links.deferralWriteConstituents = [anyArrayType]; } if (lastParamVariadicType) { // Replace the last parameter with a rest parameter. parameters.pop(); } parameters.push(syntheticArgsSymbol); return true; } function getSignatureOfTypeTag(node: SignatureDeclaration | JSDocSignature) { // should be attached to a function declaration or expression if (!(isInJSFile(node) && isFunctionLikeDeclaration(node))) return undefined; const typeTag = getJSDocTypeTag(node); return typeTag?.typeExpression && getSingleCallSignature(getTypeFromTypeNode(typeTag.typeExpression)); } function getParameterTypeOfTypeTag(func: FunctionLikeDeclaration, parameter: ParameterDeclaration) { const signature = getSignatureOfTypeTag(func); if (!signature) return undefined; const pos = func.parameters.indexOf(parameter); return parameter.dotDotDotToken ? getRestTypeAtPosition(signature, pos) : getTypeAtPosition(signature, pos); } 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 (node as Identifier).escapedText === argumentsSymbol.escapedName && getReferencedValueSymbol(node as Identifier) === argumentsSymbol; case SyntaxKind.PropertyDeclaration: case SyntaxKind.MethodDeclaration: case SyntaxKind.GetAccessor: case SyntaxKind.SetAccessor: return (node as NamedDeclaration).name!.kind === SyntaxKind.ComputedPropertyName && traverse((node as NamedDeclaration).name!); case SyntaxKind.PropertyAccessExpression: case SyntaxKind.ElementAccessExpression: return traverse((node as PropertyAccessExpression | ElementAccessExpression).expression); case SyntaxKind.PropertyAssignment: return traverse((node as PropertyAssignment).initializer); default: return !nodeStartsNewLexicalEnvironment(node) && !isPartOfTypeNode(node) && !!forEachChild(node, traverse); } } } function getSignaturesOfSymbol(symbol: Symbol | undefined): Signature[] { if (!symbol || !symbol.declarations) 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; } } if (isInJSFile(decl) && decl.jsDoc) { let hasJSDocOverloads = false; for (const node of decl.jsDoc) { if (node.tags) { for (const tag of node.tags) { if (isJSDocOverloadTag(tag)) { const jsDocSignature = tag.typeExpression; if (jsDocSignature.type === undefined && !isConstructorDeclaration(decl)) { reportImplicitAny(jsDocSignature, anyType); } result.push(getSignatureFromDeclaration(jsDocSignature)); hasJSDocOverloads = true; } } } } if (hasJSDocOverloads) { continue; } } // If this is a function or method declaration, get the signature from the @type tag for the sake of optional parameters. // Exclude contextually-typed kinds because we already apply the @type tag to the context, plus applying it here to the initializer would supress checks that the two are compatible. result.push( (!isFunctionExpressionOrArrowFunction(decl) && !isObjectLiteralMethod(decl) && getSignatureOfTypeTag(decl)) || 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 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.compositeSignatures) { signature.resolvedTypePredicate = getUnionOrIntersectionTypePredicate(signature.compositeSignatures, signature.compositeKind) || noTypePredicate; } else { const type = signature.declaration && getEffectiveReturnTypeNode(signature.declaration); let jsdocPredicate: TypePredicate | undefined; if (!type) { const jsdocSignature = getSignatureOfTypeTag(signature.declaration!); if (jsdocSignature && signature !== jsdocSignature) { jsdocPredicate = getTypePredicateOfSignature(jsdocSignature); } } signature.resolvedTypePredicate = type && isTypePredicateNode(type) ? createTypePredicateFromTypePredicateNode(type, signature) : jsdocPredicate || noTypePredicate; } Debug.assert(!!signature.resolvedTypePredicate); } return signature.resolvedTypePredicate === noTypePredicate ? undefined : signature.resolvedTypePredicate; } function createTypePredicateFromTypePredicateNode(node: TypePredicateNode, signature: Signature): TypePredicate { const parameterName = node.parameterName; const type = node.type && getTypeFromTypeNode(node.type); return parameterName.kind === SyntaxKind.ThisType ? createTypePredicate(node.assertsModifier ? TypePredicateKind.AssertsThis : TypePredicateKind.This, /*parameterName*/ undefined, /*parameterIndex*/ undefined, type) : createTypePredicate(node.assertsModifier ? TypePredicateKind.AssertsIdentifier : TypePredicateKind.Identifier, parameterName.escapedText as string, findIndex(signature.parameters, p => p.escapedName === parameterName.escapedText), type); } function getUnionOrIntersectionType(types: Type[], kind: TypeFlags | undefined, unionReduction?: UnionReduction) { return kind !== TypeFlags.Intersection ? getUnionType(types, unionReduction) : getIntersectionType(types); } 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.compositeSignatures ? instantiateType(getUnionOrIntersectionType(map(signature.compositeSignatures, getReturnTypeOfSignature), signature.compositeKind, UnionReduction.Subtype), signature.mapper) : getReturnTypeFromAnnotation(signature.declaration!) || (nodeIsMissing((signature.declaration as FunctionLikeDeclaration).body) ? anyType : getReturnTypeFromBody(signature.declaration as FunctionLikeDeclaration)); if (signature.flags & SignatureFlags.IsInnerCallChain) { type = addOptionalTypeMarker(type); } else if (signature.flags & SignatureFlags.IsOuterCallChain) { type = getOptionalType(type); } 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 = signature.declaration as 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((declaration.parent as ClassDeclaration).symbol)); } const typeNode = getEffectiveReturnTypeNode(declaration); if (isJSDocSignature(declaration)) { const root = getJSDocRoot(declaration); if (root && isConstructorDeclaration(root.parent) && !typeNode) { return getDeclaredTypeOfClassOrInterface(getMergedSymbol((root.parent.parent as ClassDeclaration).symbol)); } } if (isJSDocConstructSignature(declaration)) { return getTypeFromTypeNode((declaration.parameters[0] as ParameterDeclaration).type!); // TODO: GH#18217 } if (typeNode) { return getTypeFromTypeNode(typeNode); } if (declaration.kind === SyntaxKind.GetAccessor && hasBindableName(declaration)) { const jsDocType = isInJSFile(declaration) && getTypeForDeclarationFromJSDocComment(declaration); if (jsDocType) { return jsDocType; } const setter = getDeclarationOfKind(getSymbolOfDeclaration(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 (signatureHasRestParameter(signature)) { const sigRestType = getTypeOfSymbol(signature.parameters[signature.parameters.length - 1]); const restType = isTupleType(sigRestType) ? getRestTypeOfTupleType(sigRestType) : sigRestType; return restType && getIndexTypeOfType(restType, numberType); } return undefined; } function getSignatureInstantiation(signature: Signature, typeArguments: Type[] | undefined, isJavascript: boolean, inferredTypeParameters?: readonly TypeParameter[]): Signature { const instantiatedSignature = getSignatureInstantiationWithoutFillingInTypeArguments(signature, fillMissingTypeArguments(typeArguments, signature.typeParameters, getMinTypeArgumentCount(signature.typeParameters), isJavascript)); if (inferredTypeParameters) { const returnSignature = getSingleCallOrConstructSignature(getReturnTypeOfSignature(instantiatedSignature)); if (returnSignature) { const newReturnSignature = cloneSignature(returnSignature); newReturnSignature.typeParameters = inferredTypeParameters; const newInstantiatedSignature = cloneSignature(instantiatedSignature); newInstantiatedSignature.resolvedReturnType = getOrCreateTypeFromSignature(newReturnSignature); return newInstantiatedSignature; } } return instantiatedSignature; } function getSignatureInstantiationWithoutFillingInTypeArguments(signature: Signature, typeArguments: readonly Type[] | undefined): Signature { const instantiations = signature.instantiations || (signature.instantiations = new Map()); 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: readonly Type[] | undefined): Signature { return instantiateSignature(signature, createSignatureTypeMapper(signature, typeArguments), /*eraseTypeParameters*/ true); } function createSignatureTypeMapper(signature: Signature, typeArguments: readonly 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) { if (signature.baseSignatureCache) { return signature.baseSignatureCache; } const typeEraser = createTypeEraser(typeParameters); const baseConstraintMapper = createTypeMapper(typeParameters, map(typeParameters, tp => getConstraintOfTypeParameter(tp) || unknownType)); let baseConstraints: readonly Type[] = map(typeParameters, tp => instantiateType(tp, baseConstraintMapper) || unknownType); // Run N type params thru the immediate constraint mapper up to N times // This way any noncircular interdependent type parameters are definitely resolved to their external dependencies for (let i = 0; i < typeParameters.length - 1; i++) { baseConstraints = instantiateTypes(baseConstraints, baseConstraintMapper); } // and then apply a type eraser to remove any remaining circularly dependent type parameters baseConstraints = instantiateTypes(baseConstraints, typeEraser); return signature.baseSignatureCache = 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 kind = signature.declaration?.kind; // If declaration is undefined, it is likely to be the signature of the default constructor. const isConstructor = kind === undefined || kind === SyntaxKind.Constructor || kind === SyntaxKind.ConstructSignature || kind === SyntaxKind.ConstructorType; const type = createObjectType(ObjectFlags.Anonymous); type.members = emptySymbols; type.properties = emptyArray; type.callSignatures = !isConstructor ? [signature] : emptyArray; type.constructSignatures = isConstructor ? [signature] : emptyArray; type.indexInfos = emptyArray; signature.isolatedSignatureType = type; } return signature.isolatedSignatureType; } function getIndexSymbol(symbol: Symbol): Symbol | undefined { return symbol.members ? getIndexSymbolFromSymbolTable(symbol.members) : undefined; } function getIndexSymbolFromSymbolTable(symbolTable: SymbolTable): Symbol | undefined { return symbolTable.get(InternalSymbolName.Index); } function createIndexInfo(keyType: Type, type: Type, isReadonly: boolean, declaration?: IndexSignatureDeclaration): IndexInfo { return { keyType, type, isReadonly, declaration }; } function getIndexInfosOfSymbol(symbol: Symbol): IndexInfo[] { const indexSymbol = getIndexSymbol(symbol); return indexSymbol ? getIndexInfosOfIndexSymbol(indexSymbol) : emptyArray; } function getIndexInfosOfIndexSymbol(indexSymbol: Symbol): IndexInfo[] { if (indexSymbol.declarations) { const indexInfos: IndexInfo[] = []; for (const declaration of (indexSymbol.declarations as IndexSignatureDeclaration[])) { if (declaration.parameters.length === 1) { const parameter = declaration.parameters[0]; if (parameter.type) { forEachType(getTypeFromTypeNode(parameter.type), keyType => { if (isValidIndexKeyType(keyType) && !findIndexInfo(indexInfos, keyType)) { indexInfos.push(createIndexInfo(keyType, declaration.type ? getTypeFromTypeNode(declaration.type) : anyType, hasEffectiveModifier(declaration, ModifierFlags.Readonly), declaration)); } }); } } } return indexInfos; } return emptyArray; } function isValidIndexKeyType(type: Type): boolean { return !!(type.flags & (TypeFlags.String | TypeFlags.Number | TypeFlags.ESSymbol)) || isPatternLiteralType(type) || !!(type.flags & TypeFlags.Intersection) && !isGenericType(type) && some((type as IntersectionType).types, isValidIndexKeyType); } function getConstraintDeclaration(type: TypeParameter): TypeNode | undefined { return mapDefined(filter(type.symbol && type.symbol.declarations, isTypeParameterDeclaration), getEffectiveConstraintOfTypeParameter)[0]; } function getInferredTypeParameterConstraint(typeParameter: TypeParameter, omitTypeReferences?: boolean) { let inferences: Type[] | undefined; if (typeParameter.symbol?.declarations) { 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'), 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 [childTypeParameter = declaration.parent, grandParent] = walkUpParenthesizedTypesAndGetParentAndChild(declaration.parent.parent); if (grandParent.kind === SyntaxKind.TypeReference && !omitTypeReferences) { const typeReference = grandParent as TypeReferenceNode; const typeParameters = getTypeParametersForTypeReferenceOrImport(typeReference); if (typeParameters) { const index = typeReference.typeArguments!.indexOf(childTypeParameter as TypeNode); 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, U]; // type Bar = T extends Foo ? Foo : T; // the instantiated constraint for U is X, so we discard that inference. const mapper = makeDeferredTypeMapper(typeParameters, typeParameters.map((_, index) => () => { return getEffectiveTypeArgumentAtIndex(typeReference, typeParameters, index); })); 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, a rest type // or a named rest tuple element, we infer an 'unknown[]' constraint. else if (grandParent.kind === SyntaxKind.Parameter && (grandParent as ParameterDeclaration).dotDotDotToken || grandParent.kind === SyntaxKind.RestType || grandParent.kind === SyntaxKind.NamedTupleMember && (grandParent as NamedTupleMember).dotDotDotToken) { inferences = append(inferences, createArrayType(unknownType)); } // When an 'infer T' declaration is immediately contained in a string template type, we infer a 'string' // constraint. else if (grandParent.kind === SyntaxKind.TemplateLiteralTypeSpan) { inferences = append(inferences, stringType); } // When an 'infer T' declaration is in the constraint position of a mapped type, we infer a 'keyof any' // constraint. else if (grandParent.kind === SyntaxKind.TypeParameter && grandParent.parent.kind === SyntaxKind.MappedType) { inferences = append(inferences, keyofConstraintType); } // When an 'infer T' declaration is the template of a mapped type, and that mapped type is the extends // clause of a conditional whose check type is also a mapped type, give it a constraint equal to the template // of the check type's mapped type else if (grandParent.kind === SyntaxKind.MappedType && (grandParent as MappedTypeNode).type && skipParentheses((grandParent as MappedTypeNode).type!) === declaration.parent && grandParent.parent.kind === SyntaxKind.ConditionalType && (grandParent.parent as ConditionalTypeNode).extendsType === grandParent && (grandParent.parent as ConditionalTypeNode).checkType.kind === SyntaxKind.MappedType && ((grandParent.parent as ConditionalTypeNode).checkType as MappedTypeNode).type) { const checkMappedType = (grandParent.parent as ConditionalTypeNode).checkType as MappedTypeNode; const nodeType = getTypeFromTypeNode(checkMappedType.type!); inferences = append(inferences, instantiateType(nodeType, makeUnaryTypeMapper(getDeclaredTypeOfTypeParameter(getSymbolOfDeclaration(checkMappedType.typeParameter)), checkMappedType.typeParameter.constraint ? getTypeFromTypeNode(checkMappedType.typeParameter.constraint) : keyofConstraintType) )); } } } } 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); if (!constraintDeclaration) { typeParameter.constraint = getInferredTypeParameterConstraint(typeParameter) || noConstraintType; } else { let type = getTypeFromTypeNode(constraintDeclaration); if (type.flags & TypeFlags.Any && !isErrorType(type)) { // Allow errorType to propegate to keep downstream errors suppressed // use keyofConstraintType as the base constraint for mapped type key constraints (unknown isn;t assignable to that, but `any` was), // use unknown otherwise type = constraintDeclaration.parent.parent.kind === SyntaxKind.MappedType ? keyofConstraintType : unknownType; } typeParameter.constraint = type; } } } return typeParameter.constraint === noConstraintType ? undefined : typeParameter.constraint; } function getParentSymbolOfTypeParameter(typeParameter: TypeParameter): Symbol | undefined { const tp = getDeclarationOfKind(typeParameter.symbol, SyntaxKind.TypeParameter)!; const host = isJSDocTemplateTag(tp.parent) ? getEffectiveContainerForJSDocTemplateTag(tp.parent) : tp.parent; return host && getSymbolOfNode(host); } function getTypeListId(types: readonly 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; } function getAliasId(aliasSymbol: Symbol | undefined, aliasTypeArguments: readonly Type[] | undefined) { return aliasSymbol ? `@${getSymbolId(aliasSymbol)}` + (aliasTypeArguments ? `:${getTypeListId(aliasTypeArguments)}` : "") : ""; } // 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 a non-inferrable type. 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: readonly Type[], excludeKinds?: TypeFlags): ObjectFlags { let result: ObjectFlags = 0; for (const type of types) { if (excludeKinds === undefined || !(type.flags & excludeKinds)) { result |= getObjectFlags(type); } } return result & ObjectFlags.PropagatingFlags; } function tryCreateTypeReference(target: GenericType, typeArguments: readonly Type[] | undefined): Type { if (some(typeArguments) && target === emptyGenericType) { return unknownType; } return createTypeReference(target, typeArguments); } function createTypeReference(target: GenericType, typeArguments: readonly Type[] | undefined): TypeReference { const id = getTypeListId(typeArguments); let type = target.instantiations.get(id); if (!type) { type = createObjectType(ObjectFlags.Reference, target.symbol) as TypeReference; target.instantiations.set(id, type); type.objectFlags |= typeArguments ? getPropagatingFlagsOfTypes(typeArguments) : 0; type.target = target; type.resolvedTypeArguments = typeArguments; } return type; } function cloneTypeReference(source: TypeReference): TypeReference { const type = createTypeWithSymbol(source.flags, source.symbol) as TypeReference; type.objectFlags = source.objectFlags; type.target = source.target; type.resolvedTypeArguments = source.resolvedTypeArguments; return type; } function createDeferredTypeReference(target: GenericType, node: TypeReferenceNode | ArrayTypeNode | TupleTypeNode, mapper?: TypeMapper, aliasSymbol?: Symbol, aliasTypeArguments?: readonly Type[]): DeferredTypeReference { if (!aliasSymbol) { aliasSymbol = getAliasSymbolForTypeNode(node); const localAliasTypeArguments = getTypeArgumentsForAliasSymbol(aliasSymbol); aliasTypeArguments = mapper ? instantiateTypes(localAliasTypeArguments, mapper) : localAliasTypeArguments; } const type = createObjectType(ObjectFlags.Reference, target.symbol) as DeferredTypeReference; type.target = target; type.node = node; type.mapper = mapper; type.aliasSymbol = aliasSymbol; type.aliasTypeArguments = aliasTypeArguments; return type; } function getTypeArguments(type: TypeReference): readonly Type[] { if (!type.resolvedTypeArguments) { if (!pushTypeResolution(type, TypeSystemPropertyName.ResolvedTypeArguments)) { return type.target.localTypeParameters?.map(() => errorType) || emptyArray; } const node = type.node; const typeArguments = !node ? emptyArray : node.kind === SyntaxKind.TypeReference ? concatenate(type.target.outerTypeParameters, getEffectiveTypeArguments(node, type.target.localTypeParameters!)) : node.kind === SyntaxKind.ArrayType ? [getTypeFromTypeNode(node.elementType)] : map(node.elements, getTypeFromTypeNode); if (popTypeResolution()) { type.resolvedTypeArguments = type.mapper ? instantiateTypes(typeArguments, type.mapper) : typeArguments; } else { type.resolvedTypeArguments = type.target.localTypeParameters?.map(() => errorType) || emptyArray; error( type.node || currentNode, type.target.symbol ? Diagnostics.Type_arguments_for_0_circularly_reference_themselves : Diagnostics.Tuple_type_arguments_circularly_reference_themselves, type.target.symbol && symbolToString(type.target.symbol) ); } } return type.resolvedTypeArguments; } 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): Type { const type = getDeclaredTypeOfSymbol(getMergedSymbol(symbol)) as InterfaceType; 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; } } if (node.kind === SyntaxKind.TypeReference && isDeferredTypeReferenceNode(node as TypeReferenceNode, length(node.typeArguments) !== typeParameters.length)) { return createDeferredTypeReference(type as GenericType, node as TypeReferenceNode, /*mapper*/ undefined); } // 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(typeArgumentsFromTypeReferenceNode(node), typeParameters, minTypeArgumentCount, isJs)); return createTypeReference(type as GenericType, typeArguments); } return checkNoTypeArguments(node, symbol) ? type : errorType; } function getTypeAliasInstantiation(symbol: Symbol, typeArguments: readonly Type[] | undefined, aliasSymbol?: Symbol, aliasTypeArguments?: readonly Type[]): Type { const type = getDeclaredTypeOfSymbol(symbol); if (type === intrinsicMarkerType && intrinsicTypeKinds.has(symbol.escapedName as string) && typeArguments && typeArguments.length === 1) { return getStringMappingType(symbol, typeArguments[0]); } const links = getSymbolLinks(symbol); const typeParameters = links.typeParameters!; const id = getTypeListId(typeArguments) + getAliasId(aliasSymbol, aliasTypeArguments); let instantiation = links.instantiations!.get(id); if (!instantiation) { links.instantiations!.set(id, instantiation = instantiateTypeWithAlias(type, createTypeMapper(typeParameters, fillMissingTypeArguments(typeArguments, typeParameters, getMinTypeArgumentCount(typeParameters), isInJSFile(symbol.valueDeclaration))), aliasSymbol, aliasTypeArguments)); } 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): Type { if (getCheckFlags(symbol) & CheckFlags.Unresolved) { const typeArguments = typeArgumentsFromTypeReferenceNode(node); const id = getAliasId(symbol, typeArguments); let errorType = errorTypes.get(id); if (!errorType) { errorType = createIntrinsicType(TypeFlags.Any, "error"); errorType.aliasSymbol = symbol; errorType.aliasTypeArguments = typeArguments; errorTypes.set(id, errorType); } return errorType; } 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; } // We refrain from associating a local type alias with an instantiation of a top-level type alias // because the local alias may end up being referenced in an inferred return type where it is not // accessible--which in turn may lead to a large structural expansion of the type when generating // a .d.ts file. See #43622 for an example. const aliasSymbol = getAliasSymbolForTypeNode(node); let newAliasSymbol = aliasSymbol && (isLocalTypeAlias(symbol) || !isLocalTypeAlias(aliasSymbol)) ? aliasSymbol : undefined; let aliasTypeArguments: Type[] | undefined; if (newAliasSymbol) { aliasTypeArguments = getTypeArgumentsForAliasSymbol(newAliasSymbol); } else if (isTypeReferenceType(node)) { const aliasSymbol = resolveTypeReferenceName(node, SymbolFlags.Alias, /*ignoreErrors*/ true); // refers to an alias import/export/reexport - by making sure we use the target as an aliasSymbol, // we ensure the exported symbol is used to refer to the type when it's reserialized later if (aliasSymbol && aliasSymbol !== unknownSymbol) { const resolved = resolveAlias(aliasSymbol); if (resolved && resolved.flags & SymbolFlags.TypeAlias) { newAliasSymbol = resolved; aliasTypeArguments = typeArgumentsFromTypeReferenceNode(node) || (typeParameters ? [] : undefined); } } } return getTypeAliasInstantiation(symbol, typeArgumentsFromTypeReferenceNode(node), newAliasSymbol, aliasTypeArguments); } return checkNoTypeArguments(node, symbol) ? type : errorType; } function isLocalTypeAlias(symbol: Symbol) { const declaration = symbol.declarations?.find(isTypeAlias); return !!(declaration && getContainingFunction(declaration)); } 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 getSymbolPath(symbol: Symbol): string { return symbol.parent ? `${getSymbolPath(symbol.parent)}.${symbol.escapedName}` : symbol.escapedName as string; } function getUnresolvedSymbolForEntityName(name: EntityNameOrEntityNameExpression) { const identifier = name.kind === SyntaxKind.QualifiedName ? name.right : name.kind === SyntaxKind.PropertyAccessExpression ? name.name : name; const text = identifier.escapedText; if (text) { const parentSymbol = name.kind === SyntaxKind.QualifiedName ? getUnresolvedSymbolForEntityName(name.left) : name.kind === SyntaxKind.PropertyAccessExpression ? getUnresolvedSymbolForEntityName(name.expression) : undefined; const path = parentSymbol ? `${getSymbolPath(parentSymbol)}.${text}` : text as string; let result = unresolvedSymbols.get(path); if (!result) { unresolvedSymbols.set(path, result = createSymbol(SymbolFlags.TypeAlias, text, CheckFlags.Unresolved)); result.parent = parentSymbol; result.links.declaredType = unresolvedType; } return result; } return unknownSymbol; } function resolveTypeReferenceName(typeReference: TypeReferenceType, meaning: SymbolFlags, ignoreErrors?: boolean) { const name = getTypeReferenceName(typeReference); if (!name) { return unknownSymbol; } const symbol = resolveEntityName(name, meaning, ignoreErrors); return symbol && symbol !== unknownSymbol ? symbol : ignoreErrors ? unknownSymbol : getUnresolvedSymbolForEntityName(name); } function getTypeReferenceType(node: NodeWithTypeArguments, symbol: Symbol): Type { if (symbol === unknownSymbol) { return errorType; } symbol = getExpandoSymbol(symbol) || symbol; if (symbol.flags & (SymbolFlags.Class | SymbolFlags.Interface)) { return getTypeFromClassOrInterfaceReference(node, symbol); } if (symbol.flags & SymbolFlags.TypeAlias) { return getTypeFromTypeAliasReference(node, symbol); } // 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) ? getRegularTypeOfLiteralType(res) : errorType; } if (symbol.flags & SymbolFlags.Value && isJSDocTypeReference(node)) { const jsdocType = getTypeFromJSDocValueReference(node, symbol); if (jsdocType) { return jsdocType; } else { // Resolve the type reference as a Type for the purpose of reporting errors. resolveTypeReferenceName(node, SymbolFlags.Type); return getTypeOfSymbol(symbol); } } return errorType; } /** * A JSdoc TypeReference may be to a value, but resolve it as a type anyway. * Example: import('./b').ConstructorFunction */ function getTypeFromJSDocValueReference(node: NodeWithTypeArguments, symbol: Symbol): Type | undefined { const links = getNodeLinks(node); if (!links.resolvedJSDocType) { const valueType = getTypeOfSymbol(symbol); let typeType = valueType; if (symbol.valueDeclaration) { const isImportTypeWithQualifier = node.kind === SyntaxKind.ImportType && (node as ImportTypeNode).qualifier; // valueType might not have a symbol, eg, {import('./b').STRING_LITERAL} if (valueType.symbol && valueType.symbol !== symbol && isImportTypeWithQualifier) { typeType = getTypeReferenceType(node, valueType.symbol); } } links.resolvedJSDocType = typeType; } return links.resolvedJSDocType; } function getSubstitutionType(baseType: Type, constraint: Type) { if (constraint.flags & TypeFlags.AnyOrUnknown || constraint === baseType || baseType.flags & TypeFlags.Any) { return baseType; } const id = `${getTypeId(baseType)}>${getTypeId(constraint)}`; const cached = substitutionTypes.get(id); if (cached) { return cached; } const result = createType(TypeFlags.Substitution) as SubstitutionType; result.baseType = baseType; result.constraint = constraint; substitutionTypes.set(id, result); return result; } function getSubstitutionIntersection(substitutionType: SubstitutionType) { return getIntersectionType([substitutionType.constraint, substitutionType.baseType]); } function isUnaryTupleTypeNode(node: TypeNode) { return node.kind === SyntaxKind.TupleType && (node as TupleTypeNode).elements.length === 1; } function getImpliedConstraint(type: Type, checkNode: TypeNode, extendsNode: TypeNode): Type | undefined { return isUnaryTupleTypeNode(checkNode) && isUnaryTupleTypeNode(extendsNode) ? getImpliedConstraint(type, (checkNode as TupleTypeNode).elements[0], (extendsNode as TupleTypeNode).elements[0]) : getActualTypeVariable(getTypeFromTypeNode(checkNode)) === getActualTypeVariable(type) ? getTypeFromTypeNode(extendsNode) : undefined; } function getConditionalFlowTypeOfType(type: Type, node: Node) { let constraints: Type[] | undefined; let covariant = true; while (node && !isStatement(node) && node.kind !== SyntaxKind.JSDoc) { const parent = node.parent; // only consider variance flipped by parameter locations - `keyof` types would usually be considered variance inverting, but // often get used in indexed accesses where they behave sortof invariantly, but our checking is lax if (parent.kind === SyntaxKind.Parameter) { covariant = !covariant; } // Always substitute on type parameters, regardless of variance, since even // in contravariant positions, they may rely on substituted constraints to be valid if ((covariant || type.flags & TypeFlags.TypeVariable) && parent.kind === SyntaxKind.ConditionalType && node === (parent as ConditionalTypeNode).trueType) { const constraint = getImpliedConstraint(type, (parent as ConditionalTypeNode).checkType, (parent as ConditionalTypeNode).extendsType); if (constraint) { constraints = append(constraints, constraint); } } // Given a homomorphic mapped type { [K in keyof T]: XXX }, where T is constrained to an array or tuple type, in the // template type XXX, K has an added constraint of number | `${number}`. else if (type.flags & TypeFlags.TypeParameter && parent.kind === SyntaxKind.MappedType && node === (parent as MappedTypeNode).type) { const mappedType = getTypeFromTypeNode(parent as TypeNode) as MappedType; if (getTypeParameterFromMappedType(mappedType) === getActualTypeVariable(type)) { const typeParameter = getHomomorphicTypeVariable(mappedType); if (typeParameter) { const constraint = getConstraintOfTypeParameter(typeParameter); if (constraint && everyType(constraint, isArrayOrTupleType)) { constraints = append(constraints, getUnionType([numberType, numericStringType])); } } } } node = parent; } return constraints ? getSubstitutionType(type, getIntersectionType(constraints)) : type; } 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) : (node as TypeReferenceNode).typeName ? declarationNameToString((node as TypeReferenceNode).typeName) : anon); 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": return (!typeArgs || !typeArgs.length) && !noImplicitAny ? anyArrayType : undefined; case "promise": return (!typeArgs || !typeArgs.length) && !noImplicitAny ? createPromiseType(anyType) : undefined; case "Object": if (typeArgs && typeArgs.length === 2) { if (isJSDocIndexSignature(node)) { const indexed = getTypeFromTypeNode(typeArgs[0]); const target = getTypeFromTypeNode(typeArgs[1]); const indexInfo = indexed === stringType || indexed === numberType ? [createIndexInfo(indexed, target, /*isReadonly*/ false)] : emptyArray; return createAnonymousType(/*symbol*/ undefined, emptySymbols, emptyArray, emptyArray, indexInfo); } return anyType; } checkNoTypeArguments(node); return !noImplicitAny ? anyType : undefined; } } } 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) { // handle LS queries on the `const` in `x as const` by resolving to the type of `x` if (isConstTypeReference(node) && isAssertionExpression(node.parent)) { links.resolvedSymbol = unknownSymbol; return links.resolvedType = checkExpressionCached(node.parent.expression); } let symbol: Symbol | undefined; let type: Type | undefined; const meaning = SymbolFlags.Type; if (isJSDocTypeReference(node)) { type = getIntendedTypeFromJSDocTypeReference(node); if (!type) { symbol = resolveTypeReferenceName(node, meaning, /*ignoreErrors*/ true); if (symbol === unknownSymbol) { symbol = resolveTypeReferenceName(node, meaning | SymbolFlags.Value); } else { resolveTypeReferenceName(node, meaning); // Resolve again to mark errors, if any } type = getTypeReferenceType(node, symbol); } } if (!type) { symbol = resolveTypeReferenceName(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. const type = checkExpressionWithTypeArguments(node); links.resolvedType = getRegularTypeOfLiteralType(getWidenedType(type)); } return links.resolvedType; } function getTypeOfGlobalSymbol(symbol: Symbol | undefined, arity: number): ObjectType { function getTypeDeclaration(symbol: Symbol): Declaration | undefined { const declarations = symbol.declarations; if (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((type as InterfaceType).typeParameters) !== arity) { error(getTypeDeclaration(symbol), Diagnostics.Global_type_0_must_have_1_type_parameter_s, symbolName(symbol), arity); return arity ? emptyGenericType : emptyObjectType; } return type as ObjectType; } 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 getGlobalTypeAliasSymbol(name: __String, arity: number, reportErrors: boolean): Symbol | undefined { const symbol = getGlobalSymbol(name, SymbolFlags.Type, reportErrors ? Diagnostics.Cannot_find_global_type_0 : undefined); if (symbol) { // Resolve the declared type of the symbol. This resolves type parameters for the type // alias so that we can check arity. getDeclaredTypeOfSymbol(symbol); if (length(getSymbolLinks(symbol).typeParameters) !== arity) { const decl = symbol.declarations && find(symbol.declarations, isTypeAliasDeclaration); error(decl, Diagnostics.Global_type_0_must_have_1_type_parameter_s, symbolName(symbol), arity); return undefined; } } return symbol; } 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(/*location*/ undefined, name, meaning, diagnostic, name, /*isUse*/ false, /*excludeGlobals*/ false, /*getSpellingSuggestions*/ false); } function getGlobalType(name: __String, arity: 0, reportErrors: true): ObjectType; function getGlobalType(name: __String, arity: 0, reportErrors: boolean): ObjectType | undefined; function getGlobalType(name: __String, arity: number, reportErrors: true): GenericType; function getGlobalType(name: __String, arity: number, reportErrors: boolean): GenericType | undefined; function getGlobalType(name: __String, arity: number, reportErrors: boolean): ObjectType | undefined { const symbol = getGlobalTypeSymbol(name, reportErrors); return symbol || reportErrors ? getTypeOfGlobalSymbol(symbol, arity) : undefined; } function getGlobalTypedPropertyDescriptorType() { // We always report an error, so store a result in the event we could not resolve the symbol to prevent reporting it multiple times return deferredGlobalTypedPropertyDescriptorType ||= getGlobalType("TypedPropertyDescriptor" as __String, /*arity*/ 1, /*reportErrors*/ true) || emptyGenericType; } function getGlobalTemplateStringsArrayType() { // We always report an error, so store a result in the event we could not resolve the symbol to prevent reporting it multiple times return deferredGlobalTemplateStringsArrayType ||= getGlobalType("TemplateStringsArray" as __String, /*arity*/ 0, /*reportErrors*/ true) || emptyObjectType; } function getGlobalImportMetaType() { // We always report an error, so store a result in the event we could not resolve the symbol to prevent reporting it multiple times return deferredGlobalImportMetaType ||= getGlobalType("ImportMeta" as __String, /*arity*/ 0, /*reportErrors*/ true) || emptyObjectType; } function getGlobalImportMetaExpressionType() { if (!deferredGlobalImportMetaExpressionType) { // Create a synthetic type `ImportMetaExpression { meta: MetaProperty }` const symbol = createSymbol(SymbolFlags.None, "ImportMetaExpression" as __String); const importMetaType = getGlobalImportMetaType(); const metaPropertySymbol = createSymbol(SymbolFlags.Property, "meta" as __String, CheckFlags.Readonly); metaPropertySymbol.parent = symbol; metaPropertySymbol.links.type = importMetaType; const members = createSymbolTable([metaPropertySymbol]); symbol.members = members; deferredGlobalImportMetaExpressionType = createAnonymousType(symbol, members, emptyArray, emptyArray, emptyArray); } return deferredGlobalImportMetaExpressionType; } function getGlobalImportCallOptionsType(reportErrors: boolean) { return (deferredGlobalImportCallOptionsType ||= getGlobalType("ImportCallOptions" as __String, /*arity*/ 0, reportErrors)) || emptyObjectType; } function getGlobalESSymbolConstructorSymbol(reportErrors: boolean): Symbol | undefined { return deferredGlobalESSymbolConstructorSymbol ||= getGlobalValueSymbol("Symbol" as __String, reportErrors); } function getGlobalESSymbolConstructorTypeSymbol(reportErrors: boolean): Symbol | undefined { return deferredGlobalESSymbolConstructorTypeSymbol ||= getGlobalTypeSymbol("SymbolConstructor" as __String, reportErrors); } function getGlobalESSymbolType() { return (deferredGlobalESSymbolType ||= getGlobalType("Symbol" as __String, /*arity*/ 0, /*reportErrors*/ false)) || emptyObjectType; } function getGlobalPromiseType(reportErrors: boolean) { return (deferredGlobalPromiseType ||= getGlobalType("Promise" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType; } function getGlobalPromiseLikeType(reportErrors: boolean) { return (deferredGlobalPromiseLikeType ||= getGlobalType("PromiseLike" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType; } function getGlobalPromiseConstructorSymbol(reportErrors: boolean): Symbol | undefined { return deferredGlobalPromiseConstructorSymbol ||= getGlobalValueSymbol("Promise" as __String, reportErrors); } function getGlobalPromiseConstructorLikeType(reportErrors: boolean) { return (deferredGlobalPromiseConstructorLikeType ||= getGlobalType("PromiseConstructorLike" as __String, /*arity*/ 0, reportErrors)) || emptyObjectType; } function getGlobalAsyncIterableType(reportErrors: boolean) { return (deferredGlobalAsyncIterableType ||= getGlobalType("AsyncIterable" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType; } function getGlobalAsyncIteratorType(reportErrors: boolean) { return (deferredGlobalAsyncIteratorType ||= getGlobalType("AsyncIterator" as __String, /*arity*/ 3, reportErrors)) || emptyGenericType; } function getGlobalAsyncIterableIteratorType(reportErrors: boolean) { return (deferredGlobalAsyncIterableIteratorType ||= getGlobalType("AsyncIterableIterator" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType; } function getGlobalAsyncGeneratorType(reportErrors: boolean) { return (deferredGlobalAsyncGeneratorType ||= getGlobalType("AsyncGenerator" as __String, /*arity*/ 3, reportErrors)) || emptyGenericType; } function getGlobalIterableType(reportErrors: boolean) { return (deferredGlobalIterableType ||= getGlobalType("Iterable" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType; } function getGlobalIteratorType(reportErrors: boolean) { return (deferredGlobalIteratorType ||= getGlobalType("Iterator" as __String, /*arity*/ 3, reportErrors)) || emptyGenericType; } function getGlobalIterableIteratorType(reportErrors: boolean) { return (deferredGlobalIterableIteratorType ||= getGlobalType("IterableIterator" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType; } function getGlobalGeneratorType(reportErrors: boolean) { return (deferredGlobalGeneratorType ||= getGlobalType("Generator" as __String, /*arity*/ 3, reportErrors)) || emptyGenericType; } function getGlobalIteratorYieldResultType(reportErrors: boolean) { return (deferredGlobalIteratorYieldResultType ||= getGlobalType("IteratorYieldResult" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType; } function getGlobalIteratorReturnResultType(reportErrors: boolean) { return (deferredGlobalIteratorReturnResultType ||= getGlobalType("IteratorReturnResult" as __String, /*arity*/ 1, reportErrors)) || emptyGenericType; } function getGlobalTypeOrUndefined(name: __String, arity = 0): ObjectType | undefined { const symbol = getGlobalSymbol(name, SymbolFlags.Type, /*diagnostic*/ undefined); return symbol && getTypeOfGlobalSymbol(symbol, arity) as GenericType; } function getGlobalExtractSymbol(): Symbol | undefined { // We always report an error, so cache a result in the event we could not resolve the symbol to prevent reporting it multiple times deferredGlobalExtractSymbol ||= getGlobalTypeAliasSymbol("Extract" as __String, /*arity*/ 2, /*reportErrors*/ true) || unknownSymbol; return deferredGlobalExtractSymbol === unknownSymbol ? undefined : deferredGlobalExtractSymbol; } function getGlobalOmitSymbol(): Symbol | undefined { // We always report an error, so cache a result in the event we could not resolve the symbol to prevent reporting it multiple times deferredGlobalOmitSymbol ||= getGlobalTypeAliasSymbol("Omit" as __String, /*arity*/ 2, /*reportErrors*/ true) || unknownSymbol; return deferredGlobalOmitSymbol === unknownSymbol ? undefined : deferredGlobalOmitSymbol; } function getGlobalAwaitedSymbol(reportErrors: boolean): Symbol | undefined { // Only cache `unknownSymbol` if we are reporting errors so that we don't report the error more than once. deferredGlobalAwaitedSymbol ||= getGlobalTypeAliasSymbol("Awaited" as __String, /*arity*/ 1, reportErrors) || (reportErrors ? unknownSymbol : undefined); return deferredGlobalAwaitedSymbol === unknownSymbol ? undefined : deferredGlobalAwaitedSymbol; } function getGlobalBigIntType() { return (deferredGlobalBigIntType ||= getGlobalType("BigInt" as __String, /*arity*/ 0, /*reportErrors*/ false)) || emptyObjectType; } function getGlobalClassDecoratorContextType(reportErrors: boolean) { return (deferredGlobalClassDecoratorContextType ??= getGlobalType("ClassDecoratorContext" as __String, /*arity*/ 1, reportErrors)) ?? emptyGenericType; } function getGlobalClassMethodDecoratorContextType(reportErrors: boolean) { return (deferredGlobalClassMethodDecoratorContextType ??= getGlobalType("ClassMethodDecoratorContext" as __String, /*arity*/ 2, reportErrors)) ?? emptyGenericType; } function getGlobalClassGetterDecoratorContextType(reportErrors: boolean) { return (deferredGlobalClassGetterDecoratorContextType ??= getGlobalType("ClassGetterDecoratorContext" as __String, /*arity*/ 2, reportErrors)) ?? emptyGenericType; } function getGlobalClassSetterDecoratorContextType(reportErrors: boolean) { return (deferredGlobalClassSetterDecoratorContextType ??= getGlobalType("ClassSetterDecoratorContext" as __String, /*arity*/ 2, reportErrors)) ?? emptyGenericType; } function getGlobalClassAccessorDecoratorContextType(reportErrors: boolean) { return (deferredGlobalClassAccessorDecoratorContextType ??= getGlobalType("ClassAccessorDecoratorContext" as __String, /*arity*/ 2, reportErrors)) ?? emptyGenericType; } function getGlobalClassAccessorDecoratorTargetType(reportErrors: boolean) { return (deferredGlobalClassAccessorDecoratorTargetType ??= getGlobalType("ClassAccessorDecoratorTarget" as __String, /*arity*/ 2, reportErrors)) ?? emptyGenericType; } function getGlobalClassAccessorDecoratorResultType(reportErrors: boolean) { return (deferredGlobalClassAccessorDecoratorResultType ??= getGlobalType("ClassAccessorDecoratorResult" as __String, /*arity*/ 2, reportErrors)) ?? emptyGenericType; } function getGlobalClassFieldDecoratorContextType(reportErrors: boolean) { return (deferredGlobalClassFieldDecoratorContextType ??= getGlobalType("ClassFieldDecoratorContext" as __String, /*arity*/ 2, reportErrors)) ?? emptyGenericType; } function getGlobalNaNSymbol(): Symbol | undefined { return (deferredGlobalNaNSymbol ||= getGlobalValueSymbol("NaN" as __String, /*reportErrors*/ false)); } function getGlobalRecordSymbol(): Symbol | undefined { deferredGlobalRecordSymbol ||= getGlobalTypeAliasSymbol("Record" as __String, /*arity*/ 2, /*reportErrors*/ true) || unknownSymbol; return deferredGlobalRecordSymbol === unknownSymbol ? undefined : deferredGlobalRecordSymbol; } /** * Instantiates a global type that is generic with some element type, and returns that instantiation. */ function createTypeFromGenericGlobalType(genericGlobalType: GenericType, typeArguments: readonly Type[]): ObjectType { return genericGlobalType !== emptyGenericType ? createTypeReference(genericGlobalType, typeArguments) : emptyObjectType; } function createTypedPropertyDescriptorType(propertyType: Type): Type { return createTypeFromGenericGlobalType(getGlobalTypedPropertyDescriptorType(), [propertyType]); } function createIterableType(iteratedType: Type): Type { return createTypeFromGenericGlobalType(getGlobalIterableType(/*reportErrors*/ true), [iteratedType]); } function createArrayType(elementType: Type, readonly?: boolean): ObjectType { return createTypeFromGenericGlobalType(readonly ? globalReadonlyArrayType : globalArrayType, [elementType]); } function getTupleElementFlags(node: TypeNode) { switch (node.kind) { case SyntaxKind.OptionalType: return ElementFlags.Optional; case SyntaxKind.RestType: return getRestTypeElementFlags(node as RestTypeNode); case SyntaxKind.NamedTupleMember: return (node as NamedTupleMember).questionToken ? ElementFlags.Optional : (node as NamedTupleMember).dotDotDotToken ? getRestTypeElementFlags(node as NamedTupleMember) : ElementFlags.Required; default: return ElementFlags.Required; } } function getRestTypeElementFlags(node: RestTypeNode | NamedTupleMember) { return getArrayElementTypeNode(node.type) ? ElementFlags.Rest : ElementFlags.Variadic; } function getArrayOrTupleTargetType(node: ArrayTypeNode | TupleTypeNode): GenericType { const readonly = isReadonlyTypeOperator(node.parent); const elementType = getArrayElementTypeNode(node); if (elementType) { return readonly ? globalReadonlyArrayType : globalArrayType; } const elementFlags = map((node as TupleTypeNode).elements, getTupleElementFlags); const missingName = some((node as TupleTypeNode).elements, e => e.kind !== SyntaxKind.NamedTupleMember); return getTupleTargetType(elementFlags, readonly, /*associatedNames*/ missingName ? undefined : (node as TupleTypeNode).elements as readonly NamedTupleMember[]); } // Return true if the given type reference node is directly aliased or if it needs to be deferred // because it is possibly contained in a circular chain of eagerly resolved types. function isDeferredTypeReferenceNode(node: TypeReferenceNode | ArrayTypeNode | TupleTypeNode, hasDefaultTypeArguments?: boolean) { return !!getAliasSymbolForTypeNode(node) || isResolvedByTypeAlias(node) && ( node.kind === SyntaxKind.ArrayType ? mayResolveTypeAlias(node.elementType) : node.kind === SyntaxKind.TupleType ? some(node.elements, mayResolveTypeAlias) : hasDefaultTypeArguments || some(node.typeArguments, mayResolveTypeAlias)); } // Return true when the given node is transitively contained in type constructs that eagerly // resolve their constituent types. We include SyntaxKind.TypeReference because type arguments // of type aliases are eagerly resolved. function isResolvedByTypeAlias(node: Node): boolean { const parent = node.parent; switch (parent.kind) { case SyntaxKind.ParenthesizedType: case SyntaxKind.NamedTupleMember: case SyntaxKind.TypeReference: case SyntaxKind.UnionType: case SyntaxKind.IntersectionType: case SyntaxKind.IndexedAccessType: case SyntaxKind.ConditionalType: case SyntaxKind.TypeOperator: case SyntaxKind.ArrayType: case SyntaxKind.TupleType: return isResolvedByTypeAlias(parent); case SyntaxKind.TypeAliasDeclaration: return true; } return false; } // Return true if resolving the given node (i.e. getTypeFromTypeNode) possibly causes resolution // of a type alias. function mayResolveTypeAlias(node: Node): boolean { switch (node.kind) { case SyntaxKind.TypeReference: return isJSDocTypeReference(node) || !!(resolveTypeReferenceName(node as TypeReferenceNode, SymbolFlags.Type).flags & SymbolFlags.TypeAlias); case SyntaxKind.TypeQuery: return true; case SyntaxKind.TypeOperator: return (node as TypeOperatorNode).operator !== SyntaxKind.UniqueKeyword && mayResolveTypeAlias((node as TypeOperatorNode).type); case SyntaxKind.ParenthesizedType: case SyntaxKind.OptionalType: case SyntaxKind.NamedTupleMember: case SyntaxKind.JSDocOptionalType: case SyntaxKind.JSDocNullableType: case SyntaxKind.JSDocNonNullableType: case SyntaxKind.JSDocTypeExpression: return mayResolveTypeAlias((node as ParenthesizedTypeNode | OptionalTypeNode | JSDocTypeReferencingNode | NamedTupleMember).type); case SyntaxKind.RestType: return (node as RestTypeNode).type.kind !== SyntaxKind.ArrayType || mayResolveTypeAlias(((node as RestTypeNode).type as ArrayTypeNode).elementType); case SyntaxKind.UnionType: case SyntaxKind.IntersectionType: return some((node as UnionOrIntersectionTypeNode).types, mayResolveTypeAlias); case SyntaxKind.IndexedAccessType: return mayResolveTypeAlias((node as IndexedAccessTypeNode).objectType) || mayResolveTypeAlias((node as IndexedAccessTypeNode).indexType); case SyntaxKind.ConditionalType: return mayResolveTypeAlias((node as ConditionalTypeNode).checkType) || mayResolveTypeAlias((node as ConditionalTypeNode).extendsType) || mayResolveTypeAlias((node as ConditionalTypeNode).trueType) || mayResolveTypeAlias((node as ConditionalTypeNode).falseType); } return false; } function getTypeFromArrayOrTupleTypeNode(node: ArrayTypeNode | TupleTypeNode): Type { const links = getNodeLinks(node); if (!links.resolvedType) { const target = getArrayOrTupleTargetType(node); if (target === emptyGenericType) { links.resolvedType = emptyObjectType; } else if (!(node.kind === SyntaxKind.TupleType && some(node.elements, e => !!(getTupleElementFlags(e) & ElementFlags.Variadic))) && isDeferredTypeReferenceNode(node)) { links.resolvedType = node.kind === SyntaxKind.TupleType && node.elements.length === 0 ? target : createDeferredTypeReference(target, node, /*mapper*/ undefined); } else { const elementTypes = node.kind === SyntaxKind.ArrayType ? [getTypeFromTypeNode(node.elementType)] : map(node.elements, getTypeFromTypeNode); links.resolvedType = createNormalizedTypeReference(target, elementTypes); } } return links.resolvedType; } function isReadonlyTypeOperator(node: Node) { return isTypeOperatorNode(node) && node.operator === SyntaxKind.ReadonlyKeyword; } function createTupleType(elementTypes: readonly Type[], elementFlags?: readonly ElementFlags[], readonly = false, namedMemberDeclarations?: readonly (NamedTupleMember | ParameterDeclaration)[]) { const tupleTarget = getTupleTargetType(elementFlags || map(elementTypes, _ => ElementFlags.Required), readonly, namedMemberDeclarations); return tupleTarget === emptyGenericType ? emptyObjectType : elementTypes.length ? createNormalizedTypeReference(tupleTarget, elementTypes) : tupleTarget; } function getTupleTargetType(elementFlags: readonly ElementFlags[], readonly: boolean, namedMemberDeclarations?: readonly (NamedTupleMember | ParameterDeclaration)[]): GenericType { if (elementFlags.length === 1 && elementFlags[0] & ElementFlags.Rest) { // [...X[]] is equivalent to just X[] return readonly ? globalReadonlyArrayType : globalArrayType; } const key = map(elementFlags, f => f & ElementFlags.Required ? "#" : f & ElementFlags.Optional ? "?" : f & ElementFlags.Rest ? "." : "*").join() + (readonly ? "R" : "") + (namedMemberDeclarations && namedMemberDeclarations.length ? "," + map(namedMemberDeclarations, getNodeId).join(",") : ""); let type = tupleTypes.get(key); if (!type) { tupleTypes.set(key, type = createTupleTargetType(elementFlags, readonly, namedMemberDeclarations)); } return type; } // We represent tuple types as type references to synthesized generic interface types created by // this function. The types are of the form: // // interface Tuple extends Array { 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 createTupleTargetType(elementFlags: readonly ElementFlags[], readonly: boolean, namedMemberDeclarations: readonly (NamedTupleMember | ParameterDeclaration)[] | undefined): TupleType { const arity = elementFlags.length; const minLength = countWhere(elementFlags, f => !!(f & (ElementFlags.Required | ElementFlags.Variadic))); let typeParameters: TypeParameter[] | undefined; const properties: Symbol[] = []; let combinedFlags = 0 as ElementFlags; if (arity) { typeParameters = new Array(arity); for (let i = 0; i < arity; i++) { const typeParameter = typeParameters[i] = createTypeParameter(); const flags = elementFlags[i]; combinedFlags |= flags; if (!(combinedFlags & ElementFlags.Variable)) { const property = createSymbol(SymbolFlags.Property | (flags & ElementFlags.Optional ? SymbolFlags.Optional : 0), "" + i as __String, readonly ? CheckFlags.Readonly : 0); property.links.tupleLabelDeclaration = namedMemberDeclarations?.[i]; property.links.type = typeParameter; properties.push(property); } } } const fixedLength = properties.length; const lengthSymbol = createSymbol(SymbolFlags.Property, "length" as __String, readonly ? CheckFlags.Readonly : 0); if (combinedFlags & ElementFlags.Variable) { lengthSymbol.links.type = numberType; } else { const literalTypes = []; for (let i = minLength; i <= arity; i++) literalTypes.push(getNumberLiteralType(i)); lengthSymbol.links.type = getUnionType(literalTypes); } properties.push(lengthSymbol); const type = createObjectType(ObjectFlags.Tuple | ObjectFlags.Reference) as TupleType & InterfaceTypeWithDeclaredMembers; type.typeParameters = typeParameters; type.outerTypeParameters = undefined; type.localTypeParameters = typeParameters; type.instantiations = new Map(); type.instantiations.set(getTypeListId(type.typeParameters), type as GenericType); type.target = type as GenericType; type.resolvedTypeArguments = type.typeParameters; type.thisType = createTypeParameter(); type.thisType.isThisType = true; type.thisType.constraint = type; type.declaredProperties = properties; type.declaredCallSignatures = emptyArray; type.declaredConstructSignatures = emptyArray; type.declaredIndexInfos = emptyArray; type.elementFlags = elementFlags; type.minLength = minLength; type.fixedLength = fixedLength; type.hasRestElement = !!(combinedFlags & ElementFlags.Variable); type.combinedFlags = combinedFlags; type.readonly = readonly; type.labeledElementDeclarations = namedMemberDeclarations; return type; } function createNormalizedTypeReference(target: GenericType, typeArguments: readonly Type[] | undefined) { return target.objectFlags & ObjectFlags.Tuple ? createNormalizedTupleType(target as TupleType, typeArguments!) : createTypeReference(target, typeArguments); } function createNormalizedTupleType(target: TupleType, elementTypes: readonly Type[]): Type { if (!(target.combinedFlags & ElementFlags.NonRequired)) { // No need to normalize when we only have regular required elements return createTypeReference(target, elementTypes); } if (target.combinedFlags & ElementFlags.Variadic) { // Transform [A, ...(X | Y | Z)] into [A, ...X] | [A, ...Y] | [A, ...Z] const unionIndex = findIndex(elementTypes, (t, i) => !!(target.elementFlags[i] & ElementFlags.Variadic && t.flags & (TypeFlags.Never | TypeFlags.Union))); if (unionIndex >= 0) { return checkCrossProductUnion(map(elementTypes, (t, i) => target.elementFlags[i] & ElementFlags.Variadic ? t : unknownType)) ? mapType(elementTypes[unionIndex], t => createNormalizedTupleType(target, replaceElement(elementTypes, unionIndex, t))) : errorType; } } // We have optional, rest, or variadic elements that may need normalizing. Normalization ensures that all variadic // elements are generic and that the tuple type has one of the following layouts, disregarding variadic elements: // (1) Zero or more required elements, followed by zero or more optional elements, followed by zero or one rest element. // (2) Zero or more required elements, followed by a rest element, followed by zero or more required elements. // In either layout, zero or more generic variadic elements may be present at any location. const expandedTypes: Type[] = []; const expandedFlags: ElementFlags[] = []; let expandedDeclarations: (NamedTupleMember | ParameterDeclaration)[] | undefined = []; let lastRequiredIndex = -1; let firstRestIndex = -1; let lastOptionalOrRestIndex = -1; for (let i = 0; i < elementTypes.length; i++) { const type = elementTypes[i]; const flags = target.elementFlags[i]; if (flags & ElementFlags.Variadic) { if (type.flags & TypeFlags.InstantiableNonPrimitive || isGenericMappedType(type)) { // Generic variadic elements stay as they are. addElement(type, ElementFlags.Variadic, target.labeledElementDeclarations?.[i]); } else if (isTupleType(type)) { const elements = getElementTypes(type); if (elements.length + expandedTypes.length >= 10_000) { error(currentNode, isPartOfTypeNode(currentNode!) ? Diagnostics.Type_produces_a_tuple_type_that_is_too_large_to_represent : Diagnostics.Expression_produces_a_tuple_type_that_is_too_large_to_represent); return errorType; } // Spread variadic elements with tuple types into the resulting tuple. forEach(elements, (t, n) => addElement(t, type.target.elementFlags[n], type.target.labeledElementDeclarations?.[n])); } else { // Treat everything else as an array type and create a rest element. addElement(isArrayLikeType(type) && getIndexTypeOfType(type, numberType) || errorType, ElementFlags.Rest, target.labeledElementDeclarations?.[i]); } } else { // Copy other element kinds with no change. addElement(type, flags, target.labeledElementDeclarations?.[i]); } } // Turn optional elements preceding the last required element into required elements for (let i = 0; i < lastRequiredIndex; i++) { if (expandedFlags[i] & ElementFlags.Optional) expandedFlags[i] = ElementFlags.Required; } if (firstRestIndex >= 0 && firstRestIndex < lastOptionalOrRestIndex) { // Turn elements between first rest and last optional/rest into a single rest element expandedTypes[firstRestIndex] = getUnionType(sameMap(expandedTypes.slice(firstRestIndex, lastOptionalOrRestIndex + 1), (t, i) => expandedFlags[firstRestIndex + i] & ElementFlags.Variadic ? getIndexedAccessType(t, numberType) : t)); expandedTypes.splice(firstRestIndex + 1, lastOptionalOrRestIndex - firstRestIndex); expandedFlags.splice(firstRestIndex + 1, lastOptionalOrRestIndex - firstRestIndex); expandedDeclarations?.splice(firstRestIndex + 1, lastOptionalOrRestIndex - firstRestIndex); } const tupleTarget = getTupleTargetType(expandedFlags, target.readonly, expandedDeclarations); return tupleTarget === emptyGenericType ? emptyObjectType : expandedFlags.length ? createTypeReference(tupleTarget, expandedTypes) : tupleTarget; function addElement(type: Type, flags: ElementFlags, declaration: NamedTupleMember | ParameterDeclaration | undefined) { if (flags & ElementFlags.Required) { lastRequiredIndex = expandedFlags.length; } if (flags & ElementFlags.Rest && firstRestIndex < 0) { firstRestIndex = expandedFlags.length; } if (flags & (ElementFlags.Optional | ElementFlags.Rest)) { lastOptionalOrRestIndex = expandedFlags.length; } expandedTypes.push(flags & ElementFlags.Optional ? addOptionality(type, /*isProperty*/ true) : type); expandedFlags.push(flags); if (expandedDeclarations && declaration) { expandedDeclarations.push(declaration); } else { expandedDeclarations = undefined; } } } function sliceTupleType(type: TupleTypeReference, index: number, endSkipCount = 0) { const target = type.target; const endIndex = getTypeReferenceArity(type) - endSkipCount; return index > target.fixedLength ? getRestArrayTypeOfTupleType(type) || createTupleType(emptyArray) : createTupleType(getTypeArguments(type).slice(index, endIndex), target.elementFlags.slice(index, endIndex), /*readonly*/ false, target.labeledElementDeclarations && target.labeledElementDeclarations.slice(index, endIndex)); } function getKnownKeysOfTupleType(type: TupleTypeReference) { return getUnionType(append(arrayOf(type.target.fixedLength, i => getStringLiteralType("" + i)), getIndexType(type.target.readonly ? globalReadonlyArrayType : globalArrayType))); } // Return count of starting consecutive tuple elements of the given kind(s) function getStartElementCount(type: TupleType, flags: ElementFlags) { const index = findIndex(type.elementFlags, f => !(f & flags)); return index >= 0 ? index : type.elementFlags.length; } // Return count of ending consecutive tuple elements of the given kind(s) function getEndElementCount(type: TupleType, flags: ElementFlags) { return type.elementFlags.length - findLastIndex(type.elementFlags, f => !(f & flags)) - 1; } function getElementTypes(type: TupleTypeReference): readonly Type[] { const typeArguments = getTypeArguments(type); const arity = getTypeReferenceArity(type); return typeArguments.length === arity ? typeArguments : typeArguments.slice(0, arity); } function getTypeFromOptionalTypeNode(node: OptionalTypeNode): Type { return addOptionality(getTypeFromTypeNode(node.type), /*isProperty*/ true); } function getTypeId(type: Type): TypeId { return type.id; } function containsType(types: readonly 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; } function addTypeToUnion(typeSet: Type[], includes: TypeFlags, type: Type) { const flags = type.flags; // We ignore 'never' types in unions if (!(flags & TypeFlags.Never)) { includes |= flags & TypeFlags.IncludesMask; if (flags & TypeFlags.Instantiable) includes |= TypeFlags.IncludesInstantiable; 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: readonly Type[]): TypeFlags { let lastType: Type | undefined; for (const type of types) { // We skip the type if it is the same as the last type we processed. This simple test particularly // saves a lot of work for large lists of the same union type, such as when resolving `Record[A]`, // where A and B are large union types. if (type !== lastType) { includes = type.flags & TypeFlags.Union ? addTypesToUnion(typeSet, includes | (isNamedUnionType(type) ? TypeFlags.Union : 0), (type as UnionType).types) : addTypeToUnion(typeSet, includes, type); lastType = type; } } return includes; } function removeSubtypes(types: Type[], hasObjectTypes: boolean): Type[] | undefined { // [] and [T] immediately reduce to [] and [T] respectively if (types.length < 2) { return types; } const id = getTypeListId(types); const match = subtypeReductionCache.get(id); if (match) { return match; } // We assume that redundant primitive types have already been removed from the types array and that there // are no any and unknown types in the array. Thus, the only possible supertypes for primitive types are empty // object types, and if none of those are present we can exclude primitive types from the subtype check. const hasEmptyObject = hasObjectTypes && some(types, t => !!(t.flags & TypeFlags.Object) && !isGenericMappedType(t) && isEmptyResolvedType(resolveStructuredTypeMembers(t as ObjectType))); const len = types.length; let i = len; let count = 0; while (i > 0) { i--; const source = types[i]; if (hasEmptyObject || source.flags & TypeFlags.StructuredOrInstantiable) { // A type parameter with a union constraint may be a subtype of some union, but not a subtype of the // individual constituents of that union. For example, `T extends A | B` is a subtype of `A | B`, but not // a subtype of just `A` or just `B`. When we encounter such a type parameter, we therefore check if the // type parameter is a subtype of a union of all the other types. if (source.flags & TypeFlags.TypeParameter && getBaseConstraintOrType(source).flags & TypeFlags.Union) { if (isTypeRelatedTo(source, getUnionType(map(types, t => t === source ? neverType : t)), strictSubtypeRelation)) { orderedRemoveItemAt(types, i); } continue; } // Find the first property with a unit type, if any. When constituents have a property by the same name // but of a different unit type, we can quickly disqualify them from subtype checks. This helps subtype // reduction of large discriminated union types. const keyProperty = source.flags & (TypeFlags.Object | TypeFlags.Intersection | TypeFlags.InstantiableNonPrimitive) ? find(getPropertiesOfType(source), p => isUnitType(getTypeOfSymbol(p))) : undefined; const keyPropertyType = keyProperty && getRegularTypeOfLiteralType(getTypeOfSymbol(keyProperty)); 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 1M we deem the union type too complex to represent. This for example // caps union types at 1000 unique object types. const estimatedCount = (count / (len - i)) * len; if (estimatedCount > 1000000) { tracing?.instant(tracing.Phase.CheckTypes, "removeSubtypes_DepthLimit", { typeIds: types.map(t => t.id) }); error(currentNode, Diagnostics.Expression_produces_a_union_type_that_is_too_complex_to_represent); return undefined; } } count++; if (keyProperty && target.flags & (TypeFlags.Object | TypeFlags.Intersection | TypeFlags.InstantiableNonPrimitive)) { const t = getTypeOfPropertyOfType(target, keyProperty.escapedName); if (t && isUnitType(t) && getRegularTypeOfLiteralType(t) !== keyPropertyType) { continue; } } if (isTypeRelatedTo(source, target, strictSubtypeRelation) && ( !(getObjectFlags(getTargetType(source)) & ObjectFlags.Class) || !(getObjectFlags(getTargetType(target)) & ObjectFlags.Class) || isTypeDerivedFrom(source, target))) { orderedRemoveItemAt(types, i); break; } } } } } subtypeReductionCache.set(id, types); return types; } function removeRedundantLiteralTypes(types: Type[], includes: TypeFlags, reduceVoidUndefined: boolean) { let i = types.length; while (i > 0) { i--; const t = types[i]; const flags = t.flags; const remove = flags & (TypeFlags.StringLiteral | TypeFlags.TemplateLiteral | TypeFlags.StringMapping) && includes & TypeFlags.String || flags & TypeFlags.NumberLiteral && includes & TypeFlags.Number || flags & TypeFlags.BigIntLiteral && includes & TypeFlags.BigInt || flags & TypeFlags.UniqueESSymbol && includes & TypeFlags.ESSymbol || reduceVoidUndefined && flags & TypeFlags.Undefined && includes & TypeFlags.Void || isFreshLiteralType(t) && containsType(types, (t as LiteralType).regularType); if (remove) { orderedRemoveItemAt(types, i); } } } function removeStringLiteralsMatchedByTemplateLiterals(types: Type[]) { const templates = filter(types, t => !!(t.flags & TypeFlags.TemplateLiteral) && isPatternLiteralType(t)) as TemplateLiteralType[]; if (templates.length) { let i = types.length; while (i > 0) { i--; const t = types[i]; if (t.flags & TypeFlags.StringLiteral && some(templates, template => isTypeMatchedByTemplateLiteralType(t, template))) { orderedRemoveItemAt(types, i); } } } } function isNamedUnionType(type: Type) { return !!(type.flags & TypeFlags.Union && (type.aliasSymbol || (type as UnionType).origin)); } function addNamedUnions(namedUnions: Type[], types: readonly Type[]) { for (const t of types) { if (t.flags & TypeFlags.Union) { const origin = (t as UnionType).origin; if (t.aliasSymbol || origin && !(origin.flags & TypeFlags.Union)) { pushIfUnique(namedUnions, t); } else if (origin && origin.flags & TypeFlags.Union) { addNamedUnions(namedUnions, (origin as UnionType).types); } } } } function createOriginUnionOrIntersectionType(flags: TypeFlags, types: Type[]) { const result = createOriginType(flags) as UnionOrIntersectionType; result.types = types; return result; } // 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: readonly Type[], unionReduction: UnionReduction = UnionReduction.Literal, aliasSymbol?: Symbol, aliasTypeArguments?: readonly Type[], origin?: Type): Type { if (types.length === 0) { return neverType; } if (types.length === 1) { return types[0]; } // We optimize for the common case of unioning a union type with some other type (such as `undefined`). if (types.length === 2 && !origin && (types[0].flags & TypeFlags.Union || types[1].flags & TypeFlags.Union)) { const infix = unionReduction === UnionReduction.None ? "N" : unionReduction === UnionReduction.Subtype ? "S" : "L"; const index = types[0].id < types[1].id ? 0 : 1; const id = types[index].id + infix + types[1 - index].id + getAliasId(aliasSymbol, aliasTypeArguments); let type = unionOfUnionTypes.get(id); if (!type) { type = getUnionTypeWorker(types, unionReduction, aliasSymbol, aliasTypeArguments, /*origin*/ undefined); unionOfUnionTypes.set(id, type); } return type; } return getUnionTypeWorker(types, unionReduction, aliasSymbol, aliasTypeArguments, origin); } function getUnionTypeWorker(types: readonly Type[], unionReduction: UnionReduction, aliasSymbol: Symbol | undefined, aliasTypeArguments: readonly Type[] | undefined, origin: Type | undefined): Type { let typeSet: Type[] | undefined = []; const includes = addTypesToUnion(typeSet, 0 as TypeFlags, types); if (unionReduction !== UnionReduction.None) { if (includes & TypeFlags.AnyOrUnknown) { return includes & TypeFlags.Any ? includes & TypeFlags.IncludesWildcard ? wildcardType : anyType : includes & TypeFlags.Null || containsType(typeSet, unknownType) ? unknownType : nonNullUnknownType; } if (includes & TypeFlags.Undefined) { // If type set contains both undefinedType and missingType, remove missingType if (typeSet.length >= 2 && typeSet[0] === undefinedType && typeSet[1] === missingType) { orderedRemoveItemAt(typeSet, 1); } } if (includes & (TypeFlags.Enum | TypeFlags.Literal | TypeFlags.UniqueESSymbol | TypeFlags.TemplateLiteral | TypeFlags.StringMapping) || includes & TypeFlags.Void && includes & TypeFlags.Undefined) { removeRedundantLiteralTypes(typeSet, includes, !!(unionReduction & UnionReduction.Subtype)); } if (includes & TypeFlags.StringLiteral && includes & TypeFlags.TemplateLiteral) { removeStringLiteralsMatchedByTemplateLiterals(typeSet); } if (unionReduction === UnionReduction.Subtype) { typeSet = removeSubtypes(typeSet, !!(includes & TypeFlags.Object)); if (!typeSet) { return errorType; } } if (typeSet.length === 0) { return includes & TypeFlags.Null ? includes & TypeFlags.IncludesNonWideningType ? nullType : nullWideningType : includes & TypeFlags.Undefined ? includes & TypeFlags.IncludesNonWideningType ? undefinedType : undefinedWideningType : neverType; } } if (!origin && includes & TypeFlags.Union) { const namedUnions: Type[] = []; addNamedUnions(namedUnions, types); const reducedTypes: Type[] = []; for (const t of typeSet) { if (!some(namedUnions, union => containsType((union as UnionType).types, t))) { reducedTypes.push(t); } } if (!aliasSymbol && namedUnions.length === 1 && reducedTypes.length === 0) { return namedUnions[0]; } // We create a denormalized origin type only when the union was created from one or more named unions // (unions with alias symbols or origins) and when there is no overlap between those named unions. const namedTypesCount = reduceLeft(namedUnions, (sum, union) => sum + (union as UnionType).types.length, 0); if (namedTypesCount + reducedTypes.length === typeSet.length) { for (const t of namedUnions) { insertType(reducedTypes, t); } origin = createOriginUnionOrIntersectionType(TypeFlags.Union, reducedTypes); } } const objectFlags = (includes & TypeFlags.NotPrimitiveUnion ? 0 : ObjectFlags.PrimitiveUnion) | (includes & TypeFlags.Intersection ? ObjectFlags.ContainsIntersections : 0); return getUnionTypeFromSortedList(typeSet, objectFlags, aliasSymbol, aliasTypeArguments, origin); } function getUnionOrIntersectionTypePredicate(signatures: readonly Signature[], kind: TypeFlags | undefined): TypePredicate | undefined { let last: TypePredicate | undefined; const types: Type[] = []; for (const sig of signatures) { const pred = getTypePredicateOfSignature(sig); if (pred) { // Constituent type predicates must all have matching kinds. We don't create composite type predicates for assertions. if (pred.kind !== TypePredicateKind.This && pred.kind !== TypePredicateKind.Identifier || last && !typePredicateKindsMatch(last, pred)) { return undefined; } last = pred; types.push(pred.type); } else { // In composite union signatures we permit and ignore signatures with a return type `false`. const returnType = kind !== TypeFlags.Intersection ? getReturnTypeOfSignature(sig) : undefined; if (returnType !== falseType && returnType !== regularFalseType) { return undefined; } } } if (!last) { return undefined; } const compositeType = getUnionOrIntersectionType(types, kind); return createTypePredicate(last.kind, last.parameterName, last.parameterIndex, compositeType); } function typePredicateKindsMatch(a: TypePredicate, b: TypePredicate): boolean { return a.kind === b.kind && a.parameterIndex === b.parameterIndex; } // This function assumes the constituent type list is sorted and deduplicated. function getUnionTypeFromSortedList(types: Type[], precomputedObjectFlags: ObjectFlags, aliasSymbol?: Symbol, aliasTypeArguments?: readonly Type[], origin?: Type): Type { if (types.length === 0) { return neverType; } if (types.length === 1) { return types[0]; } const typeKey = !origin ? getTypeListId(types) : origin.flags & TypeFlags.Union ? `|${getTypeListId((origin as UnionType).types)}` : origin.flags & TypeFlags.Intersection ? `&${getTypeListId((origin as IntersectionType).types)}` : `#${(origin as IndexType).type.id}|${getTypeListId(types)}`; // origin type id alone is insufficient, as `keyof x` may resolve to multiple WIP values while `x` is still resolving const id = typeKey + getAliasId(aliasSymbol, aliasTypeArguments); let type = unionTypes.get(id); if (!type) { type = createType(TypeFlags.Union) as UnionType; type.objectFlags = precomputedObjectFlags | getPropagatingFlagsOfTypes(types, /*excludeKinds*/ TypeFlags.Nullable); type.types = types; type.origin = origin; type.aliasSymbol = aliasSymbol; type.aliasTypeArguments = aliasTypeArguments; if (types.length === 2 && types[0].flags & TypeFlags.BooleanLiteral && types[1].flags & TypeFlags.BooleanLiteral) { type.flags |= TypeFlags.Boolean; (type as UnionType & IntrinsicType).intrinsicName = "boolean"; } unionTypes.set(id, type); } 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: Map, includes: TypeFlags, type: Type) { const flags = type.flags; if (flags & TypeFlags.Intersection) { return addTypesToIntersection(typeSet, includes, (type as IntersectionType).types); } if (isEmptyAnonymousObjectType(type)) { if (!(includes & TypeFlags.IncludesEmptyObject)) { includes |= TypeFlags.IncludesEmptyObject; typeSet.set(type.id.toString(), type); } } else { if (flags & TypeFlags.AnyOrUnknown) { if (type === wildcardType) includes |= TypeFlags.IncludesWildcard; } else if (strictNullChecks || !(flags & TypeFlags.Nullable)) { if (type === missingType) { includes |= TypeFlags.IncludesMissingType; type = undefinedType; } if (!typeSet.has(type.id.toString())) { if (type.flags & TypeFlags.Unit && includes & TypeFlags.Unit) { // We have seen two distinct unit types which means we should reduce to an // empty intersection. Adding TypeFlags.NonPrimitive causes that to happen. includes |= TypeFlags.NonPrimitive; } typeSet.set(type.id.toString(), type); } } includes |= flags & TypeFlags.IncludesMask; } 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: Map, includes: TypeFlags, types: readonly Type[]) { for (const type of types) { includes = addTypeToIntersection(typeSet, includes, getRegularTypeOfLiteralType(type)); } return includes; } function removeRedundantSupertypes(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 | TypeFlags.TemplateLiteral | TypeFlags.StringMapping) || t.flags & TypeFlags.Number && includes & TypeFlags.NumberLiteral || t.flags & TypeFlags.BigInt && includes & TypeFlags.BigIntLiteral || t.flags & TypeFlags.ESSymbol && includes & TypeFlags.UniqueESSymbol || t.flags & TypeFlags.Void && includes & TypeFlags.Undefined || isEmptyAnonymousObjectType(t) && includes & TypeFlags.DefinitelyNonNullable; 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.Enum | TypeFlags.NumberLiteral) ? numberType : type.flags & TypeFlags.BigIntLiteral ? bigintType : type.flags & TypeFlags.UniqueESSymbol ? esSymbolType : undefined; if (!primitive || !containsType(u.types, primitive)) { return false; } } } return true; } /** * Returns `true` if the intersection of the template literals and string literals is the empty set, eg `get${string}` & "setX", and should reduce to `never` */ function extractRedundantTemplateLiterals(types: Type[]): boolean { let i = types.length; const literals = filter(types, t => !!(t.flags & TypeFlags.StringLiteral)); while (i > 0) { i--; const t = types[i]; if (!(t.flags & TypeFlags.TemplateLiteral)) continue; for (const t2 of literals) { if (isTypeSubtypeOf(t2, t)) { // eg, ``get${T}` & "getX"` is just `"getX"` orderedRemoveItemAt(types, i); break; } else if (isPatternLiteralType(t)) { return true; } } } return false; } function removeFromEach(types: Type[], flag: TypeFlags) { for (let i = 0; i < types.length; i++) { types[i] = filterType(types[i], t => !(t.flags & flag)); } } // 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 = [types[index] as UnionType])).push(t as UnionType); 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; } function createIntersectionType(types: Type[], aliasSymbol?: Symbol, aliasTypeArguments?: readonly Type[]) { const result = createType(TypeFlags.Intersection) as IntersectionType; result.objectFlags = getPropagatingFlagsOfTypes(types, /*excludeKinds*/ TypeFlags.Nullable); result.types = types; result.aliasSymbol = aliasSymbol; result.aliasTypeArguments = aliasTypeArguments; return result; } // 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 & { next: List }" 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: readonly Type[], aliasSymbol?: Symbol, aliasTypeArguments?: readonly Type[], noSupertypeReduction?: boolean): Type { const typeMembershipMap: Map = new Map(); const includes = addTypesToIntersection(typeMembershipMap, 0 as TypeFlags, types); const typeSet: Type[] = arrayFrom(typeMembershipMap.values()); // An intersection type is considered empty if it contains // the type never, or // 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. if (includes & TypeFlags.Never) { return contains(typeSet, silentNeverType) ? silentNeverType : neverType; } if (strictNullChecks && includes & TypeFlags.Nullable && includes & (TypeFlags.Object | TypeFlags.NonPrimitive | TypeFlags.IncludesEmptyObject) || includes & TypeFlags.NonPrimitive && includes & (TypeFlags.DisjointDomains & ~TypeFlags.NonPrimitive) || includes & TypeFlags.StringLike && includes & (TypeFlags.DisjointDomains & ~TypeFlags.StringLike) || includes & TypeFlags.NumberLike && includes & (TypeFlags.DisjointDomains & ~TypeFlags.NumberLike) || includes & TypeFlags.BigIntLike && includes & (TypeFlags.DisjointDomains & ~TypeFlags.BigIntLike) || includes & TypeFlags.ESSymbolLike && includes & (TypeFlags.DisjointDomains & ~TypeFlags.ESSymbolLike) || includes & TypeFlags.VoidLike && includes & (TypeFlags.DisjointDomains & ~TypeFlags.VoidLike)) { return neverType; } if (includes & TypeFlags.TemplateLiteral && includes & TypeFlags.StringLiteral && extractRedundantTemplateLiterals(typeSet)) { return neverType; } if (includes & TypeFlags.Any) { return includes & TypeFlags.IncludesWildcard ? wildcardType : anyType; } if (!strictNullChecks && includes & TypeFlags.Nullable) { return includes & TypeFlags.IncludesEmptyObject ? neverType : includes & TypeFlags.Undefined ? undefinedType : nullType; } if (includes & TypeFlags.String && includes & (TypeFlags.StringLiteral | TypeFlags.TemplateLiteral | TypeFlags.StringMapping) || includes & TypeFlags.Number && includes & TypeFlags.NumberLiteral || includes & TypeFlags.BigInt && includes & TypeFlags.BigIntLiteral || includes & TypeFlags.ESSymbol && includes & TypeFlags.UniqueESSymbol || includes & TypeFlags.Void && includes & TypeFlags.Undefined || includes & TypeFlags.IncludesEmptyObject && includes & TypeFlags.DefinitelyNonNullable) { if (!noSupertypeReduction) removeRedundantSupertypes(typeSet, includes); } if (includes & TypeFlags.IncludesMissingType) { typeSet[typeSet.indexOf(undefinedType)] = missingType; } if (typeSet.length === 0) { return unknownType; } if (typeSet.length === 1) { return typeSet[0]; } const id = getTypeListId(typeSet) + getAliasId(aliasSymbol, aliasTypeArguments); let result = intersectionTypes.get(id); if (!result) { 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. result = getIntersectionType(typeSet, aliasSymbol, aliasTypeArguments); } else if (every(typeSet, t => !!(t.flags & TypeFlags.Union && (t as UnionType).types[0].flags & TypeFlags.Undefined))) { const containedUndefinedType = some(typeSet, containsMissingType) ? missingType : undefinedType; removeFromEach(typeSet, TypeFlags.Undefined); result = getUnionType([getIntersectionType(typeSet), containedUndefinedType], UnionReduction.Literal, aliasSymbol, aliasTypeArguments); } else if (every(typeSet, t => !!(t.flags & TypeFlags.Union && ((t as UnionType).types[0].flags & TypeFlags.Null || (t as UnionType).types[1].flags & TypeFlags.Null)))) { removeFromEach(typeSet, TypeFlags.Null); result = getUnionType([getIntersectionType(typeSet), nullType], UnionReduction.Literal, aliasSymbol, aliasTypeArguments); } else { // We are attempting to construct a type of the form X & (A | B) & (C | D). Transform this into a type of // the form X & A & C | X & A & D | X & B & C | X & B & D. If the estimated size of the resulting union type // exceeds 100000 constituents, report an error. if (!checkCrossProductUnion(typeSet)) { return errorType; } const constituents = getCrossProductIntersections(typeSet); // We attach a denormalized origin type when at least one constituent of the cross-product union is an // intersection (i.e. when the intersection didn't just reduce one or more unions to smaller unions) and // the denormalized origin has fewer constituents than the union itself. const origin = some(constituents, t => !!(t.flags & TypeFlags.Intersection)) && getConstituentCountOfTypes(constituents) > getConstituentCountOfTypes(typeSet) ? createOriginUnionOrIntersectionType(TypeFlags.Intersection, typeSet) : undefined; result = getUnionType(constituents, UnionReduction.Literal, aliasSymbol, aliasTypeArguments, origin); } } else { result = createIntersectionType(typeSet, aliasSymbol, aliasTypeArguments); } intersectionTypes.set(id, result); } return result; } function getCrossProductUnionSize(types: readonly Type[]) { return reduceLeft(types, (n, t) => t.flags & TypeFlags.Union ? n * (t as UnionType).types.length : t.flags & TypeFlags.Never ? 0 : n, 1); } function checkCrossProductUnion(types: readonly Type[]) { const size = getCrossProductUnionSize(types); if (size >= 100000) { tracing?.instant(tracing.Phase.CheckTypes, "checkCrossProductUnion_DepthLimit", { typeIds: types.map(t => t.id), size }); error(currentNode, Diagnostics.Expression_produces_a_union_type_that_is_too_complex_to_represent); return false; } return true; } function getCrossProductIntersections(types: readonly Type[]) { const count = getCrossProductUnionSize(types); const intersections: Type[] = []; for (let i = 0; i < count; i++) { const constituents = types.slice(); let n = i; for (let j = types.length - 1; j >= 0; j--) { if (types[j].flags & TypeFlags.Union) { const sourceTypes = (types[j] as UnionType).types; const length = sourceTypes.length; constituents[j] = sourceTypes[n % length]; n = Math.floor(n / length); } } const t = getIntersectionType(constituents); if (!(t.flags & TypeFlags.Never)) intersections.push(t); } return intersections; } function getConstituentCount(type: Type): number { return !(type.flags & TypeFlags.UnionOrIntersection) || type.aliasSymbol ? 1 : type.flags & TypeFlags.Union && (type as UnionType).origin ? getConstituentCount((type as UnionType).origin!) : getConstituentCountOfTypes((type as UnionOrIntersectionType).types); } function getConstituentCountOfTypes(types: Type[]): number { return reduceLeft(types, (n, t) => n + getConstituentCount(t), 0); } function areIntersectedTypesAvoidingPrimitiveReduction(t1: Type, t2: Type) { return !!(t1.flags & (TypeFlags.String | TypeFlags.Number | TypeFlags.BigInt)) && t2 === emptyTypeLiteralType; } function getTypeFromIntersectionTypeNode(node: IntersectionTypeNode): Type { const links = getNodeLinks(node); if (!links.resolvedType) { const aliasSymbol = getAliasSymbolForTypeNode(node); const types = map(node.types, getTypeFromTypeNode); const noSupertypeReduction = types.length === 2 && (areIntersectedTypesAvoidingPrimitiveReduction(types[0], types[1]) || areIntersectedTypesAvoidingPrimitiveReduction(types[1], types[0])); links.resolvedType = getIntersectionType(types, aliasSymbol, getTypeArgumentsForAliasSymbol(aliasSymbol), noSupertypeReduction); } return links.resolvedType; } function createIndexType(type: InstantiableType | UnionOrIntersectionType, indexFlags: IndexFlags) { const result = createType(TypeFlags.Index) as IndexType; result.type = type; result.indexFlags = indexFlags; return result; } function createOriginIndexType(type: InstantiableType | UnionOrIntersectionType) { const result = createOriginType(TypeFlags.Index) as IndexType; result.type = type; return result; } function getIndexTypeForGenericType(type: InstantiableType | UnionOrIntersectionType, indexFlags: IndexFlags) { return indexFlags & IndexFlags.StringsOnly ? type.resolvedStringIndexType || (type.resolvedStringIndexType = createIndexType(type, IndexFlags.StringsOnly)) : type.resolvedIndexType || (type.resolvedIndexType = createIndexType(type, IndexFlags.None)); } /** * This roughly mirrors `resolveMappedTypeMembers` in the nongeneric case, except only reports a union of the keys calculated, * rather than manufacturing the properties. We can't just fetch the `constraintType` since that would ignore mappings * and mapping the `constraintType` directly ignores how mapped types map _properties_ and not keys (thus ignoring subtype * reduction in the constraintType) when possible. * @param noIndexSignatures Indicates if _string_ index signatures should be elided. (other index signatures are always reported) */ function getIndexTypeForMappedType(type: MappedType, indexFlags: IndexFlags) { const typeParameter = getTypeParameterFromMappedType(type); const constraintType = getConstraintTypeFromMappedType(type); const nameType = getNameTypeFromMappedType(type.target as MappedType || type); if (!nameType && !(indexFlags & IndexFlags.NoIndexSignatures)) { // no mapping and no filtering required, just quickly bail to returning the constraint in the common case return constraintType; } const keyTypes: Type[] = []; if (isMappedTypeWithKeyofConstraintDeclaration(type)) { // We have a { [P in keyof T]: X } // `getApparentType` on the T in a generic mapped type can trigger a circularity // (conditionals and `infer` types create a circular dependency in the constraint resolution) // so we only eagerly manifest the keys if the constraint is nongeneric if (!isGenericIndexType(constraintType)) { const modifiersType = getApparentType(getModifiersTypeFromMappedType(type)); // The 'T' in 'keyof T' forEachMappedTypePropertyKeyTypeAndIndexSignatureKeyType(modifiersType, TypeFlags.StringOrNumberLiteralOrUnique, !!(indexFlags & IndexFlags.StringsOnly), addMemberForKeyType); } else { // we have a generic index and a homomorphic mapping (but a distributive key remapping) - we need to defer the whole `keyof whatever` for later // since it's not safe to resolve the shape of modifier type return getIndexTypeForGenericType(type, indexFlags); } } else { forEachType(getLowerBoundOfKeyType(constraintType), addMemberForKeyType); } if (isGenericIndexType(constraintType)) { // include the generic component in the resulting type forEachType(constraintType, addMemberForKeyType); } // we had to pick apart the constraintType to potentially map/filter it - compare the final resulting list with the original constraintType, // so we can return the union that preserves aliases/origin data if possible const result = indexFlags & IndexFlags.NoIndexSignatures ? filterType(getUnionType(keyTypes), t => !(t.flags & (TypeFlags.Any | TypeFlags.String))) : getUnionType(keyTypes); if (result.flags & TypeFlags.Union && constraintType.flags & TypeFlags.Union && getTypeListId((result as UnionType).types) === getTypeListId((constraintType as UnionType).types)){ return constraintType; } return result; function addMemberForKeyType(keyType: Type) { const propNameType = nameType ? instantiateType(nameType, appendTypeMapping(type.mapper, typeParameter, keyType)) : keyType; // `keyof` currently always returns `string | number` for concrete `string` index signatures - the below ternary keeps that behavior for mapped types // See `getLiteralTypeFromProperties` where there's a similar ternary to cause the same behavior. keyTypes.push(propNameType === stringType ? stringOrNumberType : propNameType); } } // Ordinarily we reduce a keyof M, where M is a mapped type { [P in K as N

]: X }, to simply N. This however presumes // that N distributes over union types, i.e. that N is equivalent to N | N | N. Specifically, we only // want to perform the reduction when the name type of a mapped type is distributive with respect to the type variable // introduced by the 'in' clause of the mapped type. Note that non-generic types are considered to be distributive because // they're the same type regardless of what's being distributed over. function hasDistributiveNameType(mappedType: MappedType) { const typeVariable = getTypeParameterFromMappedType(mappedType); return isDistributive(getNameTypeFromMappedType(mappedType) || typeVariable); function isDistributive(type: Type): boolean { return type.flags & (TypeFlags.AnyOrUnknown | TypeFlags.Primitive | TypeFlags.Never | TypeFlags.TypeParameter | TypeFlags.Object | TypeFlags.NonPrimitive) ? true : type.flags & TypeFlags.Conditional ? (type as ConditionalType).root.isDistributive && (type as ConditionalType).checkType === typeVariable : type.flags & (TypeFlags.UnionOrIntersection | TypeFlags.TemplateLiteral) ? every((type as UnionOrIntersectionType | TemplateLiteralType).types, isDistributive) : type.flags & TypeFlags.IndexedAccess ? isDistributive((type as IndexedAccessType).objectType) && isDistributive((type as IndexedAccessType).indexType) : type.flags & TypeFlags.Substitution ? isDistributive((type as SubstitutionType).baseType) && isDistributive((type as SubstitutionType).constraint): type.flags & TypeFlags.StringMapping ? isDistributive((type as StringMappingType).type) : false; } } function getLiteralTypeFromPropertyName(name: PropertyName | JsxAttributeName) { if (isPrivateIdentifier(name)) { return neverType; } if (isNumericLiteral(name)) { return getRegularTypeOfLiteralType(checkExpression(name)); } if (isComputedPropertyName(name)) { return getRegularTypeOfLiteralType(checkComputedPropertyName(name)); } const propertyName = getPropertyNameForPropertyNameNode(name); if (propertyName !== undefined) { return getStringLiteralType(unescapeLeadingUnderscores(propertyName)); } if (isExpression(name)) { return getRegularTypeOfLiteralType(checkExpression(name)); } return neverType; } function getLiteralTypeFromProperty(prop: Symbol, include: TypeFlags, includeNonPublic?: boolean) { if (includeNonPublic || !(getDeclarationModifierFlagsFromSymbol(prop) & ModifierFlags.NonPublicAccessibilityModifier)) { let type = getSymbolLinks(getLateBoundSymbol(prop)).nameType; if (!type) { const name = getNameOfDeclaration(prop.valueDeclaration) as PropertyName | JsxAttributeName; type = prop.escapedName === InternalSymbolName.Default ? getStringLiteralType("default") : name && getLiteralTypeFromPropertyName(name) || (!isKnownSymbol(prop) ? getStringLiteralType(symbolName(prop)) : undefined); } if (type && type.flags & include) { return type; } } return neverType; } function isKeyTypeIncluded(keyType: Type, include: TypeFlags): boolean { return !!(keyType.flags & include || keyType.flags & TypeFlags.Intersection && some((keyType as IntersectionType).types, t => isKeyTypeIncluded(t, include))); } function getLiteralTypeFromProperties(type: Type, include: TypeFlags, includeOrigin: boolean) { const origin = includeOrigin && (getObjectFlags(type) & (ObjectFlags.ClassOrInterface | ObjectFlags.Reference) || type.aliasSymbol) ? createOriginIndexType(type) : undefined; const propertyTypes = map(getPropertiesOfType(type), prop => getLiteralTypeFromProperty(prop, include)); const indexKeyTypes = map(getIndexInfosOfType(type), info => info !== enumNumberIndexInfo && isKeyTypeIncluded(info.keyType, include) ? info.keyType === stringType && include & TypeFlags.Number ? stringOrNumberType : info.keyType : neverType); return getUnionType(concatenate(propertyTypes, indexKeyTypes), UnionReduction.Literal, /*aliasSymbol*/ undefined, /*aliasTypeArguments*/ undefined, origin); } function shouldDeferIndexType(type: Type, indexFlags = IndexFlags.None) { return !!(type.flags & TypeFlags.InstantiableNonPrimitive || isGenericTupleType(type) || isGenericMappedType(type) && !hasDistributiveNameType(type) || type.flags & TypeFlags.Union && !(indexFlags & IndexFlags.NoReducibleCheck) && isGenericReducibleType(type) || type.flags & TypeFlags.Intersection && maybeTypeOfKind(type, TypeFlags.Instantiable) && some((type as IntersectionType).types, isEmptyAnonymousObjectType)); } function getIndexType(type: Type, indexFlags = defaultIndexFlags): Type { type = getReducedType(type); return shouldDeferIndexType(type, indexFlags) ? getIndexTypeForGenericType(type as InstantiableType | UnionOrIntersectionType, indexFlags) : type.flags & TypeFlags.Union ? getIntersectionType(map((type as UnionType).types, t => getIndexType(t, indexFlags))) : type.flags & TypeFlags.Intersection ? getUnionType(map((type as IntersectionType).types, t => getIndexType(t, indexFlags))) : getObjectFlags(type) & ObjectFlags.Mapped ? getIndexTypeForMappedType(type as MappedType, indexFlags) : type === wildcardType ? wildcardType : type.flags & TypeFlags.Unknown ? neverType : type.flags & (TypeFlags.Any | TypeFlags.Never) ? keyofConstraintType : getLiteralTypeFromProperties(type, (indexFlags & IndexFlags.NoIndexSignatures ? TypeFlags.StringLiteral : TypeFlags.StringLike) | (indexFlags & IndexFlags.StringsOnly ? 0 : TypeFlags.NumberLike | TypeFlags.ESSymbolLike), indexFlags === defaultIndexFlags); } 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; default: Debug.assertNever(node.operator); } } return links.resolvedType; } function getTypeFromTemplateTypeNode(node: TemplateLiteralTypeNode) { const links = getNodeLinks(node); if (!links.resolvedType) { links.resolvedType = getTemplateLiteralType( [node.head.text, ...map(node.templateSpans, span => span.literal.text)], map(node.templateSpans, span => getTypeFromTypeNode(span.type))); } return links.resolvedType; } function getTemplateLiteralType(texts: readonly string[], types: readonly Type[]): Type { const unionIndex = findIndex(types, t => !!(t.flags & (TypeFlags.Never | TypeFlags.Union))); if (unionIndex >= 0) { return checkCrossProductUnion(types) ? mapType(types[unionIndex], t => getTemplateLiteralType(texts, replaceElement(types, unionIndex, t))) : errorType; } if (contains(types, wildcardType)) { return wildcardType; } const newTypes: Type[] = []; const newTexts: string[] = []; let text = texts[0]; if (!addSpans(texts, types)) { return stringType; } if (newTypes.length === 0) { return getStringLiteralType(text); } newTexts.push(text); if (every(newTexts, t => t === "")) { if (every(newTypes, t => !!(t.flags & TypeFlags.String))) { return stringType; } // Normalize `${Mapping}` into Mapping if (newTypes.length === 1 && isPatternLiteralType(newTypes[0])) { return newTypes[0]; } } const id = `${getTypeListId(newTypes)}|${map(newTexts, t => t.length).join(",")}|${newTexts.join("")}`; let type = templateLiteralTypes.get(id); if (!type) { templateLiteralTypes.set(id, type = createTemplateLiteralType(newTexts, newTypes)); } return type; function addSpans(texts: readonly string[], types: readonly Type[]): boolean { for (let i = 0; i < types.length; i++) { const t = types[i]; if (t.flags & (TypeFlags.Literal | TypeFlags.Null | TypeFlags.Undefined)) { text += getTemplateStringForType(t) || ""; text += texts[i + 1]; } else if (t.flags & TypeFlags.TemplateLiteral) { text += (t as TemplateLiteralType).texts[0]; if (!addSpans((t as TemplateLiteralType).texts, (t as TemplateLiteralType).types)) return false; text += texts[i + 1]; } else if (isGenericIndexType(t) || isPatternLiteralPlaceholderType(t)) { newTypes.push(t); newTexts.push(text); text = texts[i + 1]; } else { return false; } } return true; } } function getTemplateStringForType(type: Type) { return type.flags & TypeFlags.StringLiteral ? (type as StringLiteralType).value : type.flags & TypeFlags.NumberLiteral ? "" + (type as NumberLiteralType).value : type.flags & TypeFlags.BigIntLiteral ? pseudoBigIntToString((type as BigIntLiteralType).value) : type.flags & (TypeFlags.BooleanLiteral | TypeFlags.Nullable) ? (type as IntrinsicType).intrinsicName : undefined; } function createTemplateLiteralType(texts: readonly string[], types: readonly Type[]) { const type = createType(TypeFlags.TemplateLiteral) as TemplateLiteralType; type.objectFlags = getPropagatingFlagsOfTypes(types, /*excludeKinds*/ TypeFlags.Nullable); type.texts = texts; type.types = types; return type; } function getStringMappingType(symbol: Symbol, type: Type): Type { return type.flags & (TypeFlags.Union | TypeFlags.Never) ? mapType(type, t => getStringMappingType(symbol, t)) : type.flags & TypeFlags.StringLiteral ? getStringLiteralType(applyStringMapping(symbol, (type as StringLiteralType).value)) : type.flags & TypeFlags.TemplateLiteral ? getTemplateLiteralType(...applyTemplateStringMapping(symbol, (type as TemplateLiteralType).texts, (type as TemplateLiteralType).types)) : // Mapping> === Mapping type.flags & TypeFlags.StringMapping && symbol === type.symbol ? type : type.flags & (TypeFlags.Any | TypeFlags.String | TypeFlags.StringMapping) || isGenericIndexType(type) ? getStringMappingTypeForGenericType(symbol, type) : // This handles Mapping<`${number}`> and Mapping<`${bigint}`> isPatternLiteralPlaceholderType(type) ? getStringMappingTypeForGenericType(symbol, getTemplateLiteralType(["", ""], [type])) : type; } function applyStringMapping(symbol: Symbol, str: string) { switch (intrinsicTypeKinds.get(symbol.escapedName as string)) { case IntrinsicTypeKind.Uppercase: return str.toUpperCase(); case IntrinsicTypeKind.Lowercase: return str.toLowerCase(); case IntrinsicTypeKind.Capitalize: return str.charAt(0).toUpperCase() + str.slice(1); case IntrinsicTypeKind.Uncapitalize: return str.charAt(0).toLowerCase() + str.slice(1); } return str; } function applyTemplateStringMapping(symbol: Symbol, texts: readonly string[], types: readonly Type[]): [texts: readonly string[], types: readonly Type[]] { switch (intrinsicTypeKinds.get(symbol.escapedName as string)) { case IntrinsicTypeKind.Uppercase: return [texts.map(t => t.toUpperCase()), types.map(t => getStringMappingType(symbol, t))]; case IntrinsicTypeKind.Lowercase: return [texts.map(t => t.toLowerCase()), types.map(t => getStringMappingType(symbol, t))]; case IntrinsicTypeKind.Capitalize: return [texts[0] === "" ? texts : [texts[0].charAt(0).toUpperCase() + texts[0].slice(1), ...texts.slice(1)], texts[0] === "" ? [getStringMappingType(symbol, types[0]), ...types.slice(1)] : types]; case IntrinsicTypeKind.Uncapitalize: return [texts[0] === "" ? texts : [texts[0].charAt(0).toLowerCase() + texts[0].slice(1), ...texts.slice(1)], texts[0] === "" ? [getStringMappingType(symbol, types[0]), ...types.slice(1)] : types]; } return [texts, types]; } function getStringMappingTypeForGenericType(symbol: Symbol, type: Type): Type { const id = `${getSymbolId(symbol)},${getTypeId(type)}`; let result = stringMappingTypes.get(id); if (!result) { stringMappingTypes.set(id, result = createStringMappingType(symbol, type)); } return result; } function createStringMappingType(symbol: Symbol, type: Type) { const result = createTypeWithSymbol(TypeFlags.StringMapping, symbol) as StringMappingType; result.type = type; return result; } function createIndexedAccessType(objectType: Type, indexType: Type, accessFlags: AccessFlags, aliasSymbol: Symbol | undefined, aliasTypeArguments: readonly Type[] | undefined) { const type = createType(TypeFlags.IndexedAccess) as IndexedAccessType; type.objectType = objectType; type.indexType = indexType; type.accessFlags = accessFlags; type.aliasSymbol = aliasSymbol; type.aliasTypeArguments = aliasTypeArguments; 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) { const constraint = getResolvedBaseConstraint(type); return constraint !== type && isJSLiteralType(constraint); } return false; } function getPropertyNameFromIndex(indexType: Type, accessNode: StringLiteral | Identifier | PrivateIdentifier | ObjectBindingPattern | ArrayBindingPattern | ComputedPropertyName | NumericLiteral | IndexedAccessTypeNode | ElementAccessExpression | SyntheticExpression | undefined) { return isTypeUsableAsPropertyName(indexType) ? getPropertyNameFromType(indexType) : accessNode && isPropertyName(accessNode) ? // late bound names are handled in the first branch, so here we only need to handle normal names getPropertyNameForPropertyNameNode(accessNode) : undefined; } function isUncalledFunctionReference(node: Node, symbol: Symbol) { if (symbol.flags & (SymbolFlags.Function | SymbolFlags.Method)) { const parent = findAncestor(node.parent, n => !isAccessExpression(n)) || node.parent; if (isCallLikeExpression(parent)) { return isCallOrNewExpression(parent) && isIdentifier(node) && hasMatchingArgument(parent, node); } return every(symbol.declarations, d => !isFunctionLike(d) || !!(getCombinedNodeFlags(d) & NodeFlags.Deprecated)); } return true; } function getPropertyTypeForIndexType(originalObjectType: Type, objectType: Type, indexType: Type, fullIndexType: Type, accessNode: ElementAccessExpression | IndexedAccessTypeNode | PropertyName | BindingName | SyntheticExpression | undefined, accessFlags: AccessFlags) { const accessExpression = accessNode && accessNode.kind === SyntaxKind.ElementAccessExpression ? accessNode : undefined; const propName = accessNode && isPrivateIdentifier(accessNode) ? undefined : getPropertyNameFromIndex(indexType, accessNode); if (propName !== undefined) { if (accessFlags & AccessFlags.Contextual) { return getTypeOfPropertyOfContextualType(objectType, propName) || anyType; } const prop = getPropertyOfType(objectType, propName); if (prop) { if (accessFlags & AccessFlags.ReportDeprecated && accessNode && prop.declarations && isDeprecatedSymbol(prop) && isUncalledFunctionReference(accessNode, prop)) { const deprecatedNode = accessExpression?.argumentExpression ?? (isIndexedAccessTypeNode(accessNode) ? accessNode.indexType : accessNode); addDeprecatedSuggestion(deprecatedNode, prop.declarations, propName as string); } if (accessExpression) { markPropertyAsReferenced(prop, accessExpression, isSelfTypeAccess(accessExpression.expression, objectType.symbol)); if (isAssignmentToReadonlyEntity(accessExpression, prop, getAssignmentTargetKind(accessExpression))) { error(accessExpression.argumentExpression, Diagnostics.Cannot_assign_to_0_because_it_is_a_read_only_property, symbolToString(prop)); return undefined; } if (accessFlags & AccessFlags.CacheSymbol) { getNodeLinks(accessNode!).resolvedSymbol = prop; } if (isThisPropertyAccessInConstructor(accessExpression, prop)) { return autoType; } } const propType = getTypeOfSymbol(prop); return accessExpression && getAssignmentTargetKind(accessExpression) !== AssignmentKind.Definite ? getFlowTypeOfReference(accessExpression, propType) : accessNode && isIndexedAccessTypeNode(accessNode) && containsMissingType(propType) ? getUnionType([propType, undefinedType]) : propType; } if (everyType(objectType, isTupleType) && isNumericLiteralName(propName)) { const index = +propName; if (accessNode && everyType(objectType, t => !(t as TupleTypeReference).target.hasRestElement) && !(accessFlags & AccessFlags.NoTupleBoundsCheck)) { const indexNode = getIndexNodeForAccessExpression(accessNode); if (isTupleType(objectType)) { if (index < 0) { error(indexNode, Diagnostics.A_tuple_type_cannot_be_indexed_with_a_negative_value); return undefinedType; } 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)); } } if (index >= 0) { errorIfWritingToReadonlyIndex(getIndexInfoOfType(objectType, numberType)); return mapType(objectType, t => { const restType = getRestTypeOfTupleType(t as TupleTypeReference) || undefinedType; return accessFlags & AccessFlags.IncludeUndefined ? getUnionType([restType, missingType]) : restType; }); } } } if (!(indexType.flags & TypeFlags.Nullable) && isTypeAssignableToKind(indexType, TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.ESSymbolLike)) { if (objectType.flags & (TypeFlags.Any | TypeFlags.Never)) { return objectType; } // If no index signature is applicable, we default to the string index signature. In effect, this means the string // index signature applies even when accessing with a symbol-like type. const indexInfo = getApplicableIndexInfo(objectType, indexType) || getIndexInfoOfType(objectType, stringType); if (indexInfo) { if (accessFlags & AccessFlags.NoIndexSignatures && indexInfo.keyType !== numberType) { if (accessExpression) { error(accessExpression, Diagnostics.Type_0_cannot_be_used_to_index_type_1, typeToString(indexType), typeToString(originalObjectType)); } return undefined; } if (accessNode && indexInfo.keyType === stringType && !isTypeAssignableToKind(indexType, TypeFlags.String | TypeFlags.Number)) { const indexNode = getIndexNodeForAccessExpression(accessNode); error(indexNode, Diagnostics.Type_0_cannot_be_used_as_an_index_type, typeToString(indexType)); return accessFlags & AccessFlags.IncludeUndefined ? getUnionType([indexInfo.type, missingType]) : indexInfo.type; } errorIfWritingToReadonlyIndex(indexInfo); // When accessing an enum object with its own type, // e.g. E[E.A] for enum E { A }, undefined shouldn't // be included in the result type if ((accessFlags & AccessFlags.IncludeUndefined) && !(objectType.symbol && objectType.symbol.flags & (SymbolFlags.RegularEnum | SymbolFlags.ConstEnum) && (indexType.symbol && indexType.flags & TypeFlags.EnumLiteral && getParentOfSymbol(indexType.symbol) === objectType.symbol))) { return getUnionType([indexInfo.type, missingType]); } return indexInfo.type; } if (indexType.flags & TypeFlags.Never) { return neverType; } if (isJSLiteralType(objectType)) { return anyType; } if (accessExpression && !isConstEnumObjectType(objectType)) { if (isObjectLiteralType(objectType)) { if (noImplicitAny && indexType.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral)) { diagnostics.add(createDiagnosticForNode(accessExpression, Diagnostics.Property_0_does_not_exist_on_type_1, (indexType as StringLiteralType).value, typeToString(objectType))); return undefinedType; } else if (indexType.flags & (TypeFlags.Number | TypeFlags.String)) { const types = map((objectType as ResolvedType).properties, property => { return getTypeOfSymbol(property); }); return getUnionType(append(types, undefinedType)); } } if (objectType.symbol === globalThisSymbol && propName !== undefined && globalThisSymbol.exports!.has(propName) && (globalThisSymbol.exports!.get(propName)!.flags & SymbolFlags.BlockScoped)) { error(accessExpression, Diagnostics.Property_0_does_not_exist_on_type_1, unescapeLeadingUnderscores(propName), typeToString(objectType)); } else if (noImplicitAny && !compilerOptions.suppressImplicitAnyIndexErrors && !(accessFlags & AccessFlags.SuppressNoImplicitAnyError)) { if (propName !== undefined && typeHasStaticProperty(propName, objectType)) { const typeName = typeToString(objectType); error(accessExpression, Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_mean_to_access_the_static_member_2_instead, propName as string, typeName, typeName + "[" + getTextOfNode(accessExpression.argumentExpression) + "]"); } else if (getIndexTypeOfType(objectType, numberType)) { 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 { const suggestion = getSuggestionForNonexistentIndexSignature(objectType, accessExpression, indexType); if (suggestion !== undefined) { error(accessExpression, Diagnostics.Element_implicitly_has_an_any_type_because_type_0_has_no_index_signature_Did_you_mean_to_call_1, typeToString(objectType), suggestion); } else { let errorInfo: DiagnosticMessageChain | undefined; if (indexType.flags & TypeFlags.EnumLiteral) { errorInfo = chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Property_0_does_not_exist_on_type_1, "[" + typeToString(indexType) + "]", typeToString(objectType)); } else if (indexType.flags & TypeFlags.UniqueESSymbol) { const symbolName = getFullyQualifiedName((indexType as UniqueESSymbolType).symbol, accessExpression); errorInfo = chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Property_0_does_not_exist_on_type_1, "[" + symbolName + "]", typeToString(objectType)); } else if (indexType.flags & TypeFlags.StringLiteral) { errorInfo = chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Property_0_does_not_exist_on_type_1, (indexType as StringLiteralType).value, typeToString(objectType)); } else if (indexType.flags & TypeFlags.NumberLiteral) { errorInfo = chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Property_0_does_not_exist_on_type_1, (indexType as NumberLiteralType).value, typeToString(objectType)); } else if (indexType.flags & (TypeFlags.Number | TypeFlags.String)) { errorInfo = chainDiagnosticMessages(/*details*/ undefined, Diagnostics.No_index_signature_with_a_parameter_of_type_0_was_found_on_type_1, typeToString(indexType), typeToString(objectType)); } errorInfo = chainDiagnosticMessages( errorInfo, Diagnostics.Element_implicitly_has_an_any_type_because_expression_of_type_0_can_t_be_used_to_index_type_1, typeToString(fullIndexType), typeToString(objectType) ); diagnostics.add(createDiagnosticForNodeFromMessageChain(getSourceFileOfNode(accessExpression), accessExpression, errorInfo)); } } } } return undefined; } } 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, "" + (indexType as StringLiteralType | NumberLiteralType).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 undefined; function errorIfWritingToReadonlyIndex(indexInfo: IndexInfo | undefined): void { if (indexInfo && indexInfo.isReadonly && accessExpression && (isAssignmentTarget(accessExpression) || isDeleteTarget(accessExpression))) { error(accessExpression, Diagnostics.Index_signature_in_type_0_only_permits_reading, typeToString(objectType)); } } } 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 isPatternLiteralPlaceholderType(type: Type): boolean { if (type.flags & TypeFlags.Intersection) { return some((type as IntersectionType).types, t => !!(t.flags & (TypeFlags.Literal | TypeFlags.Null | TypeFlags.Undefined)) || isPatternLiteralPlaceholderType(t)); } return !!(type.flags & (TypeFlags.Any | TypeFlags.String | TypeFlags.Number | TypeFlags.BigInt)) || isPatternLiteralType(type); } function isPatternLiteralType(type: Type) { return !!(type.flags & TypeFlags.TemplateLiteral) && every((type as TemplateLiteralType).types, isPatternLiteralPlaceholderType) || !!(type.flags & TypeFlags.StringMapping) && isPatternLiteralPlaceholderType((type as StringMappingType).type); } function isGenericType(type: Type): boolean { return !!getGenericObjectFlags(type); } function isGenericObjectType(type: Type): boolean { return !!(getGenericObjectFlags(type) & ObjectFlags.IsGenericObjectType); } function isGenericIndexType(type: Type): boolean { return !!(getGenericObjectFlags(type) & ObjectFlags.IsGenericIndexType); } function getGenericObjectFlags(type: Type): ObjectFlags { if (type.flags & (TypeFlags.UnionOrIntersection | TypeFlags.TemplateLiteral)) { if (!((type as UnionOrIntersectionType | TemplateLiteralType).objectFlags & ObjectFlags.IsGenericTypeComputed)) { (type as UnionOrIntersectionType | TemplateLiteralType).objectFlags |= ObjectFlags.IsGenericTypeComputed | reduceLeft((type as UnionOrIntersectionType | TemplateLiteralType).types, (flags, t) => flags | getGenericObjectFlags(t), 0); } return (type as UnionOrIntersectionType | TemplateLiteralType).objectFlags & ObjectFlags.IsGenericType; } if (type.flags & TypeFlags.Substitution) { if (!((type as SubstitutionType).objectFlags & ObjectFlags.IsGenericTypeComputed)) { (type as SubstitutionType).objectFlags |= ObjectFlags.IsGenericTypeComputed | getGenericObjectFlags((type as SubstitutionType).baseType) | getGenericObjectFlags((type as SubstitutionType).constraint); } return (type as SubstitutionType).objectFlags & ObjectFlags.IsGenericType; } return (type.flags & TypeFlags.InstantiableNonPrimitive || isGenericMappedType(type) || isGenericTupleType(type) ? ObjectFlags.IsGenericObjectType : 0) | (type.flags & (TypeFlags.InstantiableNonPrimitive | TypeFlags.Index | TypeFlags.StringMapping) && !isPatternLiteralType(type) ? ObjectFlags.IsGenericIndexType : 0); } function getSimplifiedType(type: Type, writing: boolean): Type { return type.flags & TypeFlags.IndexedAccess ? getSimplifiedIndexedAccessType(type as IndexedAccessType, writing) : type.flags & TypeFlags.Conditional ? getSimplifiedConditionalType(type as ConditionalType, writing) : type; } function distributeIndexOverObjectType(objectType: Type, indexType: Type, writing: boolean) { // (T | U)[K] -> T[K] | U[K] (reading) // (T | U)[K] -> T[K] & U[K] (writing) // (T & U)[K] -> T[K] & U[K] if (objectType.flags & TypeFlags.Union || objectType.flags & TypeFlags.Intersection && !shouldDeferIndexType(objectType)) { const types = map((objectType as UnionOrIntersectionType).types, t => getSimplifiedType(getIndexedAccessType(t, indexType), writing)); return objectType.flags & TypeFlags.Intersection || writing ? getIntersectionType(types) : getUnionType(types); } } function distributeObjectOverIndexType(objectType: Type, indexType: Type, writing: boolean) { // T[A | B] -> T[A] | T[B] (reading) // T[A | B] -> T[A] & T[B] (writing) if (indexType.flags & TypeFlags.Union) { const types = map((indexType as UnionType).types, t => getSimplifiedType(getIndexedAccessType(objectType, t), writing)); return writing ? getIntersectionType(types) : getUnionType(types); } } // Transform an indexed access to a simpler form, if possible. Return the simpler form, or return // the type itself if no transformation is possible. The writing flag indicates that the type is // the target of an assignment. function getSimplifiedIndexedAccessType(type: IndexedAccessType, writing: boolean): Type { const cache = writing ? "simplifiedForWriting" : "simplifiedForReading"; if (type[cache]) { return type[cache] === circularConstraintType ? type : type[cache]!; } type[cache] = 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, writing); const indexType = getSimplifiedType(type.indexType, writing); // T[A | B] -> T[A] | T[B] (reading) // T[A | B] -> T[A] & T[B] (writing) const distributedOverIndex = distributeObjectOverIndexType(objectType, indexType, writing); if (distributedOverIndex) { return type[cache] = distributedOverIndex; } // Only do the inner distributions if the index can no longer be instantiated to cause index distribution again if (!(indexType.flags & TypeFlags.Instantiable)) { // (T | U)[K] -> T[K] | U[K] (reading) // (T | U)[K] -> T[K] & U[K] (writing) // (T & U)[K] -> T[K] & U[K] const distributedOverObject = distributeIndexOverObjectType(objectType, indexType, writing); if (distributedOverObject) { return type[cache] = distributedOverObject; } } // So ultimately (reading): // ((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] // A generic tuple type indexed by a number exists only when the index type doesn't select a // fixed element. We simplify to either the combined type of all elements (when the index type // the actual number type) or to the combined type of all non-fixed elements. if (isGenericTupleType(objectType) && indexType.flags & TypeFlags.NumberLike) { const elementType = getElementTypeOfSliceOfTupleType(objectType, indexType.flags & TypeFlags.Number ? 0 : objectType.target.fixedLength, /*endSkipCount*/ 0, writing); if (elementType) { return type[cache] = elementType; } } // If the object type is a mapped type { [P in K]: E }, where K is generic, or { [P in K as N]: E }, where // K is generic and N is assignable to P, instantiate E using a mapper that substitutes the index type for P. // For example, for an index access { [P in K]: Box }[X], we construct the type Box. if (isGenericMappedType(objectType)) { if (!getNameTypeFromMappedType(objectType) || isFilteringMappedType(objectType)) { return type[cache] = mapType(substituteIndexedMappedType(objectType, type.indexType), t => getSimplifiedType(t, writing)); } } return type[cache] = type; } function getSimplifiedConditionalType(type: ConditionalType, writing: boolean) { const checkType = type.checkType; const extendsType = type.extendsType; const trueType = getTrueTypeFromConditionalType(type); const falseType = getFalseTypeFromConditionalType(type); // Simplifications for types of the form `T extends U ? T : never` and `T extends U ? never : T`. if (falseType.flags & TypeFlags.Never && getActualTypeVariable(trueType) === getActualTypeVariable(checkType)) { if (checkType.flags & TypeFlags.Any || isTypeAssignableTo(getRestrictiveInstantiation(checkType), getRestrictiveInstantiation(extendsType))) { // Always true return getSimplifiedType(trueType, writing); } else if (isIntersectionEmpty(checkType, extendsType)) { // Always false return neverType; } } else if (trueType.flags & TypeFlags.Never && getActualTypeVariable(falseType) === getActualTypeVariable(checkType)) { if (!(checkType.flags & TypeFlags.Any) && isTypeAssignableTo(getRestrictiveInstantiation(checkType), getRestrictiveInstantiation(extendsType))) { // Always true return neverType; } else if (checkType.flags & TypeFlags.Any || isIntersectionEmpty(checkType, extendsType)) { // Always false return getSimplifiedType(falseType, writing); } } return type; } /** * Invokes union simplification logic to determine if an intersection is considered empty as a union constituent */ function isIntersectionEmpty(type1: Type, type2: Type) { return !!(getUnionType([intersectTypes(type1, type2), neverType]).flags & TypeFlags.Never); } function substituteIndexedMappedType(objectType: MappedType, index: Type) { const mapper = createTypeMapper([getTypeParameterFromMappedType(objectType)], [index]); const templateMapper = combineTypeMappers(objectType.mapper, mapper); return instantiateType(getTemplateTypeFromMappedType(objectType.target as MappedType || objectType), templateMapper); } function getIndexedAccessType(objectType: Type, indexType: Type, accessFlags = AccessFlags.None, accessNode?: ElementAccessExpression | IndexedAccessTypeNode | PropertyName | BindingName | SyntheticExpression, aliasSymbol?: Symbol, aliasTypeArguments?: readonly Type[]): Type { return getIndexedAccessTypeOrUndefined(objectType, indexType, accessFlags, accessNode, aliasSymbol, aliasTypeArguments) || (accessNode ? errorType : unknownType); } function indexTypeLessThan(indexType: Type, limit: number) { return everyType(indexType, t => { if (t.flags & TypeFlags.StringOrNumberLiteral) { const propName = getPropertyNameFromType(t as StringLiteralType | NumberLiteralType); if (isNumericLiteralName(propName)) { const index = +propName; return index >= 0 && index < limit; } } return false; }); } function getIndexedAccessTypeOrUndefined(objectType: Type, indexType: Type, accessFlags = AccessFlags.None, accessNode?: ElementAccessExpression | IndexedAccessTypeNode | PropertyName | BindingName | SyntheticExpression, aliasSymbol?: Symbol, aliasTypeArguments?: readonly Type[]): Type | undefined { if (objectType === wildcardType || indexType === wildcardType) { return wildcardType; } objectType = getReducedType(objectType); // If the object type has a string index signature and no other members we know that the result will // always be the type of that index signature and we can simplify accordingly. if (isStringIndexSignatureOnlyType(objectType) && !(indexType.flags & TypeFlags.Nullable) && isTypeAssignableToKind(indexType, TypeFlags.String | TypeFlags.Number)) { indexType = stringType; } // In noUncheckedIndexedAccess mode, indexed access operations that occur in an expression in a read position and resolve to // an index signature have 'undefined' included in their type. if (compilerOptions.noUncheckedIndexedAccess && accessFlags & AccessFlags.ExpressionPosition) accessFlags |= AccessFlags.IncludeUndefined; // If the index type is generic, or if the object type is generic and doesn't originate in an expression and // the operation isn't exclusively indexing the fixed (non-variadic) portion of a tuple type, 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 ? isGenericTupleType(objectType) && !indexTypeLessThan(indexType, objectType.target.fixedLength) : isGenericObjectType(objectType) && !(isTupleType(objectType) && indexTypeLessThan(indexType, objectType.target.fixedLength)) || isGenericReducibleType(objectType))) { if (objectType.flags & TypeFlags.AnyOrUnknown) { return objectType; } // Defer the operation by creating an indexed access type. const persistentAccessFlags = accessFlags & AccessFlags.Persistent; const id = objectType.id + "," + indexType.id + "," + persistentAccessFlags + getAliasId(aliasSymbol, aliasTypeArguments); let type = indexedAccessTypes.get(id); if (!type) { indexedAccessTypes.set(id, type = createIndexedAccessType(objectType, indexType, persistentAccessFlags, aliasSymbol, aliasTypeArguments)); } 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 = getReducedApparentType(objectType); if (indexType.flags & TypeFlags.Union && !(indexType.flags & TypeFlags.Boolean)) { const propTypes: Type[] = []; let wasMissingProp = false; for (const t of (indexType as UnionType).types) { const propType = getPropertyTypeForIndexType(objectType, apparentObjectType, t, indexType, accessNode, accessFlags | (wasMissingProp ? AccessFlags.SuppressNoImplicitAnyError : 0)); if (propType) { propTypes.push(propType); } else if (!accessNode) { // If there's no error node, we can immeditely stop, since error reporting is off return undefined; } else { // Otherwise we set a flag and return at the end of the loop so we still mark all errors wasMissingProp = true; } } if (wasMissingProp) { return undefined; } return accessFlags & AccessFlags.Writing ? getIntersectionType(propTypes, aliasSymbol, aliasTypeArguments) : getUnionType(propTypes, UnionReduction.Literal, aliasSymbol, aliasTypeArguments); } return getPropertyTypeForIndexType(objectType, apparentObjectType, indexType, indexType, accessNode, accessFlags | AccessFlags.CacheSymbol | AccessFlags.ReportDeprecated); } function getTypeFromIndexedAccessTypeNode(node: IndexedAccessTypeNode) { const links = getNodeLinks(node); if (!links.resolvedType) { const objectType = getTypeFromTypeNode(node.objectType); const indexType = getTypeFromTypeNode(node.indexType); const potentialAlias = getAliasSymbolForTypeNode(node); links.resolvedType = getIndexedAccessType(objectType, indexType, AccessFlags.None, node, potentialAlias, getTypeArgumentsForAliasSymbol(potentialAlias)); } return links.resolvedType; } function getTypeFromMappedTypeNode(node: MappedTypeNode): Type { const links = getNodeLinks(node); if (!links.resolvedType) { const type = createObjectType(ObjectFlags.Mapped, node.symbol) as MappedType; 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): Type { if (type.flags & TypeFlags.Substitution) { return getActualTypeVariable((type as SubstitutionType).baseType); } if (type.flags & TypeFlags.IndexedAccess && ( (type as IndexedAccessType).objectType.flags & TypeFlags.Substitution || (type as IndexedAccessType).indexType.flags & TypeFlags.Substitution)) { return getIndexedAccessType(getActualTypeVariable((type as IndexedAccessType).objectType), getActualTypeVariable((type as IndexedAccessType).indexType)); } return type; } function maybeCloneTypeParameter(p: TypeParameter) { const constraint = getConstraintOfTypeParameter(p); return constraint && (isGenericObjectType(constraint) || isGenericIndexType(constraint)) ? cloneTypeParameter(p) : p; } function isSimpleTupleType(node: TypeNode) { return isTupleTypeNode(node) && length(node.elements) > 0 && !some(node.elements, e => isOptionalTypeNode(e) || isRestTypeNode(e) || isNamedTupleMember(e) && !!(e.questionToken || e.dotDotDotToken)); } function isDeferredType(type: Type, checkTuples: boolean) { return isGenericType(type) || checkTuples && isTupleType(type) && some(getElementTypes(type), isGenericType); } function getConditionalType(root: ConditionalRoot, mapper: TypeMapper | undefined, aliasSymbol?: Symbol, aliasTypeArguments?: readonly Type[]): Type { let result; let extraTypes: Type[] | undefined; let tailCount = 0; // We loop here for an immediately nested conditional type in the false position, effectively treating // types of the form 'A extends B ? X : C extends D ? Y : E extends F ? Z : ...' as a single construct for // purposes of resolution. We also loop here when resolution of a conditional type ends in resolution of // another (or, through recursion, possibly the same) conditional type. In the potentially tail-recursive // cases we increment the tail recursion counter and stop after 1000 iterations. while (true) { if (tailCount === 1000) { error(currentNode, Diagnostics.Type_instantiation_is_excessively_deep_and_possibly_infinite); return errorType; } const checkType = instantiateType(getActualTypeVariable(root.checkType), mapper); const extendsType = instantiateType(root.extendsType, mapper); if (checkType === errorType || extendsType === errorType) { return errorType; } if (checkType === wildcardType || extendsType === wildcardType) { return wildcardType; } // When the check and extends types are simple tuple types of the same arity, we defer resolution of the // conditional type when any tuple elements are generic. This is such that non-distributable conditional // types can be written `[X] extends [Y] ? ...` and be deferred similarly to `X extends Y ? ...`. const checkTuples = isSimpleTupleType(root.node.checkType) && isSimpleTupleType(root.node.extendsType) && length((root.node.checkType as TupleTypeNode).elements) === length((root.node.extendsType as TupleTypeNode).elements); const checkTypeDeferred = isDeferredType(checkType, checkTuples); let combinedMapper: TypeMapper | undefined; if (root.inferTypeParameters) { // When we're looking at making an inference for an infer type, when we get its constraint, it'll automagically be // instantiated with the context, so it doesn't need the mapper for the inference contex - however the constraint // may refer to another _root_, _uncloned_ `infer` type parameter [1], or to something mapped by `mapper` [2]. // [1] Eg, if we have `Foo` and `Foo` - `B` is constrained to `T`, which, in turn, has been instantiated // as `number` // Conversely, if we have `Foo`, `B` is still constrained to `T` and `T` is instantiated as `A` // [2] Eg, if we have `Foo` and `Foo` where `Q` is mapped by `mapper` into `number` - `B` is constrained to `T` // which is in turn instantiated as `Q`, which is in turn instantiated as `number`. // So we need to: // * Clone the type parameters so their constraints can be instantiated in the context of `mapper` (otherwise theyd only get inference context information) // * Set the clones to both map the conditional's enclosing `mapper` and the original params // * instantiate the extends type with the clones // * incorporate all of the component mappers into the combined mapper for the true and false members // This means we have three mappers that need applying: // * The original `mapper` used to create this conditional // * The mapper that maps the old root type parameter to the clone (`freshMapper`) // * The mapper that maps the clone to its inference result (`context.mapper`) const freshParams = sameMap(root.inferTypeParameters, maybeCloneTypeParameter); const freshMapper = freshParams !== root.inferTypeParameters ? createTypeMapper(root.inferTypeParameters, freshParams) : undefined; const context = createInferenceContext(freshParams, /*signature*/ undefined, InferenceFlags.None); if (freshMapper) { const freshCombinedMapper = combineTypeMappers(mapper, freshMapper); for (let i = 0; i < freshParams.length; i++) { if (freshParams[i] !== root.inferTypeParameters[i]) { freshParams[i].mapper = freshCombinedMapper; } } } if (!checkTypeDeferred) { // 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, instantiateType(extendsType, freshMapper), InferencePriority.NoConstraints | InferencePriority.AlwaysStrict); } const innerMapper = combineTypeMappers(freshMapper, context.mapper); // It's possible for 'infer T' type paramteters to be given uninstantiated constraints when the // those type parameters are used in type references (see getInferredTypeParameterConstraint). For // that reason we need context.mapper to be first in the combined mapper. See #42636 for examples. combinedMapper = mapper ? combineTypeMappers(innerMapper, mapper) : innerMapper; } // 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 (!checkTypeDeferred && !isDeferredType(inferredExtendsType, checkTuples)) { // 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 (!(inferredExtendsType.flags & TypeFlags.AnyOrUnknown) && (checkType.flags & TypeFlags.Any || !isTypeAssignableTo(getPermissiveInstantiation(checkType), getPermissiveInstantiation(inferredExtendsType)))) { // Return union of trueType and falseType for 'any' since it matches anything if (checkType.flags & TypeFlags.Any) { (extraTypes || (extraTypes = [])).push(instantiateType(getTypeFromTypeNode(root.node.trueType), combinedMapper || mapper)); } // If falseType is an immediately nested conditional type that isn't distributive or has an // identical checkType, switch to that type and loop. const falseType = getTypeFromTypeNode(root.node.falseType); if (falseType.flags & TypeFlags.Conditional) { const newRoot = (falseType as ConditionalType).root; if (newRoot.node.parent === root.node && (!newRoot.isDistributive || newRoot.checkType === root.checkType)) { root = newRoot; continue; } if (canTailRecurse(falseType, mapper)) { continue; } } result = instantiateType(falseType, mapper); break; } // 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: string } ? string : number // doesn't immediately resolve to 'string' instead of being deferred. if (inferredExtendsType.flags & TypeFlags.AnyOrUnknown || isTypeAssignableTo(getRestrictiveInstantiation(checkType), getRestrictiveInstantiation(inferredExtendsType))) { const trueType = getTypeFromTypeNode(root.node.trueType); const trueMapper = combinedMapper || mapper; if (canTailRecurse(trueType, trueMapper)) { continue; } result = instantiateType(trueType, trueMapper); break; } } // Return a deferred type for a check that is neither definitely true nor definitely false result = createType(TypeFlags.Conditional) as ConditionalType; result.root = root; result.checkType = instantiateType(root.checkType, mapper); result.extendsType = instantiateType(root.extendsType, mapper); result.mapper = mapper; result.combinedMapper = combinedMapper; result.aliasSymbol = aliasSymbol || root.aliasSymbol; result.aliasTypeArguments = aliasSymbol ? aliasTypeArguments : instantiateTypes(root.aliasTypeArguments, mapper!); // TODO: GH#18217 break; } return extraTypes ? getUnionType(append(extraTypes, result)) : result; // We tail-recurse for generic conditional types that (a) have not already been evaluated and cached, and // (b) are non distributive, have a check type that is unaffected by instantiation, or have a non-union check // type. Note that recursion is possible only through aliased conditional types, so we only increment the tail // recursion counter for those. function canTailRecurse(newType: Type, newMapper: TypeMapper | undefined) { if (newType.flags & TypeFlags.Conditional && newMapper) { const newRoot = (newType as ConditionalType).root; if (newRoot.outerTypeParameters) { const typeParamMapper = combineTypeMappers((newType as ConditionalType).mapper, newMapper); const typeArguments = map(newRoot.outerTypeParameters, t => getMappedType(t, typeParamMapper)); const newRootMapper = createTypeMapper(newRoot.outerTypeParameters, typeArguments); const newCheckType = newRoot.isDistributive ? getMappedType(newRoot.checkType, newRootMapper) : undefined; if (!newCheckType || newCheckType === newRoot.checkType || !(newCheckType.flags & (TypeFlags.Union | TypeFlags.Never))) { root = newRoot; mapper = newRootMapper; aliasSymbol = undefined; aliasTypeArguments = undefined; if (newRoot.aliasSymbol) { tailCount++; } return true; } } } return false; } } function getTrueTypeFromConditionalType(type: ConditionalType) { return type.resolvedTrueType || (type.resolvedTrueType = instantiateType(getTypeFromTypeNode(type.root.node.trueType), type.mapper)); } function getFalseTypeFromConditionalType(type: ConditionalType) { return type.resolvedFalseType || (type.resolvedFalseType = instantiateType(getTypeFromTypeNode(type.root.node.falseType), type.mapper)); } function getInferredTrueTypeFromConditionalType(type: ConditionalType) { return type.resolvedInferredTrueType || (type.resolvedInferredTrueType = type.combinedMapper ? instantiateType(getTypeFromTypeNode(type.root.node.trueType), type.combinedMapper) : getTrueTypeFromConditionalType(type)); } 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 isDistributionDependent(root: ConditionalRoot) { return root.isDistributive && ( isTypeParameterPossiblyReferenced(root.checkType as TypeParameter, root.node.trueType) || isTypeParameterPossiblyReferenced(root.checkType as TypeParameter, root.node.falseType)); } function getTypeFromConditionalTypeNode(node: ConditionalTypeNode): Type { const lin