#### Prepare Call Hierarchy Request (:leftwards_arrow_with_hook:)
> *Since version 3.16.0*
The call hierarchy request is sent from the client to the server to return a call hierarchy for the language element of given text document positions. The call hierarchy requests are executed in two steps:
1. first a call hierarchy item is resolved for the given text document position
1. for a call hierarchy item the incoming or outgoing call hierarchy items are resolved.
_Client Capability_:
* property name (optional): `textDocument.callHierarchy`
* property type: `CallHierarchyClientCapabilities` defined as follows:
```typescript
interface CallHierarchyClientCapabilities {
/**
* Whether implementation supports dynamic registration. If this is set to
* `true` the client supports the new `(TextDocumentRegistrationOptions &
* StaticRegistrationOptions)` return value for the corresponding server
* capability as well.
*/
dynamicRegistration?: boolean;
}
```
_Server Capability_:
* property name (optional): `callHierarchyProvider`
* property type: `boolean | CallHierarchyOptions | CallHierarchyRegistrationOptions` where `CallHierarchyOptions` is defined as follows:
```typescript
export interface CallHierarchyOptions extends WorkDoneProgressOptions {
}
```
_Registration Options_: `CallHierarchyRegistrationOptions` defined as follows:
```typescript
export interface CallHierarchyRegistrationOptions extends
TextDocumentRegistrationOptions, CallHierarchyOptions,
StaticRegistrationOptions {
}
```
_Request_:
* method: `textDocument/prepareCallHierarchy`
* params: `CallHierarchyPrepareParams` defined as follows:
```typescript
export interface CallHierarchyPrepareParams extends TextDocumentPositionParams,
WorkDoneProgressParams {
}
```
_Response_:
* result: `CallHierarchyItem[] | null` defined as follows:
```typescript
export interface CallHierarchyItem {
/**
* The name of this item.
*/
name: string;
/**
* The kind of this item.
*/
kind: SymbolKind;
/**
* Tags for this item.
*/
tags?: SymbolTag[];
/**
* More detail for this item, e.g. the signature of a function.
*/
detail?: string;
/**
* The resource identifier of this item.
*/
uri: DocumentUri;
/**
* The range enclosing this symbol not including leading/trailing whitespace
* but everything else, e.g. comments and code.
*/
range: Range;
/**
* The range that should be selected and revealed when this symbol is being
* picked, e.g. the name of a function. Must be contained by the
* [`range`](#CallHierarchyItem.range).
*/
selectionRange: Range;
/**
* A data entry field that is preserved between a call hierarchy prepare and
* incoming calls or outgoing calls requests.
*/
data?: LSPAny;
}
```
* error: code and message set in case an exception happens during the 'textDocument/prepareCallHierarchy' request
#### Call Hierarchy Incoming Calls (:leftwards_arrow_with_hook:)
> *Since version 3.16.0*
The request is sent from the client to the server to resolve incoming calls for a given call hierarchy item. The request doesn't define its own client and server capabilities. It is only issued if a server registers for the [`textDocument/prepareCallHierarchy` request](#textDocument_prepareCallHierarchy).
_Request_:
* method: `callHierarchy/incomingCalls`
* params: `CallHierarchyIncomingCallsParams` defined as follows:
```typescript
export interface CallHierarchyIncomingCallsParams extends
WorkDoneProgressParams, PartialResultParams {
item: CallHierarchyItem;
}
```
_Response_:
* result: `CallHierarchyIncomingCall[] | null` defined as follows:
```typescript
export interface CallHierarchyIncomingCall {
/**
* The item that makes the call.
*/
from: CallHierarchyItem;
/**
* The ranges at which the calls appear. This is relative to the caller
* denoted by [`this.from`](#CallHierarchyIncomingCall.from).
*/
fromRanges: Range[];
}
```
* partial result: `CallHierarchyIncomingCall[]`
* error: code and message set in case an exception happens during the 'callHierarchy/incomingCalls' request
#### Call Hierarchy Outgoing Calls (:leftwards_arrow_with_hook:)
> *Since version 3.16.0*
The request is sent from the client to the server to resolve outgoing calls for a given call hierarchy item. The request doesn't define its own client and server capabilities. It is only issued if a server registers for the [`textDocument/prepareCallHierarchy` request](#textDocument_prepareCallHierarchy).
_Request_:
* method: `callHierarchy/outgoingCalls`
* params: `CallHierarchyOutgoingCallsParams` defined as follows:
```typescript
export interface CallHierarchyOutgoingCallsParams extends
WorkDoneProgressParams, PartialResultParams {
item: CallHierarchyItem;
}
```
_Response_:
* result: `CallHierarchyOutgoingCall[] | null` defined as follows:
```typescript
export interface CallHierarchyOutgoingCall {
/**
* The item that is called.
*/
to: CallHierarchyItem;
/**
* The range at which this item is called. This is the range relative to
* the caller, e.g the item passed to `callHierarchy/outgoingCalls` request.
*/
fromRanges: Range[];
}
```
* partial result: `CallHierarchyOutgoingCall[]`
* error: code and message set in case an exception happens during the 'callHierarchy/outgoingCalls' request