Go to Implementation

src/harness/fourslash.ts

@@ -1622,6 +1622,15 @@ namespace FourSlash {
             assertFn(actualCount, expectedCount, this.messageAtLastKnownMarker("Type definitions Count"));
         }
 
+        public verifyImplementationsCount(negative: boolean, expectedCount: number) {
+            const assertFn = negative ? assert.notEqual : assert.equal;
+
+            const implementations = this.languageService.getImplementationAtPosition(this.activeFile.fileName, this.currentCaretPosition);
+            const actualCount = implementations && implementations.length || 0;
+
+            assertFn(actualCount, expectedCount, this.messageAtLastKnownMarker("Implementations Count"));
+        }
+
         public verifyDefinitionsName(negative: boolean, expectedName: string, expectedContainerName: string) {
             const definitions = this.languageService.getDefinitionAtPosition(this.activeFile.fileName, this.currentCaretPosition);
             const actualDefinitionName = definitions && definitions.length ? definitions[0].name : "";
@@ -1636,6 +1645,47 @@ namespace FourSlash {
             }
         }
 
+        public goToImplementation(implIndex: number) {
+            const implementations = this.languageService.getImplementationAtPosition(this.activeFile.fileName, this.currentCaretPosition);
+            if (!implementations || !implementations.length) {
+                this.raiseError("goToImplementation failed - expected to at least one implementation location but got 0");
+            }
+
+            if (implIndex >= implementations.length) {
+                this.raiseError(`goToImplementation failed - implIndex value (${implIndex}) exceeds implementation list size (${implementations.length})`);
+            }
+
+            const implementation = implementations[implIndex];
+            this.openFile(implementation.fileName);
+            this.currentCaretPosition = implementation.textSpan.start;
+        }
+
+        public verifyRangesInImplementationList() {
+            const implementations = this.languageService.getImplementationAtPosition(this.activeFile.fileName, this.currentCaretPosition);
+            if (!implementations || !implementations.length) {
+                this.raiseError("verifyRangesInImplementationList failed - expected to at least one implementation location but got 0");
+            }
+
+            const ranges = this.getRanges();
+
+            if (!ranges || !ranges.length) {
+                this.raiseError("verifyRangesInImplementationList failed - expected to at least one range in test source");
+            }
+
+            for (const range of ranges) {
+                let rangeIsPresent = false;
+                const length = range.end - range.start;
+                for (const impl of implementations) {
+                    if (range.fileName === impl.fileName && range.start === impl.textSpan.start && length === impl.textSpan.length) {
+                        rangeIsPresent = true;
+                        break;
+                    }
+                }
+                assert.isTrue(rangeIsPresent, `No implementation found for range ${range.start}, ${range.end} in ${range.fileName}: ${this.rangeText(range)}`);
+            }
+            assert.equal(implementations.length, ranges.length, `Different number of implementations (${implementations.length}) and ranges (${ranges.length})`);
+        }
+
         public getMarkers(): Marker[] {
             //  Return a copy of the list
             return this.testData.markers.slice(0);
@@ -2786,6 +2836,10 @@ namespace FourSlashInterface {
             this.state.goToTypeDefinition(definitionIndex);
         }
 
+        public implementation(implementationIndex = 0) {
+            this.state.goToImplementation(implementationIndex);
+        }
+
         public position(position: number, fileIndex?: number): void;
         public position(position: number, fileName?: string): void;
         public position(position: number, fileNameOrIndex?: any): void {
@@ -2894,6 +2948,10 @@ namespace FourSlashInterface {
             this.state.verifyTypeDefinitionsCount(this.negative, expectedCount);
         }
 
+        public implementationCountIs(expectedCount: number) {
+            this.state.verifyImplementationsCount(this.negative, expectedCount);
+        }
+
         public definitionLocationExists() {
             this.state.verifyDefinitionLocationExists(this.negative);
         }
@@ -3135,6 +3193,10 @@ namespace FourSlashInterface {
         public ProjectInfo(expected: string[]) {
             this.state.verifyProjectInfo(expected);
         }
+
+        public allRangesAppearInImplementationList() {
+            this.state.verifyRangesInImplementationList();
+        }
     }
 
     export class Edit {

src/harness/harnessLanguageService.ts

@@ -408,6 +408,9 @@ namespace Harness.LanguageService {
         getTypeDefinitionAtPosition(fileName: string, position: number): ts.DefinitionInfo[] {
             return unwrapJSONCallResult(this.shim.getTypeDefinitionAtPosition(fileName, position));
         }
+        getImplementationAtPosition(fileName: string, position: number): ts.ImplementationLocation[] {
+            return unwrapJSONCallResult(this.shim.getImplementationAtPosition(fileName, position));
+        }
         getReferencesAtPosition(fileName: string, position: number): ts.ReferenceEntry[] {
             return unwrapJSONCallResult(this.shim.getReferencesAtPosition(fileName, position));
         }

src/server/client.ts

@@ -353,6 +353,28 @@ namespace ts.server {
             });
         }
 
+        getImplementationAtPosition(fileName: string, position: number): ImplementationLocation[] {
+            const lineOffset = this.positionToOneBasedLineOffset(fileName, position);
+            const args: protocol.FileLocationRequestArgs = {
+                file: fileName,
+                line: lineOffset.line,
+                offset: lineOffset.offset,
+            };
+
+            const request = this.processRequest<protocol.ImplementationRequest>(CommandNames.Implementation, args);
+            const response = this.processResponse<protocol.ImplementationResponse>(request);
+
+            return response.body.map(entry => {
+                const fileName = entry.file;
+                const start = this.lineOffsetToPosition(fileName, entry.start);
+                const end = this.lineOffsetToPosition(fileName, entry.end);
+                return {
+                    fileName,
+                    textSpan: ts.createTextSpanFromBounds(start, end)
+                };
+            });
+        }
+
         findReferences(fileName: string, position: number): ReferencedSymbol[] {
             // Not yet implemented.
             return [];

src/server/protocol.d.ts

@@ -193,6 +193,14 @@ declare namespace ts.server.protocol {
     export interface TypeDefinitionRequest extends FileLocationRequest {
     }
 
+    /**
+      * Go to implementation request; value of command field is
+      * "implementation". Return response giving the file locations that
+      * implement the symbol found in file at location line, col.
+      */
+    export interface ImplementationRequest extends FileLocationRequest {
+    }
+
     /**
       * Location in source code expressed as (one-based) line and character offset.
       */
@@ -240,6 +248,13 @@ declare namespace ts.server.protocol {
         body?: FileSpan[];
     }
 
+    /**
+      * Implementation response message.  Gives text range for implementations.
+      */
+    export interface ImplementationResponse extends Response {
+        body?: FileSpan[];
+    }
+
     /**
       * Get occurrences request; value of command field is
       * "occurrences". Return response giving spans that are relevant

src/server/session.ts

@@ -111,6 +111,7 @@ namespace ts.server {
         export const Formatonkey = "formatonkey";
         export const Geterr = "geterr";
         export const GeterrForProject = "geterrForProject";
+        export const Implementation = "implementation";
         export const SemanticDiagnosticsSync = "semanticDiagnosticsSync";
         export const SyntacticDiagnosticsSync = "syntacticDiagnosticsSync";
         export const NavBar = "navbar";
@@ -363,6 +364,28 @@ namespace ts.server {
             }));
         }
 
+        private getImplementation(line: number, offset: number, fileName: string): protocol.FileSpan[] {
+            const file = ts.normalizePath(fileName);
+            const project = this.projectService.getProjectForFile(file);
+            if (!project || project.languageServiceDiabled) {
+                throw Errors.NoProject;
+            }
+
+            const compilerService = project.compilerService;
+            const implementations = compilerService.languageService.getImplementationAtPosition(file,
+                compilerService.host.lineOffsetToPosition(file, line, offset));
+
+            if (!implementations) {
+                return undefined;
+            }
+
+            return implementations.map(impl => ({
+                file: impl.fileName,
+                start: compilerService.host.positionToLineOffset(impl.fileName, impl.textSpan.start),
+                end: compilerService.host.positionToLineOffset(impl.fileName, ts.textSpanEnd(impl.textSpan))
+            }));
+        }
+
         private getOccurrences(line: number, offset: number, fileName: string): protocol.OccurrencesResponseItem[] {
             fileName = ts.normalizePath(fileName);
             const project = this.projectService.getProjectForFile(fileName);
@@ -1080,6 +1103,10 @@ namespace ts.server {
                 const defArgs = <protocol.FileLocationRequestArgs>request.arguments;
                 return { response: this.getTypeDefinition(defArgs.line, defArgs.offset, defArgs.file), responseRequired: true };
             },
+            [CommandNames.Implementation]: (request: protocol.Request) => {
+                const implArgs = <protocol.FileLocationRequestArgs>request.arguments;
+                return { response: this.getImplementation(implArgs.line, implArgs.offset, implArgs.file), responseRequired: true };
+            },
             [CommandNames.References]: (request: protocol.Request) => {
                 const defArgs = <protocol.FileLocationRequestArgs>request.arguments;
                 return { response: this.getReferences(defArgs.line, defArgs.offset, defArgs.file), responseRequired: true };