Merge remote-tracking branch 'origin/master' into go_to_implementation_pr

Refactored goToImplementation out of services

src/services/goToImplementation.ts

@@ -0,0 +1,27 @@
+/* @internal */
+namespace ts.GoToImplementation {
+        export function getImplementationAtPosition(typeChecker: TypeChecker, cancellationToken: CancellationToken, sourceFiles: SourceFile[], node: Node): ImplementationLocation[] {
+            // If invoked directly on a shorthand property assignment, then return
+            // the declaration of the symbol being assigned (not the symbol being assigned to).
+            if (node.parent.kind === SyntaxKind.ShorthandPropertyAssignment) {
+                const result: ReferenceEntry[] = [];
+                FindAllReferences.getReferenceEntriesForShorthandPropertyAssignment(node, typeChecker, result);
+                return result.length > 0 ? result : undefined;
+            }
+            else if (node.kind === SyntaxKind.SuperKeyword || isSuperProperty(node.parent)) {
+                // References to and accesses on the super keyword only have one possible implementation, so no
+                // need to "Find all References"
+                const symbol = typeChecker.getSymbolAtLocation(node);
+                return symbol.valueDeclaration && [FindAllReferences.getReferenceEntryFromNode(symbol.valueDeclaration)];
+            }
+            else {
+                // Perform "Find all References" and retrieve only those that are implementations
+                const referencedSymbols = FindAllReferences.getReferencedSymbolsForNode(typeChecker, cancellationToken,
+                    node, sourceFiles, /*findInStrings*/false, /*findInComments*/false, /*implementations*/true);
+                const result = flatMap(referencedSymbols, symbol =>
+                    map(symbol.references, ({ textSpan, fileName }) => ({ textSpan, fileName })));
+
+                return result && result.length > 0 ? result : undefined;
+            }
+        }
+}