Merge pull request #14343 from Microsoft/undefined_declarations

Add check for undefined declarations

src/services/goToDefinition.ts

@@ -198,7 +198,11 @@ namespace ts.GoToDefinition {
             return false;
         }
 
-        function tryAddSignature(signatureDeclarations: Declaration[], selectConstructors: boolean, symbolKind: string, symbolName: string, containerName: string, result: DefinitionInfo[]) {
+        function tryAddSignature(signatureDeclarations: Declaration[] | undefined, selectConstructors: boolean, symbolKind: string, symbolName: string, containerName: string, result: DefinitionInfo[]) {
+            if (!signatureDeclarations) {
+                return false;
+            }
+
             const declarations: Declaration[] = [];
             let definition: Declaration | undefined;
 

tests/cases/fourslash/goToDefinition_untypedModule.ts

@@ -0,0 +1,10 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: /node_modules/foo/index.js
+////not read
+
+// @Filename: /a.ts
+////import { f } from "foo";
+/////**/f();
+
+verify.goToDefinition("", []);