Handle when declarationSpan from declarationNode is undefined

Author: sheetalkamat

src/services/goToDefinition.ts

@@ -273,18 +273,21 @@ namespace ts.GoToDefinition {
     function createDefinitionInfoFromName(declaration: Declaration, symbolKind: ScriptElementKind, symbolName: string, containerName: string): DefinitionInfo {
         const name = getNameOfDeclaration(declaration) || declaration;
         const sourceFile = name.getSourceFile();
-        const declarationNode = FindAllReferences.getDeclarationForDeclarationSpan(declaration)!;
-        return {
+        const result: DefinitionInfo = {
             fileName: sourceFile.fileName,
             textSpan: createTextSpanFromNode(name, sourceFile),
             kind: symbolKind,
             name: symbolName,
             containerKind: undefined!, // TODO: GH#18217
             containerName,
-            declarationSpan: FindAllReferences.isDeclarationNodeWithStartAndEnd(declarationNode) ?
-                createTextSpanFromNode(declarationNode.start, sourceFile, declarationNode.end) :
-                createTextSpanFromNode(declarationNode, sourceFile),
         };
+        const declarationNode = FindAllReferences.getDeclarationForDeclarationSpan(declaration);
+        if (declarationNode) {
+            result.declarationSpan = FindAllReferences.isDeclarationNodeWithStartAndEnd(declarationNode) ?
+                createTextSpanFromNode(declarationNode.start, sourceFile, declarationNode.end) :
+                createTextSpanFromNode(declarationNode, sourceFile);
+        }
+        return result;
     }
 
     function createDefinitionFromSignatureDeclaration(typeChecker: TypeChecker, decl: SignatureDeclaration): DefinitionInfo {