diff --git a/packages/language-service/src/locate_symbol.ts b/packages/language-service/src/locate_symbol.ts
index 63423b8671..36d09f80d7 100644
--- a/packages/language-service/src/locate_symbol.ts
+++ b/packages/language-service/src/locate_symbol.ts
@@ -148,12 +148,16 @@ function findAttribute(info: AstResult, position: number): Attribute|undefined {
   return path.first(Attribute);
 }
 
+// TODO: remove this function after the path includes 'DirectiveAst'.
+// Find the directive that corresponds to the specified 'binding'
+// at the specified 'position' in the 'ast'.
 function findParentOfBinding(
-    ast: TemplateAst[], binding: BoundDirectivePropertyAst, position: number) {
+    ast: TemplateAst[], binding: BoundDirectivePropertyAst, position: number): DirectiveAst|
+    undefined {
   let res: DirectiveAst|undefined;
   const visitor = new class extends RecursiveTemplateAstVisitor {
     visit(ast: TemplateAst): any {
-      let span = spanOf(ast);
+      const span = spanOf(ast);
       if (!inSpan(position, span)) {
         // Returning a value here will result in the children being skipped.
         return true;
diff --git a/packages/language-service/test/definitions_spec.ts b/packages/language-service/test/definitions_spec.ts
index 3c13af8087..1d9da99af6 100644
--- a/packages/language-service/test/definitions_spec.ts
+++ b/packages/language-service/test/definitions_spec.ts
@@ -314,11 +314,8 @@ describe('definitions', () => {
     expect(def.name).toBe('model');
     expect(def.kind).toBe('property');
     const content = mockHost.readFile(refFileName) !;
-    const ref = `@Input() model: string = 'model';`;
-    expect(def.textSpan).toEqual({
-      start: content.indexOf(ref),
-      length: ref.length,
-    });
+    expect(content.substring(def.textSpan.start, def.textSpan.start + def.textSpan.length))
+        .toEqual(`@Input() model: string = 'model';`);
   });
 
   it('should be able to find a template from a url', () => {