diff --git a/spec-dtslint/operators/buffer-spec.ts b/spec-dtslint/operators/buffer-spec.ts
index 2acb64d1461..d4b79e68de1 100644
--- a/spec-dtslint/operators/buffer-spec.ts
+++ b/spec-dtslint/operators/buffer-spec.ts
@@ -12,5 +12,4 @@ it('should enforce types', () => {
 
 it('should support Promises', () => {
   const o = of(1, 2, 3).pipe(buffer(Promise.resolve('foo'))); // $ExpectType Observable<number[]>
-  const p = of(1, 2, 3).pipe(buffer(async () => {})); // $ExpectType Observable<number[]>
 });