|  | // Copyright (c) 2018, the Dart project authors.  Please see the AUTHORS file | 
|  | // for details. All rights reserved. Use of this source code is governed by a | 
|  | // BSD-style license that can be found in the LICENSE file. | 
|  |  | 
|  | // dart2jsOptions=--strong | 
|  |  | 
|  | import 'package:expect/expect.dart'; | 
|  |  | 
|  | abstract class A { | 
|  | m(); | 
|  | } | 
|  |  | 
|  | abstract class B implements A { | 
|  | noSuchMethod(Invocation i) { | 
|  | return 42; | 
|  | } | 
|  | } | 
|  |  | 
|  | class C extends B {} | 
|  |  | 
|  | class D extends C { | 
|  | noSuchMethod(Invocation i) => 87; | 
|  |  | 
|  | method() => super.m(); | 
|  | } | 
|  |  | 
|  | void main() { | 
|  | D x = new D(); | 
|  | Expect.equals(87, x.method()); | 
|  | } |