|  | // Copyright (c) 2011, 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. | 
|  |  | 
|  | import "package:expect/expect.dart"; | 
|  |  | 
|  | class A { | 
|  | const A(); | 
|  | } | 
|  |  | 
|  | class B extends A { | 
|  | const B(); | 
|  | } | 
|  |  | 
|  | main() { | 
|  | var map1 = new Map<B, B>(); | 
|  | map1[const B()] = const B(); | 
|  | var map2 = new Map<B, B>(); | 
|  | var list = <B>[const B()]; | 
|  |  | 
|  | var maps = [map1, map2]; | 
|  | for (var map in maps) { | 
|  | // Test that the map accepts a key is not of the same type: | 
|  | //   Map<B, ?>.remove(A) | 
|  | Expect.isNull(map.remove(new A())); | 
|  | } | 
|  | } |