| // Copyright (c) 2017, 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. | 
 |  | 
 | // Regression test for dart2js inference. Class.field6b should be known to be | 
 | // potentially `null`. | 
 |  | 
 | import 'package:expect/expect.dart'; | 
 |  | 
 | class Class6 { | 
 |   var field6a; | 
 |   var field6b; | 
 |  | 
 |   Class6() : field6a = 42 { | 
 |     field6b = field6a; | 
 |   } | 
 | } | 
 |  | 
 | class SubClass6 extends Class6 { | 
 |   var field6b; | 
 |  | 
 |   SubClass6() : field6b = 42; | 
 |  | 
 |   get access => super.field6b; | 
 | } | 
 |  | 
 | subclassField2() { | 
 |   new Class6(); | 
 |   return new SubClass6().access; | 
 | } | 
 |  | 
 | main() { | 
 |   Expect.isTrue(subclassField2() == null); | 
 | } |