|  | // 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. | 
|  |  | 
|  | import 'package:expect/expect.dart'; | 
|  |  | 
|  | typedef Bar = int Function(int); | 
|  |  | 
|  | int defaultBar(int value) => value + 1; | 
|  |  | 
|  | class Foo { | 
|  | final Bar bar; | 
|  |  | 
|  | const Foo._(Bar? bar) : bar = bar ?? defaultBar; | 
|  |  | 
|  | const Foo.baz({Bar? bar}) : this._(bar); | 
|  | } | 
|  |  | 
|  | void main() { | 
|  | final foo = const Foo.baz(); | 
|  | Expect.equals(2, foo.bar(1)); | 
|  | } |