| // Copyright (c) 2016, 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. |
| |
| /// @assertion Evaluation of a compound assignment of the form e1.v ??= e2 is |
| /// equivalent to the evaluation of the expression |
| /// ((x) => ((y) => y == null ? x.v = e2 : y)(x.v))(e1) where x and y are |
| /// distinct fresh variables that are not used in e2. |
| /// @description Checks that an expression of the form e1.v ??= e2 is equivalent |
| /// to ((x) => ((y) => y == null ? x.v = e2 : y)(x.v))(e1) where x and y are |
| /// distinct fresh variables that are not used in e2. |
| /// @author sgrekhov@unipro.ru |
| |
| |
| import '../../../../Utils/expect.dart'; |
| |
| class C { |
| int? _v; |
| int getterInvocation = 0; |
| int setterInvocation = 0; |
| |
| C(val) { |
| _v = val; |
| } |
| |
| get v { |
| ++getterInvocation; |
| return _v; |
| } |
| |
| set v(val) { |
| ++setterInvocation; |
| _v = val; |
| } |
| } |
| |
| main() { |
| C c1 = new C(null); |
| var res1 = (c1.v ??= 1); |
| Expect.equals(1, c1.getterInvocation); |
| Expect.equals(1, c1.setterInvocation); |
| Expect.equals(1, c1.v); |
| Expect.equals(1, res1); |
| |
| |
| C c2 = new C(1); |
| var res2 = (c2.v ??= 2); |
| Expect.equals(1, c2.getterInvocation); |
| Expect.equals(0, c2.setterInvocation); |
| Expect.equals(1, c2.v); |
| Expect.equals(1, res2); |
| } |