| // Copyright (c) 2019, 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. |
| |
| // @dart = 2.9 |
| |
| /// @assertion The [??] operator only evaluates its second operand if the first |
| /// evaluates to [null], and the second operand must be a potentially constant |
| /// expression. |
| /// @description Checks that operator [??] rejects the second operand if the |
| /// first one is not [null] in constant expression. |
| /// @author iarkh@unipro.ru |
| |
| import "../../Utils/expect.dart"; |
| |
| const dynamic d1 = "12345"; |
| const dynamic d2 = 11; |
| const int i = 14; |
| |
| main() { |
| const int a1 = 20 ?? (null as String).length; |
| Expect.equals(20, a1); |
| |
| const String a2 = "testme" ?? "wrong"; |
| Expect.equals("testme", a2); |
| |
| const int a3 = i ?? d1; |
| Expect.equals(14, a3); |
| |
| const int a4 = i ?? d2; |
| Expect.equals(14, a4); |
| |
| const a5 = d1 ?? null; |
| Expect.equals(a5, a5); |
| } |
