| /* |
| * Copyright (c) 2020, 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 The NORM relation defines the canonical representative of classes |
| * of equivalent types... |
| * This is based on the following equations: |
| * Null? == Null |
| * |
| * @description Checks that Null? == Null |
| * |
| * @author sgrekhov@unipro.ru |
| */ |
| // Requirements=nnbd-strong |
| class A<X> {} |
| class B<X> implements A<X> {} |
| |
| class C extends B<Null?> implements A<Null> {} |
| |
| main() { |
| new C(); |
| } |
