| /* |
| * Copyright (c) 2021, the Dart project authors. Please see the AUTHORS file |
| * Copyright (c) 2021, 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 |
| * NORM(T?) = |
| * let S be NORM(T) |
| * if S is a top type then S |
| * if S is Never then Null |
| * if S is Never* then Null |
| * if S is Null then Null |
| * if S is FutureOr<R> and R is nullable then S |
| * if S is FutureOr<R>* and R is nullable then FutureOr<R> |
| * if S is R? then R? |
| * if S is R* then R? |
| * else S? |
| * |
| * @description Checks that if NORM(T) is Never then NORM(T?) = Null |
| * |
| * @author sgrekhov@unipro.ru |
| */ |
| // Requirements=nnbd-weak |
| |
| class A<X> {} |
| class B<X> implements A<X> {} |
| |
| class C extends B<Never?> implements A<Null> {} |
| |
| main() { |
| new C(); |
| } |