| // 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 Null then NORM(T?) = Null |
| /// |
| /// @author sgrekhov@unipro.ru |
| |
| // Requirements=nnbd-weak |
| class A<X> {} |
| class B1<X> implements A<X> {} |
| class B2<X> implements A<X?> {} |
| |
| class C1 extends B1<Null?> implements A<Null> {} |
| class C2 extends B1<Never?> implements A<Null> {} |
| |
| main() { |
| new C1(); |
| new C2(); |
| } |