blob: caa707eb302e31bce5e2bb51b4b29a876cc83a27 [file] [log] [blame]
// 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
/// 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
// Requirements=nnbd-strong
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();