// 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(FutureOr<T>) =
///  let S be NORM(T)
///  if S is a top type then S
///  if S is Object then S
///  if S is Object* then S
///  if S is Never then Future<Never>
///  if S is Null then Future<Null>?
///  else FutureOr<S>
///
/// @description Checks that if NORM(T) is a top type then NORM(FutureOr<T>) =
/// NORM(T)
///
/// @author sgrekhov@unipro.ru

// Requirements=nnbd-strong
import 'dart:async';

class A<X> {}
class B<X> implements A<X> {}

class CD1 extends B<FutureOr<dynamic>> implements A<dynamic> {}
class CD2 extends B<FutureOr<dynamic>> implements A<dynamic?> {}

class CO extends B<FutureOr<Object?>> implements A<Object?> {}
class CV extends B<FutureOr<void>> implements A<void> {}

main() {
  new CD1();
  new CD2();
  new CO();
  new CV();
}