/*
 * 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(R Function<X extends B>(S)) = R1 Function<X extends B1>(S1)
 *  where R1 = NORM(R)
 *  and B1 = NORM(B)
 *  and S1 = NORM(S)
 *
 * @description Checks that NORM(R Function<X extends B>(S)) =
 * R1 Function<X extends B1>(S1).
 *
 * @author sgrekhov@unipro.ru
 */
// Requirements=nnbd-strong
class A<X> {}
class B<X> implements A<X> {}

typedef dynamic? F1<X>(Never? x);
typedef dynamic F2<X>(Null x);

class C extends B<F1<Never?>> implements A<F2<Null>> {}

main() {
  new C();
}