LanguageFeatures/nnbd/weak/overriding/override_checking_A01_CLASSPARAM_t32.dart

// 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 In an unmigrated library, override checking is done using legacy
 * types. This means that an unmigrated library can bring together otherwise
 * incompatible methods. When choosing the most specific signature during
 * interface computation, all nullability and requiredness annotations are
 * ignored, and the [Never] type is treated as [Null].
 *
 * @description Check that if generic legacy class extends legacy class and
 * implements opted-in class, all nullability annotations in the parent interface
 * are ignored in the child class and child class type parameter can be [Null]
 * even if parent class type parameter is non-nullable.
 *
 * @Issue 40398
 * @author iarkh@unipro.ru
 */
// Requirements=nnbd-weak
// @dart=2.6

import "../../../../Utils/expect.dart";
import "override_checking_A01_opted_in_lib.dart";

class B1<T> { dynamic getParamType() => typeOf<T>(); }
class B2<T> { dynamic getParamType() => typeOf<T>(); }
class B3<T> { dynamic getParamType() => typeOf<T>(); }

class A1<T extends Null> extends B1<T> implements OPTED_NONNULLABLE_INT<T>      {}
class A2<T extends Null> extends B2<T> implements OPTED_NONNULLABLE_OBJECT<T>   {}
class A3<T extends Null> extends B3<T> implements OPTED_NONNULLABLE_FUNCTION<T> {}

main() {
  Expect.equals(Null, A1().getParamType());
  Expect.equals(Null, A1<Null>().getParamType());

  Expect.equals(Null, A2().getParamType());
  Expect.equals(Null, A2<Null>().getParamType());

  Expect.equals(Null, A3().getParamType());
  Expect.equals(Null, A3<Null>().getParamType());
}