LanguageFeatures/nnbd/override_checking_A01_RETURN_t04.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 legacy class extends opted-in class, legacy method
 * can return [null] if parent method return type is nullable.
 *
 * @author iarkh@unipro.ru
 */
// SharedOptions=--enable-experiment=non-nullable
// @dart=2.6

import "dart:async";
import "../../Utils/expect.dart";
import "override_checking_opted_in_lib.dart";

class A extends OPTED_NULLABLE_RETURN {
  int getInt()           { return null; }
  Object getObject()     { return null; }
  Function getFunction() { return null; }
  FutureOr getFutureOr() { return null; }
  dynamic getDynamic()   { return null; }
  Null getNull()         { return null; }
}

main() {
  A a = A();

  Expect.isNull(a.getInt());
  Expect.isNull(a.getObject());
  Expect.isNull(a.getFutureOr());
  Expect.isNull(a.getDynamic());
  Expect.isNull(a.getFunction());
  Expect.isNull(a.getNull());
}