// 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 legacy class and implements
/// opted-in class, legacy method cannot return anything but [null] if parent
/// method return type is [Never].
///
/// @author iarkh@unipro.ru

// Requirements=nnbd-weak
// @dart=2.6

import "dart:async";
import "override_checking_A01_opted_in_lib.dart";

class B1 { int getNever() => 1; }
class A1 extends B1 implements OPTED_NEVER_RETURN {
//    ^^
// [analyzer] unspecified
// [cfe] unspecified
}

class B2 { Object getNever() => 1; }
class A2 extends B2 implements OPTED_NEVER_RETURN {
//    ^^
// [analyzer] unspecified
// [cfe] unspecified
}

class B3 { dynamic getNever() => 1; }
class A3 extends B3 implements OPTED_NEVER_RETURN {
//    ^^
// [analyzer] unspecified
// [cfe] unspecified
}

class B4 { FutureOr getNever() => 1; }
class A4 extends B4 implements OPTED_NEVER_RETURN {
//    ^^
// [analyzer] unspecified
// [cfe] unspecified
}

main() {
  A1();
  A2();
  A3();
  A4();
}