Language/Classes/Instance_Methods/covariant_A01_t06.dart

// Copyright (c) 2023, 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 For each parameter p of m where covariant is present, it is a
/// compile-time error if there exists a direct or indirect superinterface of C
/// which has an accessible method signature m′′ with the same name as m, such
/// that m′′ has a parameter p′′ that corresponds to p, unless the type of p is
/// a subtype or a supertype of the type of p′′
///
/// @description Checks that it is a compile-time error if there is a member
/// with a covariant parameter `p` and there is another member with the same
/// name but with the parameter which is not a subtype or supertype of `p`
/// @author sgrekhov22@gmail.com

class A {
  void m1(num a) {}
  void m2([num a = 0]) {}
  void m3({a = 0}) {}
  void m4({required num a}) {}

  void set s(num n) {}
  void operator +(num n) {}
}

abstract mixin class B {
  void m1(covariant String a);
  void m2([covariant String a = ""]);
  void m3({covariant String a = ""});
  void m4({required covariant String a});

  void set s(covariant String s);
  void operator +(covariant String n);
}

class C extends A with B {
//    ^
// [cfe] unspecified

  void m1(int a) {}
//     ^^
// [analyzer] unspecified
// [cfe] unspecified

  void m2([int a = 1]) {}
//     ^^
// [analyzer] unspecified
// [cfe] unspecified

  void m3({int a = 1}) {}
//     ^^
// [analyzer] unspecified
// [cfe] unspecified

  void m4({required int a}) {}
//     ^^
// [analyzer] unspecified
// [cfe] unspecified

  void set s(int s) {}
//         ^
// [analyzer] unspecified
// [cfe] unspecified

  void operator +(int n) {}
//              ^
// [analyzer] unspecified
// [cfe] unspecified
}

main() {
  print(C);
}