Language/Classes/Instance_Methods/override_subtype_t09.dart

// Copyright (c) 2019, 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 It is a compile error if an instance method m1 overrides an
/// instance member m2 and the type of m1 is not a subtype of the type of m2.
/// @description Checks that a compile error is produced if m1 is not a subtype
/// of m2 because their respective optional positional parameter types are not 
/// mutually assignable.
/// @compile-error
/// @author sgrekhov@unipro.ru

// SharedOptions=--enable-experiment=nonfunction-type-aliases

class A {
  foo([double? name]) {}
}
typedef AAlias = A;

class C extends AAlias {
  foo([int? name]) {}
}

main() {
  new A().foo(1.0);
  new C().foo(0);
}