LanguageFeatures/nnbd/static_errors_A06_t20.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 It is an error if a mixin declaration or a class declaration with
/// no generative constructors declares an instance variable without an
/// initializing expression which is final or whose type is potentially
/// non-nullable, unless the variable is marked with a `late`, `abstract`, or
/// `external` modifier.
///
/// @description Check that it is an error if a mixin declaration with no
/// generative constructors declares an instance variable with a potentially
/// non-nullable type and no initializing expression. Test `FutureOr<A>` where
/// `A` is some class.
/// @author sgrekhov@unipro.ru
/// @issue 40940

import "dart:async";

class A {}
class X {}

mixin M on X {
  FutureOr<A> f;
//            ^
// [analyzer] unspecified
// [cfe] unspecified
}

main() {
  print(M);
}