Language/Interfaces/Superinterfaces/definition_t05.dart

// Copyright (c) 2011, 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.

// @dart = 2.9

/// @assertion An interface has a set of direct superinterfaces.
/// An interface J is a superinterface of an interface I iff either J is a
/// direct superinterface of I or J is a superinterface of a direct
/// superinterface of I.
/// @description Checks that it is a compile-time error if the implements clause
/// of an interface is empty.
/// @author rodionov


abstract class I implements {
//                          ^
// [analyzer] unspecified
// [cfe] unspecified
}

class C implements I {
}

main() {
 try {
   I i1 = new C();
   assert (i1 != null);
 } catch (x) {
 }
}