// Copyright (c) 2018, 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 We say that a type T0 is a subtype of a type T1 (written T0 <: T1)
 * when:
 * Right FutureOr: T1 is FutureOr<S1> and
 *   either T0 <: Future<S1>
 *   or T0 <: S1
 *   or T0 is X0 and X0 has bound S0 and S0 <: T1
 *   or T0 is X0 & S0 and S0 <: T1
 * @description Check that if a type T1 is S1 and a type T0 is X0 and X0 has
 * bound S0 and S0 <: S1, then a type T0 is a subtype of a type T1.
 * @author ngl@unipro.ru
 */
import "dart:async";

class S1 {
  const S1();
}
class S0 extends S1 {
}
class X0 extends S0 {
}

X0 t0Instance = new X0();
FutureOr<S1> t1Instance = new S1();

const t1Default = const S1();

//# @T0 = X0
//# @T1 = FutureOr<S1>