blob: 53231ba86f3f2fa7ca69d6195f80c0f25e7d813b [file] [log] [blame]
// 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 We say that a type T0 is a subtype of a type T1 (written T0 <: T1)
/// when:
/// Left Null: if T0 is Null then:
/// - if T1 is a type variable (promoted or not) the query is false
/// - If T1 is FutureOr<S> for some S, then the query is true iff Null <: S.
/// - If T1 is Null, S? or S* for some S, then the query is true.
/// - Otherwise, the query is false
/// @description Check that if type T0 is Null and If T1 is S? then T0 is
/// subtype of T1
/// @author
class S {
const S();
Null t0Instance = null;
S? t1Instance = new S();
const t1Default = const S();
//# @T0 = Null
//# @T1 = S?