| // 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 Nullable: if T0 is S0? then: |
| /// - T0 <: T1 iff S0 <: T1 and Null <: T1 |
| /// @description Check that if type T0 is S0? and S0 <: T1 and Null <: T1 then |
| /// T0 is subtype of T1. |
| /// @author sgrekhov@unipro.ru |
| |
| class T1 { |
| const T1(); |
| } |
| class S0 extends T1 { |
| const S0(); |
| } |
| |
| S0? t0Instance = new S0(); |
| T1? t1Instance = new T1(); |
| |
| const t1Default = const T1(); |
| |
| //# @T0 = S0? |
| //# @T1 = T1? |
