| // Copyright (c) 2019, 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 T is non-nullable if T <: Object. This is |
| /// equivalent to the syntactic criterion that T is any of: |
| /// Never |
| /// Any function type (including Function) |
| /// Any interface type except Null. |
| /// S* for some S where S is non-nullable |
| /// FutureOr<S> where S is non-nullable |
| /// X extends S where S is non-nullable |
| /// X & S where S is non-nullable |
| /// |
| /// @description Check that type which is not subtype of Object cannot be |
| /// assigned to non-nullable type. Test X & S where S is non-nullable |
| /// @author sgrekhov@unipro.ru |
| |
| class A {} |
| class S extends A {} |
| |
| typedef AAlias = A; |
| typedef SAlias = S; |
| |
| main() { |
| AAlias a = new S(); |
| if (a is SAlias) { |
| a = null; |
| // ^^^^ |
| // [analyzer] unspecified |
| // [cfe] unspecified |
| } |
| } |
