| /* |
| * 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 If a class [C] in an opted-in library implements the same generic |
| * class [I] more than once as [I0], .., [In], and at least one of the [Ii] is |
| * not syntactically equal to the others, then it is an error if |
| * [NNBD_TOP_MERGE(S0, ..., Sn)] is not defined where [Si] is [NORM(Ii)]. |
| * Otherwise, for the purposes of runtime subtyping checks, [C] is considered to |
| * implement the canonical interface given by [NNBD_TOP_MERGE(S0, ..., Sn)]. |
| * |
| * @description Check that error occurs as a result of [NNBD_TOP_MERGE(Null, |
| * Never)]. |
| * |
| * @author iarkh@unipro.ru |
| */ |
| |
| class A<T> {} |
| class B implements A<Null> {} |
| class C implements A<Never> {} |
| |
| class D1 extends B implements C {} |
| // ^^ |
| // [analyzer] unspecified |
| // [cfe] unspecified |
| |
| class D2 extends C implements B {} |
| // ^^ |
| // [analyzer] unspecified |
| // [cfe] unspecified |
| |
| void main() {} |
