1/*
2 * Copyright (c) 2024 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16class A {
17  prev_: A|undefined = undefined;
18  next_: A|undefined = undefined;
19
20  m() {
21    const prev = this.prev_;
22    const next = this.next_;
23
24    if (prev) {
25      this.prev_ = undefined;
26      prev.next_ = next;
27    } 
28
29    if (next) {
30      this.next_ = undefined;
31      next.prev_ = prev;
32    }
33
34  }
35}
36
37function main(): void {
38}
39