1/* 2 * Copyright (c) 2024-2025 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 protected count: int; 18 getCount(): int { 19 return this.count 20 } 21} 22 23class B extends A { 24 increment(): void { 25 this.count++; 26 } 27} 28 29class C extends A { 30} 31 32function main(): void { 33 let b = new B(); 34 let c = new C(); 35 b.increment(); 36 let a = b ?? c; 37 /* @@ label */a./* @@ label1 */increment(); 38} 39 40/* @@@ label1 Error TypeError: Property 'increment' does not exist on type 'C' */ 41/* @@@ label Error TypeError: Member type must be the same for all union objects. */ 42