13af6ab5fSopenharmony_ci/* 23af6ab5fSopenharmony_ci * Copyright (c) 2024 Huawei Device Co., Ltd. 33af6ab5fSopenharmony_ci * Licensed under the Apache License, Version 2.0 (the "License"); 43af6ab5fSopenharmony_ci * you may not use this file except in compliance with the License. 53af6ab5fSopenharmony_ci * You may obtain a copy of the License at 63af6ab5fSopenharmony_ci * 73af6ab5fSopenharmony_ci * http://www.apache.org/licenses/LICENSE-2.0 83af6ab5fSopenharmony_ci * 93af6ab5fSopenharmony_ci * Unless required by applicable law or agreed to in writing, software 103af6ab5fSopenharmony_ci * distributed under the License is distributed on an "AS IS" BASIS, 113af6ab5fSopenharmony_ci * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 123af6ab5fSopenharmony_ci * See the License for the specific language governing permissions and 133af6ab5fSopenharmony_ci * limitations under the License. 143af6ab5fSopenharmony_ci */ 153af6ab5fSopenharmony_ci 163af6ab5fSopenharmony_ciclass A { 173af6ab5fSopenharmony_ci protected count: int; 183af6ab5fSopenharmony_ci getCount(): int { 193af6ab5fSopenharmony_ci return this.count 203af6ab5fSopenharmony_ci } 213af6ab5fSopenharmony_ci} 223af6ab5fSopenharmony_ci 233af6ab5fSopenharmony_ciclass B extends A { 243af6ab5fSopenharmony_ci increment(): void { 253af6ab5fSopenharmony_ci this.count++; 263af6ab5fSopenharmony_ci } 273af6ab5fSopenharmony_ci} 283af6ab5fSopenharmony_ci 293af6ab5fSopenharmony_ciclass C extends A { 303af6ab5fSopenharmony_ci} 313af6ab5fSopenharmony_ci 323af6ab5fSopenharmony_cifunction main(): void { 333af6ab5fSopenharmony_ci let b = new B(); 343af6ab5fSopenharmony_ci let c = new C(); 353af6ab5fSopenharmony_ci b.increment(); 363af6ab5fSopenharmony_ci let a = b ?? c; 373af6ab5fSopenharmony_ci a.increment(); 383af6ab5fSopenharmony_ci} 393af6ab5fSopenharmony_ci 403af6ab5fSopenharmony_ci/* @@? 37:3 Error TypeError: Member type must be the same for all union objects. */ 413af6ab5fSopenharmony_ci/* @@? 37:5 Error TypeError: Property 'increment' does not exist on type 'C' */ 42