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 X {
173af6ab5fSopenharmony_ci    public foo: number
183af6ab5fSopenharmony_ci
193af6ab5fSopenharmony_ci    constructor() {
203af6ab5fSopenharmony_ci       this.foo = 0
213af6ab5fSopenharmony_ci    }
223af6ab5fSopenharmony_ci}
233af6ab5fSopenharmony_ci
243af6ab5fSopenharmony_ciclass Y {
253af6ab5fSopenharmony_ci    public foo: number
263af6ab5fSopenharmony_ci    constructor() {
273af6ab5fSopenharmony_ci        this.foo = 0
283af6ab5fSopenharmony_ci    }
293af6ab5fSopenharmony_ci}
303af6ab5fSopenharmony_ci
313af6ab5fSopenharmony_cilet x = new X()
323af6ab5fSopenharmony_cilet y = new Y()
333af6ab5fSopenharmony_ci
343af6ab5fSopenharmony_ciconsole.log("Assign X to Y")
353af6ab5fSopenharmony_ciy = x
363af6ab5fSopenharmony_ci
373af6ab5fSopenharmony_ciconsole.log("Assign Y to X")
383af6ab5fSopenharmony_cix = y
393af6ab5fSopenharmony_ci
403af6ab5fSopenharmony_ci
413af6ab5fSopenharmony_ci
423af6ab5fSopenharmony_ci
433af6ab5fSopenharmony_ciinterface Z {
443af6ab5fSopenharmony_ci    foo: number
453af6ab5fSopenharmony_ci }
463af6ab5fSopenharmony_ci
473af6ab5fSopenharmony_ci // X implements interface Z, which makes relation between X and Y explicit.
483af6ab5fSopenharmony_ci class C implements Z {
493af6ab5fSopenharmony_ci     public foo: number
503af6ab5fSopenharmony_ci
513af6ab5fSopenharmony_ci     constructor() {
523af6ab5fSopenharmony_ci        this.foo = 0
533af6ab5fSopenharmony_ci     }
543af6ab5fSopenharmony_ci }
553af6ab5fSopenharmony_ci
563af6ab5fSopenharmony_ci // Y implements interface Z, which makes relation between X and Y explicit.
573af6ab5fSopenharmony_ci class C2 implements Z {
583af6ab5fSopenharmony_ci     public foo: number
593af6ab5fSopenharmony_ci
603af6ab5fSopenharmony_ci     constructor() {
613af6ab5fSopenharmony_ci        this.foo = 0
623af6ab5fSopenharmony_ci     }
633af6ab5fSopenharmony_ci }
643af6ab5fSopenharmony_ci
653af6ab5fSopenharmony_ci let x1: Z = new C()
663af6ab5fSopenharmony_ci let y1: Z = new C2()
673af6ab5fSopenharmony_ci
683af6ab5fSopenharmony_ci console.log("Assign X to Y")
693af6ab5fSopenharmony_ci y1 = x1 // ok, both are of the same type
703af6ab5fSopenharmony_ci
713af6ab5fSopenharmony_ci console.log("Assign Y to X")
723af6ab5fSopenharmony_ci x1 = y1 // ok, both are of the same type