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 16/*--- 17desc: 05 Generics 18name: 05.generics/genericTypeArgumentWithDefaultParameterValue_06 19tags: [] 20---*/ 21 22class UserType { 23 name: string 24} 25 26interface I<T = UserType> { 27 foo(p: T) : T 28} 29 30class A : implements I { 31 data: T 32 constructor(p: T) { 33 this.data = p.type 34 } 35 36 foo(p : T) : T { 37 return data; 38 } 39} 40 41class B : extends A {} 42 43 44function main(): void { 45 let a1 = new A(); 46 let a2 = new A<UserType>(); 47 let a3 = new A<string>; 48 49 let b1 = new B(); 50 let b2 = new B<UserType>(); 51 let b3 = new B<string>; 52 53 54 let ra1 = a1.foo(new UserType()); 55 let ra2 = a2.foo(new UserType()); 56 let ra3 = a3.foo("hello") 57 58 assertTrue( ra1 instanceof UserType) 59 assertTrue( ra2 instanceof UserType) 60 assertTrue( ra3 instanceof string) 61} 62 63