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
16interface RA<T> {
17  foo(c: T, a?: Number): number | undefined
18}
19class A<T> implements RA<T> {
20  foo(c: T, a?: Number): number | undefined {
21    return a;
22  }
23}
24
25function main(): void {
26    let a = new A<Number>();
27    assert (a.foo(1, 2) == 2);
28    assert (a.foo(1) == undefined);
29}
30