1/*
2 * Copyright (c) 2023-2024 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
16type funcType = () => String;
17
18function getMelon(): String { return "melon" }
19
20function dummy(): funcType | null {
21  return (() => { return "peach"; }) as funcType; // #15577
22}
23
24function foo(a: funcType | null) {
25    let fruit: String = a?.() ?? "apple";
26
27    let getPeach: funcType | null = dummy();
28    fruit = getPeach?.() ?? "banana";
29    assert(fruit == "peach");
30
31    fruit = getMelon() ?? "strawberry";
32    assert(fruit == "melon");
33
34    let test = false;
35    try {
36        fruit = a!();
37    } catch (e: NullPointerError) {
38        test = true;
39    }
40
41    assert(test == true);
42}
43
44function main(): void {
45    let getFruit = null;
46    foo(getFruit);
47
48    let getPeach: funcType | null = dummy();
49    let b = getPeach?.();
50    assert(b == "peach");
51}
52