1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
10
11// template<class U> constexpr T value_or(U&& v) const &;
12// template<class U> constexpr T value_or(U&& v) &&;
13
14#include <cassert>
15#include <concepts>
16#include <expected>
17#include <type_traits>
18#include <utility>
19
20#include "MoveOnly.h"
21#include "test_macros.h"
22
23constexpr bool test() {
24 // const &, has_value()
25 {
26 const std::expected<int, int> e(5);
27 std::same_as<int> decltype(auto) x = e.value_or(10);
28 assert(x == 5);
29 }
30
31 // const &, !has_value()
32 {
33 const std::expected<int, int> e(std::unexpect, 5);
34 std::same_as<int> decltype(auto) x = e.value_or(10);
35 assert(x == 10);
36 }
37
38 // &&, has_value()
39 {
40 std::expected<MoveOnly, int> e(std::in_place, 5);
41 std::same_as<MoveOnly> decltype(auto) x = std::move(e).value_or(10);
42 assert(x == 5);
43 }
44
45 // &&, !has_value()
46 {
47 std::expected<MoveOnly, int> e(std::unexpect, 5);
48 std::same_as<MoveOnly> decltype(auto) x = std::move(e).value_or(10);
49 assert(x == 10);
50 }
51
52 return true;
53}
54
55int main(int, char**) {
56 test();
57 static_assert(test());
58 return 0;
59}
60

source code of libcxx/test/std/utilities/expected/expected.expected/observers/value_or.pass.cpp