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// constexpr const E& error() const & noexcept;
12
13#include <cassert>
14#include <concepts>
15#include <expected>
16#include <utility>
17
18template <class T>
19concept ErrorNoexcept =
20 requires(const T& t) {
21 { t.error() } noexcept;
22 };
23
24static_assert(!ErrorNoexcept<int>);
25static_assert(ErrorNoexcept<std::unexpected<int>>);
26
27constexpr bool test() {
28 const std::unexpected<int> unex(5);
29 decltype(auto) i = unex.error();
30 static_assert(std::same_as<decltype(i), const int&>);
31 assert(i == 5);
32 return true;
33}
34
35int main(int, char**) {
36 test();
37 static_assert(test());
38 return 0;
39}
40

source code of libcxx/test/std/utilities/expected/expected.unexpected/observer/error.const_ref.pass.cpp