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 bool has_value() const noexcept;
12
13#include <cassert>
14#include <concepts>
15#include <expected>
16#include <type_traits>
17#include <utility>
18
19#include "test_macros.h"
20#include "../../types.h"
21
22// Test noexcept
23template <class T>
24concept HasValueNoexcept =
25 requires(T t) {
26 { t.has_value() } noexcept;
27 };
28
29struct Foo {};
30static_assert(!HasValueNoexcept<Foo>);
31
32static_assert(HasValueNoexcept<std::expected<int, int>>);
33static_assert(HasValueNoexcept<const std::expected<int, int>>);
34
35constexpr bool test() {
36 // has_value
37 {
38 const std::expected<void, int> e;
39 assert(e.has_value());
40 }
41
42 // !has_value
43 {
44 const std::expected<void, int> e(std::unexpect, 5);
45 assert(!e.has_value());
46 }
47
48 // See comments of the corresponding test in
49 // "expected.expected/observers/has_value.pass.cpp".
50 {
51 const std::expected<void, TailClobberer<1>> e(std::unexpect);
52 // clang-cl does not support [[no_unique_address]] yet.
53#if !(defined(TEST_COMPILER_CLANG) && defined(_MSC_VER))
54 LIBCPP_STATIC_ASSERT(sizeof(TailClobberer<1>) == sizeof(e));
55#endif
56 assert(!e.has_value());
57 }
58
59 return true;
60}
61
62int main(int, char**) {
63 test();
64 static_assert(test());
65 return 0;
66}
67

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