1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
|
//===----------------------------------------------------------------------===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
// constexpr const T& value() const &;
// constexpr T& value() &;
// constexpr T&& value() &&;
// constexpr const T&& value() const &&;
#include <cassert>
#include <concepts>
#include <expected>
#include <type_traits>
#include <utility>
#include "test_macros.h"
constexpr bool test() {
// non-const &
{
std::expected<int, int> e(5);
decltype(auto) x = e.value();
static_assert(std::same_as<decltype(x), int&>);
assert(&x == &(*e));
assert(x == 5);
}
// const &
{
const std::expected<int, int> e(5);
decltype(auto) x = e.value();
static_assert(std::same_as<decltype(x), const int&>);
assert(&x == &(*e));
assert(x == 5);
}
// non-const &&
{
std::expected<int, int> e(5);
decltype(auto) x = std::move(e).value();
static_assert(std::same_as<decltype(x), int&&>);
assert(&x == &(*e));
assert(x == 5);
}
// const &&
{
const std::expected<int, int> e(5);
decltype(auto) x = std::move(e).value();
static_assert(std::same_as<decltype(x), const int&&>);
assert(&x == &(*e));
assert(x == 5);
}
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
// int
{
const std::expected<int, int> e(std::unexpect, 5);
try {
(void) e.value();
assert(false);
} catch (const std::bad_expected_access<int>& ex) {
assert(ex.error() == 5);
}
}
#endif // TEST_HAS_NO_EXCEPTIONS
}
void testAsConst() {
#ifndef TEST_HAS_NO_EXCEPTIONS
struct Error {
enum { Default, MutableRefCalled, ConstRefCalled } From = Default;
Error() = default;
Error(const Error&) { From = ConstRefCalled; }
Error(Error&) { From = MutableRefCalled; }
Error(Error&& e) { From = e.From; }
};
// Test & overload
{
std::expected<int, Error> e(std::unexpect, Error());
try {
(void)e.value();
assert(false);
} catch (const std::bad_expected_access<Error>& ex) {
assert(ex.error().From == Error::ConstRefCalled);
}
}
// There are no effects for `const &` overload.
#endif // TEST_HAS_NO_EXCEPTIONS
}
int main(int, char**) {
test();
static_assert(test());
testException();
testAsConst();
return 0;
}
|
