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
|
//===----------------------------------------------------------------------===//
// 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
// template<class U, class... Args>
// constexpr T& emplace(initializer_list<U> il, Args&&... args) noexcept;
// Constraints: is_nothrow_constructible_v<T, initializer_list<U>&, Args...> is true.
//
// Effects: Equivalent to:
// if (has_value()) {
// destroy_at(addressof(val));
// } else {
// destroy_at(addressof(unex));
// has_val = true;
// }
// return *construct_at(addressof(val), il, std::forward<Args>(args)...);
#include <algorithm>
#include <cassert>
#include <concepts>
#include <expected>
#include <type_traits>
#include <utility>
#include "../../types.h"
#include "test_macros.h"
template <class T, class... Args>
concept CanEmplace = requires(T t, Args&&... args) { t.emplace(std::forward<Args>(args)...); };
static_assert(CanEmplace<std::expected<int, int>, int>);
template <bool Noexcept>
struct CtorFromInitalizerList {
CtorFromInitalizerList(std::initializer_list<int>&) noexcept(Noexcept);
CtorFromInitalizerList(std::initializer_list<int>&, int) noexcept(Noexcept);
};
static_assert(CanEmplace<std::expected<CtorFromInitalizerList<true>, int>, std::initializer_list<int>&>);
static_assert(!CanEmplace<std::expected<CtorFromInitalizerList<false>, int>, std::initializer_list<int>&>);
static_assert(CanEmplace<std::expected<CtorFromInitalizerList<true>, int>, std::initializer_list<int>&, int>);
static_assert(!CanEmplace<std::expected<CtorFromInitalizerList<false>, int>, std::initializer_list<int>&, int>);
struct Data {
std::initializer_list<int> il;
int i;
constexpr Data(std::initializer_list<int>& l, int ii) noexcept : il(l), i(ii) {}
};
constexpr bool test() {
// has_value
{
auto list1 = {1, 2, 3};
auto list2 = {4, 5, 6};
std::expected<Data, int> e(std::in_place, list1, 5);
decltype(auto) x = e.emplace(list2, 10);
static_assert(std::same_as<decltype(x), Data&>);
assert(&x == &(*e));
assert(e.has_value());
assert(std::ranges::equal(e.value().il, list2));
assert(e.value().i == 10);
}
// !has_value
{
auto list = {4, 5, 6};
std::expected<Data, int> e(std::unexpect, 5);
decltype(auto) x = e.emplace(list, 10);
static_assert(std::same_as<decltype(x), Data&>);
assert(&x == &(*e));
assert(e.has_value());
assert(std::ranges::equal(e.value().il, list));
assert(e.value().i == 10);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
|
