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... Args>
12// constexpr explicit expected(in_place_t, Args&&... args);
13//
14// Constraints: is_constructible_v<T, Args...> is true.
15//
16// Effects: Direct-non-list-initializes val with std::forward<Args>(args)....
17//
18// Postconditions: has_value() is true.
19//
20// Throws: Any exception thrown by the initialization of val.
21
22#include <cassert>
23#include <expected>
24#include <type_traits>
25#include <tuple>
26#include <utility>
27
28#include "MoveOnly.h"
29#include "test_macros.h"
30#include "../../types.h"
31
32// Test Constraints:
33static_assert(std::is_constructible_v<std::expected<int, int>, std::in_place_t>);
34static_assert(std::is_constructible_v<std::expected<int, int>, std::in_place_t, int>);
35
36// !is_constructible_v<T, Args...>
37struct foo {};
38static_assert(!std::is_constructible_v<std::expected<foo, int>, std::in_place_t, int>);
39
40// test explicit
41template <class T>
42void conversion_test(T);
43
44template <class T, class... Args>
45concept ImplicitlyConstructible = requires(Args&&... args) { conversion_test<T>({std::forward<Args>(args)...}); };
46static_assert(ImplicitlyConstructible<int, int>);
47
48static_assert(!ImplicitlyConstructible<std::expected<int, int>, std::in_place_t>);
49static_assert(!ImplicitlyConstructible<std::expected<int, int>, std::in_place_t, int>);
50
51struct CopyOnly {
52 int i;
53 constexpr CopyOnly(int ii) : i(ii) {}
54 CopyOnly(const CopyOnly&) = default;
55 CopyOnly(CopyOnly&&) = delete;
56 friend constexpr bool operator==(const CopyOnly& mi, int ii) { return mi.i == ii; }
57};
58
59template <class T, class E = int>
60constexpr void testInt() {
61 std::expected<T, E> e(std::in_place, 5);
62 assert(e.has_value());
63 assert(e.value() == 5);
64}
65
66template <class T, class E = int>
67constexpr void testLValue() {
68 T t(5);
69 std::expected<T, E> e(std::in_place, t);
70 assert(e.has_value());
71 assert(e.value() == 5);
72}
73
74template <class T, class E = int>
75constexpr void testRValue() {
76 std::expected<T, E> e(std::in_place, T(5));
77 assert(e.has_value());
78 assert(e.value() == 5);
79}
80
81constexpr bool test() {
82 testInt<int>();
83 testInt<CopyOnly>();
84 testInt<MoveOnly>();
85 testInt<TailClobberer<0>, bool>();
86 testLValue<int>();
87 testLValue<CopyOnly>();
88 testLValue<TailClobberer<0>, bool>();
89 testRValue<int>();
90 testRValue<MoveOnly>();
91 testRValue<TailClobberer<0>, bool>();
92
93 // no arg
94 {
95 std::expected<int, int> e(std::in_place);
96 assert(e.has_value());
97 assert(e.value() == 0);
98 }
99
100 // one arg
101 {
102 std::expected<int, int> e(std::in_place, 5);
103 assert(e.has_value());
104 assert(e.value() == 5);
105 }
106
107 // multi args
108 {
109 std::expected<std::tuple<int, short, MoveOnly>, int> e(std::in_place, 1, short{2}, MoveOnly(3));
110 assert(e.has_value());
111 assert((e.value() == std::tuple<int, short, MoveOnly>(1, short{2}, MoveOnly(3))));
112 }
113
114 return true;
115}
116
117void testException() {
118#ifndef TEST_HAS_NO_EXCEPTIONS
119 struct Throwing {
120 Throwing(int) { throw Except{}; };
121 };
122
123 try {
124 std::expected<Throwing, int> u(std::in_place, 5);
125 assert(false);
126 } catch (Except) {
127 }
128#endif // TEST_HAS_NO_EXCEPTIONS
129}
130
131int main(int, char**) {
132 test();
133 static_assert(test());
134 testException();
135 return 0;
136}
137

source code of libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.inplace.pass.cpp