1//===----------------------------------------------------------------------===//
2// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
3// See https://llvm.org/LICENSE.txt for license information.
4// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
5//
6//===----------------------------------------------------------------------===//
7
8// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
9
10// template<class U, class G>
11// constexpr explicit(see below) expected(expected<U, G>&&);
12//
13// Let:
14// - UF be const U
15// - GF be const G
16//
17// Constraints:
18// - is_constructible_v<T, UF> is true; and
19// - is_constructible_v<E, GF> is true; and
20// - is_constructible_v<T, expected<U, G>&> is false; and
21// - is_constructible_v<T, expected<U, G>> is false; and
22// - is_constructible_v<T, const expected<U, G>&> is false; and
23// - is_constructible_v<T, const expected<U, G>> is false; and
24// - is_convertible_v<expected<U, G>&, T> is false; and
25// - is_convertible_v<expected<U, G>&&, T> is false; and
26// - is_convertible_v<const expected<U, G>&, T> is false; and
27// - is_convertible_v<const expected<U, G>&&, T> is false; and
28// - is_constructible_v<unexpected<E>, expected<U, G>&> is false; and
29// - is_constructible_v<unexpected<E>, expected<U, G>> is false; and
30// - is_constructible_v<unexpected<E>, const expected<U, G>&> is false; and
31// - is_constructible_v<unexpected<E>, const expected<U, G>> is false.
32//
33// Effects: If rhs.has_value(), direct-non-list-initializes val with std::forward<UF>(*rhs). Otherwise, direct-non-list-initializes unex with std::forward<GF>(rhs.error()).
34//
35// Postconditions: rhs.has_value() is unchanged; rhs.has_value() == this->has_value() is true.
36//
37// Throws: Any exception thrown by the initialization of val or unex.
38//
39// Remarks: The expression inside explicit is equivalent to !is_convertible_v<UF, T> || !is_convertible_v<GF, E>.
40
41#include <cassert>
42#include <concepts>
43#include <expected>
44#include <type_traits>
45#include <utility>
46
47#include "MoveOnly.h"
48#include "test_macros.h"
49#include "../../types.h"
50
51// Test Constraints:
52template <class T1, class Err1, class T2, class Err2>
53concept canCstrFromExpected = std::is_constructible_v<std::expected<T1, Err1>, std::expected<T2, Err2>&&>;
54
55struct CtorFromInt {
56 CtorFromInt(int);
57};
58
59static_assert(canCstrFromExpected<CtorFromInt, int, int, int>);
60
61struct NoCtorFromInt {};
62
63// !is_constructible_v<T, UF>
64static_assert(!canCstrFromExpected<NoCtorFromInt, int, int, int>);
65
66// !is_constructible_v<E, GF>
67static_assert(!canCstrFromExpected<int, NoCtorFromInt, int, int>);
68
69template <class T>
70struct CtorFrom {
71 explicit CtorFrom(int)
72 requires(!std::same_as<T, int>);
73 explicit CtorFrom(T);
74 explicit CtorFrom(auto&&) = delete;
75};
76
77// is_constructible_v<T, expected<U, G>&>
78static_assert(!canCstrFromExpected<CtorFrom<std::expected<int, int>&>, int, int, int>);
79
80// is_constructible_v<T, expected<U, G>>
81// note that this is true because it is covered by the other overload
82// template<class U = T> constexpr explicit(see below) expected(U&& v);
83// The fact that it is not ambiguous proves that the overload under testing is removed
84static_assert(canCstrFromExpected<CtorFrom<std::expected<int, int>&&>, int, int, int>);
85
86// is_constructible_v<T, expected<U, G>&>
87static_assert(!canCstrFromExpected<CtorFrom<std::expected<int, int> const&>, int, int, int>);
88
89// is_constructible_v<T, expected<U, G>>
90static_assert(!canCstrFromExpected<CtorFrom<std::expected<int, int> const&&>, int, int, int>);
91
92template <class T>
93struct ConvertFrom {
94 ConvertFrom(int)
95 requires(!std::same_as<T, int>);
96 ConvertFrom(T);
97 ConvertFrom(auto&&) = delete;
98};
99
100// is_convertible_v<expected<U, G>&, T>
101static_assert(!canCstrFromExpected<ConvertFrom<std::expected<int, int>&>, int, int, int>);
102
103// is_convertible_v<expected<U, G>&&, T>
104// note that this is true because it is covered by the other overload
105// template<class U = T> constexpr explicit(see below) expected(U&& v);
106// The fact that it is not ambiguous proves that the overload under testing is removed
107static_assert(canCstrFromExpected<ConvertFrom<std::expected<int, int>&&>, int, int, int>);
108
109// is_convertible_v<const expected<U, G>&, T>
110static_assert(!canCstrFromExpected<ConvertFrom<std::expected<int, int> const&>, int, int, int>);
111
112// is_convertible_v<const expected<U, G>&&, T>
113static_assert(!canCstrFromExpected<ConvertFrom<std::expected<int, int> const&&>, int, int, int>);
114
115// is_constructible_v<unexpected<E>, expected<U, G>&>
116static_assert(!canCstrFromExpected<int, CtorFrom<std::expected<int, int>&>, int, int>);
117
118// is_constructible_v<unexpected<E>, expected<U, G>>
119static_assert(!canCstrFromExpected<int, CtorFrom<std::expected<int, int>&&>, int, int>);
120
121// is_constructible_v<unexpected<E>, const expected<U, G>&> is false
122static_assert(!canCstrFromExpected<int, CtorFrom<std::expected<int, int> const&>, int, int>);
123
124// is_constructible_v<unexpected<E>, const expected<U, G>>
125static_assert(!canCstrFromExpected<int, CtorFrom<std::expected<int, int> const&&>, int, int>);
126
127// test explicit
128static_assert(std::is_convertible_v<std::expected<int, int>&&, std::expected<short, long>>);
129
130// !is_convertible_v<UF, T>
131static_assert(std::is_constructible_v<std::expected<CtorFrom<int>, int>, std::expected<int, int>&&>);
132static_assert(!std::is_convertible_v<std::expected<int, int>&&, std::expected<CtorFrom<int>, int>>);
133
134// !is_convertible_v<GF, E>.
135static_assert(std::is_constructible_v<std::expected<int, CtorFrom<int>>, std::expected<int, int>&&>);
136static_assert(!std::is_convertible_v<std::expected<int, int>&&, std::expected<int, CtorFrom<int>>>);
137
138struct Data {
139 MoveOnly data;
140 constexpr Data(MoveOnly&& m) : data(std::move(m)) {}
141};
142
143constexpr bool test() {
144 // convert the value
145 {
146 std::expected<MoveOnly, int> e1(5);
147 std::expected<Data, int> e2 = std::move(e1);
148 assert(e2.has_value());
149 assert(e2.value().data.get() == 5);
150 assert(e1.has_value());
151 assert(e1.value().get() == 0);
152 }
153
154 // convert the error
155 {
156 std::expected<int, MoveOnly> e1(std::unexpect, 5);
157 std::expected<int, Data> e2 = std::move(e1);
158 assert(!e2.has_value());
159 assert(e2.error().data.get() == 5);
160 assert(!e1.has_value());
161 assert(e1.error().get() == 0);
162 }
163
164 // convert TailClobberer
165 {
166 std::expected<TailClobbererNonTrivialMove<0>, char> e1;
167 std::expected<TailClobberer<0>, char> e2 = std::move(e1);
168 assert(e2.has_value());
169 assert(e1.has_value());
170 }
171
172 return true;
173}
174
175void testException() {
176#ifndef TEST_HAS_NO_EXCEPTIONS
177 struct ThrowingInt {
178 ThrowingInt(int) { throw Except{}; }
179 };
180
181 // throw on converting value
182 {
183 const std::expected<int, int> e1;
184 try {
185 [[maybe_unused]] std::expected<ThrowingInt, int> e2 = e1;
186 assert(false);
187 } catch (Except) {
188 }
189 }
190
191 // throw on converting error
192 {
193 const std::expected<int, int> e1(std::unexpect);
194 try {
195 [[maybe_unused]] std::expected<int, ThrowingInt> e2 = e1;
196 assert(false);
197 } catch (Except) {
198 }
199 }
200
201#endif // TEST_HAS_NO_EXCEPTIONS
202}
203
204int main(int, char**) {
205 test();
206 static_assert(test());
207 testException();
208 return 0;
209}
210

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