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// constexpr expected& operator=(const expected& rhs);
11//
12// Effects:
13// - If this->has_value() && rhs.has_value() is true, no effects.
14// - Otherwise, if this->has_value() is true, equivalent to: construct_at(addressof(unex), rhs.unex); has_val = false;
15// - Otherwise, if rhs.has_value() is true, destroys unex and sets has_val to true.
16// - Otherwise, equivalent to unex = rhs.error().
17//
18// Returns: *this.
19//
20// Remarks: This operator is defined as deleted unless is_copy_assignable_v<E> is true and is_copy_constructible_v<E> is true.
21
22#include <cassert>
23#include <concepts>
24#include <expected>
25#include <type_traits>
26#include <utility>
27
28#include "../../types.h"
29#include "test_macros.h"
30
31struct NotCopyConstructible {
32 NotCopyConstructible(const NotCopyConstructible&) = delete;
33 NotCopyConstructible& operator=(const NotCopyConstructible&) = default;
34};
35
36struct NotCopyAssignable {
37 NotCopyAssignable(const NotCopyAssignable&) = default;
38 NotCopyAssignable& operator=(const NotCopyAssignable&) = delete;
39};
40
41// Test constraints
42static_assert(std::is_copy_assignable_v<std::expected<void, int>>);
43
44// !is_copy_assignable_v<E>
45static_assert(!std::is_copy_assignable_v<std::expected<void, NotCopyAssignable>>);
46
47// !is_copy_constructible_v<E>
48static_assert(!std::is_copy_assignable_v<std::expected<void, NotCopyConstructible>>);
49
50constexpr bool test() {
51 // If this->has_value() && rhs.has_value() is true, no effects.
52 {
53 std::expected<void, int> e1;
54 std::expected<void, int> e2;
55 decltype(auto) x = (e1 = e2);
56 static_assert(std::same_as<decltype(x), std::expected<void, int>&>);
57 assert(&x == &e1);
58 assert(e1.has_value());
59 }
60
61 // Otherwise, if this->has_value() is true, equivalent to: construct_at(addressof(unex), rhs.unex); has_val = false;
62 {
63 Traced::state state{};
64 std::expected<void, Traced> e1;
65 std::expected<void, Traced> e2(std::unexpect, state, 5);
66 decltype(auto) x = (e1 = e2);
67 static_assert(std::same_as<decltype(x), std::expected<void, Traced>&>);
68 assert(&x == &e1);
69 assert(!e1.has_value());
70 assert(e1.error().data_ == 5);
71
72 assert(state.copyCtorCalled);
73 }
74
75 // Otherwise, if rhs.has_value() is true, destroys unex and sets has_val to true.
76 {
77 Traced::state state{};
78 std::expected<void, Traced> e1(std::unexpect, state, 5);
79 std::expected<void, Traced> e2;
80 decltype(auto) x = (e1 = e2);
81 static_assert(std::same_as<decltype(x), std::expected<void, Traced>&>);
82 assert(&x == &e1);
83 assert(e1.has_value());
84
85 assert(state.dtorCalled);
86 }
87
88 // Otherwise, equivalent to unex = rhs.error().
89 {
90 Traced::state state{};
91 std::expected<void, Traced> e1(std::unexpect, state, 5);
92 std::expected<void, Traced> e2(std::unexpect, state, 10);
93 decltype(auto) x = (e1 = e2);
94 static_assert(std::same_as<decltype(x), std::expected<void, Traced>&>);
95 assert(&x == &e1);
96 assert(!e1.has_value());
97 assert(e1.error().data_ == 10);
98
99 assert(state.copyAssignCalled);
100 }
101
102 // CheckForInvalidWrites
103 {
104 {
105 CheckForInvalidWrites<true, true> e1;
106 CheckForInvalidWrites<true, true> e2(std::unexpect);
107
108 e1 = e2;
109
110 assert(e1.check());
111 assert(e2.check());
112 }
113 {
114 CheckForInvalidWrites<false, true> e1;
115 CheckForInvalidWrites<false, true> e2(std::unexpect);
116
117 e1 = e2;
118
119 assert(e1.check());
120 assert(e2.check());
121 }
122 }
123
124 return true;
125}
126
127void testException() {
128#ifndef TEST_HAS_NO_EXCEPTIONS
129 std::expected<void, ThrowOnCopyConstruct> e1(std::in_place);
130 std::expected<void, ThrowOnCopyConstruct> e2(std::unexpect);
131 try {
132 e1 = e2;
133 assert(false);
134 } catch (Except) {
135 assert(e1.has_value());
136 }
137#endif // TEST_HAS_NO_EXCEPTIONS
138}
139
140int main(int, char**) {
141 test();
142 static_assert(test());
143 testException();
144 return 0;
145}
146

source code of libcxx/test/std/utilities/expected/expected.void/assign/assign.copy.pass.cpp