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
114
115
116
117
|
//===----------------------------------------------------------------------===//
// 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
// Older Clangs do not support the C++20 feature to constrain destructors
// XFAIL: clang-14, apple-clang-14
// template<class G>
// constexpr expected& operator=(const unexpected<G>& e);
//
// Let GF be const G&
//
// Constraints: is_constructible_v<E, GF> is true and is_assignable_v<E&, GF> is true.
//
// Effects:
// - If has_value() is true, equivalent to:
// construct_at(addressof(unex), std::forward<GF>(e.error()));
// has_val = false;
// - Otherwise, equivalent to: unex = std::forward<GF>(e.error());
//
// Returns: *this.
#include <cassert>
#include <concepts>
#include <expected>
#include <type_traits>
#include <utility>
#include "../../types.h"
#include "test_macros.h"
struct NotCopyConstructible {
NotCopyConstructible(const NotCopyConstructible&) = delete;
NotCopyConstructible& operator=(const NotCopyConstructible&) = default;
};
struct NotCopyAssignable {
NotCopyAssignable(const NotCopyAssignable&) = default;
NotCopyAssignable& operator=(const NotCopyAssignable&) = delete;
};
struct MoveMayThrow {
MoveMayThrow(MoveMayThrow const&) = default;
MoveMayThrow& operator=(const MoveMayThrow&) = default;
MoveMayThrow(MoveMayThrow&&) noexcept(false) {}
MoveMayThrow& operator=(MoveMayThrow&&) noexcept(false) { return *this; }
};
// Test constraints
static_assert(std::is_assignable_v<std::expected<void, int>&, const std::unexpected<int>&>);
// !is_constructible_v<E, GF>
static_assert(
!std::is_assignable_v<std::expected<void, NotCopyConstructible>&, const std::unexpected<NotCopyConstructible>&>);
// !is_assignable_v<E&, GF>
static_assert(
!std::is_assignable_v<std::expected<void, NotCopyAssignable>&, const std::unexpected<NotCopyAssignable>&>);
constexpr bool test() {
// - If has_value() is true, equivalent to:
// construct_at(addressof(unex), std::forward<GF>(e.error()));
// has_val = false;
{
Traced::state state{};
std::expected<void, Traced> e;
std::unexpected<Traced> un(std::in_place, state, 5);
decltype(auto) x = (e = un);
static_assert(std::same_as<decltype(x), std::expected<void, Traced>&>);
assert(&x == &e);
assert(!e.has_value());
assert(e.error().data_ == 5);
assert(state.copyCtorCalled);
}
// - Otherwise, equivalent to: unex = std::forward<GF>(e.error());
{
Traced::state state1{};
Traced::state state2{};
std::expected<void, Traced> e(std::unexpect, state1, 5);
std::unexpected<Traced> un(std::in_place, state2, 10);
decltype(auto) x = (e = un);
static_assert(std::same_as<decltype(x), std::expected<void, Traced>&>);
assert(&x == &e);
assert(!e.has_value());
assert(e.error().data_ == 10);
assert(state1.copyAssignCalled);
}
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
std::expected<void, ThrowOnCopyConstruct> e1(std::in_place);
std::unexpected<ThrowOnCopyConstruct> un(std::in_place);
try {
e1 = un;
assert(false);
} catch (Except) {
assert(e1.has_value());
}
#endif // TEST_HAS_NO_EXCEPTIONS
}
int main(int, char**) {
test();
static_assert(test());
testException();
return 0;
}
|
