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
10// <optional>
11
12// template <class U>
13// explicit optional(optional<U>&& rhs);
14
15#include <optional>
16#include <type_traits>
17#include <cassert>
18
19#include "test_macros.h"
20
21using std::optional;
22
23template <class T, class U>
24TEST_CONSTEXPR_CXX20 void test(optional<U>&& rhs, bool is_going_to_throw = false)
25{
26 static_assert(!(std::is_convertible<optional<U>&&, optional<T>>::value), "");
27 bool rhs_engaged = static_cast<bool>(rhs);
28#ifndef TEST_HAS_NO_EXCEPTIONS
29 try
30 {
31 optional<T> lhs(std::move(rhs));
32 assert(is_going_to_throw == false);
33 assert(static_cast<bool>(lhs) == rhs_engaged);
34 }
35 catch (int i)
36 {
37 assert(i == 6);
38 }
39#else
40 if (is_going_to_throw) return;
41 optional<T> lhs(std::move(rhs));
42 assert(static_cast<bool>(lhs) == rhs_engaged);
43#endif
44}
45
46class X
47{
48 int i_;
49public:
50 constexpr explicit X(int i) : i_(i) {}
51 constexpr X(X&& x) : i_(x.i_) { x.i_ = 0; }
52 TEST_CONSTEXPR_CXX20 ~X() {i_ = 0;}
53 friend constexpr bool operator==(const X& x, const X& y) {return x.i_ == y.i_;}
54};
55
56int count = 0;
57
58class Z
59{
60public:
61 explicit Z(int) { TEST_THROW(6); }
62};
63
64TEST_CONSTEXPR_CXX20 bool test()
65{
66 {
67 optional<int> rhs;
68 test<X>(std::move(rhs));
69 }
70 {
71 optional<int> rhs(3);
72 test<X>(std::move(rhs));
73 }
74
75 return true;
76}
77
78int main(int, char**)
79{
80#if TEST_STD_VER > 17
81 static_assert(test());
82#endif
83 test();
84 {
85 optional<int> rhs;
86 test<Z>(std::move(rhs));
87 }
88 {
89 optional<int> rhs(3);
90 test<Z>(std::move(rhs), true);
91 }
92
93 return 0;
94}
95

source code of libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_optional_U.pass.cpp