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(const 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
25test(const optional<U>& rhs, bool is_going_to_throw = false)
26{
27 static_assert(!(std::is_convertible<const optional<U>&, optional<T>>::value), "");
28 bool rhs_engaged = static_cast<bool>(rhs);
29#ifndef TEST_HAS_NO_EXCEPTIONS
30 try
31 {
32 optional<T> lhs(rhs);
33 assert(is_going_to_throw == false);
34 assert(static_cast<bool>(lhs) == rhs_engaged);
35 if (rhs_engaged)
36 assert(*lhs == T(*rhs));
37 }
38 catch (int i)
39 {
40 assert(i == 6);
41 }
42#else
43 if (is_going_to_throw) return;
44 optional<T> lhs(rhs);
45 assert(static_cast<bool>(lhs) == rhs_engaged);
46 if (rhs_engaged)
47 assert(*lhs == T(*rhs));
48#endif
49}
50
51class X
52{
53 int i_;
54public:
55 constexpr explicit X(int i) : i_(i) {}
56 constexpr X(const X& x) : i_(x.i_) {}
57 TEST_CONSTEXPR_CXX20 ~X() {i_ = 0;}
58 friend constexpr bool operator==(const X& x, const X& y) {return x.i_ == y.i_;}
59};
60
61class Y
62{
63 int i_;
64public:
65 constexpr explicit Y(int i) : i_(i) {}
66
67 friend constexpr bool operator==(const Y& x, const Y& y) {return x.i_ == y.i_;}
68};
69
70int count = 0;
71
72class Z
73{
74 int i_;
75public:
76 explicit Z(int i) : i_(i) {TEST_THROW(6);}
77
78 friend bool operator==(const Z& x, const Z& y) {return x.i_ == y.i_;}
79};
80
81template<class T, class U>
82constexpr bool test_all()
83{
84 {
85 optional<U> rhs;
86 test<T>(rhs);
87 }
88 {
89 optional<U> rhs(3);
90 test<T>(rhs);
91 }
92 return true;
93}
94
95
96int main(int, char**)
97{
98 test_all<X, int>();
99 test_all<Y, int>();
100#if TEST_STD_VER > 17
101 static_assert(test_all<X, int>());
102 static_assert(test_all<Y, int>());
103#endif
104 {
105 typedef Z T;
106 typedef int U;
107 optional<U> rhs;
108 test<T>(rhs);
109 }
110 {
111 typedef Z T;
112 typedef int U;
113 optional<U> rhs(3);
114 test<T>(rhs, true);
115 }
116
117 return 0;
118}
119

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