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 //   optional(optional<U>&& rhs);
14 
15 #include <cassert>
16 #include <memory>
17 #include <optional>
18 #include <type_traits>
19 #include <utility>
20 
21 #include "test_macros.h"
22 
23 using std::optional;
24 
25 template <class T, class U>
26 TEST_CONSTEXPR_CXX20 void
27 test(optional<U>&& rhs, bool is_going_to_throw = false)
28 {
29     bool rhs_engaged = static_cast<bool>(rhs);
30 #ifndef TEST_HAS_NO_EXCEPTIONS
31     try
32     {
33         optional<T> lhs = std::move(rhs);
34         assert(is_going_to_throw == false);
35         assert(static_cast<bool>(lhs) == rhs_engaged);
36     }
37     catch (int i)
38     {
39         assert(i == 6);
40     }
41 #else
42     if (is_going_to_throw) return;
43     optional<T> lhs = std::move(rhs);
44     assert(static_cast<bool>(lhs) == rhs_engaged);
45 #endif
46 }
47 
48 class X
49 {
50     int i_;
51 public:
52     TEST_CONSTEXPR_CXX20 X(int i) : i_(i) {}
53     TEST_CONSTEXPR_CXX20 X(X&& x) : i_(std::exchange(x.i_, 0)) {}
54     TEST_CONSTEXPR_CXX20 ~X() {i_ = 0;}
55     friend constexpr bool operator==(const X& x, const X& y) {return x.i_ == y.i_;}
56 };
57 
58 struct Z
59 {
60     Z(int) { TEST_THROW(6); }
61 };
62 
63 template<class T, class U>
64 TEST_CONSTEXPR_CXX20 bool test_all()
65 {
66     {
67         optional<T> rhs;
68         test<U>(std::move(rhs));
69     }
70     {
71         optional<T> rhs(short{3});
72         test<U>(std::move(rhs));
73     }
74     return true;
75 }
76 
77 int main(int, char**)
78 {
79     test_all<short, int>();
80     test_all<int, X>();
81 #if TEST_STD_VER > 17
82     static_assert(test_all<short, int>());
83     static_assert(test_all<int, X>());
84 #endif
85     {
86         optional<int> rhs;
87         test<Z>(std::move(rhs));
88     }
89     {
90         optional<int> rhs(3);
91         test<Z>(std::move(rhs), true);
92     }
93 
94     static_assert(!(std::is_constructible<optional<X>, optional<Z>>::value), "");
95 
96   return 0;
97 }
98