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 // constexpr T* optional<T>::operator->();
13 
14 #ifdef _LIBCPP_DEBUG
15 #define _LIBCPP_ASSERT(x, m) ((x) ? (void)0 : std::exit(0))
16 #endif
17 
18 #include <optional>
19 #include <type_traits>
20 #include <cassert>
21 
22 #include "test_macros.h"
23 
24 using std::optional;
25 
26 struct X
27 {
28     int test() noexcept {return 3;}
29 };
30 
31 struct Y
32 {
33     constexpr int test() {return 3;}
34 };
35 
36 constexpr int
37 test()
38 {
39     optional<Y> opt{Y{}};
40     return opt->test();
41 }
42 
43 int main(int, char**)
44 {
45     {
46         std::optional<X> opt; ((void)opt);
47         ASSERT_SAME_TYPE(decltype(opt.operator->()), X*);
48         // ASSERT_NOT_NOEXCEPT(opt.operator->());
49         // FIXME: This assertion fails with GCC because it can see that
50         // (A) operator->() is constexpr, and
51         // (B) there is no path through the function that throws.
52         // It's arguable if this is the correct behavior for the noexcept
53         // operator.
54         // Regardless this function should still be noexcept(false) because
55         // it has a narrow contract.
56     }
57     {
58         optional<X> opt(X{});
59         assert(opt->test() == 3);
60     }
61     {
62         static_assert(test() == 3, "");
63     }
64 #ifdef _LIBCPP_DEBUG
65     {
66         optional<X> opt;
67         assert(opt->test() == 3);
68         assert(false);
69     }
70 #endif  // _LIBCPP_DEBUG
71 
72   return 0;
73 }
74