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 const T& optional<T>::operator*() const &;
13 
14 #include <optional>
15 #include <type_traits>
16 #include <cassert>
17 
18 #include "test_macros.h"
19 
20 using std::optional;
21 
22 struct X
23 {
24     constexpr int test() const& {return 3;}
25     int test() & {return 4;}
26     constexpr int test() const&& {return 5;}
27     int test() && {return 6;}
28 };
29 
30 struct Y
31 {
32     int test() const {return 2;}
33 };
34 
35 int main(int, char**)
36 {
37     {
38         const optional<X> opt; ((void)opt);
39         ASSERT_SAME_TYPE(decltype(*opt), X const&);
40         // ASSERT_NOT_NOEXCEPT(*opt);
41         // FIXME: This assertion fails with GCC because it can see that
42         // (A) operator*() is constexpr, and
43         // (B) there is no path through the function that throws.
44         // It's arguable if this is the correct behavior for the noexcept
45         // operator.
46         // Regardless this function should still be noexcept(false) because
47         // it has a narrow contract.
48     }
49     {
50         constexpr optional<X> opt(X{});
51         static_assert((*opt).test() == 3, "");
52     }
53     {
54         constexpr optional<Y> opt(Y{});
55         assert((*opt).test() == 2);
56     }
57 
58     return 0;
59 }
60