1//===----------------------------------------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is dual licensed under the MIT and the University of Illinois Open
6// Source Licenses. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10// UNSUPPORTED: c++98, c++03, c++11, c++14
11// <optional>
12
13// constexpr const T& optional<T>::operator*() const &;
14
15#ifdef _LIBCPP_DEBUG
16#define _LIBCPP_ASSERT(x, m) ((x) ? (void)0 : std::exit(0))
17#endif
18
19#include <optional>
20#include <type_traits>
21#include <cassert>
22
23#include "test_macros.h"
24
25using std::optional;
26
27struct X
28{
29    constexpr int test() const& {return 3;}
30    int test() & {return 4;}
31    constexpr int test() const&& {return 5;}
32    int test() && {return 6;}
33};
34
35struct Y
36{
37    int test() const {return 2;}
38};
39
40int main()
41{
42    {
43        const optional<X> opt; ((void)opt);
44        ASSERT_SAME_TYPE(decltype(*opt), X const&);
45        // ASSERT_NOT_NOEXCEPT(*opt);
46        // FIXME: This assertion fails with GCC because it can see that
47        // (A) operator*() is constexpr, and
48        // (B) there is no path through the function that throws.
49        // It's arguable if this is the correct behavior for the noexcept
50        // operator.
51        // Regardless this function should still be noexcept(false) because
52        // it has a narrow contract.
53    }
54    {
55        constexpr optional<X> opt(X{});
56        static_assert((*opt).test() == 3, "");
57    }
58    {
59        constexpr optional<Y> opt(Y{});
60        assert((*opt).test() == 2);
61    }
62#ifdef _LIBCPP_DEBUG
63    {
64        const optional<X> opt;
65        assert((*opt).test() == 3);
66        assert(false);
67    }
68#endif  // _LIBCPP_DEBUG
69}
70