nullopt_t.pass.cpp revision 01afa5c6e407e985d9643707d7b7ab1384bd9317 
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// <optional>
11
12// constexpr optional(nullopt_t) noexcept;
13
14#include <optional>
15#include <type_traits>
16#include <cassert>
17
18#if _LIBCPP_STD_VER > 11
19
20template <class Opt>
21void
22test_constexpr()
23{
24    static_assert(noexcept(Opt(std::nullopt)), "");
25    constexpr Opt opt(std::nullopt);
26    static_assert(static_cast<bool>(opt) == false, "");
27
28    struct test_constexpr_ctor
29        : public Opt
30    {
31        constexpr test_constexpr_ctor() {}
32    };
33}
34
35template <class Opt>
36void
37test()
38{
39    static_assert(noexcept(Opt(std::nullopt)), "");
40    Opt opt(std::nullopt);
41    assert(static_cast<bool>(opt) == false);
42
43    struct test_constexpr_ctor
44        : public Opt
45    {
46        constexpr test_constexpr_ctor() {}
47    };
48}
49
50struct X
51{
52    X();
53};
54
55#endif  // _LIBCPP_STD_VER > 11
56
57int main()
58{
59#if _LIBCPP_STD_VER > 11
60    test_constexpr<std::optional<int>>();
61    test_constexpr<std::optional<int*>>();
62    test<std::optional<X>>();
63#endif  // _LIBCPP_STD_VER > 11
64}
65