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() noexcept;
13 
14 #include <experimental/optional>
15 #include <type_traits>
16 #include <cassert>
17 
18 #if _LIBCPP_STD_VER > 11
19 
20 using std::experimental::optional;
21 
22 template <class Opt>
23 void
test_constexpr()24 test_constexpr()
25 {
26     static_assert(std::is_nothrow_default_constructible<Opt>::value, "");
27     constexpr Opt opt;
28     static_assert(static_cast<bool>(opt) == false, "");
29 
30     struct test_constexpr_ctor
31         : public Opt
32     {
33         constexpr test_constexpr_ctor() {}
34     };
35 
36 }
37 
38 template <class Opt>
39 void
test()40 test()
41 {
42     static_assert(std::is_nothrow_default_constructible<Opt>::value, "");
43     Opt opt;
44     assert(static_cast<bool>(opt) == false);
45 
46     struct test_constexpr_ctor
47         : public Opt
48     {
49         constexpr test_constexpr_ctor() {}
50     };
51 }
52 
53 struct X
54 {
55     X();
56 };
57 
58 #endif  // _LIBCPP_STD_VER > 11
59 
main()60 int main()
61 {
62 #if _LIBCPP_STD_VER > 11
63     test_constexpr<optional<int>>();
64     test_constexpr<optional<int*>>();
65     test<optional<X>>();
66 #endif  // _LIBCPP_STD_VER > 11
67 }
68