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 #ifndef _LIBCPP___TYPE_TRAITS_IS_NOTHROW_CONSTRUCTIBLE_H
10 #define _LIBCPP___TYPE_TRAITS_IS_NOTHROW_CONSTRUCTIBLE_H
11 
12 #include <__config>
13 #include <__type_traits/integral_constant.h>
14 #include <__type_traits/is_constructible.h>
15 #include <__type_traits/is_reference.h>
16 #include <__utility/declval.h>
17 #include <cstddef>
18 
19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
20 #  pragma GCC system_header
21 #endif
22 
23 _LIBCPP_BEGIN_NAMESPACE_STD
24 
25 #if __has_builtin(__is_nothrow_constructible)
26 
27 template <
28     class _Tp, class... _Args>
29 struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
30     : public integral_constant<bool, __is_nothrow_constructible(_Tp, _Args...)> {};
31 #else
32 
33 template <bool, bool, class _Tp, class... _Args> struct __libcpp_is_nothrow_constructible;
34 
35 template <class _Tp, class... _Args>
36 struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/false, _Tp, _Args...>
37     : public integral_constant<bool, noexcept(_Tp(std::declval<_Args>()...))>
38 {
39 };
40 
41 template <class _Tp>
42 void __implicit_conversion_to(_Tp) noexcept { }
43 
44 template <class _Tp, class _Arg>
45 struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/true, _Tp, _Arg>
46     : public integral_constant<bool, noexcept(_VSTD::__implicit_conversion_to<_Tp>(std::declval<_Arg>()))>
47 {
48 };
49 
50 template <class _Tp, bool _IsReference, class... _Args>
51 struct __libcpp_is_nothrow_constructible</*is constructible*/false, _IsReference, _Tp, _Args...>
52     : public false_type
53 {
54 };
55 
56 template <class _Tp, class... _Args>
57 struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
58     : __libcpp_is_nothrow_constructible<is_constructible<_Tp, _Args...>::value, is_reference<_Tp>::value, _Tp, _Args...>
59 {
60 };
61 
62 template <class _Tp, size_t _Ns>
63 struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible<_Tp[_Ns]>
64     : __libcpp_is_nothrow_constructible<is_constructible<_Tp>::value, is_reference<_Tp>::value, _Tp>
65 {
66 };
67 
68 #endif // __has_builtin(__is_nothrow_constructible)
69 
70 
71 #if _LIBCPP_STD_VER > 14
72 template <class _Tp, class ..._Args>
73 inline constexpr bool is_nothrow_constructible_v = is_nothrow_constructible<_Tp, _Args...>::value;
74 #endif
75 
76 _LIBCPP_END_NAMESPACE_STD
77 
78 #endif // _LIBCPP___TYPE_TRAITS_IS_NOTHROW_CONSTRUCTIBLE_H
79