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// <tuple>
11
12// template <class... Types> class tuple;
13
14// template <class... Types>
15//   class tuple_size<tuple<Types...>>
16//     : public integral_constant<size_t, sizeof...(Types)> { };
17//
18//  LWG #2212 says that tuple_size and tuple_element must be
19//     available after including <utility>
20
21#include <cstddef>
22#include <utility>
23#include <type_traits>
24
25template <class T, std::size_t N, class U, size_t idx>
26void test()
27{
28    static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,
29                                   std::tuple_size<T> >::value), "");
30    static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,
31                                   std::tuple_size<const T> >::value), "");
32    static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,
33                                   std::tuple_size<volatile T> >::value), "");
34    static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,
35                                   std::tuple_size<const volatile T> >::value), "");
36    static_assert((std::is_same<typename std::tuple_element<idx, T>::type, U>::value), "");
37    static_assert((std::is_same<typename std::tuple_element<idx, const T>::type, const U>::value), "");
38    static_assert((std::is_same<typename std::tuple_element<idx, volatile T>::type, volatile U>::value), "");
39    static_assert((std::is_same<typename std::tuple_element<idx, const volatile T>::type, const volatile U>::value), "");
40}
41
42int main()
43{
44    test<std::pair<int, int>, 2, int, 0>();
45    test<std::pair<int, int>, 2, int, 1>();
46    test<std::pair<const int, int>, 2, int, 1>();
47    test<std::pair<int, volatile int>, 2, volatile int, 1>();
48    test<std::pair<char *, int>, 2, char *, 0>();
49    test<std::pair<char *, int>, 2, int,    1>();
50}
51