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 <size_t I, class... Types>
15 // class tuple_element<I, tuple<Types...> >
16 // {
17 // public:
18 //     typedef Ti type;
19 // };
20 
21 // UNSUPPORTED: c++98, c++03
22 
23 #include <tuple>
24 #include <type_traits>
25 
26 template <class T, std::size_t N, class U>
test()27 void test()
28 {
29     static_assert((std::is_same<typename std::tuple_element<N, T>::type, U>::value), "");
30     static_assert((std::is_same<typename std::tuple_element<N, const T>::type, const U>::value), "");
31     static_assert((std::is_same<typename std::tuple_element<N, volatile T>::type, volatile U>::value), "");
32     static_assert((std::is_same<typename std::tuple_element<N, const volatile T>::type, const volatile U>::value), "");
33 #if _LIBCPP_STD_VER > 11
34     static_assert((std::is_same<typename std::tuple_element_t<N, T>, U>::value), "");
35     static_assert((std::is_same<typename std::tuple_element_t<N, const T>, const U>::value), "");
36     static_assert((std::is_same<typename std::tuple_element_t<N, volatile T>, volatile U>::value), "");
37     static_assert((std::is_same<typename std::tuple_element_t<N, const volatile T>, const volatile U>::value), "");
38 #endif
39 }
40 
main()41 int main()
42 {
43     test<std::tuple<int>, 0, int>();
44     test<std::tuple<char, int>, 0, char>();
45     test<std::tuple<char, int>, 1, int>();
46     test<std::tuple<int*, char, int>, 0, int*>();
47     test<std::tuple<int*, char, int>, 1, char>();
48     test<std::tuple<int*, char, int>, 2, int>();
49 }
50