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// <tuple>
10
11// template <class... Types> class tuple;
12
13// template <size_t I, class... Types>
14// struct tuple_element<I, tuple<Types...> >
15// {
16// typedef Ti type;
17// };
18
19// UNSUPPORTED: c++03
20
21#include <tuple>
22#include <type_traits>
23
24#include "test_macros.h"
25
26template <class T, std::size_t N, class U>
27void 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 TEST_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
41int main(int, char**)
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 return 0;
51}
52

source code of libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp