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 // LWG #2212 says that tuple_size and tuple_element must be 20 // available after including <utility> 21 22 #include <array> 23 #include <type_traits> 24 25 template <class T, std::size_t N, class U, size_t idx> 26 void 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 42 int main(int, char**) 43 { 44 test<std::array<int, 5>, 5, int, 0>(); 45 test<std::array<int, 5>, 5, int, 1>(); 46 test<std::array<const char *, 4>, 4, const char *, 3>(); 47 test<std::array<volatile int, 4>, 4, volatile int, 3>(); 48 test<std::array<char *, 3>, 3, char *, 1>(); 49 test<std::array<char *, 3>, 3, char *, 2>(); 50 51 return 0; 52 } 53