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 <class... Types>
14 // class tuple_size<tuple<Types...>>
15 // : public integral_constant<size_t, sizeof...(Types)> { };
16
17 // UNSUPPORTED: c++03
18
19 #include <tuple>
20 #include <type_traits>
21
22 #include "test_macros.h"
23
24 template <class T, class = decltype(std::tuple_size<T>::value)>
has_value(int)25 constexpr bool has_value(int) { return true; }
has_value(long)26 template <class> constexpr bool has_value(long) { return false; }
has_value()27 template <class T> constexpr bool has_value() { return has_value<T>(0); }
28
29 struct Dummy {};
30
main(int,char **)31 int main(int, char**) {
32 // Test that the ::value member does not exist
33 static_assert(has_value<std::tuple<int> const>(), "");
34 static_assert(has_value<std::pair<int, long> volatile>(), "");
35 static_assert(!has_value<int>(), "");
36 static_assert(!has_value<const int>(), "");
37 static_assert(!has_value<volatile void>(), "");
38 static_assert(!has_value<const volatile std::tuple<int>&>(), "");
39
40 return 0;
41 }
42