libcxx/test/std/utilities/tuple/tuple.tuple/tuple.traits/uses_allocator.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <tuple>

// template <class... Types> class tuple;

// template <class... Types, class Alloc>
//   struct uses_allocator<tuple<Types...>, Alloc> : true_type { };

// UNSUPPORTED: c++98, c++03

#include <tuple>
#include <type_traits>

struct A {};

int main(int, char**)
{
    {
        typedef std::tuple<> T;
        static_assert((std::is_base_of<std::true_type,
                                       std::uses_allocator<T, A>>::value), "");
    }
    {
        typedef std::tuple<int> T;
        static_assert((std::is_base_of<std::true_type,
                                       std::uses_allocator<T, A>>::value), "");
    }
    {
        typedef std::tuple<char, int> T;
        static_assert((std::is_base_of<std::true_type,
                                       std::uses_allocator<T, A>>::value), "");
    }
    {
        typedef std::tuple<double&, char, int> T;
        static_assert((std::is_base_of<std::true_type,
                                       std::uses_allocator<T, A>>::value), "");
    }

  return 0;
}