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// Copyright (C) 2015-2016 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// { dg-options "-std=gnu++11" }
// { dg-do compile }
#include <type_traits>
#include <memory>
template<typename T, typename Base>
struct Alloc : Base
{
typedef T value_type;
Alloc();
template <typename U>
Alloc(const Alloc<U, Base>&);
T* allocate(std::size_t);
void deallocate(T*, std::size_t);
};
template<bool> struct Empty { };
template<> struct Empty<false> { int x; };
template<bool B>
struct WithType
{ using is_always_equal = std::integral_constant<bool, B>; };
struct EmptyAndTrue : Empty<true>, WithType<true> { };
struct EmptyButFalse : Empty<true>, WithType<false> { };
struct NotEmptyButTrue : Empty<false>, WithType<true> { };
struct NotEmptyAndFalse : Empty<false>, WithType<false> { };
template<typename Base>
constexpr bool test()
{
using traits = std::allocator_traits<Alloc<int, Base>>;
using test_type = typename traits::is_always_equal;
static_assert(std::is_base_of<std::true_type, test_type>::value
|| std::is_base_of<std::false_type, test_type>::value,
"has correct base characteristic");
return test_type::value;
}
static_assert( test<Empty<true>>(), "empty type is always equal" );
static_assert( !test<Empty<false>>(), "non-empty type is not always equal" );
static_assert( test<EmptyAndTrue>(), "nested type is used" );
static_assert( !test<EmptyButFalse>(), "nested type is used" );
static_assert( test<NotEmptyButTrue>(), "nested type is used" );
static_assert( !test<NotEmptyAndFalse>(), "nested type is used" );
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