can_require_concept_free.cpp
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//
// cpp11/can_require_concept_free.cpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2020 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include "asio/require_concept.hpp"
#include <cassert>
template <int>
struct prop
{
static constexpr bool is_requirable_concept = true;
};
template <int>
struct object
{
template <int N>
friend constexpr object<N> require_concept(const object&, prop<N>)
{
return object<N>();
}
};
namespace asio {
template<int N, int M>
struct is_applicable_property<object<N>, prop<M> >
{
static constexpr bool value = true;
};
} // namespace asio
int main()
{
static_assert(asio::can_require_concept<object<1>, prop<2>>::value, "");
static_assert(asio::can_require_concept<const object<1>, prop<2>>::value, "");
}