#include <boost/asio/prefer.hpp>
#include <cassert>
template <int>
struct prop
{
static constexpr bool is_preferable = true;
};
template <int>
struct object
{
};
namespace boost {
namespace asio {
namespace traits {
template<int N>
struct static_require<object<N>, prop<N> >
{
static constexpr bool is_valid = true;
};
} } }
int main()
{
static_assert(!boost::asio::can_prefer<object<1>, prop<1>>::value, "");
static_assert(!boost::asio::can_prefer<object<1>, prop<1>, prop<1>>::value, "");
static_assert(!boost::asio::can_prefer<object<1>, prop<1>, prop<1>, prop<1>>::value, "");
static_assert(!boost::asio::can_prefer<const object<1>, prop<1>>::value, "");
static_assert(!boost::asio::can_prefer<const object<1>, prop<1>, prop<1>>::value, "");
static_assert(!boost::asio::can_prefer<const object<1>, prop<1>, prop<1>, prop<1>>::value, "");
}