#include <boost/hana/config.hpp>
-BOOST_HANA_NAMESPACE_BEGIN
+namespace boost { namespace hana {
//! @ingroup group-core
//! Mark a tag-dispatched method implementation as a default implementation.
//!
template <typename T, typename = void>
struct is_default;
#endif
-BOOST_HANA_NAMESPACE_END
+}} // end namespace boost::hana
#endif // !BOOST_HANA_FWD_CORE_DEFAULT_HPP