#include <boost/hana/config.hpp>
-BOOST_HANA_NAMESPACE_BEGIN
+namespace boost { namespace hana {
//! @ingroup group-concepts
//! @defgroup group-Constant Constant
//! The `Constant` concept represents data that can be manipulated at
//! [1]: http://en.cppreference.com/w/cpp/named_req/LiteralType
template <typename C>
struct Constant;
-BOOST_HANA_NAMESPACE_END
+}} // end namespace boost::hana
#endif // !BOOST_HANA_FWD_CONCEPT_CONSTANT_HPP