Hello all, I have questions about concepts (it's related to Boost.ConceptCheckign and Boost.Generic, but it's really just about the concept syntax that was proposed and never adopted for C++11). What's the difference between typename new_type = old_type and typedef old_type new_type? Why are they both allowed? For example, what's the difference between this: auto concept HasFind < typename T > { typename key_type = typename T::key_type; // use typename typename mapped_type; std::pair<key_type, mapped_type> find ( T const&, key_type const& ); } And this: auto concept HasFind < typename T > { typedef typename T::key_type key_type; // use typedef typename mapped_type; std::pair<key_type, mapped_type> find ( T const&, key_type const& ); } Thanks a lot. --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/boost-concept-typenames-vs-typedefs-tp460... Sent from the Boost - Dev mailing list archive at Nabble.com.