The interface and behavior for the following traits and metafunctions (as they currently stand on the CallableTraits develop branch) are unlikely to change, for the most part. I explain what I mean by "for the most part" after this list:
add_member_constadd_member_volatileadd_member_cvadd_member_lvalue_referenceadd_member_rvalue_referenceadd_varargsremove_member_constremove_member_cv