First of all, this is my first boost posting, and as all I could find on "http://lists.boost.org/mailman/listinfo.cgi/boost" told my to post my proposal to this address, I did so (despite of being astonished, that there does not seem to be a directory of subgroups to browse.). However, at least on MSVC 9 as well as on ICL 11 there exists the problem, that the "BOOST_MPL_ASSERT" terms in the attached "consten.rar\consten\consten.cpp" do fail for "boost::add_const" but not for "consten", meaning, that "boost::add_const" was not capable to add constness to reference-types, which "consten" is. Hence my proposal is, to create a service-pack to "boost::add_const" based on "consten" and similarly to all other affected traits, such as "boost::add_volatile" and the like.
That's not how add_const is supposed to work - it's supposed to be the same as "T const" (where that is allowed) and if T is a reference type U&, then the result is still U&. If you want add_const to work as you suggest then you would need to compose the type_traits as follows: mpl::if_< is_reference<T>, add_reference<add_const<remove_reference<T>::type>::type>::type, add_const<T>::type
::type
HTH, John.