Hi, I'm testing with BOOST_TYPEOF_LIMIT_SIZE greater than 50 and native typeof disabled. I get a "class template has already been defined" error on "template<class V, class T> struct push_back" whenever BOOST_TYPEOF_LIMIT_SIZE is *not* a multiple of 50. This is because push_back is defined in both "typeof/vector.hpp" and, for example, "typeof/vector50.hpp". My fix is to change the push_back definition in "typeof/vector.hpp" to: # if BOOST_TYPEOF_LIMIT_SIZE < 50 template<class V, class T> struct push_back { typedef V type; }; # endif Can someone please confirm that this is the correct fix? A tiny program demonstrating the problem is listed below. Thanks, Dave Jenkins #define BOOST_TYPEOF_COMPLIANT #define BOOST_TYPEOF_LIMIT_SIZE 51 #include <boost/typeof/typeof.hpp> int main(){ return 0; }