I got a trouble when used boost::mpl. This code works for std::vector, but fail for std::map (gcc 3.4.2) #include #include #include #include <iostream> #include <vector> #include <map> #include <utility> namespace mpl=boost::mpl; template<typename Pair> struct first { typedef typename Pair::first_type type; }; template<typename Pair> struct second { typedef typename Pair::second_type type; }; int main () { typedef mpl::lambda< std::vector< second< mpl::arg<1> > > > vector; std::cout << boost::is_same< mpl::apply >::type, std::vector<int> >::value << std::endl; typedef mpl::lambda< std::map< first< mpl::arg<1> >, second< mpl::arg<1> > > > map; std::cout << boost::is_same< mpl::apply >::type, std::map >::value << std::endl; return 0; } Simple tests show that problem in std::allocator< std::pair > Looks like compiler bug, but may be it's my error. Any thought's how avoid the problem?