[Boost-users] mpl::transform<...> --- compile error: is not derived from type

hi, here's the problem i have: struct my{ template<typename UInt> struct apply{ typedef mpl::int_UInt::value type; }; }; template struct id_range{ typedef mpl::transform< mpl::range_c , my , mpl::back_inserter< mpl::vector<> > >::type type; /home/er/cpp/boost/random/mcmc/id_range.hpp|32|error: type ‘boost::mpl::transform, boost::random::mcmc::<unnamed>::my, boost::mpl::back_inserter >, mpl_::na>’ is not derived from type ‘boost::random::mcmc::id_range’| however, for example, this --instead-- compiles fine: struct id_range{ typedef mpl::transform< mpl::range_c , my , mpl::back_inserter< mpl::vector<> > >::type type; }; any suggestion appreciated. thanks!