Hi, I cannot figure out, why the following little program does not compile. It simply typedefs a variant of a specific bounded type set and then derives a class from this type. I've tried to compile it with VC 2005. It does not compile because of ambiguous overloads within the boost::variant source. It would be very helpful if somebody could shed light on the issue. Best regards Peter PS: I intended to post this to the boost developers list, but I was unable to log onto the list today. ************************************************************* #include <boost/variant.hpp> typedef boost::variant<char, int, double> numeric_type_variant; class numeric_type : public numeric_type_variant { public: /// Default constructor. numeric_type() : numeric_type_variant() { } template <typename T> /// Converting constructor. numeric_type(T const& t) : numeric_type_variant(t) { } // some more code }; int main(int argc, char* argv[]) { char ba; int bb; double bc; numeric_type a; numeric_type b(ba); numeric_type c(bb); numeric_type d(bc); a = ba; a = bb; a = bc; return 0; } ************************************************************* This is the build log: ------ Build started: Project: test_variant, Configuration: Debug Win32 ------ Compiling... test_variant.cpp c:\_ngi\toolkits\boost_1_33_1\boost\variant\variant.hpp(1342) : error C2666: 'boost::variant<T0_,T1,T2>::convert_construct' : 2 overloads have similar conversions with [ T0_=char, T1=int, T2=double ] c:\_ngi\toolkits\boost_1_33_1\boost\variant\variant.hpp(1327): could be 'void boost::variant<T0_,T1,T2>::convert_construct<char,int,double,boost::detail:: variant::void_,boost::detail::variant::void_,boost::detail::variant::void_,b oost::detail::variant::void_,boost::detail::variant::void_,boost::detail::va riant::void_,boost::detail::variant::void_,boost::detail::variant::void_,boo st::detail::variant::void_,boost::detail::variant::void_,boost::detail::vari ant::void_,boost::detail::variant::void_,boost::detail::variant::void_,boost ::detail::variant::void_,boost::detail::variant::void_,boost::detail::varian t::void_,boost::detail::variant::void_>(const boost::variant<T0_,T1,T2> &,long)' with [ T0_=char, T1=int, T2=double ] c:\_ngi\toolkits\boost_1_33_1\boost\variant\variant.hpp(1258): or 'void boost::variant<T0_,T1,T2>::convert_construct<const T>(T &,int,boost::mpl::false_)' with [ T0_=char, T1=int, T2=double, T=numeric_type ] while trying to match the argument list '(const numeric_type, long)' c:\_ngi\toolkits\boost_1_33_1\boost\variant\variant.hpp(1580) : see reference to function template instantiation 'boost::variant<T0_,T1,T2>::variant<T>(const T &)' being compiled with [ T0_=char, T1=int, T2=double, T=numeric_type ] c:\_ngi\toolkits\boost_1_33_1\boost\variant\variant.hpp(1590) : see reference to function template instantiation 'void boost::variant<T0_,T1,T2>::assign<T>(const T &)' being compiled with [ T0_=char, T1=int, T2=double, T=numeric_type ] c:\_schrott\test_variant\test_variant\test_variant.cpp(36) : see reference to function template instantiation 'boost::variant<T0_,T1,T2> &boost::variant<T0_,T1,T2>::operator =<numeric_type>(const T &)' being compiled with [ T0_=char, T1=int, T2=double, T=numeric_type ] Build log was saved at "file://c:\_schrott\test_variant\test_variant\Debug\BuildLog.htm" test_variant - 1 error(s), 0 warning(s) ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========