boost::polymorphic_upcast suggestion

Hi, I would like to propose, in the spirit of Bjarne Stroustrup book, an upcast (where target inherits source). template inline Target polymorphic_upcast(Source* x BOOST_EXPLICIT_DEFAULT_TARGET) { typedef unsigned int uint; uint offset = reinterpret_cast<uint>( static_cast( reinterpret_cast<Target>(1) ) ) - 1; Target res = reinterpret_cast<Target>( reinterpret_cast<uint>( x ) - offset ); assert( res == dynamic_cast<Target>(x) ); return res; } It would be faster to use the polymorphic_upcast, since it doesn't use dynamic_cast in NDEBUG. Regards, Jean Llorca.