I noticed that instantiated lexical_cast functions are parameterized with array types. It's not optimal as array_to_pointer_decay is applied to argument type immediately and original type is not user anywhere else. My idea is to define inlined lexical_cast that just transforms the argument type and forward a call to detail::lexical_cast: template<typename Target, typename Source> inline Target lexical_cast(const Source &arg) { typedef typename detail::array_to_pointer_decay<Source>::type NewSource; return detail::lexical_cast<Target,NewSource>(arg); } The detail::lexical_cast is almost an original lexical_cast except that it doesn't transform the argument type. Additionally, call_traits<>::value_type can be applied to the argument type: namespace detail { template<typename Target, typename Source> Target lexical_cast( BOOST_DEDUCED_TYPENAME boost::call_traits<Source>::value_type arg) { detail::lexical_stream<Target, Source> interpreter; Target result; if(!(interpreter << arg && interpreter >> result)) throw_exception(bad_lexical_cast(typeid(Source), typeid(Target))); return result; } } I tested lexical_cast_test.cpp with gcc 3.4.4 [FreeBSD] 20050518. Code was generated with bjam --v2 release. Original size: 220316 Optimized: 201940 -17.95K ( 8.34% ) Optimized & call_traits: 197108 -22.66K ( 10.54% ) Additional transfomations can be applied. For example, enums can be promoted to integral types. I'm a bit unsure about this, though. This change could break enum types that have overloaded operator<<. What is expected behavior in this case? -- Alexander Nasonov