Does cw-9_4 really support partial specialization of class templates? According to boost.config it does. xpressive's tests are failing on this compiler, with heaps of errors like: ### mwcc Compiler: # In: ..\boost\xpressive\detail\static\productions\independent_compiler.hpp # From: ..\libs\xpressive\test\misc1.cpp # ----------------------------------------- # 128: : transform_compiler<arg_transform, xpressive::detail::seq_tag> # Error: ^ # illegal partial specialization The code it's complaining about looks like: template<typename OpTag> struct compiler<OpTag, xpressive::detail::ind_tag> : transform_compiler<arg_transform, xpressive::detail::seq_tag> { }; This looks unremarkable to me. What is CodeWarrior complaining about? Any and all insights are most welcome. -- Eric Niebler Boost Consulting www.boost-consulting.com