This is only happening when I'm instrumenting code with Insure++ from Parasoft. They use an EDG based parser (not sure of the version, but I know they have it set to be very strict) and it is failing like so: /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp: In function `boost::logic::tribool boost::logic::operator&&(boost::logic::tribool, boost::logic::tribool)': /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:78: ` struct boost::logic::tribool::dummy' is private /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:203: within this context /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:78: ` struct boost::logic::tribool::dummy' is private /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:203: within this context /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:78: ` struct boost::logic::tribool::dummy' is private /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:205: within this context /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:78: ` struct boost::logic::tribool::dummy' is private /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:205: within this context /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp: In function `boost::logic::tribool boost::logic::operator||(boost::logic::tribool, boost::logic::tribool)': /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:78: ` struct boost::logic::tribool::dummy' is private /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:270: within this context /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:78: ` struct boost::logic::tribool::dummy' is private /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:270: within this context /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:78: ` struct boost::logic::tribool::dummy' is private /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:272: within this context /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:78: ` struct boost::logic::tribool::dummy' is private /usr/local/eddynet/debug_eddynet/opt/include/boost/logic/tribool.hpp:272: within this context Locally I've worked around this with changing the first part of the tribool class from: class tribool { private: to class tribool { #ifdef __INSURE__ //Symbol defined by parser when used in this context public: #endif (no #else since private is implied) Anyway, I don't mind maintaining my own mods, just thought I'd report this. If you don't mind enlightening me, I am a little curious why using safe_bool works if its private on any compiler. Seems like private typedefs usually are private. Thanks, Tom