[boost] [spirit] Causes a blizzard of warning from Boost.Format under MSVC?

I'm at a loss to explain this, but this program: #include <boost/math/special_functions.hpp> int main() { boost::math::erf(2); } Compiles cleaning with MSVC-8, but as soon as I add a particular spirit #include: #include <boost/math/special_functions.hpp> #include <boost/spirit/utility/distinct.hpp> int main() { boost::math::erf(2); } Then Boost.Format (used internally be Boost.Math for error message formatting) issues a whole blizzard of warnings, that I actually thought I had fixed. I've checked Spirit for mismatched #pragma push/pop declarations, but they all look OK to me. Does anyone have any ideas what may be going on here, 'cos I'm stumped and the warnings are really very annoying! Many thanks, John.