Jonathan Turkanis wrote:

...

Defining BOOST_MPL_METAFUNCTION_MAX_ARITY together with BOOST_MPL_NO_PREPROCESSED_HEADERS the should do it. If not, it's a bug. I'll check if that's the case with the current CVS state.

Thanks. FYI I got the errors with VC7.1.

These were caused by a hard-coded 'bind' specialization in the "if.hpp" header. The code fails only if you disable the preprocessed headers _and_ reconfigure the arity, while the usual testing procedure was to test only with BOOST_MPL_NO_PREPROCESSED_HEADERS, and that's why the regression hasn't been caught earlier. Fixed in the main trunk. Thanks for reporting it, -- Aleksey Gurtovoy MetaCommunications Engineering