As we tried to update to 1.35 today, we found some warnings with MSVC on Warning Level 4 in: lexical_cast: There was a return statement after a call to throw_exception which causes a unreachable code warning. I can see no problem by just removing that return. see http://svn.boost.org/trac/boost/ticket/1791 concept_check: BOOST_concept(SGIAssignable,(TT)) causes two warnings: C4510: default constructor could not be generated C4610: object 'class' can never be instantiated - user-defined constructor required solved thorugh pragmas see http://svn.boost.org/trac/boost/ticket/1792 and an error in range/iterator_range: see http://svn.boost.org/trac/boost/ticket/1793 for details. The patch is attached, as I was not able to discuss with Akismet that it's no spam ;) "Submission rejected as potential spam (Akismet says content is spam)" cheers, stephan