[boost] [type_erasure]any(const binding<Concept>&, ...) compile error

The attached, when compiled with with gcc4.8-20120624, produces compile error: ../../../boost/type_erasure/detail/construct.hpp: In instantiation of 'boost::type_erasure::any<Concept, T>::any(const boost::type_erasure::binding<Concept>&, U0&) [with U0 = value<boost::type_erasure::_a>; Concept = boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_a>, boost::type_erasure::copy_constructible<boost::type_erasure::_b> >; T = boost::type_erasure::_a]': binding_of.cpp:71:32: required from here ../../../boost/type_erasure/detail/construct.hpp:99:9: error: invalid use of void expression ) ^ Am I doing something wrong? TIA. -Larry