Hi Lorenzo,
1) I'd add something like this for each STL container that defines an operator==:
template< typename T, class Alloc = std::allocator<T> > struct has_equal_to< std::vector<T, Alloc> > : has_equal_to<T> {};
Halas, it is a bit more complicated because the operator traits have in fact 3 arguments: template <class Lhs, class Rhs=Lhs, class Ret=dont_care> struct has_equal_to : public true_type-or-false_type {}; So we have to deal with left hand side and right hand side case + return type. For Lhs and Rhs arguments, it is easy because we just have to deal with Lhs=Rhs. It is a bit more tricky with the return type. We also have to deal with const volatile and references. + update of <boost/detail/container_fwd.hpp> + detailed testing. I fear this is too much for 1.50 but we may plan for 1.51? It would be a good idea to have this working. Frédéric