[boost] [contract] a possible future extension

Hi Lorenzo, This is definitely outside the scope of the review, but I was wondering whether it would be feasible for the macros in Boost.Contract to handle base class aliases, as described in this proposal: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2881.html The positive "side effect" of your framework is that it has the potential to add various missing language features. I am wondering if these aliases proposed in N2881 are worth the effort. Regards, &rzej