Hi, I am writing some functions and classes that accept a sequence of type ( boost::mpl::vector/list currently) as template parameter. I'm looking for a way to enhance type checking by making sure the provided types are... type sequences. I didn't find anything relevant in standard or boost type_trait libraries. So far, I'm guessing there is no way to check that, mainly because such types would be template instances, which make checking this like checking if a type is an instance of a template which is impossible right now (as far as I know anyway). My question is: what are possible ways to enhance type checking on type sequence types? I know some boost developers around here make great efforts to make sure their meta programming libraries make early and good error reporting so maybe they have a solution? PS: I'm using Visual Studio 2012 so I can't use variadic template yet ;___; (can't rely on the CTP) Joel Lamotte