Keep in mind that in general that approach only works if you assume the template parameters are exactly the tuple types. Any extra parameters (or different repr

Keep in mind that in general that approach only works if you assume the template parameters are exactly the tuple types. Any extra parameters (or different representation) would make it not work. In general you don't want to use template template parameters because of this. It's analogous to depending on the physical layout of a struct rather than the names of its members.