I kind of agree. The worst part is that most of the problems with C++'s classic "typesafe_printf" implementation come from the fact that there is an extra pass

I kind of agree. The worst part is that most of the problems with C++'s classic "typesafe_printf" implementation come from the fact that there is an extra pass over the formatting string in order to do the actual typecheck. But this rust implementation does not have this problem (no type specifiers in the format string, just placeholders as in {fmt}), and it still looks pretty ugly (and when your reference is a ugly C++ metaprogramming version, that says something).