[eru]

Template metaprogramming makes things harder, but even in the most boring C++ hello world program, you have someone misusing a bit-shift operator for IO.

Concepts would presumably enforce some kind of thematic relationship between different overloads for the same group of functions and operators. (At least that's how we are doing it in Haskell with typeclasses. But we have a more forgiving syntax that allows us to make new operators.)