[darrencauthon]

This mistake shouldn't happen?

Mistakes always happen. Even if I dedicated myself to using braces everywhere, my mistake might be that a) I put the braces in the wrong place, or b) I forgot to put the braces.

[Jtsummers]

Shouldn't != couldn't. In Haskell and the MLs, for instance, certain classes of mistakes shouldn't happen because of the type system and pattern matching, but a single wildcard could throw that off.