Comment by mikestew
When I saw "Turkish alphabet bug", I just knew it was some version of toLower() gone horribly wrong.
(I'm sure there's a good reason, but I find it odd that compiler message tags are invariably uppercase, but in this problem code they lowercased it to go do a lookup from an enum of lowercase names. Why isn't the enum uppercase, like the things you're going to lookup?)
With Turkish you can't safely case-fold with toupper() or tolower() in a C/US locale: i->I and I->i are both wrong. Uppercasing wouldn't work. You have to use Unicode or Latin-5 to manage it.