The Haskell package imports syntax (documented in [http://haskell.org/ghc/docs/6.12.2/html/users_guide/syntax-extns.html#package-imports here in the GHC manual]) is highlighted wrong. Pygments thinks there's an error at the first " and the rest of the document comes out coloured as a string:
import "mtl" Control.Monad.Trans
main :: IO ()
main = putStrLn "hello world"
Reported by guest