Hi,
I typed:
ghc Main.hs
and then GHC said:
GHC.EXE: panic! (the `impossible' happened, GHC version 5.02.2):
Maybe.fromJust: Nothing
Please report it as a compiler bug to glasgow-haskell-bugs at haskell.org,
or http://sourceforge.net/projects/ghc/.
-- Maarten