ghc-5.04.2: panic! (the `impossible' happened, GHC version 5.04.2):

class Foo a where foo :: a -> ()

data Bar = Bar { bar :: () }

instance Foo Bar where foo = bar

test :: Bar
test = undefined { foo = () }


the last line should be rejected, since there is no `foo' in `Bar'. 

ghc-5.04.2: panic! (the `impossible' happened, GHC version 5.04.2):
        tcSplitTyConApp a{-rY6-}

best regards,
-- 
-- Johannes Waldmann ---- http://www.informatik.uni-leipzig.de/~joe/ --
-- joe@xxxxxxxxxxxxxxxxxxxxxxxxx -- phone/fax (+49) 341 9732 204/207 --