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

> Compiling LinOpt           ( Linear_opt.hs, interpreted )
> ghc-5.04.2: panic! (the `impossible' happened, GHC version 5.04.2):
>         nameModule a{-roJC-}
> 
> Please report it as a compiler bug to
> glasgow-haskell-bugs@xxxxxxxxxxx,
> 
> My module contains newly the deriving clause - well it was an 
> experiment:
> 
> newtype Matrix a i e = Matrix (a i (a i e))$
>         deriving (IArray a e)$

I believe this bug was fixed in a later version.  Could you try 6.2 and
let us know if that helps?

Cheers,
        Simon