repeatable instance of "impossible" error

Hello again,

I have a case that produces the:

ghc-6.4.1: ghc-6.4.1: panic! (the `impossible' happened, GHC version 6.4.1):
       unknown exception

Please report it as a compiler bug to glasgow-haskell-bugs@xxxxxxxxxxx,
or http://sourceforge.net/projects/ghc/.

message.  This is repeatable.  I've saved a tar of this directory; 
contact me if the directory image is needed.


Seth Kurtzberg