data T = () crash

This program causes HEAD from 15 May to crash:

         data T = ()
         main = undefined

paprika$ ghc t.hs
        ghc-6.3: panic! (the `impossible' happened, GHC version 6.3):
                ASSERT failed! file rename/RnEnv.lhs, line 79

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

The code was generated by an incorrect sed pass over a source file :}

-- Don