ghc-6.6: panic! (the 'impossible' happened)

[Jared Updike]

ghc-6.6: panic! (the 'impossible' happened)
  (GHC version 6.6 for i386-apple-darwin):
        checkKind: adding kind constraint
    t{tv a2M5} [tv] *
    t_a1pL{tv} [tau] t_a1pL{tv} [tau] ??

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
---------------

If you want the code that can cause this to happen on a Mac, let me
know, just thought I'd report this since GHC said to.

  Jared.