Reify class instances

<interactive>:1:3:
    Exception when trying to run compile-time code:
      <interactive>: panic! (the 'impossible' happened)
  (GHC version 7.0.3 for i386-unknown-mingw32):
        reifyType PredTy
    <pred>base:GHC.Num.Num{tc 2b}
            integer-gmp:GHC.Integer.Type.Integer{tc 314}

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

      Code: (>>)
              (>>=)
                (>>=)
                  classInstances 'Num [Language.Haskell.TH.Syntax.ConT 'Integer]

                  (.) reify head
                (.) runIO print
              [| 0 |]
    In the expression:
      $(classInstances 'Num [ConT 'Integer] >>= reify . head
    >>= runIO . print
  >>
    [| 0 |])
    In an equation for `it':
        it
          = $(classInstances 'Num [ConT 'Integer] >>= reify . head
          >>= runIO . print
        >>
          [| 0 |])