Impossible happens thanks to GHC 7.7

[TomMD]

Do you think this is a GHC-HQ bug or ours?

ghc-stage1: panic! (the 'impossible' happened)
  (GHC version 7.7.20140129 for x86_64-unknown-HaLVM):
        tcIfaceGlobal (local): not found:
    base:Control.Applicative.$fApplicativeWrappedMonad{v ri}
    [(0c7, Identifier ‛base:Control.Applicative.<*>{v 0c7}’),
     (0c8, Identifier ‛base:Control.Applicative.pure{v 0c8}’),
     (0c9, Class ‛base:Control.Applicative.Alternative{tc 0c9}’),
     (2y, Class ‛base:Control.Applicative.Applicative{tc 2y}’),
     (rE,
      Data constructor ‛base:Control.Applicative.D:Alternative{d rE}’),
     (r1J,
      Coercion axiom ‛base:Control.Applicative.NTCo:ZipList{tc r1J}’),
     (r2K,
      Coercion axiom ‛base:Control.Applicative.NTCo:Const{tc r2K}’),
     (r3c,
      Coercion axiom ‛base:Control.Applicative.NTCo:WrappedMonad{tc r3c}’),
     (r3i,
      Coercion axiom ‛base:Control.Applicative.NTCo:WrappedArrow{tc r3i}’),
     (r3T,
      Data constructor ‛base:Control.Applicative.D:Applicative{d r3T}’),
     (r45, Identifier ‛base:Control.Applicative.$p1Applicative{v r45}’),
     (r46, Identifier ‛base:Control.Applicative.$p1Alternative{v r46}’),
     (r4a, Identifier ‛base:Control.Applicative.getZipList{v r4a}’),
     (r4b, Data constructor ‛base:Control.Applicative.ZipList{d r4b}’),
     (r4c, Type constructor ‛base:Control.Applicative.ZipList{tc r4c}’),
     ...

[acw]

I would tend to think that's an upstream problem. Is the problem repeatable with a similar version of HEAD? If not, I can do an upstream merge and see if that fixes it.