Exotic form of kind ghc-prim:GHC.Prim.?{(w) tc 34g}

with this code here:

https://gist.github.com/1115357

I was able to produce this panic in ghci:

/home/alios/tmp/foo.hs:19:12:ghc: panic! (the 'impossible' happened)
  (GHC version 7.0.4 for i386-unknown-linux):
	Exotic form of kind ghc-prim:GHC.Prim.?{(w) tc 34g}

Trac metadata

Trac field	Value
Version	7.0.4
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
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Blocking
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Exotic form of kind ghc-prim:GHC.Prim.?{(w) tc 34g}