Simplifier bug(?)

Not sure if it is really a bug. I was playing around with the following infinite loop in GHC 7.6:

{-# LANGUAGE GADTs, KindSignatures #-}

data False

data I (c :: * -> *)

data R (c :: *) where
  R :: (a (I a) -> False) -> R (I a)

delta :: R (I R) -> False
delta = \ (R f) -> f (R f)

omega :: False
omega = delta (R delta)

main :: IO ()
main = seq omega (return ())

And I got the following result. It's supposed to be an infinite loop, though, so maybe it is ok. GHC 7.4 just hangs on this example.

spaceman:haskell sweirich$ ghc inj4.hs
[1 of 1] Compiling Main             ( inj4.hs, inj4.o )
ghc: panic! (the 'impossible' happened)
  (GHC version 7.6.1 for i386-apple-darwin):
	Simplifier ticks exhausted
    When trying UnfoldingDone main:Main.$WR{v reV} [gid[DataConWrapper]]
    To increase the limit, use -fsimpl-tick-factor=N (default 100)
    If you need to do this, let GHC HQ know, and what factor you needed
    To see detailed counts use -ddump-simpl-stats
    Total ticks: 5160

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

Trac metadata

Trac field	Value
Version	7.6.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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