[GHC] #8168: ghc "Simplifier ticks exhausted" "When trying UnfoldingDone"

[GHC]

#8168: ghc "Simplifier ticks exhausted" "When trying UnfoldingDone"
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       Reporter:  sp55aa             |             Owner:
           Type:  bug                |            Status:  new
       Priority:  high               |         Milestone:
      Component:  Compiler           |           Version:  7.6.3
       Keywords:  Simplifier,        |  Operating System:  Windows
  UnfoldingDone, simpl-tick-factor   |   Type of failure:  GHC rejects
   Architecture:  x86                |  valid program
     Difficulty:  Unknown            |         Test Case:
     Blocked By:                     |          Blocking:
Related Tickets:                     |
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 ghc fail to compile this file:

 ---- begin Y.hs ----
 newtype Rec a = Rec { unRec :: Rec a -> a }

 y :: (a -> a) -> a
 y = \f -> (\x -> f (unRec x x)) (Rec (\x -> f (unRec x x)))

 foo :: (a -> a) -> a -> a
 foo f n = f n

 main = print $ y foo 4
 ---- end Y.hs ----

 C:\Users\user\Desktop>ghc Y.lhs
 [1 of 1] Compiling Main             ( Y.lhs, Y.o )
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.6.3 for i386-unknown-mingw32):
         Simplifier ticks exhausted
     When trying UnfoldingDone a_sqe{v} [lid]
     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: 5601

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

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8168>
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