[GHC] #10527: Panic Simplifier ticks exhausted with type families

[GHC]

#10527: Panic Simplifier ticks exhausted with type families
-------------------------------------+-------------------------------------
        Reporter:  sopvop            |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  high              |               Milestone:  7.10.2
       Component:  Compiler          |                 Version:  7.10.1-rc1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
-------------------------------------+-------------------------------------
Changes (by thomie):

 * priority:  normal => high
 * milestone:   => 7.10.2


Comment:

 Confirmed regression from 7.10.1.

 {{{
 $ /opt/ghc/7.10.1/bin/ghc -O -fforce-recomp Bug.hs -fsimpl-tick-factor=50
 [1 of 1] Compiling Bug              ( Bug.hs, Bug.o )

 $ /opt/ghc/7.10.2/bin/ghc -O -fforce-recomp Bug.hs -fsimpl-tick-
 factor=5000
 [1 of 1] Compiling Bug              ( Bug.hs, Bug.o )
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.10.1.20150609 for x86_64-unknown-linux):
         Simplifier ticks exhausted
   When trying UnfoldingDone $fFunctorConst_$cfmap
   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: 11274000
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10527#comment:1>
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