[GHC] #11822: Pattern match checker exceeded (2000000) iterations

[GHC]

#11822: Pattern match checker exceeded (2000000) iterations
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        Reporter:  j.waldmann        |                Owner:  gkaracha
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1-rc3
      Resolution:                    |             Keywords:
                                     |  PatternMatchWarnings
Operating System:  Unknown/Multiple  |         Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 > Starting next week I will start spending time on it to see what can be
 done.

 George, how's it going?

 I've just noticed that in the compiler itself `PrelRules.hs` doesn't
 currently blow the limit, but the changes in [Phab:D2858] require `-fmax-
 pmcheck-iterations=6000000`.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11822#comment:21>
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