[GHC] #8848: Warning: Rule too complicated to desugar

[GHC]

#8848: Warning: Rule too complicated to desugar
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        Reporter:  carter            |                   Owner:
            Type:  bug               |                  Status:  closed
        Priority:  normal            |               Milestone:  7.10.1
       Component:  Compiler          |                 Version:  7.8.1-rc2
      Resolution:  fixed             |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |  simplCore/should_compile/T8848,
                                     |  T8848a
                                     |                Blocking:
                                     |  Differential Revisions:
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Comment (by simonpj):

 I don't think that comment:12 has much to do with this ticket although
 it's hard to tell without a repro case.

 It's easy to make GHC diverge using rules.  Most crudely
 {{{
 {-# RULE map2 = map2 #-}
 }}}
 would do it, by making the rule fire repeatedly.  Your code looks sort of
 like that, although as I say it is hard to tell.

 You can see more of what is happening with `-ddump-inlinings` and `-ddump-
 rule-firings`.

 For now I think this probably a user error.

 Simon

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8848#comment:16>
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