[GHC] #12368: Demand Analyzer: Cunnig plan not adhered to with aborting fixpoint interation

[GHC]

#12368: Demand Analyzer: Cunnig plan not adhered to with aborting fixpoint
interation
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        Reporter:  nomeata           |                Owner:
            Type:  bug               |               Status:  patch
        Priority:  low               |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2392
       Wiki Page:                    |
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Comment (by simonpj):

 Yes that's the reason for the lazy_fv fuss!  But that fuss is needed even
 when we do find a fixpoint.

 >  What about demand and strictness signatures attached to binders
 somewhere nested in the RHS of one of the equation. Should we zap them as
 well?

 Ah, now that is an excellent point!  Which should be carefully documented
 in a Note, eventually

 Yes ok.  (I was not fussed about an extra iteration, just about clarity.)
 Let's do one more iteration.  But we can do that simply with the original,
 unextended environment. I htink there is no need to do
 `addPessimisticSigs`.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12368#comment:10>
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