[GHC] #3100: GHC Panic "reifyType PredTy" in HAppS.Data.IxSet.inferIxSet

[GHC]

#3100: GHC Panic "reifyType PredTy" in HAppS.Data.IxSet.inferIxSet
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    Reporter:  mightybyte      |        Owner:         
        Type:  bug             |       Status:  new    
    Priority:  normal          |    Milestone:         
   Component:  Compiler        |      Version:  6.10.1 
    Severity:  minor           |   Resolution:         
    Keywords:                  |   Difficulty:  Unknown
    Testcase:                  |           Os:  Linux  
Architecture:  x86_64 (amd64)  |  
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Comment (by mightybyte):

 The new file I attached contains a workaround I found.  It seems like
 Happs(tack) may be at fault here, although GHC still panics, so I think
 something needs to be fixed in GHC as well.  I eliminated the inferIxSet
 call and substituted the code that I believe it should be generating.
 This got rid of the panic, so presumably the panic is being induced by
 something inferIxSet is doing and not it's generated code.  I'm not
 familiar with the details of inferIxSet, so unfortunately I can't give
 more help here.  With the workaround, the bug is no longer blocking my
 progress, so I downgraded it to minor.  Ultimately I think you would at
 least want to prevent GHC from panicing on this though.

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Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3100#comment:3>
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