[GHC] #11371: Bogus in-scope set in substitutions

[GHC]

#11371: Bogus in-scope set in substitutions
-------------------------------------+-------------------------------------
        Reporter:  simonpj           |                Owner:  niteria
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #11360            |  Differential Rev(s):  phab:D1792,
       Wiki Page:                    |  phab:D1801, phab:D1802
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Comment (by niteria):

 I got 2 traces
 {{{
 CallStack (from HasCallStack):
   pprSTrace, called at compiler/coreSyn/CoreSyn.hs:1595:33 in ghc:CoreSyn
   exprToType2, called at compiler/coreSyn/CoreSyn.hs:1585:53 in
 ghc:CoreSyn
   applyTypeToArg2, called at compiler/simplCore/SimplUtils.hs:251:37 in
 ghc:SimplUtils
   addValArgTo, called at compiler/simplCore/Simplify.hs:1114:57 in
 ghc:Simplify
   rebuild, called at compiler/simplCore/Simplify.hs:1477:5 in ghc:Simplify
   rebuildCall, called at compiler/simplCore/Simplify.hs:1406:11 in
 ghc:Simplify
   bad $fMonadIO

 CallStack (from HasCallStack):
   pprSTrace, called at compiler/coreSyn/CoreSyn.hs:1595:33 in ghc:CoreSyn
   exprToType2, called at compiler/coreSyn/CoreSyn.hs:1585:53 in
 ghc:CoreSyn
   applyTypeToArg2, called at compiler/simplCore/SimplUtils.hs:251:37 in
 ghc:SimplUtils
   addValArgTo, called at compiler/simplCore/Simplify.hs:1468:28 in
 ghc:Simplify
   rebuildCall, called at compiler/simplCore/Simplify.hs:1446:5 in
 ghc:Simplify
   rebuildCall, called at compiler/simplCore/Simplify.hs:1406:11 in
 ghc:Simplify
   bad Permute @ Flag
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11371#comment:39>
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