[GHC] #11414: Panic with -XStrict: StgCmmEnv: variable not found

[GHC]

#11414: Panic with -XStrict: StgCmmEnv: variable not found
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        Reporter:  thomie            |                Owner:
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.11
      Resolution:                    |             Keywords:  Strict
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:  T11414
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by bgamari):

 It appears that the issue is introduced quite early in compilation as the
 output from desugaring fails core lint,
 {{{
 *** Core Linted result of Desugar (after optimization):
 *** Core Lint errors : in result of Desugar (after optimization) ***
 <no location info>: warning:
     In the expression: (\ (@ a_aKO) -> undefined)
                          @ a_aKO @ 'Lifted @ a_aKO $dIP_aKQ
     $dIP_aKQ :: ?callStack::CallStack
     [LclId, Str=DmdType] is out of scope
 *** Offending Program ***
 main :: IO ()
 [LclIdX, Str=DmdType]
 main =
   $ @ 'Lifted
     @ Bool
     @ (IO ())
     (print @ Bool $fShowBool)
     (case \ (@ a_aKO) ->
             (\ (@ a_aKO) -> undefined) @ a_aKO @ 'Lifted @ a_aKO $dIP_aKQ
      of _ [Occ=Dead] { __DEFAULT ->
      True
      })

 main :: IO ()
 [LclIdX, Str=DmdType]
 main = runMainIO @ () main

 $trModule :: Module
 [LclIdX[ReflectionId], Str=DmdType]
 $trModule = Module (TrNameS "main"#) (TrNameS "Main"#)

 *** End of Offense ***
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11414#comment:4>
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