[GHC] #15175: ghc: panic! (the 'impossible' happened)

[GHC]

#15175: ghc: panic! (the 'impossible' happened)
-------------------------------------+-------------------------------------
        Reporter:  MADjestic         |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.0.2
      Resolution:                    |             Keywords:
Operating System:  Linux             |         Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by sighingnow):

 The code lint error message:

 {{{
 λ inplace\bin\ghc-stage2.exe --make ObjectBehavior.hs -dcore-lint -fforce-
 recomp
 [1 of 1] Compiling ObjectBehavior   ( ObjectBehavior.hs, ObjectBehavior.o
 )
 *** Core Lint errors : in result of Desugar (before optimization) ***
 <no location info>: warning:
     In the expression: $WPoint2
                          @ Double
                          $dRealFloat_a2Zv
                          (x_a1iF @ Double)
                          (+ @ Double
                             $dNum_a2Zy
                             y0_a1iC
                             (/ @ Double $dFractional_a2ZA (D# 0.0##) (D#
 2.0##)))
     $dRealFloat_a2Zv :: RealFloat Double
     [LclId] is out of scope
 <no location info>: warning:
     In the expression: + @ Double
                          $dNum_a2Zy
                          y0_a1iC
                          (/ @ Double $dFractional_a2ZA (D# 0.0##) (D#
 2.0##))
     $dNum_a2Zy :: Num Double
     [LclId] is out of scope
 *** Offending Program ***
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15175#comment:2>
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