[GHC] #8120: ghc: panic! (the 'impossible' happened)

[GHC]

#8120: ghc: panic! (the 'impossible' happened)
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       Reporter:  EyalLotem         |             Owner:
           Type:  bug               |            Status:  new
       Priority:  normal            |         Milestone:
      Component:  Compiler          |           Version:  7.6.3
       Keywords:                    |  Operating System:  Unknown/Multiple
   Architecture:  Unknown/Multiple  |   Type of failure:  None/Unknown
     Difficulty:  Unknown           |         Test Case:
     Blocked By:                    |          Blocking:
Related Tickets:                    |
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 Foo.hs:6:3:ghc: panic! (the 'impossible' happened)
   (GHC version 7.6.3 for i386-unknown-linux):
         kindFunResult ghc-prim:GHC.Prim.*{(w) tc 34d}

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

 The source file has to contain, merely:

 {{{
 l :: m a -> t m a
 l = undefined

 f :: a -> f b
 f = do
   x <- undefined
   l $ x undefined

 main = return ()
 }}}

 This panic reproduces on at least: 7.6.1, 7.6.2, 7.6.3.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8120>
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