[GHC] #10999: ghc: panic! (the 'impossible' happened)

[GHC]

#10999: ghc: panic! (the 'impossible' happened)
-------------------------------------+-------------------------------------
           Reporter:  res            |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  7.10.2
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  Compile-time
  Unknown/Multiple                   |  crash
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 The attached program elicits the following error from GHC 7.10.2:

 {{{
     Couldn't match type ‘a’ with ‘(t0, t1, t2)’
       ‘a’ is untouchable
         inside the constraints ()
         bound by the inferred type of
                  updateKeytab :: FilePath -> Handle -> IO ()
         at /u/res/g/src/remctl-tools/foo.hs:(58,1)-(69,26)ghc: panic! (the
 'impossible' happened)
   (GHC version 7.10.2 for x86_64-unknown-linux):
         No skolem info: a_akOb[sk]

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

 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10999>
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