[GHC] #10432: panic with kind polymorphism

[GHC]

#10432: panic with kind polymorphism
-------------------------------------+-------------------------------------
        Reporter:  Ashley Yakeley    |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  7.10.1
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
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Comment (by simonpj):

 It does not work in HEAD for me.  I get
 {{{
 simonpj at cam-05-unx:~/tmp$ ~/5builds/HEAD-4/inplace/bin/ghc-stage1 -c
 -dcore-lint T10432.hs
 RAE1
   [W] cobox_arV :: ka1_arO[sk] ~ kb1_arP[sk] (CNonCanonical)
   ka1_arO[sk]
   kb1_arP[sk]
   False

 T10432.hs:17:15: error:
     Couldn't match kind ‘ka1’ with ‘kb1’
       ‘ka1’ is untouchable
         inside the constraints: 'WrapType a1 ~ 'WrapType b1
         bound by the type signature for:
                    foo :: ('WrapType a1 ~ 'WrapType b1) => r1
         at T10432.hs:17:15-46ghc-stage1: panic! (the 'impossible'
 happened)
   (GHC version 7.11.20151006 for x86_64-unknown-linux):
         No skolem info: kb1_arP[sk]
 }}}
 for the code in comment:1

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10432#comment:3>
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