[GHC] #11142: Type-level skolem capture leads to core lint error

[GHC]

#11142: Type-level skolem capture leads to core lint error
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        Reporter:  goldfire          |                Owner:  bgamari
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.0.1
       Component:  Compiler (Type    |              Version:  7.10.2
  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):
       Wiki Page:                    |
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Changes (by simonpj):

 * owner:   => bgamari
 * priority:  normal => high
 * milestone:   => 8.0.1


Comment:

 Works fine with `wip/spj-wildcard-refactor`.  Ben please add this as a
 regression test.

 We get
 {{{
 $ ghc-stage1 -c T11142.hs  -dcore-lint -fforce-recomp -ddump-types
 TYPE SIGNATURES
   foo ::
     forall (k :: BOX) (b :: k). (forall (a :: k). SameKind a b) -> ()
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11142#comment:1>
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