[GHC] #8856: ScopedTypeVariables & PolyKinds lead to weird error message

[GHC]

#8856: ScopedTypeVariables & PolyKinds lead to weird error message
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        Reporter:  goldfire          |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  Compiler          |          Version:  7.8.1-rc2
      Resolution:                    |         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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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"cf1a0f971966af633fbd932ad012ce716680465b/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="cf1a0f971966af633fbd932ad012ce716680465b"
 Fix the treatment of lexically scoped kind variables (Trac #8856)

 The issue here is described in Note [Binding scoped type variables] in
 TcPat.  When implementing this fix I was able to make things quite a
 bit simpler:
  * The type variables in a type signature now never unify
    with each other, and so can be straightfoward skolems.
  * We only need the SigTv stuff for signatures in patterns,
    and for kind variables.
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8856#comment:1>
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