[GHC] #11405: Incorrect failure of type-level skolem escape check

[GHC]

#11405: Incorrect failure of type-level skolem escape check
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           Reporter:  goldfire       |             Owner:  goldfire
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.1
           Keywords:  TypeInType     |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 From Phab:D1739.

 When you say

 {{{
 undefined :: forall (v :: Levity). forall (a :: TYPE v). (?callStack ::
 CallStack) => a
 }}}

 you get a skolem escape failure because GHC things that the kind of
 `(?callStack :: CallStack) => a` is `TYPE v`. It should be `*`.

 I will fix.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11405>
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