[GHC] #15664: Core Lint error

[GHC]

#15664: Core Lint error
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        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.6.1-beta1
      Resolution:                    |             Keywords:  TypeInType
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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Comment (by monoidal):

 A bit shorter version:

 {{{
 {-# Language RankNTypes, TypeOperators, DataKinds, PolyKinds, GADTs,
 TypeInType, TypeFamilies #-}

 {-# Options_GHC -dcore-lint #-}

 import Data.Kind

 type family Apply (f :: Type) :: Type

 type F f = forall x. x

 unravel :: F Apply
 unravel = unravel
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15664#comment:2>
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