[GHC] #15795: Core lint error with visible kind patterns

[GHC]

#15795: Core lint error with visible kind patterns
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        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.6.1
      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):

 Smaller version:

 {{{
 #!haskell
 {-# Language    RankNTypes       #-}
 {-# Language    PolyKinds        #-}
 {-# Language    GADTs            #-}
 {-# Options_GHC -dcore-lint      #-}

 module DF where
 import Data.Kind

 data F :: forall (cat1 :: ob1). ob1 -> Type where
   Prod :: F (a :: u)
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15795#comment:2>
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