[GHC] #15979: Core Lint error with LiberalTypeSynonyms

[GHC]

#15979: Core Lint error with LiberalTypeSynonyms
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.8.1
       Component:  Compiler          |              Version:  8.6.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by RyanGlScott):

 This //passes// `-dcore-lint`, however:

 {{{#!hs
 {-# LANGUAGE RankNTypes #-}
 module Works where

 f :: (forall. Maybe) a
 f = Nothing
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15979#comment:6>
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