[GHC] #14917: Allow levity polymorphism in binding position

[GHC]

#14917: Allow levity polymorphism in binding position
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        Reporter:  andrewthad        |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
                                     |  LevityPolymorphism
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 sgraf):

 Another place where this could be useful is for abstracting the pattern in
 [https://hackage.haskell.org/package/base-4.11.0.0/docs/src/GHC.Enum.html#efdtIntUpFB
 efdt{Word,Int}{Up,Dn}FB].

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14917#comment:17>
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