[GHC] #15628: Higher-rank kinds

[GHC]

#15628: Higher-rank kinds
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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:
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 simonpj):

 Instantiating a polymorphic type variable with a polytype (or polykind) is
 called "imprediative polymorphism" and is a swamp.  GHC just does not have
 a decent story at the moment.  But I think that is what you are asking
 for.

 But see https://www.microsoft.com/en-us/research/publication/guarded-
 impredicative-polymorphism/ (PLDI'18).

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15628#comment:1>
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