[GHC] #15591: Inconsistent kind variable binder visibility between associated and non-associated type families

[GHC]

#15591: Inconsistent kind variable binder visibility between associated and non-
associated type families
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.5
      Resolution:                    |             Keywords:
                                     |  TypeApplications, TypeFamilies
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):

 Let's agree the specification first.  In this declaration
 {{{
 class C (a :: Type) where
   type T2 (x :: f a)
 }}}
 Then `a` is `Required` for `C`, but presumably it is only `Specified` for
 `T2`?

 And what are the rules for Required/Specified/Inferred for type/class
 declarations that do not have a CUSK?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15591#comment:4>
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