[GHC] #11376: Inconsistent specified type variables among functions and datatypes/classes when using -XTypeApplications

[GHC]

#11376: Inconsistent specified type variables among functions and datatypes/classes
when using -XTypeApplications
-------------------------------------+-------------------------------------
        Reporter:  RyanGlScott       |                Owner:  goldfire
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.1
  checker)                           |             Keywords:
      Resolution:                    |  TypeApplications
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Other             |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by kosmikus):

 I also noticed that
 {{{
 $ ghci -XTypeInType -XTypeApplications -XScopedTypeVariables -fprint-
 explicit-foralls
 GHCi, version 7.11.20151229: http://www.haskell.org/ghc/  :? for help
 Prelude> data Prox a = Prox
 Prelude> prox1 :: forall a . Prox a; prox1 = Prox
 Prelude> prox2 :: forall (a :: k) . Prox a; prox2 = Prox
 Prelude> :t prox1
 prox1 :: forall {k} (a :: k). Prox a
 Prelude> :t prox2
 prox2 :: forall k (a :: k). Prox a
 }}}

 Is this difference in treatment deliberate? I would have expected that for
 `k` to be explicit, I'd have to write
 {{{
 Prelude> prox3 :: forall k (a :: k). Prox a; prox3 = Prox
 }}}

 Is there a way to mention a type/kind variable but to still make it
 implicit?

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11376#comment:7>
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