[GHC] #12045: Visible kind application

[GHC]

#12045: Visible kind application
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        Reporter:  Iceland_jack      |                Owner:  Iceland_jack
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
                                     |  TypeApplications TypeInType
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  ​Phab:D2216
       Wiki Page:                    |
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Comment (by Iceland_jack):

 We can rewrite

 {{{#!hs
 type Typeable1 (a :: Type -> Type)                 = Typeable a
 type Typeable2 (a :: Type -> Type -> Type)         = Typeable a
 type Typeable3 (a :: Type -> Type -> Type -> Type) = Typeable a
 ...
 }}}

 as the more natural

 {{{#!hs
 type Typeable1 = Typeable @(Type -> Type)
 type Typeable2 = Typeable @(Type -> Type -> Type)
 type Typeable3 = Typeable @(Type -> Type -> Type -> Type)
 ...
 }}}

 which is how it appears in

 > {{{#!hs
 > type Typeable1 = Typeable @(* -> *)
 > }}}
 > — ExplicitTypeApplication#Typekindinstantiationinclasses

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12045#comment:13>
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