[GHC] #11714: Kind of (->) type constructor is overly constrained

[GHC]

#11714: Kind of (->) type constructor is overly constrained
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        Reporter:  bgamari           |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.1
      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 bgamari):

 As described in ticket:11011#comment:39, the current constrained kind of
 `(->)` causes Core lint violations on my `wip/ttypeable` branch. The Core
 lint violation in `T11120` mentioned  appears to be the result of `(->)`
 overly constrained kind when used in prefix position, `* -> * -> *`,
 {{{
     Kind application error in type ‘(->) Char#’
       Function kind = * -> * -> *
       Arg kinds = [(Char#, TYPE 'WordRep)]
 }}}
 Where this type appears in a use of `mkTrApp`,
 {{{#!hs
 mkTrApp @* @* @((->) Char#) @CharHash ...
 }}}
 which was produced as evidence for the `Typeable` representation for,
 {{{#!hs
 data CharHash = CharHash Char#
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11714#comment:1>
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