[GHC] #6024: Allow defining kinds alone, without a datatype

[GHC]

#6024: Allow defining kinds alone, without a datatype
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        Reporter:  dreixel           |                Owner:
            Type:  feature request   |               Status:  infoneeded
        Priority:  normal            |            Milestone:  8.0.1
       Component:  Compiler (Type    |              Version:  7.5
  checker)                           |
      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 goldfire):

 Yes, though it's a shade less useful. Types and kinds are indeed the same
 now, but terms are not. I see this ticket as a request for an ability to
 define a datatype whose constructors are defined only in types, never in
 terms. From a user standpoint, this ticket is largely unaffected by
 type=kind.

 It's a shade less useful because you can now say

 {{{#!hs
 data Foo = MkFoo1 Type   -- Type is a.k.a. *
          | MkFoo2 Int
 }}}

 so some of the motivation for kind-only has gone away. A kind-only
 definition would still prevent clients from constructing the object at
 runtime, though.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/6024#comment:12>
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