[GHC] #15658: strange inferred kind with TypeInType

[GHC]

#15658: strange inferred kind with TypeInType
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        Reporter:  dmwit             |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.4.2
      Resolution:                    |             Keywords:  TypeInType,
                                     |  GHCProposal
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 dmwit):

 I agree: it should be documented with some care. Here is another case
 worth discussing when writing the documentation.

 If I try to follow your reasoning for a modified type family, say:

 {{{
 type family G a :: a
 }}}

 I reason that it should be:

 {{{
 G :: forall (a :: *) -> a
 }}}

 So without the explicit kinding, I would expect ghci to give `G` the kind
 `forall a -> a`. But ghci does not agree:

 {{{
 > :k G
 G :: a
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15658#comment:2>
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