[GHC] #11621: GHC doesn't see () as a Constraint in type family

[GHC]

#11621: GHC doesn't see () as a Constraint in type family
-------------------------------------+-------------------------------------
        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  7.10.1
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #11715            |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by RyanGlScott):

 * related:   => #11715


Comment:

 Replying to [comment:3 spacekitteh]:
 > Has this been fixed?

 No.

 {{{
 GHCi, version 8.3.20170516: http://www.haskell.org/ghc/  :? for help
 Loaded GHCi configuration from /home/rgscott/.ghci
 [1 of 1] Compiling Main             ( Bug.hs, interpreted )

 Bug.hs:10:14: error:
     • Expected a constraint, but ‘()’ has kind ‘*’
     • In the type ‘()’
       In the type family declaration for ‘F’
    |
 10 |   F 'True  = ()
    |              ^^
 }}}

 Again, this probably requires fixing #11715 first.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11621#comment:4>
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