[GHC] #15264: Warn about implicit kind variables with -Wcompat

[GHC]

#15264: Warn about implicit kind variables with -Wcompat
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        Reporter:  int-index         |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  high              |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.5
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Poor/confusing    |  Unknown/Multiple
  error message                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by goldfire):

 Missing the 8.6 window with this doesn't change the release time for the
 rest of that patch. By all means try to get this one in, but there's no
 fire here -- we have no formal contract with users about `-Wcompat`.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15264#comment:1>
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