[GHC] #9103: hackage's type-level-0.2.4 fails to compile

[GHC]

#9103: hackage's type-level-0.2.4 fails to compile
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        Reporter:  slyfox            |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler (Type    |                 Version:  7.8.2
  checker)                           |                Keywords:
      Resolution:                    |            Architecture:
Operating System:  Unknown/Multiple  |  Unknown/Multiple
 Type of failure:  GHC rejects       |               Test Case:
  valid program                      |                Blocking:
      Blocked By:                    |  Differential Revisions:
 Related Tickets:  #8634             |
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Comment (by goldfire):

 My guess is that !PolyKinds is causing trouble in the not-promoted case.
 Do you have !PolyKinds enabled? Try running with `-fprint-explicit-kinds`.

 But, the "redundant constraint" warning is almost certainly wrong. I would
 post that as a separate bug, which we should try to fix by 7.10, I think.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9103#comment:8>
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