[GHC] #9123: Need for higher kinded roles

[GHC]

#9123: Need for higher kinded roles
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        Reporter:  simonpj           |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  Compiler          |          Version:  7.8.2
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by ekmett):

 Let's remove `join` from `Monad` for now, and see if we can't resolve this
 issue before we're forced to release.

 That lets GND work for `Monad`, which I agree is critical; it is a very
 common idiom to hide `transformers` monads inside a newtype wrapper and
 derive `Monad` and the related mtl instances and I'd hate to lose that.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9123#comment:14>
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