[GHC] #8913: either bug or confusing error message mixing PolyKinds and TypeFamilies

[GHC]

#8913: either bug or confusing error message mixing PolyKinds and TypeFamilies
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        Reporter:  ghorn             |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  Compiler (Type    |          Version:  7.8.1-rc2
  checker)                           |         Keywords:  PolyKinds,
      Resolution:                    |  TypeFamilies
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 Simon Peyton Jones <simonpj@…>):

 In [changeset:"c89c57e3b72a8f3de9f35e1bd6e0f70d2b18a941/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="c89c57e3b72a8f3de9f35e1bd6e0f70d2b18a941"
 For equalities with incompatible kinds, new IrredCan goes in the inert
 set, not work list

 This change makes the code for canIrred markedly simpler (and more
 efficient)
 See Note [Equalities with incompatible kinds].

 I don't think there was really a bug here, but I came across it when
 fixing Trac #8913
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8913#comment:4>
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