[GHC] #8893: -XPolyKinds causes "*** Exception: Prelude.(!!): index too large"

[GHC]

#8893: -XPolyKinds causes "*** Exception: Prelude.(!!): index too large"
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        Reporter:  ghorn               |            Owner:
            Type:  bug                 |           Status:  new
        Priority:  normal              |        Milestone:
       Component:  Compiler            |          Version:  7.8.1-rc2
      Resolution:                      |         Keywords:  PolyKinds
Operating System:  Unknown/Multiple    |     Architecture:
 Type of failure:  Compile-time crash  |  Unknown/Multiple
       Test Case:                      |       Difficulty:  Unknown
        Blocking:                      |       Blocked By:
                                       |  Related Tickets:
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Comment (by simonpj):

 Yes I'm on this.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8893#comment:3>
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