[GHC] #12583: Deriving standalone Ix instance for GADT leads to GHC panic

[GHC]

#12583: Deriving standalone Ix instance for GADT leads to GHC panic
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        Reporter:  RyanGlScott       |                Owner:
            Type:  bug               |               Status:  merge
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Compile-time      |            Test Case:
  crash                              |  deriving/should_compile/T12583
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2521
       Wiki Page:                    |
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Changes (by RyanGlScott):

 * status:  patch => merge
 * testcase:   => deriving/should_compile/T12583


Comment:

 The above two commits can be merged.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12583#comment:4>
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