[GHC] #12926: ghc master (8.1.20161202) panics with assertion failure with devel2 flavor and -O2

[GHC]

#12926: ghc master (8.1.20161202) panics with assertion failure with devel2 flavor
and -O2
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        Reporter:  pacak             |                Owner:
            Type:  bug               |               Status:  infoneeded
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by bgamari):

 * status:  new => infoneeded
 * milestone:   => 8.2.1


Comment:

 What commit is this from?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12926#comment:1>
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