[GHC] #10618: HEAD at d71b65f53a panics: ``get_op (--$)''

[GHC]

#10618: HEAD at d71b65f53a panics: ``get_op (--$)''
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        Reporter:  bjmprice          |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:  7.12.1
       Component:  Compiler (Type    |                 Version:  7.11
  checker)                           |                Keywords:
      Resolution:                    |            Architecture:
Operating System:  Unknown/Multiple  |  Unknown/Multiple
 Type of failure:  Compile-time      |               Test Case:
  crash                              |                Blocking:
      Blocked By:                    |  Differential Revisions:
 Related Tickets:                    |
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Changes (by thomie):

 * cc: simonpj (added)
 * os:  Linux => Unknown/Multiple
 * component:  Compiler => Compiler (Type checker)
 * architecture:  x86_64 (amd64) => Unknown/Multiple
 * milestone:   => 7.12.1


Comment:

 Smaller example that fails: `ghc-stage2 -e 'Just $ Nothing <> Nothing'`

 I bisected it down to the following commit:
 fb7b6922573af76a954d939c85e6af7c39a19896 (#10569).

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10618#comment:1>
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