[GHC] #9380: ghc generates seemingly incorrect code

[GHC]

#9380: ghc generates seemingly incorrect code
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              Reporter:  qnikst      |            Owner:
                  Type:  bug         |           Status:  infoneeded
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.3
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:  Incorrect   |       Blocked By:
  result at runtime                  |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by qnikst):

 There are few reasons for this report:

 1. Verify that this is a really wrong behaviour

 2. Make sure that fix will go into 7.8.4 if it will ever be

 3. Understand if it worth adding a regression test for the HEAD, in order
 track that behaviour will be correct.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9380#comment:2>
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