[GHC] #9390: Inlining prevents evaluation of ignored parts of unboxed tuples

[GHC]

#9390: Inlining prevents evaluation of ignored parts of unboxed tuples
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              Reporter:  snoyberg    |            Owner:
                  Type:  bug         |           Status:  merge
              Priority:  normal      |        Milestone:  7.8.4
             Component:  Compiler    |          Version:  7.8.3
            Resolution:              |         Keywords:
      Operating System:  Linux       |     Architecture:  x86_64 (amd64)
       Type of failure:  Incorrect   |       Difficulty:  Unknown
  result at runtime                  |       Blocked By:
             Test Case:              |  Related Tickets:
  simplCore/should_run/T9390         |
              Blocking:              |
Differential Revisions:              |
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Comment (by snoyberg):

 Thanks for the review, and enjoy the vacation. Some responses:

 * I've added a note to myself to send a pull request on the documentation
 of `seq` next week.
 * I've updated the text as you indicated.
 * Thank you for clarifying. I've left the example that I originally had,
 but instead of saying "this will work too," it says "you might think this
 will work, but due to inlining, it won't."
 * I'm confused about this last part, because the situation I'm describing
 seems to be *exactly* the bug that Carter reports in comment 2. Your
 explanation here implies to me that we never really fully explained why
 Carter's code is acting as it does, though I can guess that it is in fact
 another manifestation of this bug.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9390#comment:23>
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