[GHC] #15193: QSem makes nonsense claim

[GHC]

#15193: QSem makes nonsense claim
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        Reporter:  dfeuer            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Core Libraries    |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Documentation     |  Unknown/Multiple
  bug                                |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonmar):

 `takeMVar` does serve threads in FIFO order, although the semantics
 doesn't require it. I think we'd be unlikely to ever break this property,
 because I suspect there are things depending on it (like `QSem`).

 What is it about "first in" with respect to QSem that's problematic?

 What does `TSem` have to do with this?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15193#comment:2>
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