[GHC] #14375: Implement with# primop

[GHC]

#14375: Implement with# primop
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        Reporter:  simonpj           |                Owner:  bgamari
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.8.1
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:  JoinPoints
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #14346, #16098    |  Differential Rev(s):  ​Phab:D4110
       Wiki Page:                    |
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Comment (by osa1):

 I just saw the [https://phabricator.haskell.org/D4110#148654 last comment]
 in Phab:D4110 which implements the new `with#` primop without (2). Do we
 want to focus on #16098 first? Pinging simonpj, simonmar, bgamari.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14375#comment:26>
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