[GHC] #12620: Allow the user to prevent floating and CSE

[GHC]

#12620: Allow the user to prevent floating and CSE
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        Reporter:  nomeata           |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #9520, #8457      |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by jpbernardy):

 As it turns out, we currently have a proposal on the table which is
 capable of expressing where sharing should not occur, in a principled way,
 by using types.

 This page sums up how it may play out in Edsko's example.

 https://ghc.haskell.org/trac/ghc/wiki/LinearTypes/Examples#Controllingsharingfulllaziness

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12620#comment:20>
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