[GHC] #13227: Loss of full laziness in mapFB

[GHC]

#13227: Loss of full laziness in mapFB
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        Reporter:  simonpj           |                Owner:
            Type:  bug               |               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:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by nomeata):

 That reminds me of a question that I had a long time: What is the precise
 semantics of `ProbOneShot`? I only understand `OneShot`…

 I read `Note [Computing one-shot info, and ProbOneShot]` and it seems that
 the compiler is acting according to plan (marking this partial application
 as `ProbOneShot`, and then not floating the expression out).

 Are you saying that the plan as described in the note might be bogus, or
 is the implementation not doing what it should?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13227#comment:2>
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