[GHC] #12901: Levity polymorphic expressions mustn't be floated out

[GHC]

#12901: Levity polymorphic expressions mustn't be floated out
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        Reporter:  hsyl20            |                Owner:  hsyl20
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
                                     |  LevityPolymorphism
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2769
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"514c01eec5f2b23f278c29b61345dce6c37900f1/ghc"
 514c01ee/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="514c01eec5f2b23f278c29b61345dce6c37900f1"
 Levity polymorphic expressions mustn't be floated-out in let-bindings.

 Reviewers: simonpj, austin, bgamari

 Reviewed By: simonpj, bgamari

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D2769

 GHC Trac Issues: #12901
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12901#comment:2>
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