[GHC] #13242: Panic "StgCmmEnv: variable not found" with ApplicativeDo and ExistentialQuantification

[GHC]

#13242: Panic "StgCmmEnv: variable not found" with ApplicativeDo and
ExistentialQuantification
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        Reporter:  ljli              |                Owner:  simonmar
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.0.3
       Component:  Compiler          |              Version:  8.1
      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 Simon Peyton Jones <simonpj@…>):

 In [changeset:"484f8d35b7cb3f77d96f9f4ffc16bb8c946f47fd/ghc" 484f8d3/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="484f8d35b7cb3f77d96f9f4ffc16bb8c946f47fd"
 Fix ApplicativeDo constraint scoping

 This patch fixes Trac #13242, by a bit of fancy footwork
 with the LIE variable in which the WantedConstraints are
 collected.

 I think it can be simplified further, using a 'map'.
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13242#comment:10>
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