[GHC] #15422: GHCi debugger doesn't see free variables when using ApplicativeDo

[GHC]

#15422: GHCi debugger doesn't see free variables when using ApplicativeDo
-------------------------------------+-------------------------------------
        Reporter:  simonmar          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.4.3
      Resolution:                    |             Keywords:  ApplicativeDo
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D4991
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by Krzysztof Gogolewski <krz.gogolewski@…>):

 In [changeset:"4ea9311cc5c3b99ea6915bee23f0a6776731f20e/ghc" 4ea9311/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="4ea9311cc5c3b99ea6915bee23f0a6776731f20e"
 Fix the GHCi debugger with ApplicativeDo

 Summary:
 `collectLStmtsBinders` was returning nothing for `ApplicativeStmts`, which
 caused the debugger to not track free variables in many cases when using
 `ApplicativeDo`.

 Test Plan:
 * new test case
 * validate

 Reviewers: bgamari, erikd

 Reviewed By: bgamari

 Subscribers: rwbarton, thomie, carter

 GHC Trac Issues: #15422

 Differential Revision: https://phabricator.haskell.org/D4991
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15422#comment:2>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler