[GHC] #11680: Out-of-scope suggestion given for an out-of-scope variable when using TH

[GHC]

#11680: Out-of-scope suggestion given for an out-of-scope variable when using TH
-------------------------------------+-------------------------------------
        Reporter:  jme               |                Owner:  jme
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Template Haskell  |              Version:  8.0.1-rc2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect         |  Unknown/Multiple
  warning at compile-time            |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2000
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"470d4d5b8e7cbcc176b1f3ac26ce0d95acd35a78/ghc"
 470d4d5b/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="470d4d5b8e7cbcc176b1f3ac26ce0d95acd35a78"
 Fix suggestions for unbound variables (#11680)

 When the typechecker generates the error message for an out-of-scope
 variable, it now uses the GlobalRdrEnv with respect to which the
 variable is unbound, not the GlobalRdrEnv which is available at the time
 the error is reported.  Doing so ensures we do not provide suggestions
 which themselves are out-of-scope (because they are bound in a later
 inter-splice group).

 Nonetheless, we do note in the error message if an unambiguous, exact
 match to the out-of-scope variable is found in a later inter-splice
 group, and we specify where that match is not in scope.

 Test Plan: ./validate

 Reviewers: goldfire, austin, bgamari

 Reviewed By: goldfire

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D2000

 GHC Trac Issues: #11680
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11680#comment:8>
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