[GHC] #15611: scope errors lie about what modules are imported

[GHC]

#15611: scope errors lie about what modules are imported
-------------------------------------+-------------------------------------
        Reporter:  dmwit             |                Owner:  RolandSenn
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:  8.8.1
       Component:  Compiler          |              Version:  8.4.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:  make test
                                     |  TEST="T15611a T15611b"
      Blocked By:                    |             Blocking:
 Related Tickets:  #14225            |  Differential Rev(s):  Phab:D5284
       Wiki Page:                    |
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Comment (by Krzysztof Gogolewski <krz.gogolewski@…>):

 In [changeset:"1a3b9bd0b674ad16a41b942c738b8f34564bcd8d/ghc"
 1a3b9bd0/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="1a3b9bd0b674ad16a41b942c738b8f34564bcd8d"
 Fix for Trac #15611: Scope errors lie about what modules are imported.

 Summary:
 For the error message:
     Not in scope X.Y
     Module X does not export Y
     No module named ‘X’ is imported:
 there are 2 cases, where we don't show the last "no module named is
 imported" line:
 1. If the module X has been imported.
 2. If the module X is the current module. There are 2 subcases:

    2.1 If the unknown module name is in a input source file,
        then we can use the getModule function to get the current module
 name.

    2.2 If the unknown module name has been entered by the user in GHCi,
        then the getModule function returns something like
 "interactive:Ghci1",
        and we have to check the current module in the last added entry of
        the HomePackageTable.

 Test Plan: make test TESTS="T15611a T15611b"

 Reviewers: monoidal, hvr, thomie, dfeuer, bgamari, DavidEichmann

 Reviewed By: monoidal, DavidEichmann

 Subscribers: rwbarton, carter

 GHC Trac Issues: #15611

 Differential Revision: https://phabricator.haskell.org/D5284
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15611#comment:5>
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