[GHC] #13568: Name is reported as ambiguous and not in scope

[GHC]

#13568: Name is reported as ambiguous and not in scope
-------------------------------------+-------------------------------------
        Reporter:  mpickering        |                Owner:  mpickering
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.0.1
      Resolution:  fixed             |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D3547
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"ba46e63f3d6f7d0438a0262f6711f8a219c703bc/ghc"
 ba46e63f/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="ba46e63f3d6f7d0438a0262f6711f8a219c703bc"
 Fix #13948 by being pickier about when to suggest DataKinds

 Commit 343cb32d0983f576d344a2d04a35c3fd6eecf2c5 (#13568) made GHC a bit
 too cavalier in suggesting when data constructors are in scope (and
 suggesting the use of `DataKinds`). This tones down the suggestions so
 that `DataKinds` is only suggested if a data constructor of that name is
 actually in scope (previously, it would always suggest, even if it was
 out of scope).

 Fixes #13948.

 Test Plan: ./validate

 Reviewers: mpickering, austin, bgamari

 Reviewed By: mpickering

 Subscribers: rwbarton, thomie

 GHC Trac Issues: #13948

 Differential Revision: https://phabricator.haskell.org/D3719
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13568#comment:8>
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