[GHC] #13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope

[GHC]

#13622: Regression: can't export constructor when conflicting, qualified
constructor is also in scope
-------------------------------------+-------------------------------------
        Reporter:  RyanGlScott       |                Owner:  mpickering
            Type:  bug               |               Status:  patch
        Priority:  highest           |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.2.1-rc2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D3515
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"1829d265662ca8d052df3e5df1aa1137b19e39ce/ghc" 1829d26/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="1829d265662ca8d052df3e5df1aa1137b19e39ce"
 Implement sequential name lookup properly

 Previously we would run all the monadic actions and then
 combine their results. This caused problems if later actions
 raised errors but earlier lookups suceeded. We only want to run later
 lookups if the earlier ones fail.

 Fixes #13622

 Reviewers: RyanGlScott, austin, bgamari, simonpj

 Reviewed By: simonpj

 Subscribers: simonpj, rwbarton, thomie

 GHC Trac Issues: #13622

 Differential Revision: https://phabricator.haskell.org/D3515
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13622#comment:9>
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