[GHC] #15232: TypeError is reported as "redundant constraint" starting with GHC 8.2

[GHC]

#15232: TypeError is reported as "redundant constraint" starting with GHC 8.2
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        Reporter:  fsoikin           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.2.3
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
                                     |  CustomTypeErrors
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect         |  Unknown/Multiple
  error/warning at compile-time      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"5026840fddc86c3bc10693eed676fbf6a74f4227/ghc"
 5026840f/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="5026840fddc86c3bc10693eed676fbf6a74f4227"
 testsuite: Add test for #15232

 Subscribers: rwbarton, thomie, carter

 GHC Trac Issues: #15232

 Differential Revision: https://phabricator.haskell.org/D4807
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15232#comment:1>
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