[GHC] #14237: -Wredundant-constraints incorrectly treats all type equality constraints as redundant

[GHC]

#14237: -Wredundant-constraints incorrectly treats all type equality constraints as
redundant
-------------------------------------+-------------------------------------
        Reporter:  lexi.lambda       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect         |  Unknown/Multiple
  error/warning at compile-time      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #12700            |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"1db0f4a48e9db5e85782e32f074cc83bbc145cb7/ghc" 1db0f4a/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="1db0f4a48e9db5e85782e32f074cc83bbc145cb7"
 Fix unused-given-constraint bug

 This bug was shown up by Trac #14237.  It turned out
 to be an outright error in TcSimplify.neededEvVars,
 easily fixed.

 I improved the comments.
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14237#comment:5>
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