[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:                    |
-------------------------------------+-------------------------------------
Changes (by RyanGlScott):

 * related:   => #12700


Comment:

 Yes, this is a known pain point of `-Wredundant-constraints`. See also the
 very similar ticket #12700.

 (Among other reasons, this is why `-Wredundant-constraints` is no longer a
 part of `-Wall`.)

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14237#comment:3>
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