[GHC] #15231: UndecidableInstances validity checking is wrong in the presence of QuantifiedConstraints

[GHC]

#15231: UndecidableInstances validity checking is wrong in the presence of
QuantifiedConstraints
-------------------------------------+-------------------------------------
        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler (Type    |              Version:  8.5
  checker)                           |             Keywords:
      Resolution:  fixed             |  QuantifiedConstraints
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  GHC rejects       |            Test Case:  quantified-
  valid program                      |  constraints/T15231
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D4819
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by RyanGlScott):

 * testcase:   => quantified-constraints/T15231
 * status:  patch => closed
 * resolution:   => fixed
 * milestone:  8.8.1 => 8.6.1


Comment:

 Actually, this is //in// GHC 8.6, so this is fixed.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15231#comment:6>
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