[GHC] #15927: Weird interaction between fundeps and overlappable instances

[GHC]

#15927: Weird interaction between fundeps and overlappable instances
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        Reporter:  Darwin226         |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.3
       Component:  Compiler          |              Version:  8.6.2
      Resolution:                    |             Keywords:
                                     |  FunctionalDependencies
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC accepts       |  Unknown/Multiple
  invalid program                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  10675, 15632      |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by AntC):

 * keywords:   => FunctionalDependencies
 * related:   => 10675, 15632


Comment:

 Yes you could always evade FunDep consistency like that -- see #10675 at
 "bogus"; or #15632 for a cut-down example.

 Well done for getting that inconsistency into the same constraint!

 There's nothing stopping you putting a bunch of constraints that are
 together unsatisfiable. That would usually mean you couldn't use `f`.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15927#comment:1>
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