[GHC] #11067: Spurious superclass cycle error with type equalities

[GHC]

#11067: Spurious superclass cycle error with type equalities
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        Reporter:  oerjan            |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.0.1
       Component:  Compiler (Type    |              Version:  7.10.2
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by simonpj):

 * cc: kylcarte@… (added)


Comment:

 Can I ask: does `wip/T11067` make it easier?  It's pretty simple: with
 `UndecidableSuperClasses` the whole superclass restriction is lifted.

 Adding kylcarte at gmail.com in cc, who is the author of type-combinators

 Simon

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11067#comment:11>
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