[GHC] #12923: MultiParamTypeClasses + ExtendedDefaultRules

[GHC]

#12923: MultiParamTypeClasses + ExtendedDefaultRules
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        Reporter:  amindfv           |                Owner:
            Type:  feature request   |               Status:  patch
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2822
       Wiki Page:                    |
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Comment (by simonpj):

 OK I think we are done.  Please add a Note as suggested on Phab, then Ben
 can you land this?

 Thanks for being so patient with this.  I think it's been worth it though:
 the result is much better than were we started.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12923#comment:20>
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