[GHC] #11534: Allow class associated types to reference functional dependencies

[GHC]

#11534: Allow class associated types to reference functional dependencies
-------------------------------------+-------------------------------------
        Reporter:  ekmett            |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  7.10.3
  checker)                           |             Keywords:  TypeFamilies,
      Resolution:                    |  FunctionalDependencies
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Other             |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by dfeuer):

 Addendum to the magic name idea: the ordering of fundeps would be
 irrelevant. So

 {{{#!hs
 class Bar a b c | a b -> c
 }}}

 and

 {{{#!hs
 class Bar a b c | b a -> c
 }}}

 would both generate a family named `Bar__1_2_DET_3#`.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11534#comment:28>
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