[GHC] #8978: Type synonyms in class associated types behave strangely

[GHC]

#8978: Type synonyms in class associated types behave strangely
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        Reporter:  joelteon                   |            Owner:
            Type:  bug                        |           Status:  new
        Priority:  normal                     |        Milestone:
       Component:  Compiler                   |          Version:  7.8.1
      Resolution:                             |         Keywords:
Operating System:  Unknown/Multiple           |     Architecture:
 Type of failure:  GHC rejects valid program  |  Unknown/Multiple
       Test Case:                             |       Difficulty:  Unknown
        Blocking:                             |       Blocked By:
                                              |  Related Tickets:
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Comment (by goldfire):

 Sorry if I was unclear -- I meant to change the vanilla type synonym into
 a type family. My guess is that GHC won't care whether the new family is
 closed or open with one universal equation (if you need backward
 compatibility). You don't need to change the existing type family for my
 workaround.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8978#comment:7>
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