[GHC] #8177: Roles for type families

[GHC]

#8177: Roles for type families
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              Reporter:  simonpj     |            Owner:  goldfire
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.6.3
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:              |       Blocked By:
  None/Unknown                       |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by goldfire):

 That does look fishy, but I don't see a definition of `Mass` so I can be
 sure. Do you have a minimal test case, or a way I can check this myself?
 If so, please post that as a new ticket, as it's only very tangentially
 related to this one. Thanks!

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8177#comment:23>
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