[GHC] #8234: Remove role annotations on type synonyms

[GHC]

#8234: Remove role annotations on type synonyms
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       Reporter:  goldfire          |             Owner:  goldfire
           Type:  bug               |            Status:  new
       Priority:  normal            |         Milestone:
      Component:  Compiler          |           Version:  7.7
       Keywords:                    |  Operating System:  Unknown/Multiple
   Architecture:  Unknown/Multiple  |   Type of failure:  None/Unknown
     Difficulty:  Unknown           |         Test Case:
     Blocked By:                    |          Blocking:
Related Tickets:                    |
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 Currently, role annotations are allowed on vanilla type synonyms. However,
 Simon points out that this is very fragile, because a type synonym can be
 expanded at any time, thus losing a user's intended restriction. Solution:
 remove these annotations entirely.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8234>
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