[GHC] #8185: Change role annotation syntax

[GHC]

#8185: Change role annotation syntax
----------------------------+----------------------------------------------
        Reporter:           |            Owner:  goldfire
  goldfire                  |           Status:  new
            Type:  feature  |        Milestone:  7.8.1
  request                   |          Version:  7.7
        Priority:  normal   |         Keywords:
       Component:           |     Architecture:  Unknown/Multiple
  Compiler                  |       Difficulty:  Moderate (less than a day)
      Resolution:           |       Blocked By:
Operating System:           |  Related Tickets:
  Unknown/Multiple          |
 Type of failure:           |
  None/Unknown              |
       Test Case:           |
        Blocking:           |
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Comment (by rwbarton):

 Sorry for last-minute bikeshedding but don't GHC pragmas usually precede
 the thing they attach to, when there may be ambiguity? E.g. consider

 {{{
 data X = X !Int {-# UNPACK #-} !Int

 data Foo a {-# ROLE Nominal #-} b = ...
 }}}

 I know `data Foo {-# ROLE Nominal #-} a = ...` is ugly but...

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8185#comment:1>
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