[GHC] #10189: explicit promotions of prefix data constructors can't be parsed naturally

[GHC]

#10189: explicit promotions of prefix data constructors can't be parsed naturally
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        Reporter:  Kinokkory         |                   Owner:  Kinokkory
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:  7.12.1
       Component:  Compiler          |                 Version:  7.8.4
  (Parser)                           |                Keywords:
      Resolution:                    |            Architecture:
Operating System:  Unknown/Multiple  |  Unknown/Multiple
 Type of failure:  GHC rejects       |               Test Case:
  valid program                      |                Blocking:
      Blocked By:                    |  Differential Revisions:
 Related Tickets:  #10188            |
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Comment (by goldfire):

 Yes, that would be a new unexplored ball of wax, and I don't intend to
 explore it tonight.

 But, how about this: allow all four forms mentioned above. I have two
 reasons:

 * No breakage of existing code.
 * It's conceivable that the quote-on-the-outside form (that is, the
 existing, stupid form) will make decent sense some day.

 But please don't do this if it's hard. I fully agree on not paying now for
 something that might not happen later.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10189#comment:8>
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