[GHC] #10250: API Annotations : add Locations in hsSyn were layout occurs

[GHC]

#10250: API Annotations : add Locations in hsSyn were layout occurs
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        Reporter:  alanz             |                Owner:
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.10.1
      Resolution:                    |             Keywords:
                                     |  ApiAnnotations
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D815
       Wiki Page:                    |
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Comment (by alanz):

 Yes, it will remove a wart in the round-tripping process, at the cost of
 requiring CPP in ghc-exactprint.

 At this stage, I think it worth doing, for all the future versions to
 come.

 @mpickering, do you agree?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10250#comment:10>
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