[GHC] #3384: Add HsSyn prettyprinter tests

[GHC]

#3384: Add HsSyn prettyprinter tests
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        Reporter:  igloo             |                Owner:
            Type:  task              |               Status:  closed
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Test Suite        |              Version:
      Resolution:  fixed             |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2752
       Wiki Page:                    |
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Comment (by Alan Zimmerman <alan.zimm@…>):

 In [changeset:"258c719599f78178c75b58d9c49e10e498cb7c48/ghc" 258c719/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="258c719599f78178c75b58d9c49e10e498cb7c48"
 TH-spliced class instances are pretty-printed incorrectly post-#3384

 Summary:
 The HsSyn prettyprinter tests patch
 499e43824bda967546ebf95ee33ec1f84a114a7c
 broke the pretty-printing of Template Haskell-spliced class instances.

 Test Plan: ./validate

 Reviewers: RyanGlScott, austin, goldfire, bgamari

 Reviewed By: RyanGlScott, bgamari

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D3043
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3384#comment:20>
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