[GHC] #11283: PatternSynonms and DisambiguateRecordFields causes panic

[GHC]

#11283: PatternSynonms and DisambiguateRecordFields causes panic
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        Reporter:  adamgundry        |                Owner:  adamgundry
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.11
      Resolution:                    |             Keywords:
                                     |  PatternSynonyms
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Compile-time      |            Test Case:
  crash                              |  patsyn/should_compile/T11283
      Blocked By:                    |             Blocking:
 Related Tickets:  #9975             |  Differential Rev(s):  Phab:D1695
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"4f69203dd7892d3640e871c5914b7ee2be5f5dff/ghc"
 4f69203d/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="4f69203dd7892d3640e871c5914b7ee2be5f5dff"
 Fix panic when using pattern synonyms with DisambiguateRecordFields

 This fixes a `find_tycon` panic when constructing a record pattern
 synonym when `DisambiguateRecordFields` (turned on by `RecordWildCards`)
 is enabled.  The handling of record wild cards in such constructions
 isn't completely satisfactory, but doing better will require the
 `Parent` type to be more informative, as I'll explain on #11228.

 Test Plan: New test patsyn/should_compile/T11283.hs

 Reviewers: mpickering, austin, bgamari

 Reviewed By: bgamari

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D1695

 GHC Trac Issues: #11283
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11283#comment:2>
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