[GHC] #11970: Simplify Parent for patten synonyms

[GHC]

#11970: Simplify Parent for patten synonyms
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        Reporter:  simonpj           |                Owner:  mpickering
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by mpickering):

 I had an evening looking at this last week but got stuck trying to work
 out how to check exported children were in scope. It wasn't clear to me
 which of the `lookupOccRn` functions is needed to find the children.
 Especially after export renaming already comes after renaming all other
 top level decls I expected using one of them to just work but I need to do
 some further exploration to find out why it isn't the case.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11970#comment:7>
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