[GHC] #9023: Error when using empty record update on binary pattern synonym

[GHC]

#9023: Error when using empty record update on binary pattern synonym
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        Reporter:  Iceland_jack  |            Owner:  cactus
            Type:  bug           |           Status:  patch
        Priority:  normal        |        Milestone:
       Component:  Compiler      |          Version:  7.8.2
      Resolution:                |         Keywords:
Operating System:  Linux         |     Architecture:  x86
 Type of failure:  None/Unknown  |       Difficulty:  Unknown
       Test Case:                |       Blocked By:
        Blocking:                |  Related Tickets:
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Comment (by archblob):

 I'm sorry for hijacking this thread again but I'm trying to understand all
 of this stuff and tinkering with it does it best for me.

 As I understand it, {{{tcTyConAppArgs}}} will look through synonyms but
 not through newtypes. The thing is it will also not get us the args we
 want in the case of nested application, so in this case for tuples, but
 the bug will manifest itself for any nested application.

 I've attached a patch with a new fix and I'm wondering if you can take a
 look at it. The fix works for this test case but there may be things that
 i overlooked.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9023#comment:5>
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