[GHC] #11751: Parse error with case in where

[GHC]

#11751: Parse error with case in where
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        Reporter:  samuela           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.2
  (Parser)                           |
      Resolution:                    |             Keywords:
Operating System:  MacOS X           |         Architecture:
 Type of failure:  Incorrect         |  Unknown/Multiple
  warning at compile-time            |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by bgamari):

 * failure:  None/Unknown => Incorrect warning at compile-time
 * component:  Compiler => Compiler (Parser)


Comment:

 Thanks for the report.

 That being said, I'm not sure I see why do you say it's peculiar. It seems
 like quite a reasonable error to me: The `case` alternative falls outside
 of the virtual close-bracket delimiting the `where` clause due to its
 indentation. In particular, the fragment `(a, b) -> (3, 4)`
   * cannot be parsed as a case alternative (due to being "outside" of the
 `case` expression)
   * cannot be parsed as a binding (since it also falls outside of the
 `where` clause (again, since it has decreasing indentation)
   * cannot be a top-level binding (due to the `->`)

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11751#comment:1>
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