[GHC] #10843: Allow do blocks without dollar signs as arguments

[GHC]

#10843: Allow do blocks without dollar signs as arguments
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        Reporter:  agibiansky        |                Owner:  agibiansky
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.2
  (Parser)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #11706            |  Differential Rev(s):  Phab:D1219
       Wiki Page:                    |
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Comment (by maeder):

 Replying to [comment:27 goldfire]:
 > Replying to [comment:22 simonpj]:
 > > I'm one of those who thinks that the fact that `f R { x = e }` means
 `f (R { x = e })` is a mistake :-).
 > >
 >
 > I agree with you here, but I think the proposal in this ticket is still
 sensible, given that the perhaps-unexpected parsing started with a
 keyword. In the record update case, the perhaps-unexpected parsing isn't
 known until the open-brace, even though your brain has to parse the
 preceding space differently. To me, that's the real problem with the
 parsing of record-update: it's not left-to-right.

 I fully agree, too! The record syntax is unrelated to this proposal. Curly
 record braces are sort of a strong binding postfix operator and are thus
 different from plain parentheses.

 @aiko I would omit the point "This would make do blocks consistent with
 record creation ..." under Pros on
 https://ghc.haskell.org/trac/ghc/wiki/ArgumentDo. Record creation is only
 another kind of a more "non-atomic" aexp in the grammar.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10843#comment:28>
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