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

[GHC]

#10843: Allow do blocks without dollar signs as arguments
-------------------------------------+-------------------------------------
        Reporter:  agibiansky        |                Owner:  akio
            Type:  feature request   |               Status:  patch
        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:                    |  Phab:D4260
-------------------------------------+-------------------------------------

Comment (by Ben Gamari <ben@…>):

 In [changeset:"be84823b956f0aa09c58d94d1901f2dff13546b4/ghc" be84823/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="be84823b956f0aa09c58d94d1901f2dff13546b4"
 Implement BlockArguments (#10843)

 This patch implements the BlockArguments extension, as proposed at
 https://github.com/ghc-proposals/ghc-proposals/pull/90. It also
 fixes #10855 as a side-effect.

 This patch adds a large number of shift-reduce conflicts to the parser.
 All of them concern the ambiguity as to where constructs like `if` and
 `let` end. Fortunately they are resolved correctly by preferring shift.

 The patch is based on @gibiansky's ArgumentDo implementation (D1219).

 Test Plan: ./validate

 Reviewers: goldfire, bgamari, alanz, mpickering

 Reviewed By: bgamari, mpickering

 Subscribers: Wizek, dfeuer, gibiansky, rwbarton, thomie, mpickering,
 carter

 GHC Trac Issues: #10843, #10855

 Differential Revision: https://phabricator.haskell.org/D4260
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10843#comment:46>
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