[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:                    |  Differential Revisions:
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Comment (by Rufflewind):

 > I don't see a common usecase for case, if, and let

 I've certainly written code like this:

 {{{#!hs
 foo x = pure $ case x of
   Just _  -> True
   Nothing -> False
 }}}

 Personally I never understood why `$` was required to begin with.  There's
 no sensible way to interpret `runST do …` except as `runST (do …)`.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10843#comment:7>
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