[GHC] #3766: Parsing of lambdas is not consistent with Haskell'98 report.

[GHC]

#3766: Parsing of lambdas is not consistent with Haskell'98 report.
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    Reporter:  lilac              |       Owner:                           
        Type:  bug                |      Status:  new                      
    Priority:  normal             |   Milestone:                           
   Component:  Compiler (Parser)  |     Version:  6.10.4                   
  Resolution:                     |    Keywords:                           
          Os:  Unknown/Multiple   |    Testcase:                           
Architecture:  Unknown/Multiple   |     Failure:  GHC rejects valid program
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Comment (by lilac):

 Amusingly, with any extension which adds the 'forall x . y' syntax to
 types (such as -XExistentialQuantification) enabled, the expression is
 accepted! Cases with other operators, such as (\x -> x :: Int $ 4) still
 fail, however.

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Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3766#comment:2>
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