[GHC] #999: Misattributed parse error in do block

[GHC]

#999: Misattributed parse error in do block
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    Reporter:  red5_2 at hotmail.com  |       Owner:         
        Type:  bug                 |      Status:  new    
    Priority:  normal              |   Milestone:         
   Component:  Compiler (Parser)   |     Version:  6.4.2  
    Severity:  normal              |    Keywords:         
  Difficulty:  Unknown             |    Testcase:         
Architecture:  Unknown             |          Os:  Unknown
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In the following program, there is clearly an extra closing parenthesis.
 However, the error message doesn't point to the actual problem:
 {{{
 main = do x <- 1)
           return ()
 -- test.hs:1:10: The last statement in a 'do' construct must be an
 expression
 }}}

 The reported error is at the beginning of the statement "`x <- 1`", not at
 the closing parenthesis.  When this first happened to me, I spent a lot of
 time puzzling over the beginning of the statement and the indentation of
 various lines before I discovered the real problem.

 In this example, the error could be attributed to that unmatched
 parenthesis.  Since 'do' blocks can legitimately be enclosed in
 parentheses, it might be more usable if the error message could identify
 the locations of both the statement and the end of the 'do' block -- this
 would point out both potential problem locations.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/999>
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