[GHC] #956: improving error messages #1

GHC cvs-ghc at haskell.org
Mon Jan 21 02:29:23 CET 2013

#956: improving error messages #1
    Reporter:  Bulat Ziganshin <Bulat.Ziganshin@…>          |       Owner:  simonpj         
        Type:  feature request                              |      Status:  new             
    Priority:  normal                                       |   Milestone:  _|_             
   Component:  Compiler                                     |     Version:  6.6             
    Keywords:                                               |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple                             |     Failure:  None/Unknown    
  Difficulty:  Unknown                                      |    Testcase:                  
   Blockedby:                                               |    Blocking:                  
     Related:                                               |  

Comment(by morabbin):

 Given that GHC 7's error messages are generally more informative, and in
 these cases produce very friendly messages:
     Couldn't match expected type `IO b0'
                 with actual type `Char -> IO ()'
     In a stmt of a 'do' block: putChar
     In the expression:
       do { putChar 'a';
            putChar }
     In an equation for `main':
           = do { putChar 'a';
                  putChar }
 perhaps this ought to be closed as fixed. The message doesn't suggest a
 probable cause or fix, but I think that's fine here.

Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/956#comment:7>
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