[GHC] #674: Bad error message: varying arguments

[GHC]

#674: Bad error message: varying arguments
----------------------------------------+-----------------------------------
    Reporter:  guest                    |        Owner:         
        Type:  feature request          |       Status:  new    
    Priority:  normal                   |    Milestone:         
   Component:  Compiler (Type checker)  |      Version:  6.4.1  
    Severity:  normal                   |     Keywords:         
          Os:  Unknown                  |   Difficulty:  Unknown
Architecture:  Unknown                  |  
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A function definition like
 {{{
 f :: Maybe () -> Char
 f Nothing = 'a'
 f Just () = 'b'
 }}}
 yields the error message

   Varying number of arguments for function `f'

 under 6.4.1 (pointing to the line with Nothing as containing the error).
 The following error message would be easier to understand for beginners
 (pointing to the line with Just):

   The type signature for f specifies that the function should take one
 argument, but you have given it two arguments.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/674>
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