[GHC] #7074: Way too long, and unhelpful, error message

[GHC]

#7074: Way too long, and unhelpful, error message
------------------------------+---------------------------------------------
 Reporter:  ksf               |          Owner:                  
     Type:  bug               |         Status:  new             
 Priority:  normal            |      Component:  Compiler        
  Version:  7.4.2             |       Keywords:                  
       Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
  Failure:  None/Unknown      |       Testcase:                  
Blockedby:                    |       Blocking:                  
  Related:                    |  
------------------------------+---------------------------------------------
 GHC is repeating this nice ~140 line mdo-expression, twice, leading to
 annoying scrolling:

 http://hpaste.org/71415

 The error message

 {{{
 Frisby.hs:142:5:
     Couldn't match expected type `[Char]' with actual type `()'
     Expected type: P s0 [Char]
       Actual type: P s0 ()
 }}}

 could also be more helpful, it appears to always point to the last binding
 statement of the block.

 NB: The code is probably *very* incorrect, I just hand-translated it from
 another grammar format and was hunting down errors when coming across this
 one.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7074>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler