[GHC] #3263: Warnings for monadic values not used

[GHC]

#3263: Warnings for monadic values not used
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    Reporter:  NeilMitchell      |        Owner:                  
        Type:  feature request   |       Status:  new             
    Priority:  normal            |    Milestone:                  
   Component:  Compiler          |      Version:  6.10.2          
    Severity:  normal            |   Resolution:                  
    Keywords:                    |   Difficulty:  Unknown         
    Testcase:                    |           Os:  Unknown/Multiple
Architecture:  Unknown/Multiple  |  
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Comment (by isaacdupree):

 Stylistically: Do we want to be suggesting `_ <- ...`?  What about the
 (if-we-approve-it) `Control.Monad.ignore ...`?  Maybe not a big deal (I
 don't even know which style we'd prefer), but when there are suggestions
 that the community disapproves of (e.g., the `-XSomeExtension` ones come
 to mind that didn't mention LANGUAGE) it's generally a bit unfortunate :-)

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3263#comment:7>
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