[GHC] #2893: Implement "Quantified contexts" proposal

[GHC]

#2893: Implement "Quantified contexts" proposal
-----------------------------+----------------------------------------------
Reporter:  porges            |          Owner:                  
    Type:  feature request   |         Status:  new             
Priority:  normal            |      Component:  Compiler        
 Version:  6.10.1            |       Severity:  normal          
Keywords:  proposal          |       Testcase:                  
      Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
-----------------------------+----------------------------------------------
 See: http://haskell.org/haskellwiki/Quantified_contexts

 Motivating example is collapsing insomeway-identical classes such as
 Monoid and MonadPlus into a single class (with accompanying functions).

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2893>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler