[GHC] #6069: Rank 2 Polymorphism Compile Error

[GHC]

#6069: Rank 2 Polymorphism Compile Error
---------------------------------+------------------------------------------
    Reporter:  clinton           |       Owner:  simonpj         
        Type:  bug               |      Status:  new             
    Priority:  normal            |   Milestone:  7.8.1           
   Component:  Compiler          |     Version:  7.4.1           
    Keywords:                    |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown    
  Difficulty:  Unknown           |    Testcase:                  
   Blockedby:                    |    Blocking:                  
     Related:                    |  
---------------------------------+------------------------------------------

Comment(by simonpj):

 Really all three should be rejected without `-XImpredicativeTypes`,
 because all require instantiating `(.)` at a polymorphic type.  The
 inconsistent behaviour is a bug.

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6069#comment:3>
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