[GHC] #7854: Constrained method type accepted in Haskell 98 mode

[GHC]

#7854: Constrained method type accepted in Haskell 98 mode
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Reporter:  refold            |          Owner:                  
    Type:  bug               |         Status:  new             
Priority:  normal            |      Component:  Compiler        
 Version:  7.6.3             |       Keywords:                  
      Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
 Failure:  None/Unknown      |      Blockedby:                  
Blocking:                    |        Related:                  
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Comment(by refold):

 Also accepted by 7.0.4 and 7.2.1, but rejected by 6.12.1. However, it
 complains about `-XFlexibleContexts`, not `-XConstrainedClassMethods`:

 {{{
 [1 of 1] Compiling Main             ( Test.hs, interpreted )

 Test.hs:3:0:
     All of the type variables in the constraint `Eq a'
     are already in scope (at least one must be universally quantified
 here)
         (Use -XFlexibleContexts to lift this restriction)
     When checking the class method: comp :: (Eq a) => a -> a -> Bool
     In the class declaration for `Compare'
 Failed, modules loaded: none.
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7854#comment:1>
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