[GHC] #1781: Type equality class leads to non-termination

[GHC]

#1781: Type equality class leads to non-termination
--------------------------------------+-------------------------------------
  Reporter:  chak                     |          Owner:         
      Type:  bug                      |         Status:  new    
  Priority:  normal                   |      Milestone:         
 Component:  Compiler (Type checker)  |        Version:  6.9    
  Severity:  normal                   |       Keywords:         
Difficulty:  Unknown                  |             Os:  Unknown
  Testcase:                           |   Architecture:  Unknown
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 This program sends the type checker to the land of no return:
 {{{
 {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies #-}
 {-# LANGUAGE FlexibleInstances, FlexibleContexts #-}

 module ShouldCompile where

 class E a b | a -> b, b -> a
 instance E a a

 plus :: (E a (Int -> Int)) => Int -> a
 plus x y = x + y
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1781>
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