[Haskell-beginners] Equality error

[PATRICK BROWNE]

{-
Hi,
I am trying to get some Haskell code to run from a research paper[1]
The relevant fragment is shown below. The issue is that I cannot get the
code to run using the original Eq instance.
I have replaced the Eq instance with a set of deriving statements on the
data types and this works fine.
But I am anxious to know why I get the error when using the original code.
Also, it seems reasonable to be able to define equality based on names.
With the original Eq Instance I get the following error:

Context reduction stack overflow;...
 In the expression: elem car cars
 In an equation for `element': element car cars = elem car cars
 In the instance declaration for `Collection Cars Car'

 I am not too sure how to interpret this message.
 Any clarification of the error and possible fix  would be appreciated.
 Thanks,
 Pat

 [1] ifgi.uni-muenster.de/~sumitsen/sen_Font05.pdf
-}

{-# LANGUAGE MultiParamTypeClasses,
FlexibleInstances,FunctionalDependencies,
TypeSynonymInstances,UndecidableInstances,TypeSynonymInstances
,OverlappingInstances #-}
import Data.List

class Collection collection single  where
    empty    :: collection
    addOne    :: single -> collection -> collection
    remove    :: single -> collection -> collection
    element :: single -> collection -> Bool
    doToAll    :: (single -> single) -> collection -> collection

class Named object name | object -> name where
    name :: object -> name

-- **** in original code ****
-- All named objects can be compared for equality if names can
instance (Eq name, Named object name) => Eq object where
  object1 == object2 = (name object1) == (name object2)

-- could add (Eq, Show) here
data Edge = Edge Node Node deriving Show -- (Eq, Show)
type Name = [Char]
data Node = Node Name deriving Show -- (Eq, Show)
data Car = Car Node deriving  Show -- (Eq, Show)
type Cars = [Car]

instance Named Car Name where
  name c   = "a"

instance Collection Cars Car where
    empty = [] -- ::Cars
    addOne car cars = car:cars
    remove car cars = delete car cars
    element car cars = elem car cars
    doToAll f cars = map f cars

-- addOne (Car (Node "a")) [Car (Node "a")]
-- addOne (Car (Node "a")) []::Cars
-- addOne (Car (Node "b")) [(Car (Node "a"))]
-- remove (Car (Node "a")) (addOne (Car (Node "b")) [(Car (Node "a"))])

-- 


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