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diff --git a/testsuite/tests/indexed-types/should_compile/ColInference3.hs b/testsuite/tests/indexed-types/should_compile/ColInference3.hs
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+++ b/testsuite/tests/indexed-types/should_compile/ColInference3.hs
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+{-# LANGUAGE TypeFamilies #-}
+
+module Main where 
+
+type family Elem c
+
+class Col c where
+ isEmpty   :: c -> Bool
+ add       :: c -> Elem c -> c
+ headTail  :: c -> (Elem c,c)
+
+-- LIST
+instance Col [a] where
+  isEmpty   	  = null
+  add	   	  = flip (:)
+  headTail (x:xs) =  (x,xs)
+
+type instance Elem [a] = a
+
+-- SEQUENCE
+data Sequence a = Nil | Snoc (Sequence a) a deriving Show
+
+instance Col (Sequence a) where
+  isEmpty Nil = True
+  isEmpty _   = False
+
+  add     s x = Snoc s x
+
+  headTail (Snoc s x) = (x,s)
+
+type instance Elem (Sequence a) = a
+
+-- 
+addAll c1 c2 
+	| isEmpty c1
+	= c2
+	| otherwise
+	= let (x,c1') = headTail c1
+	  in addAll c1' (add c2 x)
+
+--
+main = print $ addAll c1 c2
+       where c1 = ['a','b','c']
+             c2 = (Snoc (Snoc (Snoc Nil 'd') 'e') 'f')