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diff --git a/ghc/compiler/utils/ListSetOps.lhs b/ghc/compiler/utils/ListSetOps.lhs
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+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1995
+%
+\section[ListSetOps]{Set-like operations on lists}
+
+\begin{code}
+module ListSetOps (
+	unionLists,
+	intersectLists,
+	minusList
+#if ! defined(COMPILING_GHC)
+	, disjointLists, intersectingLists
+#endif
+   ) where
+
+#if defined(COMPILING_GHC)
+import Util
+# ifdef USE_ATTACK_PRAGMAS
+import AbsUniType
+import Id		( Id )
+# endif
+#endif
+\end{code}
+
+\begin{code}
+unionLists :: (Eq a) => [a] -> [a] -> [a]
+unionLists []     []		= []
+unionLists []     b		= b
+unionLists a	   []		= a
+unionLists (a:as) b
+  | a `is_elem` b = unionLists as b
+  | otherwise     = a : unionLists as b
+  where
+#if defined(COMPILING_GHC)
+    is_elem = isIn "unionLists"
+#else
+    is_elem = elem
+#endif
+
+intersectLists :: (Eq a) => [a] -> [a] -> [a]
+intersectLists []     []		= []
+intersectLists []     b			= []
+intersectLists a      []		= []
+intersectLists (a:as) b
+  | a `is_elem` b = a : intersectLists as b
+  | otherwise	  = intersectLists as b
+  where
+#if defined(COMPILING_GHC)
+    is_elem = isIn "intersectLists"
+#else
+    is_elem = elem
+#endif
+\end{code}
+
+Everything in the first list that is not in the second list:
+\begin{code}
+minusList :: (Eq a) => [a] -> [a] -> [a]
+minusList xs ys = [ x | x <- xs, x `not_elem` ys]
+  where
+#if defined(COMPILING_GHC)
+    not_elem = isn'tIn "minusList"
+#else
+    not_elem = notElem
+#endif
+\end{code}
+
+\begin{code}
+#if ! defined(COMPILING_GHC)
+
+disjointLists, intersectingLists :: Eq a => [a] -> [a] -> Bool
+
+disjointLists []     bs = True
+disjointLists (a:as) bs
+  | a `elem` bs = False
+  | otherwise   = disjointLists as bs
+
+intersectingLists xs ys = not (disjointLists xs ys)
+#endif
+\end{code}
+
+\begin{code}
+#if defined(COMPILING_GHC)
+# ifdef USE_ATTACK_PRAGMAS
+
+{-# SPECIALIZE unionLists     :: [TyVar] -> [TyVar] -> [TyVar] #-}
+{-# SPECIALIZE intersectLists :: [TyVar] -> [TyVar] -> [TyVar] #-}
+
+{-# SPECIALIZE minusList :: [TyVar] -> [TyVar] -> [TyVar],
+			    [Id]    -> [Id]    -> [Id],
+			    [Int]   -> [Int]   -> [Int]
+ #-}
+
+# endif
+#endif
+\end{code}