) where
+#include "HsVersions.h"
+
import Outputable
import Unique
import UniqFM
insertList x xs | isIn "insert" x xs = xs
| otherwise = x : xs
-unionLists :: (Eq a) => [a] -> [a] -> [a]
+unionLists :: (Outputable a, Eq a) => [a] -> [a] -> [a]
-- Assumes that the arguments contain no duplicates
-unionLists xs ys = [x | x <- xs, isn'tIn "unionLists" x ys] ++ ys
+unionLists xs ys
+ = WARN(length xs > 100 || length ys > 100, ppr xs $$ ppr ys)
+ [x | x <- xs, isn'tIn "unionLists" x ys] ++ ys
minusList :: (Eq a) => [a] -> [a] -> [a]
-- Everything in the first list that is not in the second list: