Commit 4dc71b4b authored by simonpj@microsoft.com's avatar simonpj@microsoft.com
Browse files

Bleat a bit more informatively in unionLists

parent 001b9a4d
......@@ -19,6 +19,8 @@ module ListSetOps (
) where
#include "HsVersions.h"
import Outputable
import Unique
import UniqFM
......@@ -41,9 +43,11 @@ insertList :: Eq a => a -> [a] -> [a]
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:
......
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