Data.List.sort: force elements from start to end.

this prevents a stack overflow on  sort (take 10^6 [1..])

diff --git a/Data/List.hs b/Data/List.hs
index 1c52b50..19dbc7d 100644 (file)
--- a/Data/List.hs
+++ b/Data/List.hs
@@ -807,8 +807,8 @@ merge_pairs cmp [xs] = [xs]
 merge_pairs cmp (xs:ys:xss) = merge cmp xs ys : merge_pairs cmp xss
 
 merge :: (a -> a -> Ordering) -> [a] -> [a] -> [a]
-merge cmp xs [] = xs
 merge cmp [] ys = ys
+merge cmp xs [] = xs
 merge cmp (x:xs) (y:ys)
  = case x `cmp` y of
         GT -> y : merge cmp (x:xs)   ys