Data.IntMap: intersection function not sufficiently polymorphic

Hi, the function intersectionWith :: (a -> b -> a) -> IntMap a -> IntMap b -> IntMap a in Data.IntMap creates a map of elements that occur in both maps. This function can and should return a map of an arbitrary third type: intersectionWith :: (a -> b -> c) -> IntMap a -> IntMap b -> IntMap c This also applies to Data.IntMap.intersectionWithKey. Oddly enough, this is already fixed in Data.Map. Discussion period one week?! Cheers, Axel.