foldl' is:exact -package:containers -package:base -package:text package:unordered-containers

foldl' :: (a -> v -> a) -> a -> HashMap k v -> a
unordered-containers Data.HashMap.Internal Data.HashMap.Internal.Strict Data.HashMap.Lazy Data.HashMap.Strict
Reduce this map by applying a binary operator to all elements, using the given starting value (typically the left-identity of the operator). Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
foldl' :: (b -> a -> b) -> b -> Array a -> b
unordered-containers Data.HashMap.Internal.Array
foldl' :: (a -> b -> a) -> a -> HashSet b -> a
unordered-containers Data.HashSet Data.HashSet.Internal
Reduce this set by applying a binary operator to all elements, using the given starting value (typically the left-identity of the operator). Each application of the operator is evaluated before before using the result in the next application. This function is strict in the starting value.