-- | Perform a query on each level of a tree.
--
-- This is stolen directly from SYB package and copied here to not introduce
-- additional dependencies.
everything :: (r -> r -> r) -> (forall a. Data a => a -> r)
           -> (forall a. Data a => a -> r)
everything k f x = foldl k (f x) (gmapQ (everything k f) x)
everything :: (r -> r -> r) -> (forall a. Data a => a -> r)
           -> (forall a. Data a => a -> r)
everything k f x = foldl k (f x) (gmapQ (everything k f) x)
everything k f x = foldl k (f x) (gmapQ (everything k f) x)