Árvore de busca binária parcialmente implementada em Haskell

binSearchTree.hs

data Tree a = EmptyTree | Node a (Tree a) (Tree a) deriving (Show)

treeInsert :: (Ord a) => a -> Tree a -> Tree a
treeInsert x EmptyTree = Node x EmptyTree EmptyTree
treeInsert x (Node a left right)
  | x == a = Node x left right
  | x < a  = Node a (treeInsert x left) right
  | x > a  = Node a left (treeInsert x right)

treeElement :: (Ord a) => a -> Tree a -> Bool
treeElement x EmptyTree = False
treeElement x (Node a left right)
  | x == a = True
  | x < a  = treeElement x left
  | x > a  = treeElement x right