我想检查同态Applicative定律是否适用于数据类型BinTree：

{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE AllowAmbiguousTypes #-} 
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE ViewPatterns #-}

module Laws where

import Control.Applicative ((<$>), liftA3)

import Data.Monoid

import Test.QuickCheck
import Test.QuickCheck.Function
import Test.QuickCheck.Gen

data BinTree a = Empty | Node a (BinTree a) (BinTree a) deriving (Show, Eq)

instance Functor BinTree where
    fmap _ Empty = Empty
    fmap f (Node x hi hd) = Node (f x) (fmap f hi) (fmap f hd)

instance Applicative BinTree where
    -- pure :: a -> BinTree a
    pure x = Node x (pure x) (pure x)

    -- <*> :: BinTree (a -> b) -> BinTree a -> BinTree b
    _ <*> Empty = Empty -- L1, 
    Empty <*> t = Empty
    (Node f l r) <*> (Node x l' r') = Node (f x) (l <*> l') (r <*> r')

instance (Arbitrary a) => Arbitrary (BinTree a) where
    arbitrary = oneof [return Empty, -- oneof :: [Gen a] -> Gen a
                liftA3 Node arbitrary arbitrary arbitrary]
                
-- Identity
apIdentityProp :: (Applicative f, Eq (f a)) => f a -> Bool
apIdentityProp v = (pure id <*> v) == v

apHomomorphismProp :: forall f a b. (Applicative f, Eq (f b)) => Fun a b -> a -> Bool
apHomomorphismProp (apply -> g) x = (pure @f g <*> pure x) == pure (g x)

main = quickCheck $ apHomomorphismProp @BinTree @Int @Int

但是，当我执行代码时，应用于applicative属性的quickCheck返回：
（0次测试）
我该如何解决这个问题？