Copper chest on minecart

I was building a system that uses copper golems and would need a copper chest inside a minecart. I went to make the minecart with a copper chest because it naturally came to my mind "of course Mojang would adapt the copper chest to the minecarts" BUT THERE'S NO WAY HOW TO DO THAT. HELLO? How can't you put a copper chest in the carts???? That doesn't even make sense, there should be a way to put it, please fix this. "Aaaah but there's the copper golem that will follow the cart and you won't be able to take the chest out later" just break the cart and the items will separate automatically and the copper golem won't need to keep following the cart since the detection limit is well defined.