Character pushes a cart. How to prevent cart from clipping?

Hi! I'm creating a game in which the player is able to push a cart. You know, like carts in supermarkets.

I find the CharacterController do a great thing detecting collisions, but I can't get the cart to stop whenever it hits a wall.

The character is able to push the cart and all, but I can't find a way to make the character stop when the CART collides with a wall!

Everything is on screenshots.

I've tried to set a short raycast in front of the cart and then stop the character, but it makes it feel ugly when the character stops at all, instead of "sliding" along the wall.

I've also tried resizing the CharacterController capsule to fit the cart in it, but it's not working the way I'd like it to. :(

Help me, please. :(