Car Coin

The contract allows users to buy land for a specific rental period. Once purchased, the land’s ownership is stored along with an expiresAt timestamp. However, there’s no logic that resets or frees the land after the expiration time. The checkassert(land.owner == address(0)); prevents anyone from buying land that has already been purchased — even if the rental period has ended. This means once a land is bought, it becomes permanently locked in the contract, even after its expiry. No one — not even the original buyer — can renew or re-purchase the same land. This breaks the idea of land rental, making the expiration timestamp pointless and reducing the contract’s usability long-term.