Why the “Null” Lifetime Does Not Exist

In a recent conversation on the Rust community Discord, a user raised an interesting question: does Rust have an opposite to the 'static lifetime? Is there a lifetime that is shorter than any other? While the idea may seem intuitive, the answer is no. Rust's type system is designed with the assumption that given a valid lifetime, you can always make a shorter one. Therefore, any hypothetical 'null lifetime would have to be non-constructible. This post explores why Rust does not support self-referential types and how async blocks in Rust handle borrowing values across .await points. While Rust may not have a "null" lifetime, understanding the reasons behind it can help developers write safer and more robust code.