Lifetime bounds are Rust annotations that ensure references remain valid for the required duration to prevent memory safety errors.
Lifetime bounds are annotations that tell the Rust compiler how long references must remain valid to prevent dangling pointers. They ensure that a reference does not outlive the data it points to, guaranteeing memory safety without a garbage collector.
fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
if x.len() > y.len() { x } else { y }
}
Lifetime bounds are like expiration dates on borrowed items, ensuring you don't try to use something after it has been returned or destroyed. They matter because they prevent your program from crashing by accessing memory that no longer exists. You use them whenever a function returns a reference or stores one, telling the compiler exactly how long that connection must stay alive.