How does rust deal with the ownership of the returned string?

This is the code I have:

fn test_function() -> String {
    String::from("")
}

fn main() {
    test_function();
    println!("Hello");
}

I was expecting rust to complain about test_function return value not being assigned, but it just works.

How are the rules of ownership applied here?

>Solution :

I was expeting rust to complain about test_function return value not being assigned, but it just works.

Why would it complain? Rust’s type system is affine, meaning values can be used at most once. Using them 0 times is valid (you can mark types and functions as #[must_use] to trigger a warning, but even then a simple let _ = ... will silence it)

How are the rules of ownership applied here?

The string is moved out of the function, then dropped by the caller since nothing is keeping it alive.