Is Rust using region-based memory management?

Question

For instance, if we forget about return value optimization, and have the following code:

fn func() -> Box<String> {
    Box::new(String::new())
}

fn main() {
    let boxed_string = func();
}

will the compiler create regions to manage the memory or will it use normal heap allocation?

I know this simple code might be optimized, but in a more complex code, it might not be the case.