[Mutable borrows] Error in tutorial

[iyernaveenr]

Hello,

In the "Mutable borrows" tutorial:
http://intorust.com/tutorial/mutable-borrows/
https://www.youtube.com/watch?v=pd7PJ6q4I3M&t=354s

The issue discussed ~06:15 does not happen. Please find all the details below:

$ cat main.rs
fn main() {
    let mut name = format!("fellow Rustaceans");
    let r = &mut name;
    helper(r);
    helper(r);
    println!("{}", name);
}

fn helper(name: &mut String) {
	name.push_str("foo");
}
$ rustc --edition 2015 main.rs
$ echo $?
0
$ ./main
fellow Rustaceansfoofoo
$ echo $?
0
$ rustc --edition 2021 main.rs
$ echo $?
0
$ ./main
fellow Rustaceansfoofoo
$ echo $?
0
$ rustc --version
rustc 1.84.0-nightly (32b17d56e 2024-10-28)
$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 22.04.4 LTS
Release:	22.04
Codename:	jammy
$ uname -m
x86_64
$ uname -r
6.5.0-44-generic
$ 

Thanks!