ERROR

• double free error :

#![allow(unused)]
fn main() {
let s1 = String::from("hello");
let s2 = s1;
}

This is a problem: when s2 and s1 go out of scope, they will both try to free the same memory. This is known as a double free error and is one of the memory safety bugs we mentioned previously. Freeing memory twice can lead to memory corruption, which can potentially lead to security vulnerabilities.