1 A variable was borrowed as mutable more than once.
3 Erroneous code example:
10 // error: cannot borrow `i` as mutable more than once at a time
13 Please note that in rust, you can either have many immutable references, or one
14 mutable reference. Take a look at
15 https://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html for more
21 let mut x = &mut i; // ok!
26 let b = &i; // still ok!
27 let c = &i; // still ok!