1 error[E0499]: cannot borrow `i` as mutable more than once at a time
4 LL | let mut x = &mut i;
5 | ------ first mutable borrow occurs here
6 LL | let mut a = &mut i;
7 | ^^^^^^ second mutable borrow occurs here
10 | ----------- first borrow later used here
12 error: aborting due to previous error
14 For more information about this error, try `rustc --explain E0499`.