1 error[E0502]: cannot borrow `my_stuff` as mutable because it is also borrowed as immutable
2 --> $DIR/hashmap-lifetimes.rs:18:5
4 LL | let mut it = my_stuff.iter();
5 | -------- immutable borrow occurs here
6 LL | my_stuff.insert(1, 43); //~ ERROR cannot borrow
7 | ^^^^^^^^ mutable borrow occurs here
10 | - immutable borrow ends here
12 error: aborting due to previous error
14 For more information about this error, try `rustc --explain E0502`.