1 error[E0499]: cannot borrow `*s` as mutable more than once at a time
2 --> $DIR/issue-18566.rs:23:19
5 | - ---- ^ second mutable borrow occurs here
7 | | first borrow later used by call
8 | first mutable borrow occurs here
10 error: aborting due to previous error
12 For more information about this error, try `rustc --explain E0499`.