error[E0499]: cannot borrow `foo` as mutable more than once at a time --> $DIR/two-phase-across-loop.rs:17:22 | LL | strings.push(foo.get_string()); | ^^^^^^^^^^^^^^^^ `foo` was mutably borrowed here in the previous iteration of the loop error: aborting due to previous error For more information about this error, try `rustc --explain E0499`.