error[E0502]: cannot borrow `vec` as immutable because it is also borrowed as mutable --> $DIR/suggest-storing-local-var-for-vector.rs:3:9 | LL | vec[vec.len() - 1] = 123; | ----^^^^^^^^^----- | | | | | immutable borrow occurs here | mutable borrow occurs here | mutable borrow later used here | help: try adding a local storing this... --> $DIR/suggest-storing-local-var-for-vector.rs:3:9 | LL | vec[vec.len() - 1] = 123; | ^^^^^^^^^ help: ...and then using that local here --> $DIR/suggest-storing-local-var-for-vector.rs:3:5 | LL | vec[vec.len() - 1] = 123; | ^^^^^^^^^^^^^^^^^^ error: aborting due to previous error For more information about this error, try `rustc --explain E0502`.