error[E0502]: cannot borrow `vec` as immutable because it is also borrowed as mutable --> $DIR/suggest-local-var-for-vector.rs:3:9 | LL | vec[vec.len() - 1] = 123; | ----^^^----------- | | || | | |immutable borrow occurs here | | mutable borrow later used here | mutable borrow occurs here | help: try adding a local storing this... --> $DIR/suggest-local-var-for-vector.rs:3:9 | LL | vec[vec.len() - 1] = 123; | ^^^^^^^^^ help: ...and then using that local here --> $DIR/suggest-local-var-for-vector.rs:3:8 | LL | vec[vec.len() - 1] = 123; | ^^^^^^^^^^^^^^^ error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0502`.