error[E0594]: cannot assign to `*x`, which is behind a `&` reference --> $DIR/let-else-binding-immutable.rs:9:5 | LL | *x += 1; | ^^^^^^^ `x` is a `&` reference, so the data it refers to cannot be written error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0594`.