1 error[E0384]: cannot assign to immutable argument `_x`
2 --> $DIR/immutable-arg.rs:2:5
5 | -- help: consider making this binding mutable: `mut _x`
7 | ^^^^^^ cannot assign to immutable argument
9 error: aborting due to previous error
11 For more information about this error, try `rustc --explain E0384`.