| error[E0384]: cannot assign to immutable argument `_x` | |
| --> $DIR/immutable-arg.rs:2:5 | |
| | | |
| LL | fn foo(_x: u32) { | |
| | -- help: make this binding mutable: `mut _x` | |
| LL | _x = 4; | |
| | ^^^^^^ cannot assign to immutable argument | |
| error: aborting due to previous error | |
| For more information about this error, try `rustc --explain E0384`. |