| error[E0594]: cannot assign to `y`, as it is not declared as mutable | |
| --> $DIR/immutable-outer-variable.rs:14:25 | |
| | | |
| LL | foo(Box::new(use || y = !y) as Box<_>); | |
| | ^^^^^^ cannot assign | |
| | | |
| help: consider changing this to be mutable | |
| | | |
| LL | let mut y = true; | |
| | +++ | |
| error: aborting due to 1 previous error | |
| For more information about this error, try `rustc --explain E0594`. |