| error[E0596]: cannot borrow immutable local variable `v` as mutable | |
| --> $DIR/issue-33819.rs:13:39 | |
| | | |
| LL | Some(ref v) => { let a = &mut v; }, | |
| | ^ cannot borrow mutably | |
| error: aborting due to previous error | |
| For more information about this error, try `rustc --explain E0596`. |