1error[E0596]: cannot borrow `x` as mutable, as it is not declared as mutable 2 --> $DIR/issue-37139.rs:12:18 3 | 4LL | test(&mut x); 5 | ^^^^^^ 6 | | 7 | cannot borrow as mutable 8 | help: try removing `&mut` here 9 10error: aborting due to previous error 11 12For more information about this error, try `rustc --explain E0596`. 13