Static DISALLOWED_PASS_BY_REF 

pub static DISALLOWED_PASS_BY_REF: &Lint

The disallowed_pass_by_ref lint detects if types marked with #[rustc_pass_by_value] are passed by reference. Types with this marker are usually thin wrappers around references, so there is no benefit to an extra layer of indirection. (Example: Ty which is a reference to an Interned<TyKind>)