{"ast_node_type":"other","tokens":[{"end":49,"kind":"keyword","start":0,"text":"ty::GenericArgKind::Lifetime(r1)"}]}
            ty::GenericArgKind::Lifetime(r1) => {
        match arg.kind() {
                self.register_region_outlives_constraint(ty::OutlivesPredicate(r1, r2), cause);