{"ast_node_type":"other","tokens":[{"end":74,"kind":"keyword","start":0,"text":"debug_assert!(self.downgrade_mut_inside_shared());"}]}
                        debug_assert!(self.downgrade_mut_inside_shared());
                        // ruleset with Rule 4 but not Rule 3, we'll need to check that here.
                        let mutbl_cap = cmp::min(r_mutbl, pat_info.max_ref_mutbl.as_mutbl());