{"ast_node_type":"other","tokens":[{"end":91,"kind":"keyword","start":0,"text":"self.cx.typeck_results().opt_field_index(f.hir_id)"}]}
                        self.cx.typeck_results().opt_field_index(f.hir_id) == Some(f_index)
                    let is_mentioned = fields.iter().any(|f| {
                    });