{"ast_node_type":"other","tokens":[{"end":79,"kind":"keyword","start":0,"text":"err.with_span_label(span,"}]}
            err.with_span_label(span, "`fn` calls are not allowed in patterns")
            let patterns_url = "https://doc.rust-lang.org/book/ch19-00-patterns.html";
                .with_help(format!("for more information, visit {patterns_url}"))