{"ast_node_type":"other","tokens":[{"end":80,"kind":"keyword","start":0,"text":"sess.source_map().span_to_snippet(positional_arg_to_replace)"}]}
                    sess.source_map().span_to_snippet(positional_arg_to_replace)
                let span_to_replace = if let Ok(positional_arg_content) =
                    && positional_arg_content.starts_with(':')