{"ast_node_type":"variable","tokens":[{"end":30,"kind":"keyword","start":0,"text":"let"}]}
    let span = fn_.ident.span;
fn get_location_info(cx: &ExtCtxt<'_>, fn_: &ast::Fn) -> (Symbol, usize, usize, usize, usize) {
    let (source_file, lo_line, lo_col, hi_line, hi_col) =