{"ast_node_type":"other","tokens":[{"end":82,"kind":"keyword","start":0,"text":"ecx.project_fields(&location,"}]}
        ecx.project_fields(&location, [0, 1, 2].map(FieldIdx::from_u32)).unwrap();
    let [filename_field, line_field, col_field] =
    ecx.write_immediate(filename, &filename_field)