{"ast_node_type":"variable","tokens":[{"end":50,"kind":"keyword","start":0,"text":"let"}]}
    let output = Arc::new(Mutex::new(Vec::new()));
fn create_test_handler(theme: OutputTheme) -> (DiagCtxt, Arc<SourceMap>, Arc<Mutex<Vec<u8>>>) {
    let source_map = Arc::new(SourceMap::new(FilePathMapping::empty()));