{"ast_node_type":"function","tokens":[{"end":62,"kind":"keyword","start":0,"text":"fn"}]}
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
impl<S: Copy + fmt::Debug> fmt::Debug for TopSubtree<S> {
        fmt::Debug::fmt(&tt::TokenTreesView::new(&self.0), f)