{"ast_node_type":"variable","tokens":[{"end":93,"kind":"keyword","start":0,"text":"if"}]}
    if let Some(TtElement::Leaf(tt::Leaf::Punct(tt::Punct { char: ',', .. }))) = src.peek() {
fn try_eat_comma(src: &mut TtIter<'_, Span>) -> bool {
        let _ = src.next();