{"ast_node_type":"function","tokens":[{"end":57,"kind":"keyword","start":0,"text":"fn"}]}
fn eat_char<S: Copy>(iter: &mut TtIter<'_, S>, c: char) {
    if matches!(iter.peek(), Some(TtElement::Leaf(tt::Leaf::Punct(tt::Punct { char, .. }))) if *char == c)