{"ast_node_type":"variable","tokens":[{"end":44,"kind":"keyword","start":0,"text":"let"}]}
    let punct = iter.expect_single_punct()?;
fn expect_lifetime<'a, S: Copy>(iter: &mut TtIter<'a, S>) -> Result<&'a tt::Ident<S>, ()> {
    if punct.char != '\'' {