{"ast_node_type":"function","tokens":[{"end":79,"kind":"keyword","start":0,"text":"pub"}]}
    pub fn expect(&mut self, exp: ExpTokenPair<'_>) -> PResult<'a, Recovered> {
    /// Expects and consumes the token `t`. Signals an error if the next token is not `t`.
        if self.expected_token_types.is_empty() {