{"ast_node_type":"variable","tokens":[{"end":89,"kind":"keyword","start":0,"text":"let"}]}
        let policy = LetChainsPolicy::EditionDependent { current_edition: lo.edition() };
    fn parse_expr_while(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
        let cond = self.parse_expr_cond(policy).map_err(|mut err| {