{"ast_node_type":"variable","tokens":[{"end":76,"kind":"keyword","start":0,"text":"let"}]}
            let (lifetime_defs, _) = self.parse_late_bound_lifetime_defs()?;
            //   `for<'lt> Trait1<'lt> + Trait2 + 'a`
            if self.check_fn_front_matter(false, Case::Sensitive) {