{"ast_node_type":"variable","tokens":[{"end":99,"kind":"keyword","start":0,"text":"let"}]}
                let len = ty::Const::from_target_usize(self.tcx, fields.len().try_into().unwrap());
            if fields.iter().all(|&v| v == first) {
                if let Some(op) = self.try_as_operand(first, location) {