{"ast_node_type":"other","tokens":[{"end":94,"kind":"keyword","start":0,"text":"self.try_structurally_resolve_const(base.span,"}]}
            self.try_structurally_resolve_const(base.span, len).try_to_target_usize(self.tcx),
        if let (Some(len), Ok(user_index)) = (
            field.as_str().parse::<u64>(),