{"ast_node_type":"variable","tokens":[{"end":92,"kind":"keyword","start":0,"text":"let"}]}
        let prev = self.fcx.checked_opaque_types_storage_entries.replace(Some(num_entries));
        let num_entries = self.fcx.inner.borrow_mut().opaque_types().num_entries();
        debug_assert_eq!(prev, None);