{"ast_node_type":"other","tokens":[{"end":63,"kind":"keyword","start":0,"text":"assert!(ast_id_map.ast_id_for_block(&block).is_none());"}]}
        assert!(ast_id_map.ast_id_for_block(&block).is_none());
        let block = syntax.descendants().find_map(ast::BlockExpr::cast).expect("no block");
    }