[Bug] Windows function lag()/lead() function throw AnalysisException

[HappenLee]

Describe the bug
There is a table:

CREATE TABLE `baseall` (
 `k1` tinyint(4) NULL COMMENT "",
 `k2` smallint(6) NULL COMMENT "",
 `k3` int(11) NULL COMMENT "",
 `k4` bigint(20) NULL COMMENT "",
 `k5` decimal(9, 3) NULL COMMENT "",
 `k6` char(5) NULL COMMENT "",
 `k10` date NULL COMMENT "",
 `k11` datetime NULL COMMENT "",
 `k7` varchar(20) NULL COMMENT "",
 `k8` double MAX NULL COMMENT "",
 `k9` float SUM NULL COMMENT ""
) ENGINE=OLAP
AGGREGATE KEY(`k1`, `k2`, `k3`, `k4`, `k5`, `k6`, `k10`, `k11`, `k7`)
COMMENT "OLAP"
DISTRIBUTED BY HASH(`k1`) BUCKETS 5
PROPERTIES (
"replication_num" = "1",
"in_memory" = "false",
"storage_format" = "V2"
);

query:

select k7, k10 , k5, lag(k5, 1, 0) over (partition by k7 order by k10) as new_k5 from baseall;

will cause exception:

[Code: 1064, SQL State: 42000] Type = VARCHAR() can't not convert to VARCHAR()