syncer can't decode set datatype

[CrazyNash]

There is a table has a set field region defined as

`region` set('1','1001','2001','3001','4001','5001','6001','7001','8001','8100','9001')

And for a record with 5001, mysql binlog shows

### SET
...
###   @6=b'0010000000000000' /* SET(2 bytes) meta=63490 nullable=0 is_null=0 */

syncer tried to insert 8192 (b'0010000000000000') directly into the record, where it should decode the bit to '5001' first.

tidb failed for

"REPLACE INTO `u`.`t_common` (`id`,`bit`,`purpose`,`is_valid`,`is_basic`,`region`) VALUES (126,90,'XXX',1,0,8192);"
/home/jenkins/workspace/build_tidb_2.0/go/src/github.com/pingcap/tidb/types/datum.go:1554: cannot convert datum from tinyint to type set.

[july2993]

thanks for your report, we will take a look and fix it later