rt， 请问这个问题是feature还是bug，有没有对应的解决方法
$tagID = lookup on tagss where tagss.name=='Rupert_Murdoch';\
$tagMessage = go from $tagID.VertexID over comment_hasTag_tag reversely yield comment_hasTag_tag._dst as id union distinct go from $tagID.VertexID over post_hasTag_tag reversely;\
$msgLike = go from $tagMessage.id over person_likes_post reversely yield person_likes_post._src as msgID, person_likes_post._dst as personID union all go from $tagMessage.id over person_likes_comment reversely yield person_likes_comment._src as msgID, person_likes_comment._dst as personID;\
$msgLikeCount = yield $msgLike.msgID as msgID | group by $-.msgID yield $-.msgID as msgID, count(*) as likeCount, 0 as replyCount;\
$msgCom = go from $tagMessage.id over comment_replyOf_comment reversely yield comment_replyOf_comment._src as msgID, comment_replyOf_comment._dst as comID union all go from $tagMessage.id over comment_replyOf_post reversely yield comment_replyOf_post._src as msgID, comment_replyOf_post._dst as comID;\
$msgComCount = yield $msgCom.msgID as msgID| group by $-.msgID yield $-.msgID as msgID, 0 as likeCount, count(*) as replyCount;\
$msgAllCount = yield $msgLikeCount.msgID as msgID, $msgLikeCount.likeCount as likeCount, $msgLikeCount.replyCount as replyCount union all yield $msgComCount.msgID as msgID, $msgComCount.likeCount as likeCount, $msgComCount.replyCount as replyCount;\
$newMsgCombine = yield $msgAllCount.msgID as msgID , $msgAllCount.likeCount as likeCount, $msgAllCount.replyCount as replyCount union all yield $tagMessage.id as msgID, 0 as likeCount, 0 as replyCount;\
$msgCount = yield $newMsgCombine.msgID as msgID , $newMsgCombine.likeCount as likeCount, $newMsgCombine.replyCount as replyCount| group by $-.msgID yield $-.msgID as msgID, sum($-.likeCount) as likeCount ,sum($-.replyCount) as replyCount;\
#此处以上仍然正常，下面那句无法运行
go from $msgCount.msgID over post_hasCreator_person yield post_hasCreator_person._dst as id union go from $msgCount.msgID over comment_hasCreator_person
#突然失去了vid的类型??? Build internal index for input data failed. The specific vid column `msgID' is not type of VID, column index: 0l. rhs has error: Build internal index for input data failed. The specific vid column `msgID' is not type of VID, column index: 0l.
