Redis redundant codes of replicationFeedSlaves

Redis will check its replication backlog and clients list in function replicationFeedSlaves when it feed slaves. But it check this condition twice with /* a if statement and a redisAssert statement */. Do function replicationFeedSlaves need to do?

void replicationFeedSlaves(list *slaves, int dictid, robj **argv, int argc) {
    listNode *ln;
    listIter li;
    int j, len;
    char llstr[REDIS_LONGSTR_SIZE];

    /* If there aren't slaves, and there is no backlog buffer to populate,
     * we can return ASAP. */
    if (server.repl_backlog == NULL && listLength(slaves) == 0) return;

    /* We can't have slaves attached and no backlog. */
    redisAssert(!(listLength(slaves) != 0 && server.repl_backlog == NULL));
 }

Comment From: madolson

Those are not the same equality.