drush sql-sync tries to rsync unknown dump file Since I upgraded drush 5.10 -> 7.0-dev today, sql-sync fails to work with my existing alias file.  

Using the command drush sql-sync @limelive @limedev fails.

The %dump-dir paths on both local and remote aliases correctly address existing directories. --debug shows the remote sql dump success: 

 Database dump saved to /home/aegir/drush-backups/limetreethornfor/20140411235252/limetreethornfor_20140411_235252.sql.gz 


but later reports   

rsync: link_stat "/var/aegir/platforms/aventura-2014-04-11-1/Array" failed: No such file or directory  


This suggest new command syntax incorrectly diagnosed. What am I doing wrong?
This is a bug in Drush master.  Please put an issue in the queue on Github.