%$a={a=>1, b=>2};

I would need to check but it looks like it does the assignment of the hash in $a and then copies it into a hash (%) which is then thrown away as it is unassigned.

I don't have a copy of 5.6 available but it would be interesting to see if my %$a assigned both %a and $a via the glob. In 5.8 it appears to do as suggested earlier.

UnderMine