$a = [ [1],[2],[3] ];;

print @$a[1];;
ARRAY(0x1b7ae0)

print @{$a}[1];;
ARRAY(0x1b7ae0)

##</code><code>##

print @{ $a[1] };;
2

##</code><code>##

print @$a->[1];;
Using an array as a reference is deprecated at (eval 15) line 1, <STDIN> line 7.
ARRAY(0x1b7ae0)

##</code><code>##

print @{ $a->[1] };;
2