$a=[];
is_deeply($a, "$a");

##</code><code>##

my ($x,$y,$ar1);
$x=\$y;
$y=\$x;
$ar1=[$x,$y];
my $ar2;
$ar2->[0]=\$ar2->[1];
$ar2->[1]=\$ar2->[0];

is_deeply($ar1,$ar2); #this is wrong, wrong, wrong.