$  perl -wle 'print defined ref 0'
1
$  perl -wle 'my $a; print defined ref $a'
1
$ perldoc -f ref
ref EXPR
ref Returns a true value if EXPR is a reference, false otherwise.
If EXPR is not specified, $_ will be used.  The value returned
depends on the type of thing the reference is a reference to.

# Salvation?
$  perl -MScalar::Util=blessed -wle 'my $a; print defined blessed(bless [] => 0)'
1
$  perl -MScalar::Util=blessed -wle 'my $a; print defined blessed($a)'