... 'is' ... is overkill ...

I strongly agree! What's the point of bringing Scalar::Util::refaddr() et al to the party when  == != (and all the other numeric comparators, in the unlikely event they would be of any use) seem to manage just fine:

c:\@Work\Perl\monks>perl
use strict;
use warnings;

use Test::Simple tests => 4;
1..4

sub is { $_[0] == $_[1] }

my $x = 3;
my $y = 3;

my $x_ref = \$x;

my $test_ref_1 = \$x;
my $test_ref_2 = \$y;

ok(  is($test_ref_1, $x_ref), 'is Same'      );
ok( !is($test_ref_2, $x_ref), 'is Different' );

ok( $test_ref_1 == $x_ref, '==' );
ok( $test_ref_2 != $x_ref, '!=' );

__END__
ok 1 - is Same
ok 2 - is Different
ok 3 - ==
ok 4 - !=
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What's the point of bringing Scalar::Util::refaddr() et al to the party when == != (and all the other numeric comparators ... seem to manage just fine

Because it's the only solution in the whole thread that still works even in the presence of operator overloading? ;-)

use warnings;
use strict;

package Foo {
    my $x;
    use overload '<=>'=>sub{1}, 'cmp'=>sub{1}, '0+'=>sub{++$x};
}

my $x = bless {}, 'Foo';
my $y = $x;

print $x==$y ? "True\n" : "False\n";     # False

use Scalar::Util qw/refaddr/;
sub is { return refaddr $_[0] == refaddr $_[1] }

print is($x,$y) ? "True\n" : "False\n";  # True
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Hmm... Hadn't thought about that.

---

Give a man a fish:  <%-{-{-{-<

Your comment clarifies exactly what I meant. However, the documentation of the refaddr function in Scalar::Util assures us that our operatores are comparing addresses. The user documentation for references (perlref) makes no such claim.
Bill

you assume references. I don't know what python's is() does but I would expect any Perl is() to handle both is($x,$y) and is(\$x, \$y).