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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