Re^2: What is the best way to compare variables so that different types are non-equal?

[psini]

I really don't understand your example. I substituted warns with prints:

use strict;
use warnings;

my $re =qr{a};
my $re2 =qr{a};
print $re == $re2,"\n";
print $re2 == $re2,"\n";
print 0+$re,"\n";
print 0+$re2,"\n";

and this is the result:

sini@ordinalfabetix:~$ ./x.pl

1
135589228
135591376
sini@ordinalfabetix:~$

The last two lines are NOT equal, because are references to two different scalars. And, as a consequence, $re != $re2 (and $re == $re, but it was expected).

So numerical comparison doesn't tell you if two regex are equal, but only if they are the same (reference).