in reply to Autoboxing ... "Yes We Can" ( or how I learned to love TIMTOWTDI ;)
Someone much wiser than me once said it is better to remain silent and be thought a fool than to open one's mouth and remove all doubt.
That being said ... I feel compelled to ask the (obvious?) question of what does this buy us? To me, it looks a lot like using postfix notation in a way that does not contribute to making Perl read like English. That is, where next unless $foo > $bar; reads like a sentence in English, @foo->push($bar) doesn't, to me at least. (I should point out that I take strong exception to PBP discouraging postfix notation.)
I think my point can be demonstrated even better when given something like 'Hello, world!'->upper();. There is no need whatsoever for an argument to "upper" in that case. How is that more clear as to intent than upper('Hello, world!');? (I will grant that a modification-in-place such as $foo->upper() might be more concise that $foo = upper($foo), but clarity would still be open to debate, especially given a use-case such as say $foo->upper();.)
I can see where this could be useful for a language that is not as flexible or useful as Perl (i.e. strongly typed languages that resemble a straight-jacket) but I don't see that it adds to Perl other than contributing to (excessive?) code bloat in an effort to add something that Perl might not really need given its existing versatility.