I doubt your central assertion that this sort of thing happens all the time though. How many times do you see named subroutines declared inside loops? Almost never. And I have never heard of anyone accidentally creating a closure.

Personally, I find using closures a liberating experience, and since they make some hard things easy, actually reduce bugs.

You're quite incorrect. In most cases perrin's example would have been file scope. That sort of accidental closure is excessively common. So much so that I seem to recall there being a sort of relaxing about the rules of scoping for file scoped my() lexicals but I don't recall what it was or where I heard it.

Who said this was in a loop? This is a CGI script, which exhibits this problem when run in any persistent environment like mod_perl, PerlEx, etc. These are a very common target for Perl code, so this comes up all the time. I have helped several people with this exact problem on PerlMonks, and many more on the mod_perl list. They never believe me when I tell them it's a closure.

It happens in other situations too, but this is the most common one I've seen.

Well, now I understand the mechanics behind it becoming a closure, but why on earth would perl make it a closure? That doesn't make any sense to me. Why wouldn't the sub just use whatever $q it can find in the closest scope to it?