A bug is every user-visible behaviour that is contrary to the documentation. I'd not call the output of Devel::Peek user-visible (it's a Devel:: module, after all), and the the docs generally don't give performance guarantees.

That said you should still send a bug report to p5p, maybe they can do something about it (update: after reading tye's reply I think a doc patch would be appropriate).

I've taken a look inside the source code for pp_substr, but frankly, I do not understand the macro-machinations that go on in there.

I shared that experience the other day :/

In reply to Re: Bug or WAD in lvalue substr? (again.) by moritz
in thread Bug or WAD in lvalue substr? (again.) by BrowserUk

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