I don't believe so (re "further", it is, of course, part of the motivation for requiring backward compatability but is not the only such motivation). I don't see how using a lexical pragma that breaks such code is anybody's problem other than the person who broke the code by adding the pragma and not fixing the affected code to conform to the new behavior. Similarly, with Perl 6, you can use Perl 5 idioms if you tell Perl 6 that the code is "Perl 5 code" or if you know that the pragma also works in Perl 6. Though, perhaps there is already Perl 6 code in the wild that does this (no, I don't know if Perl 6 still works this way or not).