I've had code which uses substr($foo, n, n) = '';
as an rvalue. And I'm sure others have had code which used this too. If this usage is considered a bug and Perl was resultingly changed, then this code will be broken. And this code wasn't
written on a bug - it was written on undefined behaviour
. As such, then any change to the perl implementation should be considered a core language change.
With Perl 5 coming towards the latter half it's usage, is it sensible to be making core language changes? Surly it would just make more sense to define this behaviour - and change the documentation to reflect this difference.
Just wanting to be able to upgrade Perl5 without fear of code breakage.