The bug is valid, and already fixed since 5.22 or so. To repro it you need to fix the order of global destruction, e.g by PERL_HASH_SEED=0
The problem is that the unicode helper swashes were already destroyed when the regex inside the DESTROY handler, run during global destruction, requested a re-load of the unicode swashes. The fix for the user is to replace \w by [a-zA-Z0-9_], to avoid triggering the invalid swash_init during global destruction. or use the new /a flag with newer perls (since 5.14), to avoid re-loading unicode during global destruction. Reini Urban rur...@cpan.org