I believe I read somewhere that recent versions of Perl detect certain obviously pathological cases and abort them, but I don't know if they fail silently or di

I believe I read somewhere that recent versions of Perl detect certain obviously pathological cases and abort them, but I don't know if they fail silently or display an error. Whether a particular needle is pathological depends on the haystack, too, so it could just be that there was a mismatch between the two in your case.