in reply to Re^4: no way it's not a bug of Perl
in thread I thought I found a bug of Perl

100% agree. At $job - 2, we spent several days tracking a bug caused by s/$regex/$replace/ where $regex got accidentally empty and the substitution started replacing unrelated parts of the data.

Besides /b or a feature, another way would be to introduce a new construct, e.g. (*LAST), which you can use similarly to (*SKIP) etc.

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

In Section Seekers of Perl Wisdom