Re^4: no way it's not a bug of Perl

[vincentaxhe]

I expected it just do nothing, But it's more useful to take last matched pattern.

[ikegami]

s/(?:)// will do nothing (or rather, replace one-zero length string with another zero-length string). So, if you have a possibly-empty pattern in a variable, you could use

s/(?:$pat)//

or

my $re = qr/$pat/;

s/$re//

The latter was buggy before 5.18 as it resulted in the same as s/// when $pat contained an empty string.

[vincentaxhe]

glad to learn that there is a way to suppress the urge of abnormal behavior.