In the previous samples we forgot the /g option needed to match ALL
occurrences of the pattern:

"""
use Data::Dumper;

$a = "a\nb\nc";
$a =~ s/$/#/g;
print Dumper($a);

$a = "a\nb\n";
$a =~ s/$/#/g;
print Dumper($a);
"""

Which now gives the same output as Python:

$VAR1 = 'a
b
c#';
$VAR1 = 'a
b#
#';

Perl is too difficult for us ;-)

What shall we do?
- mark the issue as invalid
- diverge from Perl regular expressions
- file a bug in the PCRE issue tracker
And in every case: add these samples to the test suite.