| Subject: | \C is deprecated in regex |
See subject. https://metacpan.org/pod/release/RJBS/perl-5.22.0/pod/perldelta.pod#New-Warnings contains this notice:
| New Warnings
| * \C is deprecated in regex
|
| (D deprecated) The "/\C/" character class was deprecated in v5.20,
| and now emits a warning. It is intended that it will become an error
| in v5.24. This character class matches a single byte even if it
| appears within a multi-byte character, breaks encapsulation, and can
| corrupt UTF-8 strings.
A sample report with this warning: http://www.cpantesters.org/cpan/report/551a6d36-06e6-11e5-8de9-bb9edfbfc7aa