Well, you can suppress the warnings, as shown by Discipulus, e.g. with the pragma:

no warnings 'experimental::smartmatch';
[download]

However, you should IMHO carefully consider whether you really want to do that. The smart match was for a time a full-fledged feature of Perl 5 and has been "downgraded" to "experimental" with Perl 5.20 if I remember correctly. This implies that it could be strongly modified or even removed in a future version, meaning that your program might cease to work after a Perl upgrade. Frankly, I would not use that feature for any program that is not a one-off script and might be used in the future.

Update: Sorry for a posting mistake: this post was meant as an answer to the OP, not to Discipulus's post. Too late, I am afraid, to do anything about it.