perl - pragma base - 警告の質問

Question

Attempting to inherit from yourself generates a warning.これを実行すると、 ( base#DIAGNOSTICS )が表示されないのはなぜですか?

#!/usr/bin/env perl
use warnings;
use diagnostics;
use 5.012;

{
    package MyWebServer;

    use HTTP::Server::Simple::CGI;
    use base qw(HTTP::Server::Simple::CGI);
    ...