use strict;
use warnings FATAL => 'all';

package Base;
sub hello { print __PACKAGE__.": @{[ref $_[0] || $_[0]]}\n"; }

package Kid;
our @ISA = 'Base';

package Main;
sub hello { print __PACKAGE__.": @{[ref $_[0] || $_[0]]}\n"; }

package main;
our @ISA = 'Main';

my $main = bless {};
$main->Kid::hello;    # Base: main
$main->hello;         # Main: main

__PACKAGE__->hello;   # Main: main
BareWord->Kid::hello; # Base: BareWord