Bar.pm

package Foo::Bar;
use strict;
use warnings;

1;

Baz.pm

package Foo::Baz;
use strict;
use warnings;

1;

Foo.pm

package Foo;
use strict;
use warnings;

1;

test.pl

#!/usr/bin/env perl
use 5.010;
use strict;
use warnings;

# note, gists don't support subdirectories, so you will need to run the following commands 
# once you have checked out your gist and cd'd to it
#    mkdir -p lib/Foo
#    mv Foo.pm lib/
#    mv {Bar,Baz}.pm lib/Foo/

BEGIN {
    say "Note the error message (can't find Foo::Bar, that's the Foo.pm package.)";
    eval {
        require 'lib/Foo.pm';
    };
    say $@;
}

say "Note this loads without issue";
use lib 'lib';
use Foo;