...
lib/B.pm
...
lib/C/C1.pm
...

##</code><code>##

package C::C1;

##</code><code>##

use C1;

my $c1 = C1::->new();

##</code><code>##

use C::C1;

my $c1 = C::C1::->new();

##</code><code>##

$ ./acd.pl
A=HASH(0x9897d0)
A-bar
D=HASH(0x989890)
D-bar
whos_who() is in package: C
$self is in package: C::C1