# A.pm
package A;
use 5.014;
use Moo;

sub say_hello {
    my $self = shift;
    my ($name) = @_;
    say "Hello, $name!";
}

1;

##</code><code>##

# C.pm
package C;
use 5.014;
use Moo;
has 'name' => (is => 'rw');

sub say_goodbye {
    my $self = shift;
    say 'Goodbye, ', $self->name, '!';
}
1;

##</code><code>##

# C1.pm
package C1;
use 5.014;
use strict;
use warnings;

use Moo;
extends 'C';
use A;

has '_a' => (is => 'ro',
             default => sub { A->new() },
             handles => [qw(say_hello)]
         );

1;

##</code><code>##

use strict;
use warnings;
use C1;

my $c = C1->new(name => 'John Doe');
$c->say_hello('World');
$c->say_goodbye;

##</code><code>##

package C1;
use parent (qw(A B C D));