use v5.12;
use strict;
use warnings;

package ToJson {
	use Moo::Role;
	
	sub TO_JSON {
		my $self = shift;
		return { %$self };
	}
}

package Named {
	use Moo::Role;
	use Types::Standard -types;
	
	has NAME => (
		is       => 'bare',
		isa      => Str,
		reader   => 'getName',
	);
}

package MyClassA {
	use Moo;
	use Types::Standard -types;
	
	with 'ToJson', 'Named';	
	
	has MY_CLASS_B => (
		is       => 'bare',
		reader   => 'getClassB',
		writer   => 'setClassB',
		isa      => InstanceOf->of('MyClassB')->plus_constructors( HashRef, 'new' ),
		coerce   => 1,
	);
}

package MyClassB {
	use Moo;
	
	with 'ToJson', 'Named';	
}

use JSON::MaybeXS;

my $a = MyClassA->new(NAME => 'A instance');
my $b = MyClassB->new(NAME => 'B instance');
$a->setClassB($b);

my $json = JSON->new->convert_blessed->encode($a);
say $json;

my $inflated = MyClassA->new( JSON->new->decode($json) );
say $inflated->getClassB->getName;