<?php
class A {
	public $b;
 
	public function __construct(B $b) {
	    $this->b = $b;
	}
}
 
class B {}
 
class C extends A {
	public function __clone() {
		$this->b = clone $this->b;
	}
}
 
$a = new A(new B);
$aa = clone $a;
$b = $a;
$c = new C(new B);
$cc = clone $c;
echo "CÓPIA\n";
var_dump($a === $b);
var_dump($a->b === $b->b);
echo "SEM __CLONE\n";
var_dump($a === $aa);
var_dump($a->b === $aa->b);
echo "COM __CLONE\n";
var_dump($c === $cc);
var_dump($c->b === $cc->b);

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