<?php
#[AllowDynamicProperties]
class E {}
function f() {
    $e1 = new E;
    $e2 = new E;
    $a = ['e2' => $e2];
    $e1->a = (object)$a;
    $e2->e1 = $e1;
    $e2->a = (object)$a;
}
f();
gc_collect_cycles();
echo "End\n";
?>