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run code in 300+ PHP versions simultaneously
<?php class Foo { public $foo; public function &bar1() { return $this; } public function bar2($o) { $x =& $this->bar1(); $x = $o; } } $a = new Foo; $a->foo = 1; $b = new Foo; $b->foo = 2; var_dump($a->foo, $b->foo); $a->bar2($b); var_dump($a->foo, $b->foo);

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