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run code in 300+ PHP versions simultaneously
<?php $arr = array(1); $a =& $arr[0]; //$a and $arr[0] are in the same reference set $arr2 = $arr; //not an assignment-by-reference! var_dump($arr2); $arr2[0]++; var_dump($arr2); var_dmp($a); $arr[0]++; var_dump($arr2); var_dump($arr); var_dmp($a);

preferences:
53.7 ms | 402 KiB | 5 Q