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<?php $a = [1,2,3]; $b = [4,5,6]; foreach ($a as &$v) { $v += 10; } var_dump($a[2]); foreach ($b as $v) { var_dump($a[2]); $v *= -1; } var_dump($a, $b);
Output for 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
int(13) int(4) int(5) int(6) array(3) { [0]=> int(11) [1]=> int(12) [2]=> &int(-6) } array(3) { [0]=> int(4) [1]=> int(5) [2]=> int(6) }

preferences:
141.77 ms | 403 KiB | 155 Q