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<?php function a(&$a){$a = null; return 5;} $a = 1; var_dump($a += a($a)); var_dump($a); $b = 1; var_dump($b = $b + a($b)); var_dump($b);
Output for 5.5.0 - 5.5.38, 5.6.0 - 5.6.38, 7.0.0 - 7.0.33, 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.7
int(5) int(5) int(5) int(5)

preferences:
237.05 ms | 404 KiB | 294 Q