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run code in 300+ PHP versions simultaneously
<?php class A { private static self $singleton; private function __construct() {} public static function getInstance(): self { if(!isset(self::$singleton)) { self::$singleton = new self; } return self::$singleton; } } $a = A::getInstance(); $b = A::getInstance(); $c = A::getInstance(); var_dump($a); var_dump($b); var_dump($c);

preferences:
48.65 ms | 404 KiB | 5 Q