3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = new class() {}; class_alias($a::class, \array::class); function foo(\array $x) { print_r($x); } foo($a); ?>
Output for 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.26, 8.4.1 - 8.4.13
class@anonymous Object ( )

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64.64 ms | 406 KiB | 5 Q