3v4l.org

run code in 300+ PHP versions simultaneously
<?php function arraykey(int|string $arg) : int|string { return $arg; } var_dump([ arraykey("foo") => "foo", arraykey(42) => 42, ]);
Output for 8.1.3 - 8.1.33, 8.2.10 - 8.2.29, 8.3.0 - 8.3.26, 8.4.1 - 8.4.13
array(2) { ["foo"]=> string(3) "foo" [42]=> int(42) }
preferences:
81.32 ms | 406 KiB | 5 Q