3v4l.org

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<?php $a = NAN; var_dump($a == $a); var_dump($a === $a); $a = [NAN]; $b = [NAN]; var_dump($a == $a); var_dump($a === $a); var_dump($a == $b); var_dump($a === $b);
Output for 7.4.0 - 7.4.33, 8.0.1 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
bool(false) bool(false) bool(true) bool(true) bool(false) bool(false)

preferences:
102.9 ms | 407 KiB | 5 Q