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<?php $a = 12; $b = null; $c = $x ?? $b ?? $a; echo $c;
Output for 7.0.0 - 7.0.20, 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 - 8.3.6
12
Output for 5.5.24 - 5.5.35, 5.6.8 - 5.6.28
Parse error: syntax error, unexpected '?' in /in/ZYdQV on line 5
Process exited with code 255.

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