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<?php assert((!empty(0) ? 0 : 5) === 5); assert((0 ?? 5) === 0); // isset() is by-reference, so needs a variable. $x = 0; assert((isset($x) ? $x : 5) === 0);
Output for 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 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 - 8.1.31, 8.2.0 - 8.2.27, 8.3.0 - 8.3.15, 8.4.1 - 8.4.2
Output for 5.6.0 - 5.6.40
Parse error: syntax error, unexpected '?' in /in/Ddnjq on line 5
Process exited with code 255.

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