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run code in 500+ PHP versions simultaneously
<?php class B { const A = 1; } $c = "b"; // can't use ??, it is a fatal error echo B::{$c} ?? ''; // can't use isset() because it is an expression if (isset(B::{$c})) { echo B::{$c}; } // Must use defined() as it is a constant // and then, use the string syntax if (defined("B::$c")) { echo B::{$c}; } // This still yields a fatal error, or will check the class constant content if (defined(B::{$c})) { echo B::{$c}; }
Output for 8.5.3
Fatal error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead) in /in/pNPQG on line 13 Stack trace: #0 {main}
Process exited with code 255.
Output for 8.3.5
Fatal error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead) in /in/pNPQG on line 13
Process exited with code 255.
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