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<?php $row = array(1, 2, 3, 4); echo " <h2>question</h2> <p>".chr(64 + $row)."</p> <h2>answer</h2> <p>".chr(64 + $row)."</p>";
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Fatal error: Uncaught TypeError: Unsupported operand types: int + array in /in/nUc9r:6 Stack trace: #0 {main} thrown in /in/nUc9r on line 6
Process exited with code 255.
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33
Fatal error: Uncaught Error: Unsupported operand types in /in/nUc9r:6 Stack trace: #0 {main} thrown in /in/nUc9r on line 6
Process exited with code 255.
Output for 5.4.1 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28
Fatal error: Unsupported operand types in /in/nUc9r on line 6
Process exited with code 255.

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