Cannot set exception code for custom exception

Description

The following code:

<?php

class Example extends \Exception {
  protected $code = 5;
}

echo '  → ', (new Example(''))->getCode(), \PHP_EOL;
echo '0 → ', (new Example('', 0))->getCode(), \PHP_EOL;
echo '1 → ', (new Example('', 1))->getCode(), \PHP_EOL;

Resulted in this output:

  → 5
0 → 5
1 → 1

But I expected this output instead:

  → 5
0 → 0
1 → 1

There is a note about default parameters in exception constructor on php.net. However, case 2 in the above example explicitly passes the code parameter to the constructor.

Calling the constructor of class Exception from a subclass ignores the default arguments, if the properties $code and $message are already set. about default parameters in exception constructor on php.net.

PHP Version

PHP 8.2

Operating System

Debian 11

The report provides a PHP 8.2 reproducer involving a custom Exception subclass, the Exception constructor, and getCode(). Start by locating those entry points in php-src and reproducing all three constructor calls. Done means an explicitly passed code of 0 is preserved while the other demonstrated outputs remain correct.