PDOException::getCode() return value type is string

Description

The following code:

<?php

declare(strict_types=1);

try
{
    $pdo = new PDO('mysql:host=127.0.0.1', 'root', 'root');
    $pdo->query('select x');
}
catch (\Throwable $e)
{
    var_dump($e->getCode());
    throw new \Exception($e->getMessage(), $e->getCode(), $e);
}

Resulted in this output:

string(5) "42S22"
PHP Fatal error:  Uncaught TypeError: Exception::__construct(): Argument #2 ($code) must be of type int, string given in /mnt/d/projects/imi/imi-2.1/test.php:13
Stack trace:
#0 /mnt/d/projects/imi/imi-2.1/test.php(13): Exception->__construct()
#1 {main}
  thrown in /mnt/d/projects/imi/imi-2.1/test.php on line 13

But I expected this output instead:

string(5) "42S22"
PHP Fatal error:  Uncaught PDOException: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'x' in 'field list' in /mnt/d/projects/imi/imi-2.1/test.php:8
Stack trace:
#0 /mnt/d/projects/imi/imi-2.1/test.php(8): PDO->query()
#1 {main}

Next Exception: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'x' in 'field list' in /mnt/d/projects/imi/imi-2.1/test.php:13
Stack trace:
#0 {main}
  thrown in /mnt/d/projects/imi/imi-2.1/test.php on line 13

Is it possible to change the return value of Throwable::getCode() to int|string?

https://github.com/php/php-src/blob/eb22f1a31ad02699c718fe15ce648acd401900e4/Zend/zend_exceptions.stub.php#L12

PHP Version

8.0.21

Operating System

Ubuntu 20.04

Start by reviewing the linked Throwable declaration in Zend/zend_exceptions.stub.php and reproduce the PDOException example on PHP 8.0.21. Trace how exception codes are represented and checked, then determine the compatibility requirements for the proposed int|string return type. Done means the intended behavior and affected tests or API constraints are documented and validated.