psalm/tests/fixtures/stubs/polyfill.php

<?php
if (!function_exists('random_bytes')) {
    /**
     * @param int $bytes
     *
     * @return void
     */
    function random_bytes($bytes)
    {
        throw new \Exception('bad');
    }
}

if (!function_exists('new_random_bytes')) {
    /**
     * @param int $bytes
     *
     * @return int
     */
    function new_random_bytes($bytes)
    {
        return 5;
    }
}