class SomeClass
 {
     public function run($value)
     {
-        return is_object($value) ? get_class($value) : gettype($value);
+        return get_debug_type($value);
     }
 }

Configure your rector.php:

<?php

use Rector\Config\RectorConfig;
use Rector\Php80\Rector\Ternary\GetDebugTypeRector;

return RectorConfig::configure()
    ->withRules([
        GetDebugTypeRector::class,
    ]);

SETS:  PHP 8.0 Polyfills