function run(stdClass $stdClass)
 {
-    if (! $stdClass instanceof stdClass) {
-        return false;
-    }
-
     return true;
 }

Configure your rector.php:

<?php

use Rector\Config\RectorConfig;
use Rector\DeadCode\Rector\If_\RemoveDeadInstanceOfRector;

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

SETS:  Dead Code Instanceof