Code Quality set Rule source on GitHub

ExplicitNullableObjectInstanceRector

Make implicit nullable object checks explicit with instanceof

 final class SomeController
 {
     public function run(?\stdClass $item)
     {
-        if (!$item) {
+        if (!$item instanceof \stdClass) {
             return 'empty';
         }

-        if ($item === null) {
+        if (!$item instanceof \stdClass) {
             return 'empty';
         }
     }
 }

Configure your rector.php:

<?php

use Rector\CodeQuality\Rector\If_\ExplicitNullableObjectInstanceRector;
use Rector\Config\RectorConfig;

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

Other rules in the Code Quality set