Refactor call_user_func() with arrow function to direct call
 final class SomeClass
 {
     public function run()
     {
-        $result = \call_user_func(fn () => 100);
+        $result = 100;
     }
 }
                        Configure your rector.php:
<?php
use Rector\CodeQuality\Rector\FuncCall\CallUserFuncWithArrowFunctionToInlineRector;
use Rector\Config\RectorConfig;
return RectorConfig::configure()
    ->withRules([
        CallUserFuncWithArrowFunctionToInlineRector::class,
    ]);