ClassConstantToSelfClassRector

Change __CLASS__ to self::class

 class SomeClass
 {
    public function callOnMe()
    {
-       var_dump(__CLASS__);
+       var_dump(self::class);
    }
 }

Configure your rector.php:

<?php

use Rector\Config\RectorConfig;
use Rector\Php55\Rector\Class_\ClassConstantToSelfClassRector;

return RectorConfig::configure()
    ->withRules([
        ClassConstantToSelfClassRector::class,
    ]);
SETS:  PHP 5.5