Rector\Php55\Rector\String_\StringClassNameToClassConstantRector

Configurable

StringClassNameToClassConstantRector

Replace string class names by ::class constant

 class AnotherClass
 {
 }

 class SomeClass
 {
     public function run()
     {
-        return 'AnotherClass';
+        return \AnotherClass::class;
     }
 }

Configure your rector.php:

<?php

use Rector\Config\RectorConfig;
use Rector\Php55\Rector\String_\StringClassNameToClassConstantRector;

return RectorConfig::configure()
    ->withConfiguredRule(StringClassNameToClassConstantRector::class, [
        'ClassName',
    'AnotherClassName',
    'should_keep_pre_slash' => false,
    ]);

SETS: PHP 5.5 Coding Style