StringableForToStringRector

Add Stringable interface to classes with __toString() method

-class SomeClass
+class SomeClass implements Stringable
 {
-    public function __toString()
+    public function __toString(): string
     {
         return 'I can stringz';
     }
 }

Configure your rector.php:

<?php

use Rector\Config\RectorConfig;
use Rector\Php80\Rector\Class_\StringableForToStringRector;

return RectorConfig::configure()
    ->withRules([
        StringableForToStringRector::class,
    ]);
SETS:  PHP 8.0