Try Rector Online | Rector - Automated Way to Instantly Upgrade and Refactor any PHP code

Run Rector on your code to see what it can do for you:

 
 final class DemoFile
 {
-    public function run(bool $param)
+    public function run(bool $param): void
     {
         echo "hello, world!";
     }
 }

PHP snippet to change

<?php

final class DemoFile
{
    public function run(bool $param)
    {
        echo "hello, world!";
    }
}

Applied Rules:

AddReturnTypeDeclarationRector

Not a change you expect?

Create an issue on GitHub
...or to speed up fix – add a test fixture

Config rector.php

<?php

declare(strict_types=1);

use Rector\Config\RectorConfig;
use Rector\TypeDeclaration\Rector\ClassMethod\AddReturnTypeDeclarationRector;
use Rector\TypeDeclaration\ValueObject\AddReturnTypeDeclaration;
use PHPStan\Type\VoidType;

return RectorConfig::configure()
    ->withConfiguredRule(AddReturnTypeDeclarationRector::class, [
        new AddReturnTypeDeclaration('DemoFile', 'run', new VoidType()),
    ]);

Rector version: bb32c6 - released at 2026-01-07 13:03