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:

 <?php
 
 namespace Rector\Tests\Php80\Rector\Class_\ClassPropertyAssignToConstructorPromotionRector\Fixture;

 
 class WithInterfaceAndItsImplementation
 {
-    private SomeInterface $x;
-
-    public function __construct(
-        FirstImplementation $x,
-    ) {
-        $this->x = $x;
+    public function __construct(private SomeInterface $x)
+    {
     }
 }
 
 ?>

PHP snippet to change

<?php

namespace Rector\Tests\Php80\Rector\Class_\ClassPropertyAssignToConstructorPromotionRector\Fixture;

interface SomeInterface {}

class FirstImplementation implements SomeInterface {}

class WithInterfaceAndItsImplementation
{
    private SomeInterface $x;

    public function __construct(
        FirstImplementation $x,
    ) {
        $this->x = $x;
    }
}

?>

Applied Rules:

ClassPropertyAssignToConstructorPromotionRector

Not a change you expect?

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

Config rector.php

<?php

use Rector\Config\RectorConfig;
use Rector\Php80\Rector\Class_\ClassPropertyAssignToConstructorPromotionRector;
use Rector\ValueObject\PhpVersion;

return RectorConfig::configure()
    ->withRules([
        ClassPropertyAssignToConstructorPromotionRector::class
    ]);

Rector version: e30087 - released at 2026-04-23 17:48