Traits

A trait shares method implementations across unrelated classes — PHP's answer to not having multiple inheritance, letting you mix in reusable behavior without a shared base class.

trait Loggable
{
    public function log(string $message): void
    {
        echo "[" . static::class . "] $message";
    }
}

class Order
{
    use Loggable;
}

class User
{
    use Loggable;
}

(new Order())->log("Created"); // [Order] Created

Common mistakes

• Overusing traits for anything reusable — if the behavior and the class share a genuine "is-a" relationship, prefer inheritance or an interface; traits shine for cross-cutting behavior (like logging) that doesn't fit a class hierarchy.