Is there a way to redefine a type hint to a descendant class when extending an abstract class?

Question

I will be using the following example to illustrate my question:

class Attribute {}

class SimpleAttribute extends Attribute {}



abstract class AbstractFac         


        

Answer 1

Since PHP 7.4 it is allowed to use more specific type-hint in children classes by using interfaces

interface OtherAttributeCompatibleInterface{};
interface SimpleAttributeCompatibleInterface{};

interface AllAttributesInterface extends OtherAttributeCompatibleInterface, SimpleAttributeCompatibleInterface{};


class Attribute implements AllAttributesInterface{};

class SimpleAttribute extends Attribute  implements SimpleAttributeCompatibleInterface{};


abstract class AbstractFactory  {
    abstract public function update(AllAttributesInterface $n);
}

class SimpleFactory  extends AbstractFactory  {
  public function update (SimpleAttributeCompatibleInterface $n){
  }
}

Cause AllAttributesInterface inherits SimpleAttributeCompatibleInterface it is allowed to overwrite the update method from AbstractFactory by SimpleFactory.