Description:
------------
When we want to implement an interface in a child class that extends an abstract class that contains an abstract method that is in the interface, we get an error.

This kind of bug has already been submited in #35057 and was marked as bogus because AClasse::show obviously is not the same as IClasse::show.

But in the code we only say that IClasse::show is the same as AClasseConcrete::show.

To me, the IClasse should not care how AClasseConcrete manage to implements the interface. The important thing is that AClasseConcrete::show IS the same as IClasse::show.

I've checked the documentation and was not able to find this exact case and I've try this concept in other langages (like Java) with success.

I think at least it should be discussed.

If it has been discussed already, I'm really sorry for the time I made you spent on this.

Greatings

Reproduce code:
---------------
interface IClasse {
	public function show ();
}

abstract class AClasse  {
	abstract public function show (); 
}

class AClasseConcrete extends AClasse implements IClasse {
	public function show (){
		echo "Everything is ok";
	}
}

$classe = new AClasseConcrete ();
$classe->show (); 

Expected result:
----------------
"Everything is ok"

Actual result:
--------------
Fatal error: Can't inherit abstract function IClasse::show() (previously declared abstract in AClasse) in /home/geraldc/workspace/Copix_3/www/syntax_playground.php