Inconsistent behavior when using interfaces

Is this a problem or not?

The following will produce this notice:

Strict Standards: Declaration of Z_Concrete::__get() should be
compatible with that of Z_Abstract::__get() in xxx on line 16

<?php

error_reporting(E_ALL | E_STRICT);

interface Z_Interface
{ }

abstract class Z_Abstract implements Z_Interface
{
public function __get($name)
{
return;
}
}

class Z_Concrete extends Z_Abstract
{
public function & __get($name)
{
return null;
}
}

$t = new Z_Concrete();

This code will not produce a notice:

<?php

error_reporting(E_ALL | E_STRICT);

abstract class Z_Abstract
{
public function __get($name)
{
return;
}
}

class Z_Concrete extends Z_Abstract
{
public function & __get($name)
{
return null;
}
}

$t = new Z_Concrete();

The only difference is that the former has an interface as a parent, the
latter does not. Is this a bug?

-ralph

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