Description:
------------
My code class A, that defined abstract method `method` with one argument.
After that class B extends A. In this place I can not extend signature of `method` (for example, add new required arguments).
Code is following.
That's strange and non-intuitive behavior.
This bug is appearing on PHP 5.0.0 - 5.6.3.

Test script:
---------------
abstract class A {
    abstract function method($a);
}

abstract class B extends A {
    abstract function method($a, $b);
}

Expected result:
----------------
none printable result

Actual result:
--------------
Fatal error: Can't inherit abstract function A::method() (previously declared abstract in B) in ...