package access specifier not usable within a class

[Andrej Mitrovic]

abstract class Foo
{
    package void test();
}

class Bar : Foo
{
    override package void test() { }
}

function test.Bar.test cannot override a non-virtual function

TDPL says package can only be used at class-level (i.e. package class
Bar : Foo), outside classes or inside a struct.

I want to hide a virtual method from client code, but another free
function in a different module but in the same package as these
classes needs access to that method. Are there any technical reasons
why package is not allowed for virtual methods?