Another bug in function overloading?

[Domain via Digitalmars-d-learn]

module test;

public interface I
{
     void foo();
     void foo(int);
}

public abstract class A : I
{
     public void bar()
     {
         foo();
     }

     public void foo(int i)
     {
     }
}

public class C : A
{
     public void foo()
     {
     }

     public void bar2()
     {
         foo(1);
     }
}

Error: function test.A.foo (int i) is not callable using argument 
types ()
Error: function test.C.foo () is not callable using argument 
types (int)