When a class overloads a function from its super class, the overloaded function cannot be found by DMD.

Example:
-------------------
import std.stdio;

public class A
{
    public int X = 12;
    public void DoSomething(int x)
    {
        writeln(x);
    }
}

public class B: A
{
    public void DoSomething()
    {
        DoSomething(X);
    }    
}

void main()
{
    auto b = new B();
    b.DoSomething();
}
-------------------

This code causes the compiler error: function OverloadBug.B.DoSomething() is not callable using types (int).

You can work around the problem by using super.DoSomething(X) instead.