Why doesn't this work when the function is a static method?

[Jack]

works fine (this is defined at global scope, g and baa are same 
as static)

     int f(HWND hwnd, int n)
     {
         return n*10;
     }


     void baa()
     {
         HWND foo;
         writeln(foo.f(10));
     }


but if I wrap this within a class:

class Foo
{
     static int f(HWND hwnd, int n)
     {
         return n*10;
     }


     static void baa()
     {
         HWND foo;
         writeln(foo.f(10));
     }
}

I get the error:

Error: no property f for type void*