Alias this and inheritance

[Jacob Carlborg via Digitalmars-d]

The following code does not compile:

void foo(string a) {}

class Base
{
     alias bar this;

     string bar()
     {
         return "";
     }
}

class Sub : Base {}

void main()
{
     auto sub = new Sub;
     foo(sub);
}

But if the "alias this" is copied/moved to the subclass it works. Is 
this expected behavior?

-- 
/Jacob Carlborg