Bug or intended?

[rsw0x via Digitalmars-d-learn]

I was playing around with alias templates and came across this, I 
reduced it to:

---
struct A(alias C c){
  auto foo(){
    return c.i;
  }
}

struct B{
  C c;
  A!c a;
}

struct C{
  int i;
}
---

It gives me a "need 'this' for 'i' of type 'int'" error.