Are public/private imports implemented?

[Ary Borenszweig]

Again, testing some Descent semantic code, I was getting errors on 
undefined functions.

---
module one;

import two;

void foo() {
	char[] srcfilename = std.path.join("one", "two");
}
---

---
module two;

import std.path; // same with "private import std.path;"
---

I was getting an error on "std.path.join", because since the import on 
module two is private, join is not visible. But DMD seems to compile it 
without problems. What's the truth about imports?