For example:

---
class Output {
    this(T...)(T msg) {
        writeln(msg);
    }
}

new Output("Hello, ", 42);
---

ends in an "Error: no constructor for Output".

If you make it as an Exception:

---
class MyError : Exception {
    this(T...)(T msg) {
        super(text(msg));
    }
}
---

It ends in "Error: constructor test.MyError.this conflicts with template test.MyError.__ctor(T...)". Same with Throwable or Error as base class (probably with all others, too).

I have this not tested in other configurations ...

Ps: Sorry for bad english :)