Variadic Struct Parameter

[Jonathan Levi via Digitalmars-d-learn]

Why is this not working?

```
struct S {
    int x;
    string y;
}

void fun(S s ...) {
    writeln(s);
}

void main() {
    fun(S(5,"hi"));
    fun(5,"hi");
}
```

Why does `fun` compile if calling it does not?