From the D Blog: Crafting Self-Evident Code in D

[angel]

I think if `class` is a reference type, it should've been 
explicit:
```sh
class C {
     ...
}

auto obj = new C();

void func(ref C obj)
{
     ...
}

```

I don't mind if it does not compile without the `ref`, but it 
should be on the table - WYSIWYG.