How to declare function with the same call signature as another?

[Tofu Ninja via Digitalmars-d-learn]

On Wednesday, 23 November 2016 at 22:19:28 UTC, ketmar wrote:
> On Wednesday, 23 November 2016 at 22:14:25 UTC, Tofu Ninja 
> wrote:
>> What is a (ref int)? A tuple with "ref int" as its only 
>> member? Since when is ref int a type?
>
> it is "type with modifier", like "const int" or "immutable int".

Since when has ref been a type qualifier? It has always been a 
parameter/function attribute.