My thoughts & tries with rvalue references

[Namespace]

> I am against introducing new one-symbol meanings, it always 
> looks like a hack. scope ref is much more elegant but I still 
> can't get straight in my mind what this combination does mean 
> from the abstract type system point of view.

Addendum to scope ref: It could mean: "This ref parameter accepts 
also rvalues​​, because no reference can leave the scope". 
Therefore it is safe to pass a rvalue by ref.