Why can't I give a function's return type the scope storage class?

[Olivier FAURE]

On Saturday, 16 March 2019 at 17:59:41 UTC, Walter Bright wrote:
> Scope on function return values comes from the scope of any 
> arguments passed to the function marked as 'return scope'. 
> Scope on a function return with no such arguments is currently 
> meaningless in D.
>
> To add such a feature, there woul'd need to be compelling use 
> cases.

Wait, what?

You can apply scope to return values?

I thought in the example above, `scope` applied to the `this` 
parameter, the same way `return` did?