borrowed pointers vs ref

[Jacob Carlborg via Digitalmars-d]

On 2014-05-13 19:52, Dicebot wrote:

> It has to be transitive to be useful as borrowed pointer. Consider this
> example:
>
> {
>      scope A a; // has some internally managed resources
>      foo(a);
> }
>
> It is not safe to destruct a in the end of the scope here because foo
> may have stored references to a owned resources. But if foo signature is
> `foo(scope ref A a)` then compiler can statically verify that it is safe
> which is the very point of borrowing guarantees. It must be transitive
> to guarantee anything of course.

What is "scope ref" supposed to do in this example, compared to just 
"scope"?

-- 
/Jacob Carlborg