Very limited shared promotion

[Timon Gehr]

On 24.06.19 04:31, Walter Bright wrote:
> On 6/22/2019 4:22 PM, Manu wrote:
>> Show how to escape the pointer when it is scope...?
> 
> Use @system code. The programmer only has to ensure the escaped 
> reference ceases before the function returns to fulfill the 'scope' 
> semantics.
> 
> The scope semantics do not include memory barriers, though.

You keep saying "before" and then "but no memory barriers".

I really don't understand this "before" without memory barriers. Without 
memory barriers, there is no "before". How to formalize this? What is it 
exactly that "scope" guarantees?