How does rt_finalized function work exactly? (Fixing bugs regarding Destroy).

[Steven Schveighoffer]

On 1/19/18 10:56 AM, 12345swordy wrote:
> I can't find any documentation nor can I find any information regarding 
> it's implementation. I am asking this, as I focusing on fixing bugs that 
> destroy currently has, most noticeably bugs regarding attributes. I am 
> not sure that this requires a DIP in order to fix this.
> 
> https://issues.dlang.org/show_bug.cgi?id=17297
> https://issues.dlang.org/show_bug.cgi?id=15246

So there has been very little definition around how destructors use and 
inherit attributes. Most of this is because destructors are generally 
called from the GC, where it doesn't matter at all what the attributes are.

I think before you can fix such things, we need a clear model of how the 
destructors are called, and what is inherited and what is overridden in 
base classes. Then we can think about how to fix the situation.

Note that:

a. The GC must have a *runtime* definition of how to call the 
destructors. And we need to statically disallow the GC from calling 
destructors it shouldn't be allowed to call (if such cases exist).
b. Object.~this can't be a decider of what the attributes should be, as 
this prevents adding any additional attributes.
c. There is a push recently (by Andrei and Lucia and others) to remove 
some of the "magic" calls from the compiler, and replace them with 
templates, so we can have more library control over what happens (and 
more comiple-time introspection). This should help quite a bit in the 
implementation of such things. But we definitely are limited by the 
virtual-ness of Objects, and the opaqueness of the GC.

-Steve