unique ownership + unlimited safe generational references

[Nick Treleaven]

Hi,
This article is from 2021:
https://verdagon.dev/blog/generational-references

I've not seen Generational References mentioned on this forum but 
Reference Counting comes up a lot. I thought GR would interest 
people here. The article shows a benchmark based on naive RC vs 
naive GR, but the explanations why it was faster are interesting 
and promising. (I found this yesterday, I don't know yet if there 
is more info elsewhere).

The author explains why they believe aliasing of references was 
more common than dereferencing:
https://www.reddit.com/r/ProgrammingLanguages/comments/kpq805/vales_generational_references/gi0zmnn/

RC & GR aren't functionally equivalent, the memory is freed when 
the single owner goes out of scope. Any remaining references 
would then either halt or throw when dereferenced. So that's a 
pitfall you don't have with RC, but at least it's deterministic. 
And no lifetime annotation or restriction to only unique 
mutability a la Rust. So the programmer has more flexibility.

It also reminded me of a Microsoft idea to make calling `free` 
memory-safe, but I never found any detail on how that worked or 
what the overhead was.