Extending D's support for object-oriented design with private(this)

[Quirin Schroll]

On Saturday, 27 April 2024 at 07:39:19 UTC, Jonathan M Davis 
wrote:
> (particularly since the change from private, public, etc. being 
> protection attributes to visibility attributes seems to have 
> been tricky enough that a number of subtle bugs were introduced 
> in the process).

I know this is slightly off-topic, but I have two questions about 
that:
1. When did this happen? I don’t need an exact date, but before 
2015 and after 2015 would be helpful to me because I started 
learning D end of 2015 and so I could know if I ever used D with 
the old “protection attributes” way.
2. What is the difference? I don’t need details, maybe a single 
example does the job.