Inheritance hierachy: Class from Abstract class from Interfaces, does not enforce method implementation?

[Nicholas Wilson]

On Wednesday, 24 March 2021 at 08:22:51 UTC, zack wrote:
> Sorry for the weird title.
> I dealt with interfaces and abstract classes and came accross a 
> behavior I didn't expect. Can someone clarify if this behavior 
> is wanted?
>
> [...]

that is possibly https://issues.dlang.org/show_bug.cgi?id=19192 
which has a PR https://github.com/dlang/dmd/pull/12302 in review, 
which should be merged very soon.