Why is D unpopular?

[Dukc]

On Thursday, 19 May 2022 at 00:29:46 UTC, Walter Bright wrote:
> I did a quick look at D's undefined behavior, and nearly all of 
> it is disallowed in @safe code.
>
> It's not 100%, but we're in a strong position.

One hole that remains: 
https://forum.dlang.org/thread/kazglmjwsihfewhscioe@forum.dlang.org

According to a reply, the current langauge implementation does 
not cause anything special to happen, but it is still undefined 
behaviour in `@safe` code if we go by the spec.