Part of the problem it's trying to do too many things in too many fronts. They try to implement a borrow-checker a la Rust. But feels very poorly compared against the Rust version. It haves a "optional" GC, but it's a subpar GC. And lacks a way to use alternative GCs.

And funny, C++ has been copying many features that DLang have for many time ago. Beginning with the type inference (ie using "auto" to declare vars). And now, contractual programing and static reflection.

I really loved the language, but it's very sad that never manages to take off and become more popular and well maintained.

> But feels very poorly compared against the Rust version.

It's a prototype to gauge the interest in having a borrow checker in the language. I did not continue with it because the interest is not there.

That has been the main problem from my point of view, too much pivoting looking for the right crowd, without finalizing what was done before.

And while some features in other languages might have seen an implementation first in D, claiming first to the finish line as it usually comes up, even on this thread, hardly does anything for language adoption.

On the contrary, it is one reason less leave those languages, as eventually they get the features, and already have the ecosystem.

> Beginning with the type inference (ie using "auto" to declare vars).

GCC (and possibly other compilers) had typeof in the '90s well before D was first released. Macros in the form:

   #define    TYPEOF(name, expr) typeof(expr) name = expr

I'm sure that C++ borrowed concepts from D, but type deduction (not inference BTW) is not one of them.