if you're still looking around, you want to have a look at Nim, an alternative systems programming language with optional GC.
https://nim-lang.org/
Here's a post I made on the topic a few months ago: https://news.ycombinator.com/item?id=15251078
Take note of how the reply that tried to play with whitespace was already broken by HN's code formatting.
EDIT:
Beyond whitespace sensitivity:
* It compiles to an intermediary language rather than leveraging something like LLVM.
* Despite having sum types it appears that idomatic Nim uses null pointers.
* I'm seeing that it disallows pointer arithmetic in the same search results page that links to a runnable example of pointer arithmetic.
* It uses exceptions, which obscure control flow and make grokking code much more difficult IMO.
* Bindings are mutable by default.
I'm not seeing a good reason to use Nim over Rust in the places where I would use Rust. (For personal use: game development)
I could see it being competitive with where I use Go, but with whitespace sensitivity, exceptions instead of error values, and compiling to C, I'm not even sold on using it there.
Also I should note that I'm writing this from the perspective of developing game engine style code.
D:
* D's garbage collector can be switched off, but last I checked (to be fair a few years ago) this even locked you out of parts of the stdlib. For smaller game engine projects, this is an issue. For larger ones, they often rewrite the stdlib anyway, though I'd expect growing pains while bootstrapping up to that point.
* Memory safety guarantees appear to be much stronger in Rust than in D. The difference in approach demonstrates this well I think, Rust has an `unsafe` keyword while D has a `@safe` attribute.
* It's great at its goal, which is to be (C++)++. It sidesteps a lot of the problems found in C++ and appears much more intentionally designed.
* Despite a 7-8 year headstart for D, from the outside of both communities the Rust community appears much more vibrant.
I've not heard of Ante, I'll go take a look.
Yeah, that is a problem -- albeit one that people are currently working on fixing. Look at BetterC[1]. And I've heard rumours someone is rewriting the GC to be much more performant? And if nothing else, you can just stop the GC and manually collect your own memory, and a smart pointer implementation is probably relatively simple.
However, is the GC even a problem? You know what they say about premature optimization.
However, development on the language hadn't even started by the time Rust hit 1.0. I like to play on the bleeding edge sometimes but I wouldn't write a large sideproject in a language that new.
And of course, as you stated it is a significant whitespace language, which isn't usually my cup of tea.
I will certainly keep an eye on its development though, thanks for the heads up.