Here's where I think you are quite a bit off target, personally.
I certainly was not and I don't believe the GP you originally responded to was saying that "Rust is a second tier language due to [lack of self-hosted compiler]", so hopefully we can set that statement aside and ignore it now.
Let's instead focus on your first statement, which is directly related to what GP and I were arguing:
> It's obviously possible to write a Rust compiler in Rust end-to-end.
It is certainly possible but actually doing so is completely non-obvious because the grammar for Rust is much more complicated than C, and Rust has no formal language specification (let alone an international standard).
While Python does not have an international standard, it does have a formal language specification, which is what allows for things like PyPy to exist.
Meanwhile, to truly understand Rust, one must be an expert in C and learn the `rustc` code base.
It seems like, practically, knowing C and being able to write compilers in C is quite useful if you want to make an impact in Rust or maybe try your hand at making some future Rust replacement (hopefully with a language specification that others can follow).
The Rust compiler frontend is written in Rust. It doesn't matter how non-trivial writing a Rust frontend is if you can restrict the problem domain to writing a new backend for the existing compiler frontend.
And you can. As it stands there is the LLVM backend that everyone is familiar with, the GCC backend which is nearing completion, and the Cranelift backend which is written in Rust.
Zig is similar. Yes, they are going to replace LLVM by default, but they're not getting rid of their LLVM backend entirely. The main difference between Rust and Zig here is a matter of defaults, where Rust defaults to using LLVM while Zig will default to their self-hosted compiler.
> Meanwhile, to truly understand Rust, one must be an expert in C and learn the `rustc` code base.
Are you under the impression that the "rustc" codebase is written in C/C++? It is not... It uses LLVM, yes, but it's written in Rust.
> I certainly was not and I don't believe the GP you originally responded to was saying that "Rust is a second tier language due to [lack of self-hosted compiler]", so hopefully we can set that statement aside and ignore it now.
The discussion started with the statement that Rust will never replace unsafe languages without the ability to self-host, and then continued with the statement that "Self Hosting your own compiler traditionally was the "end-game" of making a compile-able language. It's a sort of proof of fitness that the language can literally stand on its own."
I don't think that was a completely unfair reading of these statements. The implication is that Rust is "not a fit language" because it "cannot stand on its own" and therefore "will never replace unsafe languages".
I didn't intend this. The primary gripe I had was the grammar being complicated (and to be fair...not really available in an easy way). That means the places we are most likely see such bare metal shenanigans may not adopt it because they can't draft a XYZ Co. Compiler. This is a semi-common pattern with chip manufacturers.
The conversation diverged after that. Self-hosting is simply a signal that a language is "strong enough to stand on its own". That doesn't mean non-self hosted languages are bad. It just means you still need something else to bootstrap it. In the land of bare metal stuff like this matters.
But C's grammar is so weird that it requires the lexer hack in order to parse (https://en.wikipedia.org/wiki/Lexer_hack). Rust's grammar is simple by comparison. Yes, Rust has more syntax than C, but the syntax that it has is more regular.
In the article I linked, they did not say they were replacing LLVM by default, but they did say it would become the default for DEBUG builds due to the faster speed of compilation, to be clear.
> > Meanwhile, to truly understand Rust, one must be an expert in C and learn the `rustc` code base.
> Are you under the impression that the "rustc" codebase is written in C/C++? It is not... It uses LLVM, yes, but it's written in Rust.
I am not under that impression, but I can see how my phrasing leads to that conclusion.
After reviewing Rust's Bootstrap on Github[0] I can now more precisely state that one's understanding of low-level Rust will be enhanced by knowing C/C++ (for the LLVM portions) as well as Python (for the Rust does not exist on this system downloading of the stage0 binary Cargo and Rust compilers from somewhere else).
> Cranelift backend which is written in Rust
When this happens, it seems like it'll be possible to get the LLVM bits out of the bootstrap process and lead to a fully self-hosted Rust.
So while you may not personally value that, it seems like some people in the Rust community do.
[0] https://github.com/rust-lang/rust/tree/master/src/bootstrap
What do you mean by "when this happens"? GP's point is that this has already happened: the Cranelift backend is feature-complete from the perspective of the language [0], except for inline assembly and unwinding on panic. It was merged into the upstream compiler in 2020 [1], and a compiler built with only the Cranelift backend is perfectly capable of building another compiler. LLVM hasn't been a necessary component of the Rust compiler for quite some time.
Perhaps there's something we're both missing here.
It wasn't my only response because
1) I couldn't remember if it had any significant limitations and couldn't be bothered to check
2) I still objected to the premise
> Acting like it's a second tier language because actively doing so not a top focus of the community is gatekeep-y and ridiculous.
It is probably one of the major reasons we won't see a Rust compiler shipped with an operating system for a very long time. That doesn't make it second tier. However, Rust fans seem to want to stick their head in the sand when their baby is criticized. I am a Rust (language) fan myself. I am just willing to criticize the language. I do not understand why the Rust community has such a volatile response to honest, valid, criticism.
Even most linux distros don't ship with GCC out of the box... much less MacOS and Windows with their respective compilers.
If your standard is "Gentoo and FreeBSD will never ship it out of the box" then I'm going to 100% stand by my statement that this is weird and gatekeep-y.
Especially when the Windows kernel and userspace system libraries both have Rust in them.
https://www.bleepingcomputer.com/news/microsoft/new-windows-...
https://www.thurrott.com/windows/282471/microsoft-is-rewriti...
I can't figure out what this constraint means.
My Windows laptop doesn't seem to have provided a C compiler, so, maybe that's a problem for Windows?
Huh, well I guess I can buy or download a third party compiler, that's easy enough, but then, I can do that for Rust too, so, doesn't seem like a difference.
Meanwhile on this Fedora machine, the Rust compiler came with the OS. So, is this not an operating system? Maybe the stuff it comes with isn't "shipped with" it somehow? And so there's no C compiler "shipped with" this operating system either, although GCC was installed too ? I just don't know what to make of such a criticism.
But it still feels like a trivia item. C compilers written in C exist, but almost nobody actually uses them. They use GCC, Clang, and MSVC, written in C++. Everybody knows that it's possible to self-host C, so the benefit of actually doing so in practice is minimal.
It's obviously possible to write a Rust compiler in Rust end-to-end. Acting like it's a second tier language because actively doing so not a top focus of the community is gatekeep-y and ridiculous.