Want to wade into the snowy surf of the abyss? Have a sneer percolating in your system but not enough time/energy to make a whole post about it? Go forth and be mid.
Welcome to the Stubsack, your first port of call for learning fresh Awful you’ll near-instantly regret.
Any awful.systems sub may be subsneered in this subthread, techtakes or no.
If your sneer seems higher quality than you thought, feel free to cut’n’paste it into its own post — there’s no quota for posting and the bar really isn’t that high.
The post Xitter web has spawned so many “esoteric” right wing freaks, but there’s no appropriate sneer-space for them. I’m talking redscare-ish, reality challenged “culture critics” who write about everything but understand nothing. I’m talking about reply-guys who make the same 6 tweets about the same 3 subjects. They’re inescapable at this point, yet I don’t see them mocked (as much as they should be)
Like, there was one dude a while back who insisted that women couldn’t be surgeons because they didn’t believe in the moon or in stars? I think each and every one of these guys is uniquely fucked up and if I can’t escape them, I would love to sneer at them.
(Credit and/or blame to David Gerard for starting this. A lot of people didn’t survive January, but at least we did. This also ended up going up on my account’s cake day, too, so that’s cool.)
It seems that Anthropic has vibe coded a C compiler. This one is really good! The generated code is not very efficient. Even with all optimizations enabled, it outputs less efficient code than GCC with all optimizations disabled.
The fact it doesn’t have an assembler or linker, and I am doubting it implemented its own lexical analyzer, I almost struggle to call this a compiler.
The claim it is from scratch is misleading since it has all prior training from open source.
Building a small compiler for a simple language (C is pretty simple, especially older versions) is a common learning exercise and not difficult. This is very much another situation where “AI” created an over simplified version of something with hidden details on how it got there as a way to further push the propaganda that it is so capable.
I wonder what actual experts in compilers think of this. There were some similar claims about vibe coding a browser from scratch that turned out to be a little overheated: https://pivot-to-ai.com/2026/01/27/cursor-lies-about-vibe-coding-a-web-browser-with-ai/
I do not believe that this demonstrates anything other than they kept making the AI brute force random shit until it happened to pass all the test cases. The only innovation was that they spent even more money than before. Also, it certainly doesn’t help that GCC is open source, and they have almost certainly trained the model on the GCC source code (which the model can regurgitate poorly into Rust). Hell, even their blog post talks about how half their shit doesn’t work and just calls GCC instead!
I wonder why this blog post was brazen enough to talk about these problems. Perhaps by throwing in a little humility, they can make the hype pill that much easier to swallow.
Sidenote: Rust seems to be the language of choice for a lot of these vibe coded “projects”, perhaps because they don’t want people immediately accusing them of plagiarism. But Rust syntax still reasonably follows languages like C. In most cases, blindly translating C code into Rust kinda works. Now, Rust does have the borrow checker which requires a lot of thinking to deal with, but I think this is not actually a disadvantage for the AI. Borrow checking is enforced by the compiler, so if you screw up in that department, your code won’t even compile. This is great for an AI that is just brute forcing random shit until it “works”.
I only sampled some of the docs and interesting-sounding modules. I did not carefully read anything.
First, the user-facing structure. The compiler is far too configurable; it has lots of options that surely haven’t been tested in combination. The idea of a pipeline is enticing but it’s not actually user-programmable. File headers are guessed using a combination of magic numbers and file extensions. The dog is wagged in the design decisions, which might be fair; anybody writing a new C compiler has to contend with old C code.
Next, I cannot state enough how generated the internals are. Every hunk of code tastes bland; even when it does things correctly and in a way which resembles a healthy style, the intent seems to be lacking. At best, I might say that the intent is cargo-culted from existing code without a deeper theory; more on that in a moment. Consider these two hunks. The first is generated code from my fork of META II:
while i < len(self.s) and self.clsWhitespace(ord(self.s[i])): i += 1And the second is generated code from their C compiler:
while self.pos < self.input.len() && self.input[self.pos].is_ascii_whitespace() { self.pos += 1; }In general, the lexer looks generated, but in all seriousness, lexers might be too simple to fuck up relative to our collective understanding of what they do. There’s also a lot of code which is block-copied from one place to another within a single file, in lists of options or lists of identifiers or lists of operators, and Transformers are known to be good at that sort of copying.
The backend’s layering is really bad. There’s too much optimization during lowering and assembly. Additionally, there’s not enough optimization in the high-level IR. The result is enormous amounts of spaghetti. There’s a standard algorithm for new backends, NOLTIS, which is based on building mosaics from a collection of low-level tiles; there’s no indication that the assembler uses it.
The biggest issue is that the codebase is big. The second-biggest issue is that it doesn’t have a Naur-style theory underlying it. A Naur theory is how humans conceptualize the codebase. We care about not only what it does but why it does. The docs are reasonably-accurate descriptions of what’s in each Rust module, as if they were documents to summarize, but struggle to show why certain algorithms were chosen.
Choice sneer, credit to the late Jessica Walter for the intended reading: It’s one topological sort, implemented here. What could it cost? Ten lines?
That’s the secret: any generative tool which adapts to feedback can do that. Previously, on Lobsters, I linked to a 2006/2007 paper which I’ve used for generating code; it directly uses a random number generator to make programs and also disassembles programs into gene-like snippets which can be recombined with a genetic algorithm. The LLM is a distraction and people only prefer it for the ELIZA Effect; they want that explanation and Naur-style theorizing.
This could be it’s own post. Very nice!
I wonder if this is going to hold out long enough to get some obnoxious AI-first language created that is designed to have as obnoxiously picky of a compiler as it can in order to try and turn runtime errors that the model can’t cope with into compile failures which it can silently retry until they’re ‘fixed’