July 23, 2026
Trash talk, but make it fast
Meta Garbage Collection: Using OCaml's GC to GC Rust
They found a tiny fix, got a huge speed boost, and the comments immediately lost it
TLDR: A Rust-checking tool was accidentally slowing itself down badly, and the team fixed it with a tiny change that let OCaml handle cleanup, unlocking up to a 10x speed boost. Commenters turned it into a comedy riot about one programming language cleaning up after another, mixed with real praise for the elegant fix.
This story had the kind of plot twist the internet lives for: a team built a tool to catch hidden Rust programming mistakes, discovered it was getting absurdly slow on a super simple loop, and then fixed it with about 40 lines of code by letting OCaml clean up the mess. Result: the slowdown went from painful to sane, with speeds reportedly improving by as much as 10 times. For non-programmers, that’s basically “our very smart bug-finder tripped over its own shoelaces, then found a shortcut in the next room.”
And yes, the community had a field day. The strongest reaction was equal parts respect and comedy: people loved that such a gnarly performance problem had such a weirdly elegant solution, with many joking that one language had to come rescue another from its own chaos. A second camp turned it into a full-on language rivalry spectacle, snarking that “Rust needs OCaml to take out the trash” while defenders pushed back hard, saying the real headline is clever engineering, not some fake programming-language cage match. The funniest comments leaned into the title like it was written by destiny, riffing on “garbage collection” jokes and calling it the most accidentally shady headline of the week. Even the serious crowd seemed delighted: beneath the memes was genuine admiration for a fix that was small, practical, and a reminder that sometimes the best optimization is simply stop keeping dead stuff around.
Key Points
- •The article reports that a simple increment loop in Soteria Rust was running in quadratic time rather than linear time.
- •Profiling showed the slowdown came primarily from the tool’s Tree Borrows implementation, which accounted for 87% of runtime at N=1000.
- •The stated fix was to delegate Tree Borrows state cleanup to OCaml’s garbage collector, implemented in about 40 lines of code.
- •According to the article, the change reduced the benchmark from quadratic to linear behavior and produced speedups of up to 10x.
- •The article explains that Tree Borrows tracks reborrows as nodes in a tree and updates reference states on each memory access, while analysis must be done on unoptimized Rust code to avoid hiding undefined behaviour.