A 16,000-line Rust parser written by Claude that the author never read (posthog.com)
The old parser interpreted an ANTLR grammar at runtime; the Rust rewrite is a recursive-descent parser with a Pratt expression core. It ran 70x faster on a laptop and 454x faster in production, with zero divergences across millions of shadow-mode queries.
The thread calls it the anti-vibe-coding playbook: an engineer who builds the same oracle setups says you can generate corpuses large enough to trust code you never read. A skeptic asks the question nobody answered: why not compile the grammar instead of fuzzing a code generator into agreement?
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