Ping Labs' Claude-Built Rust Port of tsc Passes 181,711 Tests

"I've never read a line of this code," reads the README for Theo Browne's new Rust port of the TypeScript 7 compiler, type checker, and language server. Browne, who founded Ping Labs, published it as tsc-rs (also called ts-rust).

The README says all 181,711 ported Go tests pass, that the port was validated on 120 open-source repositories, and that TanStack Query core and Hono "check with identical diagnostics to Go version". Over 1.3 million lines of Rust and 5,961 commits sit on main.

The cost figures sit side by side. An earlier attempt burned over $420,000 in API tokens and reached only about 84% compatibility after months. The working port came from Claude Opus, which produced a v0 in 10 hours by starting from scratch rather than using prior code, and the final run cost roughly $24,047 over two weeks.

Browne's own framing, on X: "I burned ~$400k of Codex tokens and got nowhere. Burned ~$20k of Opus and got there in 2 weeks."

Benchmarks in the README put tsc-rs at 7.25 seconds on the T3 Code project (median of five runs) against 16.10 seconds for tsc 7, with bun check at 4.07 seconds. Across real-world apps the geometric mean puts tsc-rs 1.61× faster than tsc 7 and 11.4× faster than tsc 6. The README also flags live issues: memory growth around 20 MiB per 1,000 edits in long sessions, monorepo timing variations, and stale-output risks in multi-project builds. Binaries ship for Linux x64 and macOS arm64. It joins 324 other stories we have tracked in the open-source feed over the last 90 days.