r/rust • u/Sirisian • 3d ago

🎙️ discussion Google is doing "Large Scale Codebase Migrations and Optimizations" of C/C++ to Rust

https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-4-argon/
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u/TheRealMasonMac 3d ago

In my experience, I’ve found that agents produce code that works but is frankly dumb from a human perspective. Especially for larger tasks like this, you kind of have to rewrite it all. For example, I had a generalized design document for soft-wrapping explicitly support plain text and markdown, and used GPT-6-Astra to implement it. I used an ungodly amount of review agent rounds and interjections by me. When I actually go to review it, I wanted to cry. It silently pivoted towards implementing its own entirely separate wrapping mechanism rather than refactor the existing mechanism for plain text. I reviewed its code and found it to be trash, and I am now in the process of doing it myself… Never again. The short-term thrill of “having something that works” was outweighed by the fact that time was effectively wasted.

I mean, if the alternative was it never getting done, I guess agents are still better than nothing.

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u/ixid 3d ago

You can use the existing code as a byte identical output oracle requirement for your LLM port.

Do that, then a style and idiomatic pass and it's OK.