The rust-lang/rust repository has a backlog of 1,300 open PRs. In the past, a well-structured, fully tested, and detailed PR often indicated that the author invested time, understood the code, and might be a long-term contributor; but with the proliferation of LLMs, a neatly formatted, fully tested PR can be generated in minutes, without the author necessarily understanding the design, and autonomous coding agents may not even have a human truly thinking behind them.
The Rust team is particularly concerned about a scenario: after receiving review feedback, a developer directly copies the reviewer's comments to an LLM and pastes the response back into GitHub verbatim. Policy drafters argue that maintainers can ask the LLM themselves if they want to know its answer; code review truly requires the contributor's own judgment: why this change? Were other implementations considered? What about future code structure changes?
A piece of code running only shows it fulfills a function; large foundational software also requires consideration of API design, compatibility, security boundaries, future maintenance, and long-term relationships. Therefore, Rust has always emphasized 'understanding,' and AI-generated content struggles to demonstrate that understanding.