LLM Policy for the Rust Compiler

This is a policy document that lays out standards for LLM usage in contributions to rust-lang/rust.

This policy is designed to be kept as a living document on Rust Forge, and to be linked from CONTRIBUTING.md and the rustc/std-dev-guide. The target is the rust-lang/rust repository, and subtrees, submodules, crates.io dependencies, and other rust-lang repositories are out of scope.

The core aim is to create moderatable standards to reduce slop PRs. The document includes scope limitations such as the following:

• The long-term societal and economic impact of LLMs
• Environmental impact
• Copyright issues with LLM output
• Moral judgments directed at LLM users

It also asks that feedback focus on concrete policy improvement suggestions. The main review criteria are how a team's or individual's workflow is actually broken, and whether that problem is a blocking reason before merge.

As background, the document states that there are both people who find LLM-generated code and writing off-putting and people who see it as helpful for learning and exploration. At the same time, it explains that rust-lang/rust is already experiencing an influx of low-quality LLM-based PRs, so a clear policy is needed rather than case-by-case judgment.

As alternatives, a project-wide policy, differentiated standards per person, a looser permissive policy, and a stricter blanket ban were compared, and the current proposal is a compromise leaning toward greater moderation and understandability even if it blocks too much.