rust-unsafelisted

# Rust unsafe ## Purpose Use this skill to write, review, and audit `unsafe` Rust. The rules below apply to any workspace. Derive the current unsafe inventory from the source tree before you change it. Do not trust a memory of where unsafe lives. Start every unsafe task with these four commands: ```bash # Which crates promise to contain no unsafe in their own source. rg -l '#!\[forbid\(unsafe_code\)\]' --type rust # Which unsafe a dependency macro injects, which the attribute never sees. cargo +nightly rustc -p <crate> --profile=check -- -Zunpretty=expanded | rg 'unsafe' # Where unsafe actually lives. rg -n 'unsafe\s*\{|unsafe fn|unsafe impl|unsafe extern' --type rust # Which symbols leave the crate unmangled. rg -n '#\[unsafe\(no_mangle\)\]|#\[no_mangle\]|#\[unsafe\(export_name|#\[export_name' --type rust ``` ## Governance: `#![forbid(unsafe_code)]` Every crate that holds pure logic carries `#![forbid(unsafe_code)]` at the crate root. Add the attribute when you create a crate that has no FFI and no OS-level calls. It is cheap, it is checked by the compiler, and an `#[allow]` further down cannot suppress it. A local `#[allow(unsafe_code)]` under the attribute is `error[E0453]: allow(unsafe_code) incompatible with previous forbid`. ### What the attribute covers, and what it does not The lint is checked per lexical span. It governs the crate's own source text. It does not govern the code the crate compiles to. | Where the `unsafe` comes from | Result under `#![forbi