Unsafe Rust: How and when (not) to use it

The guide provides an in-depth exploration of "unsafe" Rust, addressing common misconceptions and detailing when and why to use or avoid unsafe code. It dispels myths, such as the belief that all Rust code is inherently unsafe or that writing unsafe code bypasses safety mechanisms. The guide emphasizes the importance of maintaining safety invariants when using features like raw pointers, uninitialized memory, and foreign function interfaces. It also advises on the cautious use of unsafe code for performance gains and recommends maintaining a safe version for benchmarking. Tools such as Miri, Clippy, Prusti, and various fuzzers are highlighted for their roles in detecting undefined behavior and ensuring code correctness. Moreover, the guide touches on advanced topics like using intrinsics, inline assembly, and interfacing with foreign languages, underscoring the need for careful design and rigorous testing to maintain safety and prevent vulnerabilities.