Unsafe Rust

unsafe doesn't mean memory-unsafe. It means you are responsible for maintaining the invariants the compiler can no longer verify.

The five unsafe superpowers:

1. Dereference raw pointers
2. Call unsafe functions or methods
3. Access or modify mutable static variables
4. Implement unsafe traits
5. Access fields of unions

Everything else — including the borrow checker — still applies inside unsafe blocks.

Raw Pointers	*const T and *mut T — aliasing, alignment, validity
Unsafe Traits	Send, Sync, and custom unsafe contracts
FFI	extern "C", #[no_mangle], C interop patterns
Safety Invariants	How to document and enforce unsafe contracts