zlacker

You've got the right idea. The Rustonomicon gives a list of approximately everything that Rust considers unsound/UB (https://doc.rust-lang.org/nomicon/what-unsafe-does.html). The most common examples are:

- use after free

- breaking the aliasing rules

- causing a "data race" (e.g. writing to the same value from multiple threads without a lock)

- producing an invalid value (like a bool that's not 0 or 1)

There's some other technical stuff like "calling a foreign function with the wrong ABI", but those four above capture most of what safe Rust wants to guarantee that you never do. I contrast, the same page provides an interesting list of things that Rust doesn't consider UB and that you can do in safe code, for example:

- deadlocks and other race conditions that aren't data races

- leak memory

- overflow an integer

- abort the whole process