Function std::mem::unreachable

pub unsafe fn unreachable() -> !

🔬 This is a nightly-only experimental API. (unreachable #43751)

Tells LLVM that this point in the code is not reachable, enabling further optimizations.

NB: This is very different from the unreachable!() macro: Unlike the macro, which panics when it is executed, it is undefined behavior to reach code marked with this function.