Why does Rust allow calling functions via null pointers?

Question

I was experimenting with function pointer magic in Rust and ended up with a code snippet which I have absolutely no explanation for why it compiles and even more, why it runs.

Answer 1

Given that rust is built on top of LLVM, and that what you're doing is guaranteed UB, you're likely hitting something similar to https://kristerw.blogspot.com/2017/09/why-undefined-behavior-may-call-never.html. This is one of many reasons why safe rust works to eliminate all UB.