[tialaramex]

Rust has two macro systems, the proc macros are allowed to do absolutely whatever they please because they're actually executing in the compiler.

Now, should they do anything they please? Definitely not, but they can. That's why there's a (serious) macro which runs your Python code, and a (joke, in the sense that you should never use it, not that it wouldn't work) macro which replaces your running compiler with a different one so that code which is otherwise invalid will compile anyway...