Yeah, I just discovered this and was also amazed.

https://decasia.org/tech/2026/02/raise-not-a-reserved-word.h...

This being said, I don't think there is any requirement technically that every core method can also be re-implemented in Ruby... There are so many methods that are just thin interfaces to something written in C, whether because they are touching VM internals, or for perf reasons, or because they make system calls or call external libraries.

You reimplement `while` in terms of `loop`, but do you know that `loop` is also a method :)