And how would you conclude that "fast"?

You can have UB in "safe rust".

https://github.com/Speykious/cve-rs

You can even disable the Type check, trait check and borrow check in "safe rust"

And all of this is unsound.

https://users.rust-lang.org/t/i-finally-found-the-cheat-code...

Or you can have malicious code that is not unsafe. Does it mix sensible data with something that is being sent? Does it always accept "return break union" as a valid password? Things like that.

yes, but that is a different kind of unreadable code then in the blog

the blog focuses mainly on putting expresions into unusual positions and how some things have an implicite () type and some an implicite ! type etc.

either way if you see strange code you probably shouldn't copy/merge it without having a very good understanding of what it does