I think one measurable outcome here is what kind of error message you get when you do violate a rule and whether rust users know what to do to fix their code. As a person who loves to explore the complexity behind seemingly simple interfaces, this stuff is really cool. On the other hand, I don't relish having people break their brains to understand why similar code is accepted vs not.
I'm not a rust user myself, but I'm guessing from all the references to raw pointers that a lot of the code referenced here is actually not idiomatic for all but small snippets of high perf code, so maybe the complexity is not going to affect too many people.
