That's not true, actually. There is more than "literally zero" evidence. I don't feel like finding it for you, but at minimum Mozilla has published a case study showing that moving to Rust considerably reduced the memory safety issues they discovered. That's just one example, I believe there are others.
There are likely many other examples of, say, Java not having memory safety issues. Java makes very similar guarantees to Rust, so we can extrapolate, using common sense, that the findings roughly translate.
Common sense is a really powerful tool for these sorts of conversations. "Proof" and "evidence" are complex things, and yet the world goes on with assumptions that turn out to hold quite well.
Not sure what your last sentence means - without evidence, there are cases when we guess right, and those when we guess wrong. Are you just choosing to ignore the latter?
The Mozilla case study is not a real world study. It simply looks at the types of bugs that existed and says "I promise these wouldn't have existed if we had used Rust". Would Rust have introduced new bugs? Would there be an additional cost to using Rust? We don't know and probably never will. What we care about is preventing real world damage. Does Rust prevent real world damage? We have no idea.
> Not sure what your last sentence means - without evidence, there are cases when we guess right, and those when we guess wrong. Are you just choosing to ignore the latter?
What I'm saying is that truth is a matter of debate. We believe lots of things based on evidence much less rigorous than a formal proof in many cases - like most modern legal systems, which rely on various types of evidence, and then a jury that must form a consensus.
So saying "there is no evidence" is sort of missing the point. Safe Rust does not have memory safety issues, barring compiler bugs, therefor common sense as well as experience with other languages (Java, C#, etc), would show that that memory safety issues are likely to be far less common. Maybe that isn't the evidence that you're after, but I find that compelling.
To me, the question of "does rust improve upon memory safety relative to C/C++" is obvious to the point that it really doesn't require justification, but that's just me.
I could try to find more evidence, but I'm not sure what would convince you. There's people fuzzing rust code and finding far fewer relevant vulns - but you could find that that's not compelling, or whatever.
There are likely many other examples of, say, Java not having memory safety issues. Java makes very similar guarantees to Rust, so we can extrapolate, using common sense, that the findings roughly translate.
Common sense is a really powerful tool for these sorts of conversations. "Proof" and "evidence" are complex things, and yet the world goes on with assumptions that turn out to hold quite well.