> > Why? The static analyzer has an opinion on whether or not a program is safe. The optimizer just wants to know if it still thinks it's safe when you remove a

> > Why? The static analyzer has an opinion on whether or not a program is safe. The optimizer just wants to know if it still thinks it's safe when you remove a runtime check. > I guess I misunderstood your proposal. This sounds doable. But, again, you'd be using a weird subset of C++ that doesn't seamlessly integrate, and you're just better off using Rust at this point. My proposal is sort of language independent. I'm just suggesting a better way to address the code safety/correctness issue might be with runtime asserts, because it's more general. Some of the runtime asserts (like the ones regarding memory safety) will be automatically generated by the compiler, and others would be user defined (but compiler placed). And the static analyzer (I guess "the borrow checker" in Rust) would be repurposed to strip out the unnecessary runtime checks. And the compiler/optimizer would tell you which runtime asserts it was unable to optimize out. (Presumably good Rust code would result in all the memory runtime asserts being optimized out.) This allows for programs that are not just memory safe, but "application invariant" safe as well. Right? I mean it's not really a totally new concept, I guess it's kind of "design by contract" or whatever, but with a slight performance bent because the optimizer tells you what runtime checks it's having trouble getting rid of. And maybe there would be a way to indicate that you expect the optimizer to be able to get rid of certain runtime checks, and instruct it to generate a warning (or error) if it doesn't. I'm just sayin'...