Fair enough. In some sense you’re writing your own borrow checker. But (you may know this already) be warned: this has been tried many times for C++, with different levels of annotation burden imposed on programmers.

On one side are the many C++ “static analyzers” like Coverity or clang-analyzer, which work with unannotated C++ code. On the other side is the “Safe C++” proposal (safecpp.org), which is supposed to achieve full safety, but at the cost of basically transplanting Rust’s type system into C++, requiring all functions to have lifetime annotations and disallow mutable aliasing, and replacing the entire standard library with a new one that follows those rules. Between those two extremes there have been tools like the C++ Core Guidelines Checker and Clang’s lifetimebound attribute, which require some level of annotations, and in turn provide some level of checking.

So far, none of these have been particularly successful in preventing memory safety vulnerabilities. Static analyzers are widely used in industry but only find a fraction of bugs. Safe C++ will probably be too unpopular to make it into the spec. The intermediate solutions have some fundamental issues (see [1], though it’s written by the author of Safe C++ and may be biased), and in practice haven’t really taken off.

But I admit that only the “static analyzer” side of the solution space has been extensively explored. The other projects are just experiments whose lack of adoption may be due to inertia as much as inherent lack of merit.

And Zig may be different… I’m not a Zig programmer, but I have the impression that compared to C++ it encourages fewer allocations and smaller codebases, both of which may make lifetime analysis more tractable. It’s also a much younger language whose audience is necessarily much more open to change.

So we’ll see. Good luck - I’d sure like to see more low-level languages offering memory safety.

[1] https://www.circle-lang.org/draft-profiles.html