> It has been many years since I shipped a memory bug in C++. It is just not a real worry for me.
Can you write down the algorithm that you use to avoid writing memory bugs? Can you teach others how to do it? Experienced C++ programmers do seem to learn how to avoid those bugs (although very often what they write is still undefined according to the standard - but e.g. multithreading bugs may be rare enough not to be encountered in practice). But that's of limited use as long as it's impossible for anyone else to look at a C++ codebase and confirm, at a glance, that that codebase does not contain memory bugs.
> C++ is (still) quite a substantially more expressive language than Rust, which is to say it can capture a lot more semantics in a library.
> So it's great that Rust makes some errors harder to make, but that is no grounds for acting holier-than-thou. Rust programmers have simply chosen to have many more of the other kinds of errors, instead.
Citation needed. What desirable constructions are impossible to express in Rust? I've no doubt that you can write some super-"clever" C++ that reuses the same pointer several different ways and can't be ported to Rust - but such code is not desirable in C++ either (at least not in codebases that more than one person is expected to use). Meanwhile Rust offers a lot of opportunities for libraries to express themselves clearly in a way that's not possible in C++: sum types let you express a very common return pattern much more clearly than you can ever do in C++. Being able to return functions makes libraries much more expressive. Standardised ownership annotations make correct library use very clear, and allow a compiler to automatically check that they're used correctly.
> Every programmer who switches from C to Rust makes a better world; likewise Java to Rust, or C# to Rust, or Go to Rust. Or, any of those to C++.
> Switching from C++ to Rust, or Rust to C++, is of overwhelmingly less consequence, but the balance is still in C++'s favor because C++ still supports more powerful libraries.
> You might disagree, but it is far from obvious that you are correct.
On the contrary, it's obvious from the frequency with which we see crashes and security flaws in C++ codebases that the average programmer who switches from Java to C++, or C# to C++ makes the world a worse place. It's overwhelmingly likely to be true for Rust to C++ as well.