[orlp]

I think if you interpret it charitably it means that any bug in the emitted machine code is already a likely memory-unsafe miscompilation if it is ran.

The compiler itself might be perfectly "memory safe" but the generated binary fundamentally is always at risk (besides WebAssembly I suppose).

I'm fully aware of the separation of compiler and binary, and being able to compile untrusted code safely is nice, but a perfectly safe compiler that generates vulnerable binaries isn't that much better.

[steveklabnik]

I do think that is a good point, it's just not what the line actually says. But that's why I wasn't saying "zomg this is WRONG!!!!" but instead, trying to point out that there are subtleties here. For people who aren't as deep in the weeds in this subject, I think the details matter. But again, as I said, I like the post, this is just one thing.

I am also probably in a more pedantic mindset because, well, I'm writing a compiler in Rust, and the words as written do not resonate with me at all.

> a perfectly safe compiler that generates vulnerable binaries isn't that much better.

I do think it's much better. Eliminating classes of bugs in one component is a good thing, even if it's not every component. This is a core lesson of Rust! unsafe still exists, but going from "I don't know what is unsafe" to "only this part is unsafe" is a major improvement.

[demosthanos]

In context that's clearly not what he's saying, the next sentence is this:

> Zig has more features than Rust for making memory-unsafe code work correctly, and that was the area where we wanted the most help.

Zig definitely does not have more features for successfully emitting memory-unsafe machine code than Rust does. I can emit memory-unsafe machine code from typescript if I really want to and nothing at all in the language will get in my way. So the sentence quoted above must refer to the idea that the compiler itself needs to be unsafe, which Steve is right is simply untrue.

[Aurornis]

The section this came from was talking specifically about usages of `unsafe` in the compiler code.

It's not about the memory safety of the resulting binary.