I don't believe that either ErrorKind or 'failure' gives the same degree of automated enumeration and checking that Zig provides. I'm not a Zig apologist... I just think you should read through the Zig documentation and examine the differences for yourself.

https://ziglang.org/documentation/master/#Errors

https://ziglang.org/download/0.2.0/release-notes.html (see "Error Sets")

If I'm understanding correctly, you can use enums in rust to recreate the same, though it would be slightly more verbose.

    enum MyErrorSet {
        NotFound(ErrorKind),
        SomethingElse(ErrorKind),
    }

If you don't care about propagating the original ErrorKind then that's just

    enum MyErrorSet {
        NotFound,
        SomethingElse
    }

Yes, I think you're right. But the burden for generating and maintaining the enums is on the developer; whereas in Zig, they can be automatically inferred by the compiler.

I don't think the distinction is super important in application work (for example). But for systems code I can see the benefit of having the compiler tell you, with certainty, why a given function can fail (and why it can't). E.g., a good device driver should handle all its failure modes with care, rather than with a shotgun approach.