If there's any misunderstanding, it's probably mine. :) I'm reasonably familiar with Rust, and I understand your argument; but I only read about Zig a couple we

If there's any misunderstanding, it's probably mine. :) I'm reasonably familiar with Rust, and I understand your argument; but I only read about Zig a couple weeks ago, so my knowledge there is based only on a little reading and experimentation. My reading of the release notes: https://ziglang.org/download/0.2.0/release-notes.html https://ziglang.org/download/0.2.0/release-notes.html ...is that error sets can be inferred (at both call-site and in the function declaration); and that inferred error-sets on return types are exact, in the sense that an inferred set will only include the actually-possible errors encountered in the call-tree. To be fair, I don't know whether a function can declare that it may fail with a given, explicitly-declared error-set, where that error-set includes errors that the function actually cannot produce. (E.g., I say I can throw a network-error code, but I perform no network calls.) If this is permissible (i.e, the compiler doesn't complain), then that undercuts my argument a bit. :) On the other hand (again from the release notes), most functions are encouraged to simply declare their return type as !T, where the ! represents "the inferred error-set for the function," and this seems to support my claim.