RAII has the advantage that you can't forget to do it, but defer has the advantage that you can handle failure in ways other than panicking. Of course, in many cases (e.g. closing a file), there's generally not much you can do anyway even if you want to handle the error directly, but at least it's possible.

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bewareofscams 2 hours ago | parent [-]

Rust can handle that with RAII without panicking just fine. And not only Rust..

	▲	kbolino 24 minutes ago \| parent [-]
		Sure, you can just ignore errors entirely, and this is what Rust actually does today, at least for std::fs::File. The only other option within RAII that I can think of is that you can mutate some external, longer-lived state. The primary way to deal with error-on-clean-up in RAII languages is to not rely exclusively on RAII for it. Rust's File type, for example, has sync_data and sync_all methods (which, to be fair, only even need to be called for writable file handles). I don't think there's anything wrong with this approach, but it ends up being just as explicit and therefore forgettable as defer. It should be noted that you can (at least in Rust) actually implement defer using RAII; see e.g. the scopeguard crate. Since RAII is block-scoped, this defer is also block-scoped (like Zig) rather than function-scoped (like Go).