Where Everything Went Wrong: Error Handling and Error Messages in Rust (2020)

Re:Where Everything Went Wrong: Error Handling and Error Mes... by masklinn on Sunday February 21, 2021 @09:58AM (#26213884)

That is true, although I don't know how helpful that is aside from checking that the annotation is not broken? Much like `const`, the annotation would have to be opt-in either way:

* Rust doesn't infer function types (on purpose)

* like const (or Copy), the removal of the flag is a breaking change, so it should not happen implicitly

So functions would necessarily have to be explicitly marked as e.g. `convergent` or whatever. And while callers of `!`-functions would be easy to check for, I don't think rustc is currently smart enough to infer the totality loops in general.

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Re:Where Everything Went Wrong: Error Handling and Error Mes... by a1369209993 on Sunday February 21, 2021 @01:46PM (#26215968)

> Rust doesn't infer function types (on purpose)

> I don't think rustc is currently smart enough to infer the totality loops in general.

Well, yes; we're necessarily talking about changes to the language (or, equivalently, possible different languages).

> while callers of `!`-functions would be easy to check for, [other problems wouldn't]

That was my point, thanks: "when trying to save your crucial data to disk, in real-time code where panicking would maybe kill someone in the real world, etc", checking for the easy-to-check-for problems doesn't actually suffice to prevent disasters.

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