Comment by Groxx

Sure, it's always possible to design a system that avoids the type system of a language. At worst case you can just resort to creating an un-typed lambda calculus and re-implementing your logic there.

Community habits and language frictions matter a lot. In Go, doing the equivalent of `Result` requires custom private types for every combination, with private fields and accessor methods that protect against misuse. And you still only gain runtime safety. And they can still make a zero-valued var and use it without "initialization" (unless you use private types, which are an even bigger pain for a variety of reasons). Any other approach makes it trivial to bypass - public fields can just be accessed, multiple returns can be ignored, etc. In Rust, the community and language make `Result` common, and then you gain compile-time safety in most cases, and warnings in all others (AFAIK, as Result is annotated as "must use", so you get a warning or a `_ =` as a visible marker that you're ignoring something).

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tl;dr multiple returns of course bypass this, but in practice you won't see that in Rust unless it's intended to allow ignoring the error. Underscores on out-param funcs are a good point, but they're also fairly rare / serve as a visual warning of shenaniganry.