Comment by jerf

There's a hidden equivocation there. "Handling" errors, as far as the language is concerned, mean you do something with them, but explicitly discarding them is most definitely a "something".

From a human perspective we can consider that not handling the error.

But the language has no mechanism for "knowing" that discarding the error is wrong. Discarding errors is a fully valid mechanism that we must be able to do in a program because it is sometimes correct. There really isn't even a sensible way to define a way to "force" a user to "handle" errors. The language can only be designed to make it hard to forget to "handle" them somehow in the way the language sees, but it is always possible for the user to incorrectly handle them, of which discarding them when they shouldn't have is only one particularly cognitively-available option but is hardly the full scope of possibilities. Probably isn't even the most common mistake to make, I would imagine there are far more errors that are not handled "correctly" than ones that are spuriously discarded.

Note I keep saying "language" rather than Rust. All a language can do is surface the issue, and Rust does that. It can't force good code. No language can.