> It's never been clear to me where such a type is actually useful. In what cases do you really need to restrict it to valid UTF-8?

Because 99.999% of the time you want it to be valid and would like an error if it isn't? If you want to work with invalid UTF-8, that should be a deliberate choice.

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maxdamantus 3 days ago | parent [-]

Do you want grep to crash when your text file turned out to have a partially written character in it? 99.999% seems very high, and you haven't given an actual use case for the restriction.

	▲	empath75 3 days ago \| parent \| next [-]
		Rust doesn't crash when it gets an error unless you tell it to. You make a choice how to handle the error because you have to it or it won't compile. If you don't care about losing information when reading a file, you can use the lossy function that gracefully handles invalid bytes.
	▲	gf000 3 days ago \| parent \| prev [-]
		Crash? No. But I can safely handle the error where it happens, because the language actually helps me with this situation by returning a proper Result type. So I have to explicitly check which "variant" I have, instead of forgetting to call the validate function in case of go.