[cmrx64]

> Was there something useful you were trying to add?

Yes, the clarification about value safety, which you’ve done quite well.

Not every language is unrepentantly unsound.

I continue to identify a confusion in this thread between a property of the languages, and a property of particular code, but I have clearly exhausted your patience. thank you.

[randomdata]

> Not every language is unrepentantly unsound.

For sure. Coq does a decent job, but it's also a complete bear to use. Tradeoffs, as always.

> I continue to identify a confusion in this thread between a property of the languages, and a property of particular code

Go on. The original statement was that C and Go do not have type-safe enums. But there is no evidence of that being the case. The types are safe.

Indeed, the types are limited. An integer type, for example, cannot be further narrowed to only 1-10 in these languages. But the lack of a feature does not imply lack of type-safety. It only implies a lack of a feature.

[cmrx64]

the disagreement is that the program is typesafe just because it was typechecked. BECAUSE the system is unsound (completeness is irrelevant), typechecking doesn’t imply type safety.

… where I am using type safety to mean “no runtime type errors/UB manifest”, ie, the property that a sound typesystem would guarantee _if we had one_. You seem to be saying that just because our type system is impoverished, does not make its resulting claim of “program is type safe” any less valid, whereas I am saying “type safety is a semantic property of programs, not of languages, and this value safety idea seems like it’s what PLTers think type safety means”.

It’s a violation of the C semantics to assign the wrong value to an enumeration, so I would say that fact the language doesn’t do anything at all to enforce or check this promotes this beyond “lack of a feature” and straight into “type unsafe”. However, I’d feel less strongly if at least initializers were checked.

As you say, different language design philosophies lead to this, and it’s not surprising. Most of these ideas came _after_ C anyway!

phone dying… no response soon.