Matt Godbolt sold me on Rust by showing me C++

This seems a big silly. This is not a language issue. You can have a C++ library that does exactly all the things being shown here so that the application developer doesn't worry about. There would no C++ language features missing that would accomplish what you're able to do on the Rust side.

So is this really a language comparison, or what libraries are available for each language platform? If the latter, that's fine. But let's be clear about what the issue is. It's not the language, it's what libraries are included out of the box.

Just like language shapes the way we think and talk about things, programming languages shape both what libraries are written and how. You could write anything in anything so long as it's Turing complete, but in real life we see clearly that certain design decisions at the language level either advantage or disadvantage certain types of solutions. Everyone could in theory write C without any memory issues, but we all know how that turns out in practice. The language matters.

The core of this argument taken to its extreme kind of makes the whole discussion pointless, right? All the languages can do all the things, so why bother differentiating them?

To entertain the argument, though, it may not be a language issue, but it certainly is a selling point for the language (which to me indicates a "language issue") to me if the language takes care of this "library" (or good defaults as I might call them) for you with no additional effort -- including tight compiler and tooling integration. That's not to say Rust always has good defaults, but I think the author's point is that if you compare them apples-to-oranges, it does highlight the different focuses and feature sets.

I'm not a C++ expert by any stretch, so it's certainly a possibility that such a library exists that makes Rust's type system obsolete in this discussion around correctness, but I'm not aware of it. And I would be incredibly surprised if it held its ground in comparison to Rust in every respect!

If the default is a loaded gun pointed at your foot, you're going to end up with lots of people missing a foot. "just git gud" isn't a solution.

Yeah, I kept thinking, "doesn't mp-units basically address this entirely"?

That's an entirely different line of reasoning from the article though, and "just git gud" isn't really the solution here any more than it is to use Rust. There are facilities for avoiding these problems that you don't have to learn how to construct yourself in either language.

Sure, you can emulate some of the features and hope that everyone using your library is doing it "right". Just like you could just use a dynamic language, tag every variable with a type, and hope everyone using your library does the MANUAL work of always doing it correct. Guess we don't need types either.

And while we're at it, why not use assembly? It's all just "syntactic sugar" over bits, doesn't make any difference, right?

The Sapir Whorf hypothesis has long been debunked:

https://en.m.wikipedia.org/wiki/Linguistic_relativity

The strong hypothesis has been debunked, yes, but nobody is asserting it.

From your link:

> Nevertheless, research has produced positive empirical evidence supporting a weaker version of linguistic relativity:[5][4] that a language's structures influence a speaker's perceptions, without strictly limiting or obstructing them.