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Comment by sanxiyn | Hacker News Reader

Historically, Rust used to have separate operators for copy and move (= vs <-). It was an ergonomic disaster. You may find the current state ugly, but I assure you that if you actually used it, you would have found what you suggested even uglier.

This is one example of Rust failing initial design because developers followed intuition. They thought the same "it would be better to use a separate operator for ownership transfer!" and ignored existing research in the area. The fact is every single language having linear types do ownership transfer by default, based on type.

The experience was reported here for posterity: http://smallcultfollowing.com/babysteps/blog/2012/10/01/move...

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> but I assure you that if you actually used it, you would have found what you suggested even uglier.

It's not fair to make that judgment for someone, particularly because people using Rust at the time weren't complaining much about how ugly it was. At the time it was questioned whether the change was desirable and that very blog post braces for opposition under Wait, doesn’t this make it hard to know what your program does?

Fwiw, that's one instance where unnecessary information/features were removed I would rather had been preserved.

I exaggerated for effect. I am sorry, and I apologize.

Being a long time Rust user, it is annoying to read "why doesn't Rust do X instead of Y?", insinuating X is clearly better than Y and they can't believe why Rust developers haven't considered the obvious alternative. Because it is very frequently (estimate: >50%) the case that Rust did do X, and changed to Y only after lots of actual experience and deliberation. For most design decisions people complain about Rust, Rust tried them both ways. In a few cases, changes were reverted after trying both ways, but usually changes stuck, because they were made carefully.

> Fwiw, that's one instance where unnecessary information/features were removed I would rather had been preserved.

If the information isn't necessary to reason about your program, to write a correct and performant program, then you've just more information to consume, and instead of the unnecessary information you could consume other, necessary information.

The information isn't necessary for the compiler to reason about the program. The information is, in my opinion, useful for humans to reason about the program. The fact is I would reason about programs quicker if this was explicit.

There isn't any more information to consume. The information is exactly the same. It's just different, which is why I think it should look different.

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