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Animats ◴[] No.43979394[source]
It's like reading "A Discipline of Programming", by Dijkstra. That morality play approach was needed back then, because nobody knew how to think about this stuff.

Most explanations of ownership in Rust are far too wordy. See [1]. The core concepts are mostly there, but hidden under all the examples.

    - Each data object in Rust has exactly one owner.
      - Ownership can be transferred in ways that preserve the one-owner rule.
      - If you need multiple ownership, the real owner has to be a reference-counted cell. 
        Those cells can be cloned (duplicated.)
      - If the owner goes away, so do the things it owns.

    - You can borrow access to a data object using a reference. 
      - There's a big distinction between owning and referencing.
      - References can be passed around and stored, but cannot outlive the object.
        (That would be a "dangling pointer" error).
      - This is strictly enforced at compile time by the borrow checker.
That explains the model. Once that's understood, all the details can be tied back to those rules.

[1] https://doc.rust-lang.org/book/ch04-01-what-is-ownership.htm...

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ajross ◴[] No.43980199[source]
The second bullet in the second section is overpromising badly. In fact there are many, many, many ways to write verifiably correct code that leaves no dangling pointers yet won't compile with rustc.

Frankly most of the complexity you're complaining about stems from attempts to specify exactly what magic the borrow checker can prove correct and which incantations it can't.

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sph ◴[] No.43996681[source]
Rust feels like an excellent language paired with a beta-quality borrow checker. The issue is that the more they fix the paper cuts, the more complex the type system grows.
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1. umanwizard ◴[] No.43998564[source]
What do you mean? What are some examples of borrow checker improvements that resulted in more type system complexity?