If you can’t understand ownership I’m baffled how you believe you can write well behaved C or C++.

Rust at least embeds this information in the API with checks. C and C++ are doc comments at best.

I’m going to start this comment by specifying that I don’t know what OP was considering complex about Rust and, unfortunately, a large amount of discussion on the topic tends toward strawman-ing by people looking to argue the ‘anti-Rust’ side of said discussions. Additionally, the lack of a contextual and well considered position against some aspect of Rust, as a language, is very common, and at worst the negative take is really just a overall confrontational stance against Rust’s uptick in usage broadly and its community of users, as perceived (and also strawmanned), in a generally negative light. But since borrowing is not explicitly mentioned by GP, I will give a slightly different position than he might, but I think this is an interesting perspective difference to discuss and not a blatant ad hom argument used to ‘fight’ Rust users on the internet.

From my position the complexity incurred by ownership semantics in Rust does not stem from Rust’s ‘formalization’ and semi-reification of a particular view on ownership as a means of program constraint. The complexity of Rust, in relation to ownership, comes with the lengths I would have to go to design systems using other logical means of handling references (particularly plain hardware implemented pointers) to semantic objects: their creation, specification, and their deletion. Additionally, other means of handling resources (particularly memory acquired via allocation): its acquisition, transport through local and distributed processes (from different cores to over the wire), and its deletion or handing back to OS.

Rust adopts ownership semantics (and value semantics to a large degree) to the maximum extent possible and has enmeshed those semantics throughout all levels of abstraction in the language definition (as far as a singular authoritative ‘definition’ can be said to exist as a non-implementation related formalism). At the level of Rust the language, not merely discussions and discourse about the language, ownership semantics are baked in at a specified granularity and that ownership is compositional over the abstraction mechanisms provided. These semantics dictate how everything from a single variable on the stack to large size allocations in a general heap to non-memory ‘resources’, like files, textures, databases, and general processes, are handled in a program. On top of the ownership semantics sit the rest of Rust’s semantics and they are all checked at compile time by a singular oracular subsystem (i.e. the borrow checker).

The complexity really begins to rise, for me, if ai want to attempt to program without engaging with ownership as the methodology or semantics for handling all of the above mentioned ‘resources’. I prefer, and believe, that a broader set of formalisms should be available for ‘handling’ resources, that those formalisms should exist with parameterized granularity, and that the foundational semantics for those mechanisms should come from type systems’ ability to encode capabilities and conditions for particular types in a program. That position is in contrast to the universal and foundational ownership semantic, especially with the individualistic fixed granularity, that Rust chose.

That being said, it is bordering on insanity to attempt to program in such a ‘style’/paradigm/method in Rust. My preferences make Rust’s chosen focus on ownership seem complex at the outset, and attempts to try and impose an alternate formalism in Rust (which would, by necessity, have to try and be some abstraction over Rust’s ownership semantics which hid those semantics and tried to present a different set of semantics to thenprogrammer) take that complexity to even higher levels.

The real problem with trying to frame my position here as complexity is the following: to me Rust and its ownership semantic is complex because I do not like it’s chosen core semantic construct, so when I think about achieving something using Rust I have to deal with additional semantics, semantic objects, and their constraints on my program that I do not think are fit for purpose. But, if I wanted to program in Rust without trying to circumvent, ignore, or disregard it’s choices as a language and just decided to accept (or embrace) it’s semantic choices the complexity I perceive would decrease significantly and immediately.

For me, Rust’s ownership semantics create an impedance mismatch that at the level of language use FEELS like complexity (and acts like complexity in a lot of ways), but is probably more correctly identified as just what it is… an impedance mismatch, nothing more and nothing less. For me, I just chose not to use Rust to avoid that, but for others they get focused on these issues and don’t actually get to the bottom of their issues and just default to calling it complexity during discussion.

All in all, I am probably being entirely to optimistic about the comments about the complexity of Rust and ownership and most commenters are just fighting to fight, but I genuinely believe there is much to discuss and work through in programming language design theory and writing walls of text on HN helps me do that.