Interesting, thanks for the links! I'm curious as to how many of the apparent issues are attributable to lifetime extension specifically as opposed to something else like async-related deadlocks as mentioned in the parent to the first linked comment (which I feel I've heard much more about), especially after the Rust 2024 changes.

That being said, after a bit more searching I found this 2023 blog from one of the Rust devs [0] which supports the "widespread" description at the time:

> One very common problem is deadlocks (or panics, for ref-cell) when mutex locks occur in a match scrutinee

so I think we can chalk this up to me being insufficiently well-read. I think it would be interesting to see to what extent the Rust 2024 changes alleviated the problem since it only changed if let, but I haven't found that information (yet).

There's also this related work [1], but I think the scope of that is rather larger.

> Interestingly, Mojo might avoid some or all of that, by having some destructors be implicit, and some destructors be explicit, [] , requiring users to write the destructors manually.

There's some relevant exploration being done in Rust that in principle could enable linear types [2], though obviously it remains to be seen to what extent this work will pan out.

[0]: https://smallcultfollowing.com/babysteps/blog/2023/03/15/tem...

[1]: https://blog.m-ou.se/super-let/

[2]: https://github.com/rust-lang/goals/blob/main/src/2026/move-t...

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modularitynew 7 hours ago | parent [-]

> I think it would be interesting to see to what extent the Rust 2024 changes alleviated the problem since it only changed if let, but I haven't found that information (yet).

The second link from Reddit, https://redlib.catsarch.com/r/rust/comments/1v54et2/what_are... , claims that some issues were made worse in practice in his experience by Rust edition 2024.

Regarding "super let", it looks interesting, but I am not sure about the details of it. This is the tracking GitHub issue https://github.com/rust-lang/rust/issues/139076 . There is also the challenge of backwards compatibility, which makes the feature harder to make good, I suspect.

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aw1621107 6 hours ago | parent [-]

> claims that some issues were made worse in practice in his experience by Rust edition 2024.

That begs the question of exactly what "some issues" encompasses. To me, the poster was clearly complaining about the increased use of a particular code pattern post-Rust-2024, but it's not clear to me that they were also claiming that there is a proportional increase in deadlocks post-Rust-2024. For instance, perhaps it's the case that people use that code pattern more because it doesn't deadlock; this may not be desirable from the commenter's perspective due to the multiple locks/unlocks, but that's a distinct issue from lifetime extension causing deadlocks.

> Regarding "super let", it looks interesting, but I am not sure about the details of it.

At least from a cursory skim it looks like the specifics are still being worked on, so it's hard to fault you for being unsure about the details. It is an experiment after all :P

	▲	modularitynew 6 hours ago \| parent [-]
		Not sure about that.