> 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