The issue with the current version of this paragraph is that it refers to code
that will occur later. It can only be understood once we know what is borrowed
and when, which only becomes clear when the error message is shown.
With this new phrasing, I hope that the introduction prepares the reader to what
they'll find out.
Another solution would be to imitate the first example of this page. Introduce
the code with just "Given the following code:" and then comment why it
failed.
This was a bit confusing for me to read, as it was using an old style of rust that I am not used to
Unfortunately, this lint group isn't on by default, but I think `elided_lifetimes_in_paths` may be on track to be deny-by-default in edition 2021?
Currently, the lifetime elision doc only documents function definitions, but lifetime elision is also allowed in the following other locations:
* `fn` types, such as `fn(&T)`
* `Fn`/`FnMut`/`FnOnce`, such as `Fn(&T)`
* `impl` headers
To demo this up, I made some type aliases for `fn`/`Fn` which you can pass `&T` as a parameter to (to follow the lifetime rules of the surrounding context), and compared what you get with that instead of using `fn`/`Fn` directly, where lifetime elision takes on the rules from `fn`/`Fn`/etc.
I also demoed up an `impl` header that used lifetime elision twice, although the error message in that case is broken (filed https://github.com/rust-lang/rust/issues/87763)
The demo was half for this change description, and half just to make sure I understand Rust -- in particular, I really had to reverse engineer it for `impl` because I wasn't sure, and it didn't seem to be documented anywhere (at least not here!)
https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=f82b280de4b992f225bc32121f333e96