rustdoc: "Methods from Deref<...>" too low on sidebar

[jsha]

Steps to reproduce:

1. Visit https://doc.rust-lang.org/beta/std/string/struct.String.html
2. Scroll down the sidebar looking for "Methods from Deref<...>"

Expected result:

Methods from Deref section comes immediately after Methods.

Actual result:

Methods from Deref section comes below Trait Implementations, Auto Trait Implementations, and Blanket Implementations.

Compare vs https://doc.rust-lang.org/std/string/struct.String.html, which has the correct ordering.

[jsha]

Ah, looks like this was intentional in #83826, after conversation in #83133. Removing C-bug and regression-from-stable-to-beta. Keeping this open as a discussion issue: I think putting "Methods from Deref" further down than trait implementations is wrong for String, because so many of its important methods are on str. I'd like to either reconsider #83133 or find some way to make this work nicely for String. Vec is probably in the same boat, with its impl Deref<Target = [T]>.

[ilyvion]

I'd like to voice that I also think this is a kind of regression. 99% of the time I go to a type's page, I'm looking for methods, not traits; I've gotten used to seeing str's methods directly under Strings, and it feels like a mistake moving away from this.

[jsha]

@jyn514, @slightlyoutofphase, what do you think of reverting #83826 while we look for a better solution. From #83133:

it would almost certainly be better to have the crate-native "Trait Implementations" section appear before the "Methods From Deref" section does, since "Trait Implementations" will pretty much always be describing things that are unique to the crate being documented and so actually directly relevant

The problem with this is sometimes the "Methods from Deref" section refers to a type in the crate. Particularly for Vec and String, about half of the most useful methods are on [T] and str, respectively.

Those are types that are a critical part of the new user learning path, and it's a good user experience for those to be right next to the other methods, both in the sidebar and in the doc.

I suspect there are other ways to solve the need expressed in #83133 without affecting the page layout of Vec and String in this way.

[jyn514]

@jsha that's fine - #83826 was a response to #80653, which has since been reverted.