rustdoc: Don't add extra newlines for fully opaque structs

[ollie27]

Changes the definition for braced structs with only private or hidden fields to save space on the page.

Before:

pub struct Vec<T> {
// some fields omitted
}

After:

pub struct Vec<T> { /* fields omitted */ }

This also cleans up empty braced structs.

Before:

pub struct Foo {
}

After:

pub struct Foo {}

beforeafter

cc #34713

[rust-highfive]

r? @steveklabnik

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[steveklabnik]

I like it, but want to talk about it with the docs team

[peschkaj]

I like this as well.

[strega-nil]

I'm against until it adds back the Struct part of Struct std::vec::Vec in the title.

[GuillaumeGomez]

Same as @ubsan.

[ollie27]

@ubsan Sorry, that's an unrelated change: #35003. You can just ignore the title as far as this PR is concerned.

[steveklabnik]

Concerns raised in the docs meeting:

1. That this change also removes the struct bit, like in rustdoc: Remove item types from some title pages #35003 . That bit is controversial, so we might not want to merge this with that change. (Though, @ollie27 it seems like you just posted that this actually from the other PR, so not a real problem)
2. .. is already rust syntax, so this is a bit ambiguous. Struct(..) at least shows as Struct(RangeFull), but users may not know that.
3. Related, when there are private fields, this means that you can't use struct literal syntax to create the struct. So it's important to keep this distinction in some form.

So, we are vaguely 👍 on this idea, but have some concerns. Let's keep discussing this in-issue.

[ollie27]

1. Yeah maybe I shouldn't have use the same repo to test both of those changes.
2. I was aiming for it to match rust syntax. Specifically a pattern that would match the struct which is what we do for tuple structs with hidden fields: std::process::Stdio. I could add another . so it becomes a full ellipsis like we do for default trait methods: std::iter::Iterator if that's less confusing.
3. Right, I forgot about the case of a braced struct with no fields. I'll fix that.

[ollie27]

I've fixed the case of empty braced structs. Now they're displayed as pub struct Foo {} rather than:

pub struct Foo {
}

[peschkaj]

@ollie27 could you re-render the "after" picture so we can easily look at the change?

[ollie27]

I've updated the PR message to hopefully clear things up. Sorry for causing so much confusion.

[samlh]

I like this, but would vaguely prefer

pubstructVec<T>{/*...*/}

[steveklabnik]

@ollie27 we talked about this at the docs team meeting, and we like this, but would prefer this:

pub struct Vec<T> { /* fields omitted */ }

Can you change it to that, then? We can merge after.

[ollie27]

I've changed it to pub struct Vec<T> { /* fields omitted */ }.

[GuillaumeGomez]

👍

[steveklabnik]

@bors: r+

thank you so much!

[bors]

📌 Commit 8154a6b has been approved by steveklabnik

[bors]

⌛ Testing commit 8154a6b with merge 97b561a...

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-cargotest, auto-linux-64-cross-freebsd, auto-linux-64-debug-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-opt-rustbuild, auto-linux-64-x-android-t, auto-linux-cross-opt, auto-linux-musl-64-opt, auto-mac-32-opt, auto-mac-64-opt, auto-mac-64-opt-rustbuild, auto-mac-cross-ios-opt, auto-win-gnu-32-opt, auto-win-gnu-32-opt-rustbuild, auto-win-gnu-64-opt, auto-win-msvc-32-opt, auto-win-msvc-64-cargotest, auto-win-msvc-64-opt, auto-win-msvc-64-opt-rustbuild
Approved by: steveklabnik
Pushing 97b561a to master...