Remove doctree::StructType
Also removes it from the Union type, as unions can only ever be 'Plain'. Adds a new StructType to JSON, 'union', as the easiest way to encode the type of a union there. This leaves only one item in doctree, `Module`.
r? `@jyn514`
[rustdoc] Box ItemKind to reduce the size of `Item`
This brings the size of `Item` from
```
[src/librustdoc/lib.rs:103] std::mem::size_of::<Item>() = 536
```
to
```
[src/librustdoc/lib.rs:103] std::mem::size_of::<Item>() = 136
```
This is an alternative to https://github.com/rust-lang/rust/pull/79967; I don't think it makes sense to make both changes.
Helps with #79103.
This is a squash of these commits:
- Highlight edition-specific keywords correctly in code blocks,
accounting for code block edition modifiers
- Fix unit tests
- Revert changes to rustc_span::symbol to prepare for merge of #80272
- Use new Symbol::is_reserved API from #80272
- Remove unused import added by accident when merging
This brings the size of `Item` from
```
[src/librustdoc/lib.rs:103] std::mem::size_of::<Item>() = 680
```
to
```
[src/librustdoc/lib.rs:103] std::mem::size_of::<Item>() = 280
```
Remove `DefPath` from `Visibility` and calculate it on demand
Depends on #80090 and should not be merged before. Helps with https://github.com/rust-lang/rust/issues/79103 and https://github.com/rust-lang/rust/issues/76382.
cc https://github.com/rust-lang/rust/pull/80014#issuecomment-746810284 - `@nnethercote` I figured it out! It was simpler than I expected :)
This brings the size of `clean::Visibility` down from 40 bytes to 8.
Note that this does *not* remove `clean::Visibility`, even though it's now basically the same as `ty::Visibility`, because the `Invsible` variant means something different from `Inherited` and I thought it would be be confusing to merge the two. See the new comments on `impl Clean for ty::Visibility` for details.
Continue String to Symbol conversion in rustdoc (2)
Follow-up of #80119.
This is the last one (and I actually expected more conversions but seems like it was the last one remaining...).
r? `@jyn514`
Continue String to Symbol conversion in rustdoc
Follow-up of https://github.com/rust-lang/rust/pull/80091.
This PR is already big enough so I'll stop here before the next one.
r? `@jyn514`
Use more symbols in rustdoc
Builds on https://github.com/rust-lang/rust/pull/80044 and should not be merged before.
I want to test if this is actually faster before merging it, there was a lot of `to_string()` calls so I'm not sure it will actually help. That means I have to wait for 80044 to get merged before running perf.
r? `@ghost`
[rustdoc] Calculate span information on demand instead of storing it ahead of time
This brings `size_of<clean::types::Span>()` down from over 100 bytes (!!) to only 12, the same as rustc. It brings `Item` down even more, from `784` to `680`.
~~TODO: I need to figure out how to do this for the JSON backend too. That uses `From` impls everywhere, which don't allow passing in the `Session` as an argument. `@P1n3appl3,` `@tmandry,` maybe one of you have ideas?~~ Figured it out, fortunately only two functions needed to be changed. I like the `convert_x()` format better than `From` everywhere but I'm open to feedback.
Helps with #79103