Shorten def_span for more items.

[cjgillot]

The def_span query only returns the signature span for functions.
Struct/enum/union definitions can also have a very long body.
This PR shortens the associated span.

[rust-highfive]

r? @petrochenkov

(rust-highfive has picked a reviewer for you, use r? to override)

[petrochenkov]

Is opt_span used anywhere on a "good path"?
guess_head_span may be expensive as an operation with the source map, let's check.
@bors try @rust-timer queue

Also, some rustdoc test has failed, not sure whether it's spurious or not.

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[bors]

⌛ Trying commit 3b96c413bb87321cadff009a710d71a5b32ae940 with merge dc992527fcd1dd0d3df63152c8875601eb5781b9...

[bors]

☀️ Try build successful - checks-actions
Build commit: dc992527fcd1dd0d3df63152c8875601eb5781b9 (dc992527fcd1dd0d3df63152c8875601eb5781b9)

[rust-timer]

Queued dc992527fcd1dd0d3df63152c8875601eb5781b9 with parent 902e590, future comparison URL.

[rust-timer]

Finished benchmarking commit (dc992527fcd1dd0d3df63152c8875601eb5781b9): comparison url.

Summary: This benchmark run did not return any relevant results.

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR led to changes in compiler perf.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf -perf-regression

[cjgillot]

Is opt_span used anywhere on a "good path"? guess_head_span may be expensive as an operation with the source map, let's check.

Yes. The def_span query is implemented in terms of it, and its output goes into metadata.

Also, some rustdoc test has failed, not sure whether it's spurious or not.

It looks like I need to reflect the change in line numbers in a doctest. The the link to source will only link to the struct head instead of the whole struct. (Like functions already do.)
Is it an issue? cc @camelid

Last question: should we also do this for trait definitions?
(It's just adding one extra match arm.)

[petrochenkov]

Last question: should we also do this for trait definitions?

If we are doing this consistently, then the same span shortening is applicable to ItemKind::{Trait, Impl, Mod, ForeignMod, Macro} and also to Node::Variant as well (which is basically the same thing as ItemKind::Struct).

[camelid]

Also, some rustdoc test has failed, not sure whether it's spurious or not.

It looks like I need to reflect the change in line numbers in a doctest. The the link to source will only link to the struct head instead of the whole struct. (Like functions already do.) Is it an issue? cc @camelid

Hmm, I think it's fine, but just to be sure: @GuillaumeGomez can you check since you know this feature better?

[GuillaumeGomez]

It doesn't seem to be a spurious failure. Something changed in the rendered output.

[camelid]

Yeah, IIUC it went from highlighting these lines:

struct Foo {
  bar: i32
}

to just the first:

struct Foo {

when you do a jump-to-def.

[petrochenkov]

@bors p=1

[cjgillot]

@bors r=petrochenkov

[bors]

📌 Commit 42e4eee has been approved by petrochenkov

[bors]

⌛ Testing commit 42e4eee with merge 46b8c23...

[bors]

☀️ Test successful - checks-actions
Approved by: petrochenkov
Pushing 46b8c23 to master...

[rust-highfive]

📣 Toolstate changed by #93967!

Tested on commit 46b8c23.
Direct link to PR: #93967

💔 miri on windows: test-pass → test-fail (cc @RalfJung @oli-obk).
🎉 rls on linux: test-fail → test-pass (cc @Xanewok).

[rust-timer]

Finished benchmarking commit (46b8c23): comparison url.

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

• Primary benchmarks: 😿 relevant regression found
• Secondary benchmarks: mixed results

	mean1	max	count2
Regressions 😿 (primary)	2.1%	2.1%	1
Regressions 😿 (secondary)	3.9%	5.9%	3
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	-2.7%	-2.7%	1
All 😿🎉 (primary)	2.1%	2.1%	1

Cycles

Results

• Primary benchmarks: no relevant changes found
• Secondary benchmarks: mixed results

	mean1	max	count2
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	2.6%	3.2%	3
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	-3.6%	-4.6%	2
All 😿🎉 (primary)	N/A	N/A	0

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

@rustbot label: -perf-regression

Footnotes

1. the arithmetic mean of the percent change ↩ ↩²

2. number of relevant changes ↩ ↩²