less clones and more cleanup for `rustc_builtin_macros` by cyrgani · Pull Request #162234 · rust-lang/rust

cyrgani · 2026-09-03T12:26:27Z

Followup to #161867, with (hopefully) several small perf improvements.

panstromek · 2026-09-03T12:28:21Z

less clones and more cleanup for `rustc_builtin_macros`

rust-bors · 2026-09-03T13:27:16Z

☀️ Try build successful (CI)
Build commit: 73366f0 (73366f0da15ddcf8000af24409c8c343bb5c092c)
Base parent: 4fcf397 (4fcf39725a9c99bd495d8c73af83628a256ff9a9)

rust-timer · 2026-09-03T15:40:07Z

Finished benchmarking commit (73366f0): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

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

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.2%, 0.2%]	3
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.4%	[-1.0%, -0.2%]	7
All ❌✅ (primary)	0.2%	[0.2%, 0.2%]	3

Max RSS (memory usage)

Results (primary 1.2%, secondary 4.4%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	1.2%	[1.2%, 1.2%]	1
Regressions ❌ (secondary)	4.4%	[4.4%, 4.4%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.2%	[1.2%, 1.2%]	1

Cycles

Results (primary -3.7%, secondary -3.8%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-3.7%	[-4.6%, -2.9%]	2
Improvements ✅ (secondary)	-3.8%	[-3.8%, -3.8%]	1
All ❌✅ (primary)	-3.7%	[-4.6%, -2.9%]	2

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 476.065s -> 474.054s (-0.42%)
Artifact size: 401.18 MiB -> 400.93 MiB (-0.06%)

rustbot · 2026-09-11T19:26:10Z

Changes to the code generated for builtin derived traits.

cc @nnethercote

rustbot · 2026-09-11T19:26:12Z

r? @mu001999

rustbot has assigned @mu001999.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

Why was this reviewer chosen?

The reviewer was selected based on:

Owners of files modified in this PR: compiler
compiler expanded to 76 candidates
Random selection from 20 candidates

saethlin · 2026-09-11T19:41:44Z

@bors try @rust-timer queue

rust-timer · 2026-09-11T21:34:57Z

Finished benchmarking commit (5790cbb): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

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

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.2%, 0.2%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.2%	[-0.3%, -0.1%]	14
Improvements ✅ (secondary)	-0.3%	[-0.9%, -0.1%]	13
All ❌✅ (primary)	-0.2%	[-0.3%, 0.2%]	15

Max RSS (memory usage)

Results (primary -0.4%, secondary 2.8%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	4.8%	[4.8%, 4.8%]	1
Regressions ❌ (secondary)	2.8%	[2.5%, 3.1%]	2
Improvements ✅ (primary)	-1.5%	[-5.2%, -0.5%]	5
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.4%	[-5.2%, 4.8%]	6

Cycles

Results (primary 0.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	1.3%	[0.4%, 3.9%]	8
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.8%	[-2.1%, -0.5%]	11
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.1%	[-2.1%, 3.9%]	19

Binary size

Results (primary 0.1%, secondary 0.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.1%	[0.0%, 0.2%]	86
Regressions ❌ (secondary)	0.1%	[0.0%, 0.2%]	59
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.1%	[0.0%, 0.2%]	86

Bootstrap: 492.981s -> 494.748s (0.36%)
Artifact size: 406.85 MiB -> 407.67 MiB (0.20%)

mu001999

@rustbot author

View changes since this review

rustbot · 2026-09-12T03:04:49Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

mu001999

LGTM, thanks!

@bors r+ rollup=never

View changes since this review

rust-bors · 2026-09-12T10:41:21Z

📌 Commit 42eca86 has been approved by mu001999

It is now in the queue for this repository.

rust-bors · 2026-09-13T03:02:20Z

☀️ Test successful - CI
Approved by: mu001999
Duration: 2h 54m 28s
Pushing 67e8d9d to main...

github-actions · 2026-09-13T03:05:12Z

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing 3fcfc54 (parent) -> 67e8d9d (this PR)

Test differences

Show 4 test diffs

4 doctest diffs were found. These are ignored, as they are noisy.

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 67e8d9d65f33118199f9749343782cc287426587 --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

dist-aarch64-apple: 1h 28m -> 2h 15m (+53.5%)
test-x86_64-gnu-aux: 1h 47m -> 2h 34m (+42.9%)
test-x86_64-gnu-tools: 50m 39s -> 1h 9m (+37.2%)
test-i686-msvc: 1h 47m -> 2h 27m (+37.2%)
test-i686-gnu-1: 2h 30m -> 1h 35m (-36.8%)
dist-x86_64-musl: 2h 25m -> 1h 33m (-35.6%)
dist-powerpc64-linux-gnu: 1h 11m -> 1h 36m (+34.4%)
test-x86_64-gnu-stable: 2h -> 2h 40m (+33.3%)
dist-x86_64-llvm-mingw: 1h 37m -> 2h 10m (+32.9%)
test-x86_64-gnu-llvm-21-3: 1h 59m -> 1h 20m (-32.5%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

rust-timer · 2026-09-13T03:47:26Z

Finished benchmarking commit (67e8d9d): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.2%, 0.2%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.2%	[-0.4%, -0.1%]	21
Improvements ✅ (secondary)	-0.3%	[-0.9%, -0.0%]	13
All ❌✅ (primary)	-0.2%	[-0.4%, 0.2%]	22

Max RSS (memory usage)

Results (primary 0.8%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.8%	[0.4%, 1.2%]	3
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.8%	[0.4%, 1.2%]	3

Cycles

Results (primary -0.0%, secondary 3.3%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	1.1%	[0.4%, 2.3%]	3
Regressions ❌ (secondary)	3.3%	[3.3%, 3.3%]	1
Improvements ✅ (primary)	-0.8%	[-1.1%, -0.6%]	4
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.0%	[-1.1%, 2.3%]	7

Binary size

Results (primary 0.0%, secondary -0.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.0%	[0.0%, 0.1%]	4
Regressions ❌ (secondary)	0.0%	[0.0%, 0.1%]	2
Improvements ✅ (primary)	-0.0%	[-0.0%, -0.0%]	5
Improvements ✅ (secondary)	-0.0%	[-0.0%, -0.0%]	4
All ❌✅ (primary)	0.0%	[-0.0%, 0.1%]	9

Bootstrap: 495.498s -> 493.573s (-0.39%)
Artifact size: 407.03 MiB -> 406.95 MiB (-0.02%)

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Sep 3, 2026

cyrgani added the S-blocked Status: Blocked on something else such as an RFC or other implementation work. label Sep 3, 2026

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rust-bors Bot pushed a commit that referenced this pull request Sep 3, 2026

Auto merge of #162234 - cyrgani:builtin-macros-clean-3, r=<try>

73366f0

less clones and more cleanup for `rustc_builtin_macros`

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rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Sep 3, 2026

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rust-cloud-vms Bot force-pushed the builtin-macros-clean-3 branch from fb78a2f to 785ad11 Compare September 4, 2026 11:14

cyrgani added 4 commits September 11, 2026 18:27

make expr_for_field a closure

07d0a06

several small tweaks

2d00803

use a named struct instead of a 4-tuple

759cf27

unify span_bug message format for unreachable substructures

58ce4d0

rust-cloud-vms Bot force-pushed the builtin-macros-clean-3 branch from dc2a811 to 013cd94 Compare September 11, 2026 18:34

cyrgani marked this pull request as ready for review September 11, 2026 19:26

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Sep 11, 2026

rustbot assigned mu001999 Sep 11, 2026

cyrgani removed the S-blocked Status: Blocked on something else such as an RFC or other implementation work. label Sep 11, 2026

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rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Sep 11, 2026

rustbot removed S-waiting-on-perf Status: Waiting on a perf run to be completed. perf-regression Performance regression. labels Sep 11, 2026

mu001999 reviewed Sep 12, 2026

View reviewed changes

Comment thread compiler/rustc_builtin_macros/src/deriving/generic/mod.rs Outdated

rustbot removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Sep 12, 2026

rustbot added the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Sep 12, 2026

cyrgani added 7 commits September 12, 2026 08:38

remove some clones via owned Substructure

03c235f

less clones in cs_clone

7cd11a0

avoid collecting into intermediate Vecs

a33ec0c

remove Bounds in favor of ast::Generics

cbac5a4

avoid emitting empty assert_fields_are_equal methods

741f80a

utilize cx.pat_ident

f14e358

stop passing a &MetaItem around

42eca86

rust-cloud-vms Bot force-pushed the builtin-macros-clean-3 branch from 013cd94 to 42eca86 Compare September 12, 2026 08:39

cyrgani added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Sep 12, 2026

mu001999 approved these changes Sep 12, 2026

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rust-bors Bot added merged-by-bors This PR was explicitly merged by bors. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Sep 13, 2026

rust-bors Bot merged commit 67e8d9d into rust-lang:main Sep 13, 2026
14 checks passed

rustbot added this to the 1.100.0 milestone Sep 13, 2026

cyrgani deleted the builtin-macros-clean-3 branch September 13, 2026 08:19

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rust-timer commented Sep 3, 2026

Overall result: ❌✅ regressions and improvements - please read:

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rust-timer commented Sep 11, 2026

Overall result: ✅ improvements - no action needed

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github-actions Bot commented Sep 13, 2026

Test differences

Job duration changes

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rust-timer commented Sep 13, 2026

Overall result: ✅ improvements - no action needed

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