Re-add `#[inline]` to `Eq::assert_fields_are_eq` by madsmtm · Pull Request #153157 · rust-lang/rust

madsmtm · 2026-02-26T23:13:33Z

Fixes a compile-time regression in #149978: non-inline methods are generally codegen'd while inline methods are deferred (and this function should never be called, so deferring is the right choice).

r? JonathanBrouwer
CC @cyrgani

rustbot · 2026-02-26T23:13:36Z

Changes to the code generated for builtin derived traits.

cc @nnethercote

rustbot · 2026-02-26T23:13:38Z

JonathanBrouwer is currently at their maximum review capacity.
They may take a while to respond.

madsmtm · 2026-02-26T23:13:54Z

@bors try @rust-timer queue

…<try> Re-add `#[inline]` to `Eq::assert_fields_are_eq`

rust-bors · 2026-02-27T01:24:52Z

☀️ Try build successful (CI)
Build commit: 980e383 (980e38374c34e1b7ebef50d22d62e6e0b482cbdc, parent: 6a979b3e32522049d0acb4a47f7ae44b7c8abfd5)

compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs

rust-timer · 2026-02-27T04:02:08Z

Finished benchmarking commit (980e383): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

@bors rollup=never
@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
Regressions ❌ (secondary)	0.3%	[0.3%, 0.3%]	1
Improvements ✅ (primary)	-0.5%	[-0.9%, -0.3%]	3
Improvements ✅ (secondary)	-2.5%	[-5.6%, -0.3%]	5
All ❌✅ (primary)	-0.5%	[-0.9%, -0.3%]	3

Max RSS (memory usage)

Results (primary -2.7%, secondary -5.3%)

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

	mean	range	count
Regressions ❌ (primary)	2.7%	[2.7%, 2.7%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-3.8%	[-7.2%, -1.3%]	5
Improvements ✅ (secondary)	-5.3%	[-7.7%, -2.8%]	5
All ❌✅ (primary)	-2.7%	[-7.2%, 2.7%]	6

Cycles

Results (primary -2.3%, secondary -2.9%)

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)	-2.3%	[-2.3%, -2.3%]	1
Improvements ✅ (secondary)	-2.9%	[-2.9%, -2.9%]	1
All ❌✅ (primary)	-2.3%	[-2.3%, -2.3%]	1

Binary size

Results (primary -0.3%, secondary -2.7%)

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

	mean	range	count
Regressions ❌ (primary)	0.5%	[0.5%, 0.5%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.3%	[-1.3%, -0.0%]	31
Improvements ✅ (secondary)	-2.7%	[-11.3%, -0.1%]	15
All ❌✅ (primary)	-0.3%	[-1.3%, 0.5%]	32

Bootstrap: 484.473s -> 480.523s (-0.82%)
Artifact size: 397.64 MiB -> 395.62 MiB (-0.51%)

JonathanBrouwer

r=me after addressing nnethercotes comment

View changes since this review

JonathanBrouwer · 2026-02-27T09:33:32Z

@rustbot author

rustbot · 2026-02-27T09:33:36Z

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

Fixes a compile-time regressions, non-inline methods are generally codegen'd while inline methods are deferred (and this should never be called, so deferring is the right choice).

madsmtm · 2026-02-27T10:50:53Z

@bors r=JonathanBrouwer

rust-bors · 2026-02-27T10:50:55Z

📌 Commit 1001c0e has been approved by JonathanBrouwer

It is now in the queue for this repository.

rust-bors · 2026-03-02T06:34:09Z

☀️ Test successful - CI
Approved by: JonathanBrouwer
Duration: 3h 52m 58s
Pushing ddd36bd to main...

github-actions · 2026-03-02T06:37:48Z

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 e7d90c6 (parent) -> ddd36bd (this PR)

Test differences

Show 1 test diff

1 doctest diff were found. These are ignored, as they are noisy.

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard ddd36bd57051f796850345b76c17e9402e28a9e4 --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-x86_64-apple: 2h 25m -> 2h 1m (-16.4%)
dist-aarch64-msvc: 1h 37m -> 1h 50m (+13.0%)
dist-aarch64-apple: 2h 12m -> 1h 56m (-11.7%)
dist-arm-linux-musl: 1h 30m -> 1h 39m (+9.2%)
dist-x86_64-llvm-mingw: 1h 46m -> 1h 55m (+8.9%)
x86_64-gnu: 2h 19m -> 2h 7m (-8.8%)
dist-ohos-x86_64: 1h 21m -> 1h 14m (-8.8%)
dist-aarch64-llvm-mingw: 1h 46m -> 1h 37m (-8.2%)
i686-msvc-1: 3h 2m -> 2h 47m (-8.0%)
i686-gnu-nopt-2: 2h 15m -> 2h 4m (-7.9%)

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 · 2026-03-02T07:52:47Z

Finished benchmarking commit (ddd36bd): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Our benchmarks found a performance regression caused by this PR.
This might be an actual regression, but it can also be just noise.

Next Steps:

If the regression was expected or you think it can be justified,
please write a comment with sufficient written justification, and add
@rustbot label: +perf-regression-triaged to it, to mark the regression as triaged.
If you think that you know of a way to resolve the regression, try to create
a new PR with a fix for the regression.
If you do not understand the regression or you think that it is just noise,
you can ask the @rust-lang/wg-compiler-performance working group for help (members of this group
were already notified of this PR).

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

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
Regressions ❌ (secondary)	0.2%	[0.2%, 0.3%]	3
Improvements ✅ (primary)	-0.5%	[-0.8%, -0.3%]	4
Improvements ✅ (secondary)	-3.0%	[-5.6%, -0.4%]	4
All ❌✅ (primary)	-0.5%	[-0.8%, -0.3%]	4

Max RSS (memory usage)

Results (primary -3.9%, 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)	3.1%	[3.1%, 3.1%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-5.7%	[-7.2%, -3.3%]	4
Improvements ✅ (secondary)	-3.8%	[-4.5%, -2.5%]	3
All ❌✅ (primary)	-3.9%	[-7.2%, 3.1%]	5

Cycles

Results (secondary -4.5%)

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)	-	-	0
Improvements ✅ (secondary)	-4.5%	[-4.5%, -4.5%]	1
All ❌✅ (primary)	-	-	0

Binary size

Results (primary -0.3%, secondary -2.9%)

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)	-0.3%	[-1.3%, -0.0%]	34
Improvements ✅ (secondary)	-2.9%	[-11.3%, -0.1%]	14
All ❌✅ (primary)	-0.3%	[-1.3%, -0.0%]	34

Bootstrap: 480.149s -> 478.623s (-0.32%)
Artifact size: 396.96 MiB -> 397.00 MiB (0.01%)

panstromek · 2026-03-02T16:15:19Z

perf triage:

Net positive, addresses previous regression. Small regression in derive stress tests.

@rustbot label: +perf-regression-triaged

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Feb 26, 2026

rustbot assigned JonathanBrouwer Feb 26, 2026

madsmtm mentioned this pull request Feb 26, 2026

deprecate Eq::assert_receiver_is_total_eq and emit FCW on manual impls #149978

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rust-bors bot pushed a commit that referenced this pull request Feb 26, 2026

Auto merge of #153157 - madsmtm:fix-eq-derive-comptime-regression, r=…

980e383

…<try> Re-add `#[inline]` to `Eq::assert_fields_are_eq`

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Feb 26, 2026

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nnethercote reviewed Feb 27, 2026

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compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs Show resolved Hide resolved

rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Feb 27, 2026

lqd mentioned this pull request Feb 27, 2026

Rollup of 13 pull requests #153116

Merged

JonathanBrouwer approved these changes Feb 27, 2026

View reviewed changes

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Feb 27, 2026

Re-add #[inline] to Eq::assert_fields_are_eq

1001c0e

Fixes a compile-time regressions, non-inline methods are generally codegen'd while inline methods are deferred (and this should never be called, so deferring is the right choice).

madsmtm force-pushed the fix-eq-derive-comptime-regression branch from cfc24b4 to 1001c0e Compare February 27, 2026 10:50

rust-bors bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Feb 27, 2026

cyrgani mentioned this pull request Feb 28, 2026

Change derive macro for Eq to not impl Eq trait fn #153125

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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 Mar 2, 2026

rust-bors bot merged commit ddd36bd into rust-lang:main Mar 2, 2026
12 checks passed

rustbot added this to the 1.96.0 milestone Mar 2, 2026

madsmtm deleted the fix-eq-derive-comptime-regression branch March 2, 2026 08:50

rustbot added the perf-regression-triaged The performance regression has been triaged. label Mar 2, 2026

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Overall result: ❌✅ regressions and improvements - please read the text below

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Test differences

Job duration changes

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Overall result: ❌✅ regressions and improvements - please read the text below

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