Revert "Use drop_guard in some places in {core,alloc,std}"

[clarfonthey]

cc @panstromek @GrigorenkoPV

Reverts this PR due to perf issues, so that a fix can be verified to not affect perf. Apologies for not initially running perf; kinda tunnel-visioned "this just does the same thing" without considering the changes from non-generic functions to generic closures.

[rustbot]

r? @Mark-Simulacrum

rustbot has assigned @Mark-Simulacrum.
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: libs
• libs expanded to 12 candidates
• Random selection from JohnTitor, Mark-Simulacrum, joboet

[clarfonthey]

r? clarfonthey

(Since we don't need to review clean reverts.)

[clarfonthey]

@bors p=1 rollup=iffy note="Perf regression revert"

[panstromek]

Apologies for not initially running perf

No need to apologize, this is totally normal 😉 This is why we run perf on every merge. Perf effects can be pretty non-obvious and unpredictable, I would have trouble predicting this one too.

[clarfonthey]

I mean, in hindsight, it obviously would have affected perf, but you know :p

[panstromek]

@bors p=1 rollup=iffy note="Perf regression revert"

Looks like bors didn't pick it up. Is there r+ missing there?

[clarfonthey]

I was doing it without r+ because the tests hadn't passed yet, and wanted to wait for PR CI first just in case it wasn't actually a clean merge. And now I can just do this:

@bors r+

[rust-bors]

📌 Commit 7755d45 has been approved by clarfonthey

It is now in the queue for this repository.

[clarfonthey]

@bors rollup=iffy note="Reverting regression"

[JonathanBrouwer]

@bors rollup=never
I'd rather not have this in a rolled up, perf effect is too strong which risks masking regressions

[clarfonthey]

That is extremely fair; I know that we currently unroll for perf so I wasn't sure what the status quo is.

[JonathanBrouwer]

We unroll for perf to create builds that can be benchmarked, but triaging the performance of rollups by running benchmarks is still manual. I'm currently working on automating it

[rust-bors]

☀️ Test successful - CI
Approved by: clarfonthey
Duration: 2h 57m 2s
Pushing edc52f8 to main...

[github-actions]

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 5db7f4b (parent) -> edc52f8 (this PR)

Test differences

Show 1528 test diffs

1528 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 edc52f87c28f328c61685a02c47887a5cec7d767 --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

1. x86_64-gnu-debug: 1h 16m -> 2h 12m (+72.5%)
2. test-various: 1h 38m -> 2h 13m (+36.4%)
3. x86_64-msvc-1: 2h 8m -> 2h 47m (+30.6%)
4. x86_64-gnu: 2h 29m -> 1h 44m (-30.1%)
5. x86_64-rust-for-linux: 54m 39s -> 38m 59s (-28.7%)
6. dist-x86_64-freebsd: 1h 30m -> 1h 4m (-28.6%)
7. x86_64-gnu-aux: 1h 58m -> 2h 31m (+27.6%)
8. dist-x86_64-msvc-alt: 2h 9m -> 2h 45m (+27.4%)
9. dist-armv7-linux: 1h 16m -> 1h 36m (+25.7%)
10. dist-x86_64-musl: 2h 24m -> 1h 47m (-25.1%)

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]

Finished benchmarking commit (edc52f8): comparison URL.

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

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)	0.7%	[0.3%, 1.5%]	3
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.5%	[-1.9%, -0.2%]	46
Improvements ✅ (secondary)	-0.6%	[-1.8%, -0.2%]	26
All ❌✅ (primary)	-0.4%	[-1.9%, 1.5%]	49

Max RSS (memory usage)

Results (primary -0.9%, secondary -1.7%)

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

	mean	range	count
Regressions ❌ (primary)	1.6%	[1.4%, 1.8%]	2
Regressions ❌ (secondary)	2.5%	[2.5%, 2.5%]	1
Improvements ✅ (primary)	-1.4%	[-2.8%, -0.7%]	10
Improvements ✅ (secondary)	-2.0%	[-4.9%, -0.6%]	11
All ❌✅ (primary)	-0.9%	[-2.8%, 1.8%]	12

Cycles

Results (primary -1.0%, secondary 4.9%)

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

	mean	range	count
Regressions ❌ (primary)	4.5%	[4.5%, 4.5%]	1
Regressions ❌ (secondary)	4.9%	[2.2%, 6.8%]	9
Improvements ✅ (primary)	-2.3%	[-2.5%, -2.0%]	4
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.0%	[-2.5%, 4.5%]	5

Binary size

Results (primary -1.3%, secondary -1.6%)

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

	mean	range	count
Regressions ❌ (primary)	1.4%	[1.4%, 1.4%]	1
Regressions ❌ (secondary)	0.6%	[0.6%, 0.6%]	1
Improvements ✅ (primary)	-1.3%	[-12.8%, -0.2%]	85
Improvements ✅ (secondary)	-1.7%	[-12.8%, -0.5%]	30
All ❌✅ (primary)	-1.3%	[-12.8%, 1.4%]	86

Bootstrap: 475.082s -> 472.928s (-0.45%)
Artifact size: 400.59 MiB -> 401.53 MiB (0.23%)