Don't fold ExternalConstraintsData when it's empty

[compiler-errors]

Probably useless, but let's see.

r? lcnr

[compiler-errors]

@bors2 try @rust-timer queue

[rust-bors]

⌛ Trying commit 380d331 with merge 85e0863…

To cancel the try build, run the command @bors2 try cancel.

[rust-bors]

☀️ Try build successful (CI)
Build commit: 85e0863 (85e08638f9b9936c774ee1d4fed07275f5f13b5f, parent: 6c8138de8f1c96b2f66adbbc0e37c73525444750)

[rust-timer]

Finished benchmarking commit (85e0863): comparison URL.

Overall result: ✅ improvements - no action needed

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.

@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
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.6%	[-0.7%, -0.2%]	9
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 1.4%, secondary 2.4%)

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)	2.4%	[2.4%, 2.4%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.4%	[1.4%, 1.4%]	1

Cycles

Results (secondary -2.1%)

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)	-2.1%	[-2.1%, -2.1%]	1
All ❌✅ (primary)	-	-	0

Binary size

Results (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
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.0%	[-0.0%, -0.0%]	1
All ❌✅ (primary)	-	-	0

Bootstrap: 754.987s -> 754.149s (-0.11%)
Artifact size: 372.08 MiB -> 372.17 MiB (0.02%)

[compiler-errors]

lol

[lcnr]

r=me with CI fixed

[lcnr]

pls add a comment to the is_empty calls that they are an optimization tested in #142430

[compiler-errors]

@bors r=lcnr

[bors]

📌 Commit 73c4863 has been approved by lcnr

It is now in the queue for this repository.

[bors]

⌛ Testing commit 73c4863 with merge 7827d55...

[bors]

☀️ Test successful - checks-actions
Approved by: lcnr
Pushing 7827d55 to master...

[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 75e7cf5 (parent) -> 7827d55 (this PR)

Test differences

No test diffs found

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 7827d55852783e8d85932a938d70fff64e9b9f07 --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-apple-1: 6758.9s -> 8745.3s (29.4%)
2. x86_64-apple-2: 4697.7s -> 5562.3s (18.4%)
3. dist-apple-various: 6480.9s -> 5361.8s (-17.3%)
4. dist-x86_64-apple: 9474.1s -> 8329.7s (-12.1%)
5. mingw-check-tidy: 70.3s -> 77.3s (10.0%)
6. dist-ohos-x86_64: 4099.6s -> 4496.0s (9.7%)
7. dist-ohos-armv7: 3966.5s -> 4334.7s (9.3%)
8. dist-powerpc64le-linux-musl: 5000.7s -> 5442.7s (8.8%)
9. dist-loongarch64-linux: 5755.7s -> 6251.7s (8.6%)
10. aarch64-apple: 4925.2s -> 4629.8s (-6.0%)

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 (7827d55): 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
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.5%	[-0.7%, -0.2%]	11
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (secondary -2.5%)

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)	-2.5%	[-2.5%, -2.5%]	1
All ❌✅ (primary)	-	-	0

Cycles

Results (secondary 5.7%)

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)	5.7%	[5.7%, 5.7%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 756.494s -> 756.621s (0.02%)
Artifact size: 372.15 MiB -> 372.05 MiB (-0.03%)