Upgrade to indexmap 2.0.0

[cuviper]

The new version was already added to the tree as an indirect dependency
in #113046, but now our direct dependents are using it too.

[rustbot]

r? @Mark-Simulacrum

(rustbot has picked a reviewer for you, use r? to override)

[Mark-Simulacrum]

@bors r+

[bors]

📌 Commit 2b091ff has been approved by Mark-Simulacrum

It is now in the queue for this repository.

[bors]

⌛ Testing commit 2b091ff with merge 52d8c49...

[bors]

☀️ Test successful - checks-actions
Approved by: Mark-Simulacrum
Pushing 52d8c49 to master...

[rust-timer]

Finished benchmarking commit (52d8c49): comparison URL.

Overall result: ❌✅ regressions and improvements - ACTION NEEDED

Next Steps: If you can justify the regressions found in this perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please open an issue or create a new PR that fixes the regressions, add a comment linking to the newly created issue or PR, and then add the perf-regression-triaged label to this PR.

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

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.8%	[0.4%, 1.2%]	20
Regressions ❌ (secondary)	0.7%	[0.3%, 1.2%]	16
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.6%	[-0.6%, -0.5%]	4
All ❌✅ (primary)	0.8%	[0.4%, 1.2%]	20

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.3%	[-3.5%, -1.1%]	2
All ❌✅ (primary)	-	-	0

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	1.2%	[1.2%, 1.2%]	1
Regressions ❌ (secondary)	2.2%	[2.2%, 2.2%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.2%	[1.2%, 1.2%]	1

Binary size

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

Bootstrap: 670.369s -> 672.679s (0.34%)

[djc]

@cuviper I'm curious about this perf regression, which looks consistent enough not to be just noise. Do you have any hypotheses about why this might be the case?

[cuviper]

@djc, I don't really know -- not much actually changed in the implementation except maybe indexmap-rs/indexmap#263. But its dependency on hashbrown also went from 0.12 to 0.14, so there could be more that changed there. I'm comforted that cycles and wall-time don't show much change though, so it doesn't seem like a real loss.