Rollup of 4 pull requests

[Dylan-DPC]

Successful merges:

• Suggest derivable trait on E0277 error #95525 (Suggest derivable trait on E0277 error)
• diagnostics: use correct span for const generics #95654 (diagnostics: use correct span for const generics)
• Update panic docs to make it clearer when to use panic vs Result #95660 (Update panic docs to make it clearer when to use panic vs Result)
• Refactor: remove unused function parameters #95670 (Refactor: remove unused function parameters)

Failed merges:

r? @ghost
@rustbot modify labels: rollup

Create a similar rollup

[Dylan-DPC]

@bors r+ rollup=never p=5

[bors]

📌 Commit 6832964 has been approved by Dylan-DPC

[bors]

⌛ Testing commit 6832964 with merge d4c7839...

[bors]

☀️ Test successful - checks-actions
Approved by: Dylan-DPC
Pushing d4c7839 to master...

[rust-timer]

Finished benchmarking commit (d4c7839): comparison url.

Summary:

• Primary benchmarks: changes not relevant. 2 results were found to be statistically significant but the changes were too small to be relevant.
• Secondary benchmarks: 😿 relevant regressions found

	Regressions 😿 (primary)	Regressions 😿 (secondary)	Improvements 🎉 (primary)	Improvements 🎉 (secondary)	All 😿 🎉 (primary)
count1	2	6	0	0	2
mean2	0.4%	1.1%	N/A	N/A	0.4%
max	0.4%	1.3%	N/A	N/A	0.4%

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

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

Footnotes

1. number of relevant changes↩

2. the arithmetic mean of the percent change↩

[Mark-Simulacrum]

Regression seems maybe real, based on being across multiple profiles for keccak in particular. Cachegrind seems to point at it being in ObligationForest, though, which is not really modified by this PR -- probably inlining decisions changed, or we're seeing effects from diagnostic code being slightly slower and running in a way that doesn't end up actually emitting the diagnostic? Unclear if that can happen.

Given the limited impact though and likely difficulty of investigation, I'm going to mark this as triaged since I don't think spending further time is worthwhile.

[Mark-Simulacrum]

Looking at the graphs for keccak over the last week, it's also plausible this is mostly noise: