Add is_of_trait to get_id_for_impl

[camsteffen]

Try to undo a bit of perf regression from #144607. I'm not sure how much impact this will have.

[rustbot]

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[fmease]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: a29a6e0 (a29a6e0d0c4966dd19768133edce29ddc19a20c6, parent: 96064126a086a8428d66e07fb3b91421bb86a512)

[rust-timer]

Finished benchmarking commit (a29a6e0): 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)	-1.4%	[-1.4%, -1.4%]	1
Improvements ✅ (secondary)	-1.3%	[-1.3%, -1.3%]	1
All ❌✅ (primary)	-1.4%	[-1.4%, -1.4%]	1

Max RSS (memory usage)

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

Cycles

Results (primary 0.1%, secondary 4.6%)

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

	mean	range	count
Regressions ❌ (primary)	2.1%	[2.1%, 2.1%]	1
Regressions ❌ (secondary)	4.6%	[4.6%, 4.6%]	1
Improvements ✅ (primary)	-2.0%	[-2.0%, -2.0%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.1%	[-2.0%, 2.1%]	2

Binary size

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

Bootstrap: 473.265s -> 474.137s (0.18%)
Artifact size: 390.81 MiB -> 390.77 MiB (-0.01%)

[camsteffen]

I'm pretty sure the only "significant" result is noise. If you look at insignificant results for doc, it's all green, at some fraction of a percent. 🤷

[bors]

☔ The latest upstream changes (presumably #148692) made this pull request unmergeable. Please resolve the merge conflicts.

[camelid]

IMO the tiny perf win is not worth the increased code complexity.