Feed constness in def collection

[oli-obk]

Not all constnesses are fed, e.g. delegations can't be known at this stage.

This is an attempt at resolving part of the perf regression from #157647 (comment), which mostly happens in incremental because the constness query needs to load the HIR

r? @ghost

[oli-obk]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 3618539 (3618539102f02c768163cf07480535030c697021)
Base parent: 4429659 (4429659e4745016bd3f26a4a421843edc7fbc422)

[rust-timer]

Finished benchmarking commit (3618539): comparison URL.

Overall result: ❌ regressions - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@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)	0.1%	[0.1%, 0.2%]	9
Regressions ❌ (secondary)	0.3%	[0.3%, 0.3%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.1%	[0.1%, 0.2%]	9

Max RSS (memory usage)

Results (primary 1.1%, secondary -1.0%)

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

	mean	range	count
Regressions ❌ (primary)	1.1%	[1.1%, 1.1%]	1
Regressions ❌ (secondary)	3.6%	[2.5%, 5.0%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-5.5%	[-7.7%, -1.9%]	6
All ❌✅ (primary)	1.1%	[1.1%, 1.1%]	1

Cycles

Results (secondary -3.8%)

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)	3.5%	[3.5%, 3.5%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.5%	[-8.4%, -2.2%]	11
All ❌✅ (primary)	-	-	0

Binary size

Results (secondary -0.1%)

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)	-0.1%	[-0.2%, -0.0%]	8
All ❌✅ (primary)	-	-	0

Bootstrap: 504.341s -> 504.7s (0.07%)
Artifact size: 353.08 MiB -> 353.07 MiB (-0.00%)