Rollup of 8 pull requests

[matthiaskrgr]

Successful merges:

• Detect unused structs which derived Default #126302 (Detect unused structs which derived Default)
• Remove internal PathBuf::as_mut_vec #126885 (Remove internal PathBuf::as_mut_vec)
• Specify target specific linker for riscv64gc-gnu job #126916 (Specify target specific linker for riscv64gc-gnu job)
• Tweak a confusing comment in create_match_candidates #126926 (Tweak a confusing comment in create_match_candidates)
• core: VaArgSafe is an unsafe trait #126927 (core: VaArgSafe is an unsafe trait)
• Tweak FlatPat::new to avoid a temporarily-invalid state #126932 (Tweak FlatPat::new to avoid a temporarily-invalid state)
• Add missing slash in const_eval_select doc comment #126946 (Add missing slash in const_eval_select doc comment)
• Delegation: ast lowering refactor #126947 (Delegation: ast lowering refactor)

r? @ghost
@rustbot modify labels: rollup

Create a similar rollup

[matthiaskrgr]

@bors r+ rollup=never p=8

[bors]

📌 Commit 4ebd69c has been approved by matthiaskrgr

It is now in the queue for this repository.

[matthiaskrgr]

@bors p=101

[bors]

⌛ Testing commit 4ebd69c with merge fda509e...

[bors]

☀️ Test successful - checks-actions
Approved by: matthiaskrgr
Pushing fda509e to master...

[rust-timer]

📌 Perf builds for each rolled up PR:

PR#	Message	Perf Build Sha
#126302	Detect unused structs which derived Default	f37fcced1cbba9f7a480ad0291ce332857f580a4 (link)
#126885	Remove internal PathBuf::as_mut_vec	d928d17bcc63a749d7b626e94ee6f188555d455a (link)
#126916	Specify target specific linker for riscv64gc-gnu job	f82d77727a00edc1a69acfa28644f79c43512951 (link)
#126926	Tweak a confusing comment in create_match_candidates	ca9f23f1101b8138752a53de5fd2c19e1d3516c2 (link)
#126927	core: VaArgSafe is an unsafe trait	6fc046e0a419a4063bbce9cc953cf02e95775f25 (link)
#126932	Tweak FlatPat::new to avoid a temporarily-invalid state	d2266716514598ed5e3dc9afd225221c1348c026 (link)
#126946	Add missing slash in const_eval_select doc comment	07d6e1a20db394d58d791f1de784790c2b188d72 (link)
#126947	Delegation: ast lowering refactor	9de87f6456ec2f3c652c4d0b1daeae6f6fea0842 (link)

previous master: c290e9de32

In the case of a perf regression, run the following command for each PR you suspect might be the cause: @rust-timer build $SHA

[rust-timer]

Finished benchmarking commit (fda509e): 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
Regressions ❌ (secondary)	3.3%	[1.7%, 5.8%]	9
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.0%	[-5.7%, -0.3%]	2
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (secondary -4.2%)

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)	-4.2%	[-4.2%, -4.1%]	2
All ❌✅ (primary)	-	-	0

Cycles

Results (primary 1.7%, secondary 2.4%)

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)	1.7%	[1.7%, 1.7%]	1
Regressions ❌ (secondary)	4.5%	[4.3%, 4.8%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.8%	[-3.8%, -3.8%]	1
All ❌✅ (primary)	1.7%	[1.7%, 1.7%]	1

Binary size

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

Bootstrap: 694.374s -> 693.553s (-0.12%)
Artifact size: 324.66 MiB -> 326.78 MiB (0.65%)

[Kobzol]

@rust-timer build f37fcce

[rust-timer]

Finished benchmarking commit (f37fcce): comparison URL.

Overall result: ❌✅ regressions and improvements - ACTION NEEDED

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
Regressions ❌ (secondary)	3.3%	[1.7%, 5.8%]	9
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.9%	[-5.5%, -0.3%]	2
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (secondary -3.9%)

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)	-3.9%	[-3.9%, -3.9%]	1
All ❌✅ (primary)	-	-	0

Cycles

Results (secondary 0.7%)

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)	3.7%	[2.2%, 4.6%]	5
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.3%	[-5.4%, -3.5%]	3
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 694.374s -> 693.924s (-0.06%)
Artifact size: 324.66 MiB -> 326.74 MiB (0.64%)

[lqd]

The artifact size regression looks incredibly unexpected... There's a cyclic +2MB -2MB noise spike going on in many recent PRs. Something weird is going on.

Having graphs for artifact sizes could be cool -- at the very least so we can also see when this noise started 😓

The most recent one seems to be #125740 (comment) but I remember scottmcm mentioning this swing in an older PR than this.

[Kobzol]

Created rust-lang/rustc-perf#1932 to track this.

[pnkfelix]

visiting for weekly rustc-perf triage

• solely regressions to secondary benchmark: derive
• marking as triaged

@rustbot label: +perf-regression-triaged