Check hidden types in dead code

[oli-obk]

fixes#99490

r? @compiler-errors

best reviewed commit by commit

[compiler-errors]

Why did this code exist? What did it achieve?

[compiler-errors]

Oh, well it was dead code anyways. I should read the commit title.

[bors]

☔ The latest upstream changes (presumably #101632) made this pull request unmergeable. Please resolve the merge conflicts.

[compiler-errors]

I literally wrote up a comment that had bors r+ but it's on a computer that I don't have access to for a day or two.

Anyways this code makes sense to me and thanks for splitting it up into easily reviewable commits.

@bors r+ rollup=never (just in case we want to bisect to this PR)

[bors]

📌 Commit 3c8b46c has been approved by compiler-errors

It is now in the queue for this repository.

[bors]

⌛ Testing commit 3c8b46c with merge 60bd3f9...

[bors]

☀️ Test successful - checks-actions
Approved by: compiler-errors
Pushing 60bd3f9 to master...

[rust-timer]

Finished benchmarking commit (60bd3f9): 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.

	mean1	range	count2
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	1.2%	[1.0%, 1.3%]	4
Improvements ✅ (primary)	-0.3%	[-0.4%, -0.2%]	13
Improvements ✅ (secondary)	-0.6%	[-0.7%, -0.5%]	4
All ❌✅ (primary)	-0.3%	[-0.4%, -0.2%]	13

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.

	mean1	range	count2
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.2%	[-2.2%, -2.2%]	1
Improvements ✅ (secondary)	-2.7%	[-3.2%, -2.2%]	14
All ❌✅ (primary)	-2.2%	[-2.2%, -2.2%]	1

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.

	mean1	range	count2
Regressions ❌ (primary)	2.3%	[1.1%, 3.8%]	4
Regressions ❌ (secondary)	2.7%	[1.7%, 3.6%]	12
Improvements ✅ (primary)	-2.3%	[-2.5%, -2.0%]	2
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.8%	[-2.5%, 3.8%]	6

Footnotes

1. the arithmetic mean of the percent change↩↩²↩³

2. number of relevant changes↩↩²↩³

[oli-obk]

This is a small improvement for everything but the ctfe stress test. The stress test regressed in actual CTFE (though it also added a few additional query calls to specializes). The only reason for the longer CTFE time that I can see is that typeck's result now contains more data potentially causing more hashing/comparisons in the impl Trait heavy part of the stress test. Either way, I think we should ignore it considering this is now actually checking the right thing, so being more expensive is somewhat expected.

@rustbot label: +perf-regression-triaged