Make traits / trait methods detected by the dead code lint

[mu001999]

Fixes #118139 and #41883

[rustbot]

r? @wesleywiser

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[Urgau]

2. This change would affect many tests and current codes, the checking of edition is just a temporary solution. Are there any better solutions?

Does it manly just affect tests? If that's the case we can just put #[allow] in them.

In any case could you post (via pastebin or something else, since GitHub will probably limit you) the full output of the new warnings. So we can get a sense of scale of new warnings.

[cjgillot]

Does it manly just affect tests? If that's the case we can just put #[allow] in them.

Ui tests allow unused code lint by default. So there is nothing to do on most.

[shepmaster]

This change would affect many tests and current codes

In #92790 / #95977, I also caused a lot of new warnings to show up :-) There we started the lint as allow-by-default (and appear to still treat it as such... I should look into that).

Perhaps we start the same way here?

[rustbot]

Some changes occurred to the core trait solver

cc @rust-lang/initiative-trait-system-refactor

Some changes might have occurred in exhaustiveness checking

cc @Nadrieril

[cjgillot]

Could you extract the cleanups you do to the rest of the compiler to a standalone PR?

[shepmaster]

@bors r=@cjgillot

[bors]

📌 Commit c7519d4 has been approved by cjgillot

It is now in the queue for this repository.

[bors]

⌛ Testing commit c7519d4 with merge d4f6f9e...

[bors]

☀️ Test successful - checks-actions
Approved by: cjgillot
Pushing d4f6f9e to master...

[rust-timer]

Finished benchmarking commit (d4f6f9e): comparison URL.

Overall result: ❌ regressions - 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)	0.7%	[0.1%, 1.8%]	18
Regressions ❌ (secondary)	9.4%	[0.2%, 16.0%]	10
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.7%	[0.1%, 1.8%]	18

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.

	mean	range	count
Regressions ❌ (primary)	2.8%	[2.3%, 3.3%]	7
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.8%	[2.3%, 3.3%]	7

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.

	mean	range	count
Regressions ❌ (primary)	1.4%	[0.8%, 2.0%]	4
Regressions ❌ (secondary)	7.8%	[2.1%, 16.3%]	16
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.4%	[0.8%, 2.0%]	4

Binary size

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

Bootstrap: 663.003s -> 664.334s (0.20%)
Artifact size: 308.08 MiB -> 308.22 MiB (0.05%)

[shepmaster]

High-level check on the perf results...

1. wf-projection-stress-65510 now reports a warning when it didn't before, so it's probably the diagnostic machinery being lazy-initialized.

2. exa-0.10.1,issue-88862, syn-1.0.89 have new warnings reported in addition to previous.

3. serde-1.0.136, bitmaps-3.1.0, diesel-1.4.8 do not have new warnings produced.

[tamird]

Regression: #120770.

[Kobzol]

The compiler now does more work, so some small regressions are expected. The large regression is from initializing diagnostics (there were no warning produced before for that stress test), so that is fine, as it's a one-time cost.

@rustbot label: +perf-regression-triaged