[perf] do not parse non-crate lint attributes during pre-expansion lint passes

[mejrs]

This has the effect of skipping a lot of attribute parsing.

It also makes code like this compile:

#[expect(expect(expect))]
#[cfg(false)]
const _: () = ();

(it would also require that all pre expansion lints must be crate-level only, so this is going to lead to some clippy fallout)

[mejrs]

@bors try @rust-timer queue

[mejrs]

cc @JonathanBrouwer I do not expect this to be merged, but something like this is a solution to our lint attribute parsing woes :)

[rust-log-analyzer]

The job test-tidy failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

fmt: checked 7338 files
tidy check
tidy [rustdoc_json (src)]: `rustdoc-json-types` modified, checking format version
tidy: Skipping binary file check, read-only filesystem
tidy [style (tests)]: /checkout/tests/ui/lint/pre-expansion-parsing.rs:2: trailing whitespace
tidy [style (tests)]: FAIL
removing old virtual environment
creating virtual environment at '/checkout/obj/build/venv' using 'python3.12' and 'venv'
Requirement already satisfied: pip in ./build/venv/lib/python3.12/site-packages (24.0)
Collecting pip
  Downloading pip-26.2.1-py3-none-any.whl.metadata (4.6 kB)
---
Running eslint on rustdoc JS files
info: ES-Check: checking 7 files...
info: ✓ ES-Check passed! All files are ES10 compatible.
typechecking javascript files
tidy: The following check failed: style (tests)
Command `/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools-bin/rust-tidy --root-path=/checkout --cargo-path=/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo --output-dir=/checkout/obj/build --concurrency=4 --npm-path=/node/bin/yarn --ci=true --extra-checks=py,cpp,js,spellcheck` failed with exit code 1
Created at: src/bootstrap/src/core/build_steps/tool.rs:1627:23
Executed at: src/bootstrap/src/core/build_steps/test.rs:1747:29

Command has failed. Rerun with -v to see more details.
Bootstrap failed while executing `test src/tools/tidy tidyselftest --extra-checks=py,cpp,js,spellcheck`
Currently active steps:
test::Tidy {  } at src/bootstrap/src/core/build_steps/test.rs:1665
Build completed unsuccessfully in 0:01:53
  local time: Sat Oct  3 18:11:18 UTC 2026

[rust-bors]

☀️ Try build successful (CI)
Build commit: 95b2a87 (95b2a879d3df9d14ddb93e40233302108b8df244)
Base parent: db8f076 (db8f076d2619ce2585b0380dda06e8da25a40da4)

[rust-timer]

Finished benchmarking commit (95b2a87): comparison URL.

Overall result: no relevant changes - no action needed

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

This perf run didn't have relevant results for this metric.

Max RSS (memory usage)

Results (primary -2.5%)

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)	-2.5%	[-2.5%, -2.5%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-2.5%	[-2.5%, -2.5%]	1

Cycles

Results (secondary 1.6%)

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)	3.7%	[2.3%, 5.2%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.5%	[-2.5%, -2.5%]	1
All ❌✅ (primary)	-	-	0

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 492.227s -> 490.376s (-0.38%)
Artifact size: 408.66 MiB -> 408.72 MiB (0.01%)