Rewrite the new attribute argument parser

[JonathanBrouwer]

Fixes #143940

This rewrites the parser, should improve performance and maintainability.
This can be reviewed commit by commit

[jdonszelmann]

@bors try @rust-timer queue

[rust-bors]

⌛ Trying commit 7b3bb12 with merge acc46aa…

To cancel the try build, run the command @bors try cancel.

[jdonszelmann]

it would be pretty cool if we could explain here what an unsuffixed literal is. Maybe give an example of one with a short explanation. It's not required, but does teach the language better through diagnostics which is always cool

[JonathanBrouwer]

I improved the error a lot :)

error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `-` --> $DIR/malformed-fn-align.rs:29:15 | LL | #[rustc_align(-1)] | ^ | help: negative numbers are not literals, try removing the `-` sign | LL - #[rustc_align(-1)] LL + #[rustc_align(1)] | 

[rust-bors]

☀️ Try build successful (CI)
Build commit: acc46aa (acc46aa5d053362bb20ae7f352cba2635ef61120, parent: e5e79f8bd428d0b8d26e8240d718b134ef297459)

[rust-timer]

Finished benchmarking commit (acc46aa): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

@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)	0.2%	[0.2%, 0.2%]	1
Regressions ❌ (secondary)	0.8%	[0.0%, 1.0%]	7
Improvements ✅ (primary)	-0.3%	[-0.5%, -0.1%]	12
Improvements ✅ (secondary)	-0.2%	[-0.2%, -0.1%]	12
All ❌✅ (primary)	-0.2%	[-0.5%, 0.2%]	13

Max RSS (memory usage)

Results (secondary -1.3%)

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)	2.0%	[2.0%, 2.0%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.4%	[-2.9%, -2.0%]	3
All ❌✅ (primary)	-	-	0

Cycles

Results (secondary -0.5%)

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)	4.7%	[4.7%, 4.7%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.1%	[-3.7%, -2.5%]	2
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 469.342s -> 468.873s (-0.10%)
Artifact size: 376.86 MiB -> 376.85 MiB (-0.00%)

[lqd]

(match-stress looks currently noisy to me)

[jdonszelmann]

Mhm, we came to the same conclusion (@JonathanBrouwer )

[JonathanBrouwer]

BREAKING CHANGE:
Previously, attributes on macro calls were partially checked for correct syntax (only what check_builtin_meta_item can check).
After this PR, the attributes are fully parsed.

In any case, these attributes are always completely ignored, except for #[cfg], which was always completely parsed and still is and is not affected by this breaking change.

[JonathanBrouwer]

I've had to make quite a few of these functions public, how problematic is that?
I don't think it matters right, or at least it's better than the alternative of copying them over

[JonathanBrouwer]

@rustbot ready
r? @jdonszelmann

[rustbot]

r? @SparrowLii

rustbot has assigned @SparrowLii.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[rustbot]

jdonszelmann is currently at their maximum review capacity.
They may take a while to respond.

[rustbot]

Reminder, once the PR becomes ready for a review, use @rustbot ready.

[JonathanBrouwer]

@rustbot ready
@jdonszelmann

[bors]

☔ The latest upstream changes (presumably #145728) made this pull request unmergeable. Please resolve the merge conflicts.

[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[jdonszelmann]

@bors r+

[bors]

📌 Commit ec5b2cc has been approved by jdonszelmann

It is now in the queue for this repository.

[bors]

⌛ Testing commit ec5b2cc with merge f5703d5...

[bors]

☀️ Test successful - checks-actions
Approved by: jdonszelmann
Pushing f5703d5 to master...

[github-actions]

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing 831e291 (parent) -> f5703d5 (this PR)

Test differences

Show 31 test diffs

Stage 1

• errors::verify_parse_asm_expected_comma_183: [missing] -> pass (J0)
• errors::verify_parse_asm_expected_comma_184: pass -> [missing] (J0)
• errors::verify_parse_asm_expected_other_184: [missing] -> pass (J0)
• errors::verify_parse_asm_expected_other_185: pass -> [missing] (J0)
• errors::verify_parse_asm_expected_register_class_or_explicit_register_187: [missing] -> pass (J0)
• errors::verify_parse_asm_expected_register_class_or_explicit_register_188: pass -> [missing] (J0)
• errors::verify_parse_asm_expected_string_literal_186: [missing] -> pass (J0)
• errors::verify_parse_asm_expected_string_literal_187: pass -> [missing] (J0)
• errors::verify_parse_asm_non_abi_185: [missing] -> pass (J0)
• errors::verify_parse_asm_non_abi_186: pass -> [missing] (J0)
• errors::verify_parse_asm_requires_template_182: [missing] -> pass (J0)
• errors::verify_parse_asm_requires_template_183: pass -> [missing] (J0)
• errors::verify_parse_asm_sym_no_path_181: [missing] -> pass (J0)
• errors::verify_parse_asm_sym_no_path_182: pass -> [missing] (J0)
• errors::verify_parse_asm_underscore_input_180: [missing] -> pass (J0)
• errors::verify_parse_asm_underscore_input_181: pass -> [missing] (J0)
• errors::verify_parse_asm_unsupported_operand_179: [missing] -> pass (J0)
• errors::verify_parse_asm_unsupported_operand_180: pass -> [missing] (J0)
• errors::verify_parse_binder_and_polarity_177: [missing] -> pass (J0)
• errors::verify_parse_binder_and_polarity_178: pass -> [missing] (J0)
• errors::verify_parse_binder_before_modifiers_176: [missing] -> pass (J0)
• errors::verify_parse_binder_before_modifiers_177: pass -> [missing] (J0)
• errors::verify_parse_invalid_attr_unsafe_176: pass -> [missing] (J0)
• errors::verify_parse_modifiers_and_polarity_178: [missing] -> pass (J0)
• errors::verify_parse_modifiers_and_polarity_179: pass -> [missing] (J0)
• session_diagnostics::verify_attr_parsing_invalid_attr_unsafe_44: [missing] -> pass (J0)
• session_diagnostics::verify_attr_parsing_suffixed_literal_in_attribute_45: [missing] -> pass (J0)
• [ui] tests/ui/parser/attribute/attr-incomplete.rs: [missing] -> pass (J1)

Stage 2

• [ui] tests/ui/parser/attribute/attr-incomplete.rs: [missing] -> pass (J2)

Additionally, 2 doctest diffs were found. These are ignored, as they are noisy.

Job group index

• J0: aarch64-apple, aarch64-gnu, aarch64-gnu-llvm-19-2, aarch64-msvc-2, i686-gnu-2, i686-gnu-nopt-2, i686-msvc-2, x86_64-gnu, x86_64-gnu-llvm-19-1, x86_64-gnu-llvm-19-3, x86_64-gnu-llvm-20-1, x86_64-gnu-llvm-20-3, x86_64-gnu-nopt, x86_64-gnu-stable, x86_64-mingw-2, x86_64-msvc-2
• J1: x86_64-gnu-llvm-19-3, x86_64-gnu-llvm-20-3
• J2: aarch64-apple, aarch64-gnu, aarch64-gnu-llvm-19-1, aarch64-msvc-1, arm-android, armhf-gnu, dist-i586-gnu-i586-i686-musl, i686-gnu-1, i686-gnu-nopt-1, i686-msvc-1, test-various, x86_64-gnu, x86_64-gnu-llvm-19, x86_64-gnu-llvm-19-2, x86_64-gnu-llvm-20-2, x86_64-gnu-nopt, x86_64-gnu-stable, x86_64-mingw-1, x86_64-msvc-1

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \ test-dashboard f5703d5dd3eec176f86a6e9bf7e668b48b84eabb --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

1. dist-aarch64-apple: 6805.9s -> 7685.4s (12.9%)
2. x86_64-gnu-llvm-19: 2736.4s -> 2434.2s (-11.0%)
3. x86_64-rust-for-linux: 2960.4s -> 2689.6s (-9.1%)
4. dist-x86_64-illumos: 6304.7s -> 5842.7s (-7.3%)
5. aarch64-msvc-2: 4942.2s -> 5277.0s (6.8%)
6. x86_64-gnu-aux: 6746.3s -> 6307.6s (-6.5%)
7. test-various: 4961.2s -> 4647.0s (-6.3%)
8. dist-x86_64-apple: 7374.5s -> 6907.5s (-6.3%)
9. aarch64-apple: 6416.0s -> 6034.4s (-5.9%)
10. dist-apple-various: 4984.6s -> 4707.4s (-5.6%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

[rust-timer]

Finished benchmarking commit (f5703d5): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -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
Regressions ❌ (secondary)	1.1%	[0.7%, 1.4%]	8
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 0.2%, secondary 2.0%)

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

	mean	range	count
Regressions ❌ (primary)	1.4%	[1.4%, 1.4%]	1
Regressions ❌ (secondary)	2.7%	[2.2%, 3.9%]	7
Improvements ✅ (primary)	-1.0%	[-1.0%, -1.0%]	1
Improvements ✅ (secondary)	-0.7%	[-1.0%, -0.4%]	2
All ❌✅ (primary)	0.2%	[-1.0%, 1.4%]	2

Cycles

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

Binary size

Results (secondary -0.0%)

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)	-0.0%	[-0.0%, -0.0%]	1
All ❌✅ (primary)	-	-	0

Bootstrap: 466.749s -> 466.339s (-0.09%)
Artifact size: 378.24 MiB -> 378.27 MiB (0.01%)