Port the proc macro attributes to the new attribute parsing infrastructure #143607

JonathanBrouwer · 2025-07-07T19:08:31Z

Ports #[proc_macro], #[proc_macro_attribute], #[proc_macro_derive] and #[rustc_builtin_macro] to the new attribute parsing infrastructure for #131229 (comment)

I've split this PR into commits for reviewability, and left some comments to clarify things
I did 4 related attributes in one PR because they share a lot of their code and logic, and doing them separately is kind of annoying as I need to leave both the old and new parsing in place then.

r? @oli-obk
cc @jdonszelmann

JonathanBrouwer · 2025-07-07T19:11:03Z

compiler/rustc_expand/src/base.rs

+
+            // Not a built-in macro
+            None => (None, helper_attrs),
+        };


The logic here should be equivalent to the logic above, other than that this is a bit more readable and that we use the already parsed attribute rather than parsing it from scratch

JonathanBrouwer · 2025-07-07T19:13:59Z

tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs.rs

@@ -57,7 +57,7 @@
 // see gated-link-args.rs
 // see issue-43106-gating-of-macro_escape.rs for crate-level; but non crate-level is below at "2700"
 // (cannot easily test gating of crate-level #[no_std]; but non crate-level is below at "2600")
-#![proc_macro_derive()] //~ WARN `#[proc_macro_derive]` only has an effect
+#![proc_macro_derive(Test)] //~ WARN `#[proc_macro_derive]` only has an effect


Note that a breaking change happened here! The code before this change would now produce an error.

Previously a proc_macro_derive applied to the crate could have any arguments it wants, it was not checked. This PR fixes this bug, and this now errors.

I discussed this privately with @jdonszelmann, and she said this is fine to change, though we can consider doing a crater run for this just to make sure if you wish.

rustbot · 2025-07-07T19:16:51Z

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann

Some changes occurred in compiler/rustc_passes/src/check_attr.rs

cc @jdonszelmann

Some changes occurred in compiler/rustc_attr_data_structures

cc @jdonszelmann

rustbot · 2025-07-07T20:39:47Z

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

jdonszelmann · 2025-07-07T21:07:32Z

This could use a little squash I think

jdonszelmann · 2025-07-07T21:07:48Z

Not everything, but some commits are a bit small

JonathanBrouwer · 2025-07-08T06:25:06Z

@jdonszelmann I've squashed things down a bit. I'm experimenting a bit with what commit size is best for reviewability, this was clearly too much of a good thing :P

compiler/rustc_attr_parsing/src/attributes/proc_macro_attrs.rs

JonathanBrouwer · 2025-07-08T08:47:12Z

r? @jdonszelmann
@rustbot ready

rustbot · 2025-07-08T08:47:17Z

jdonszelmann is not on the review rotation at the moment.
They may take a while to respond.

bors · 2025-07-08T21:41:12Z

☔ The latest upstream changes (presumably #143645) made this pull request unmergeable. Please resolve the merge conflicts.

JonathanBrouwer · 2025-07-11T11:41:35Z

^ Rebased

jdonszelmann · 2025-07-11T15:17:54Z

Discussed with @oli-obk, we're going to do a crater run for this one because it's technically a breaking change.
First a try build, no need to rebase until crater's done which will take a bit :)

@bors try

Port the proc macro attributes to the new attribute parsing infrastructure Ports `#[proc_macro]`, `#[proc_macro_attribute]`, `#[proc_macro_derive]` and `#[rustc_builtin_macro]` to the new attribute parsing infrastructure for #131229 (comment) I've split this PR into commits for reviewability, and left some comments to clarify things I did 4 related attributes in one PR because they share a lot of their code and logic, and doing them separately is kind of annoying as I need to leave both the old and new parsing in place then. r? `@oli-obk` cc `@jdonszelmann`

bors · 2025-07-11T15:19:05Z

⌛ Trying commit f8c757f with merge 360f8e6...

jdonszelmann · 2025-07-11T15:23:58Z

@traviscross what's the proper way to notify T-lang on this? What label, and could you add that?

craterbot · 2025-07-14T07:03:00Z

🚧 Experiment pr-143607 is now running

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

craterbot · 2025-07-15T09:22:00Z

🎉 Experiment pr-143607 is completed!
📊 3 regressed and 7 fixed (663519 total)
📰 Open the summary report.

⚠️ If you notice any spurious failure please add them to the denylist!
ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

JonathanBrouwer · 2025-07-15T09:57:01Z

Crater results, 3 reported regressions:

[caiogeraldes.wttr.d49dfee4f21f349cc50cafd05ba44573f53d0bab](https://github.com/caiogeraldes/wttr/tree/d49dfee4f21f349cc50cafd05ba44573f53d0bab) failed because of a spurious build script
james-tharit.taro.4224a0b5def5f0154d7a39f34ccdaf87d8f6ee62 failed because of network problems, spurious
jonwolski.records-in-rust.c9160bb9cae332ff74b51056374943788f3335dc failed because of a spurious build script

So no crates are affected by this change
@rustbot ready
@jdonszelmann

JonathanBrouwer · 2025-07-15T09:58:59Z

Rebased

bors · 2025-07-15T14:54:45Z

☔ The latest upstream changes (presumably #143958) made this pull request unmergeable. Please resolve the merge conflicts.

jdonszelmann · 2025-07-15T18:02:27Z

Perfect, @rust-lang/lang crater seems clear, r=me with your approval

Signed-off-by: Jonathan Brouwer <[email protected]>

JonathanBrouwer · 2025-07-15T18:25:35Z

^ Rebased

joshtriplett · 2025-07-16T15:15:48Z

It looks like the breaking change here is that when applied in the wrong place, this was previously a warning and bailed out before it also checked the arguments of the attribute, and now it'll also produce an error if the attribute arguments aren't valid.

@rfcbot merge

rfcbot · 2025-07-16T15:15:50Z

Team member @joshtriplett has proposed to merge this. The next step is review by the rest of the tagged team members:

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

cc @rust-lang/lang-advisors: FCP proposed for lang, please feel free to register concerns.
See this document for info about what commands tagged team members can give me.

tmandry · 2025-07-16T15:16:02Z

@rfcbot reviewed

traviscross · 2025-07-16T15:16:05Z

@rfcbot reviewed

rfcbot · 2025-07-16T15:16:20Z

🔔 This is now entering its final comment period, as per the review above. 🔔

rustbot assigned oli-obk Jul 7, 2025

rustbot added A-attributes Area: Attributes (`#[…]`, `#![…]`) T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jul 7, 2025

JonathanBrouwer commented Jul 7, 2025

View reviewed changes

JonathanBrouwer marked this pull request as ready for review July 7, 2025 19:16

rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jul 7, 2025

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JonathanBrouwer force-pushed the proc_macro_attrs branch from a6b7f55 to 432cde9 Compare July 8, 2025 06:24

jdonszelmann mentioned this pull request Jul 8, 2025

Tracking issue: Attribute refactor #131229

Open

9 tasks

jdonszelmann reviewed Jul 8, 2025

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compiler/rustc_attr_parsing/src/attributes/proc_macro_attrs.rs Show resolved Hide resolved

JonathanBrouwer force-pushed the proc_macro_attrs branch from 432cde9 to 7a60c84 Compare July 8, 2025 08:46

rustbot assigned jdonszelmann and unassigned oli-obk Jul 8, 2025

JonathanBrouwer force-pushed the proc_macro_attrs branch 3 times, most recently from 2b42dae to f8c757f Compare July 11, 2025 11:41

craterbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-crater Status: Waiting on a crater run to be completed. labels Jul 15, 2025

JonathanBrouwer force-pushed the proc_macro_attrs branch from f8c757f to 3b773a0 Compare July 15, 2025 09:58

rustbot added the T-clippy Relevant to the Clippy team. label Jul 15, 2025

JonathanBrouwer force-pushed the proc_macro_attrs branch from 3b773a0 to e0a495b Compare July 15, 2025 11:51

JonathanBrouwer added 7 commits July 15, 2025 20:15

Add attributes to AttributeKind

3ea8b10

Implement check_attr

991ec52

Parsers for the attributes

22e3134

Signed-off-by: Jonathan Brouwer <[email protected]>

Use the new attributes throughout the codebase

a94f6e0

Signed-off-by: Jonathan Brouwer <[email protected]>

Update test results

1bd42e1

Signed-off-by: Jonathan Brouwer <[email protected]>

Remove now un-used code

0f0a35d

Signed-off-by: Jonathan Brouwer <[email protected]>

Fix tooling

8166ced

Signed-off-by: Jonathan Brouwer <[email protected]>

JonathanBrouwer force-pushed the proc_macro_attrs branch from e0a495b to 8166ced Compare July 15, 2025 18:25

joshtriplett removed the T-clippy Relevant to the Clippy team. label Jul 16, 2025

rfcbot added proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. disposition-merge This issue / PR is in PFCP or FCP with a disposition to merge it. labels Jul 16, 2025

rfcbot added final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. and removed proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. labels Jul 16, 2025

Port the proc macro attributes to the new attribute parsing infrastructure #143607

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Port the proc macro attributes to the new attribute parsing infrastructure #143607

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