proc_macro: preserve file module spans for inner attrs by Dnreikronos · Pull Request #158046 · rust-lang/rust

Dnreikronos · 2026-06-17T19:50:02Z

out-of-line mods with custom inner attrs were sending proc macros a pretty-printed module wrapper. the awkward bit: tokens inside the module picked up the span from the parent mod foo;, so later diags pointed at the decl instead of the file where the code actually came from.

this keeps the wrapper synthetic, but puts the loaded file body back into the token stream with its own spans. it also skips the attr currently being expanded, so we don't replay it by accident. added a small ui repro too, plus the older span-debug output changed because those spans are now real.

imo this is the least annoying fix for now. fwiw, it keeps the old fake-wrapper path instead of trying to make full token capture for file mods happen in this PR.

rustbot · 2026-06-17T19:50:05Z

The parser was modified, potentially altering the grammar of (stable) Rust
which would be a breaking change.

cc @fmease

rustbot · 2026-06-17T19:50:08Z

r? @mu001999

rustbot has assigned @mu001999.
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

Why was this reviewer chosen?

The reviewer was selected based on:

Owners of files modified in this PR: compiler, parser
compiler, parser expanded to 73 candidates
Random selection from 20 candidates

mu001999 · 2026-06-18T08:21:54Z

@rustbot reroll

zjp-CN · 2026-06-19T15:02:44Z

Could someone review the PR? The fix seems sensible, and works for me.

mati865 · 2026-06-19T16:02:17Z

@rustbot reroll

rustbot · 2026-07-06T13:44:28Z

This PR was rebased onto a different main 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.

Dnreikronos · 2026-07-14T12:59:25Z

Hi, @nikomatsakis!
Do you need something from my side to finish the work on this?

Best wishes,
Joao Soares

GuillaumeGomez · 2026-07-15T20:16:07Z

r? @Urgau

nnethercote · 2026-07-16T06:03:58Z

cc @petrochenkov

Dnreikronos · 2026-07-17T18:41:10Z

@rustbot ready

petrochenkov · 2026-07-17T20:31:25Z

+}
+
+fn lex_token_trees_for_span(psess: &ParseSess, span: Span) -> Option<TokenStream> {
+    if span.is_dummy() {


I'd rather remove this to simplify code, I don't think we need optimizations here.

View changes since the review

Yeah, makes sense. I removed the explicit is_dummy() check and let span_to_snippet handle unavailable spans.

petrochenkov · 2026-07-17T20:32:34Z

+
+    let mut body_tts = Vec::new();
+    body_tts.extend(
+        lex_token_trees_for_span(psess, spans.inner_span.until(attr.span))?.iter().cloned(),


Nit: the .iter().cloned() part can be hidden into lex_token_trees_for_span, which can return impl Iterator.

View changes since the review

Done. lex_token_trees_for_span returns an iterator now, so callers don't need .iter().cloned() anymore.

petrochenkov · 2026-07-17T20:33:05Z

r=me after addressing the remaining nits and squashing commits.
@rustbot author

rustbot · 2026-07-17T20:33:08Z

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

Dnreikronos · 2026-07-18T12:06:00Z

@rustbot ready

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jun 17, 2026

rustbot assigned mu001999 Jun 17, 2026

This comment has been minimized.

Sign in to view

rustbot assigned mati865 and unassigned mu001999 Jun 18, 2026

zjp-CN mentioned this pull request Jun 19, 2026

Add short-vis-path crate and replace restricted visibility paths by short subsystem names asterinas/asterinas#3247

Draft

rustbot assigned nikomatsakis and unassigned mati865 Jun 19, 2026

coolcatcoder reviewed Jun 20, 2026

View reviewed changes

Comment thread compiler/rustc_parse/src/lib.rs Outdated

This comment has been minimized.

Sign in to view

Dnreikronos force-pushed the proc_macro/file_mod_inner_attr_spans branch from 9633953 to 8a1f71e Compare July 6, 2026 13:44

Kat-zorn mentioned this pull request Jul 15, 2026

custom inner attributes remove source view for module #158768

Open

rustbot assigned Urgau and unassigned nikomatsakis Jul 15, 2026

petrochenkov self-assigned this Jul 16, 2026

petrochenkov reviewed Jul 16, 2026

View reviewed changes

Comment thread tests/ui/proc-macro/inner-attr-file-mod-diagnostics.rs Outdated

Comment thread compiler/rustc_expand/src/expand.rs

Comment thread compiler/rustc_parse/src/lib.rs Outdated

Comment thread compiler/rustc_parse/src/lib.rs Outdated

petrochenkov added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jul 16, 2026

Urgau removed their assignment Jul 16, 2026

petrochenkov removed the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Jul 17, 2026

petrochenkov added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jul 17, 2026

petrochenkov reviewed Jul 17, 2026

View reviewed changes

Comment thread compiler/rustc_parse/src/lib.rs Outdated

Comment thread compiler/rustc_parse/src/lib.rs Outdated

Comment thread compiler/rustc_parse/src/lib.rs Outdated

Comment thread compiler/rustc_parse/src/lib.rs Outdated

petrochenkov added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jul 17, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jul 17, 2026

petrochenkov reviewed Jul 17, 2026

View reviewed changes

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jul 17, 2026

Preserve file module spans for inner attributes

daff591

Dnreikronos force-pushed the proc_macro/file_mod_inner_attr_spans branch from 46fdb65 to daff591 Compare July 18, 2026 12:04

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jul 18, 2026

Uh oh!

Uh oh!

Conversation

Dnreikronos commented Jun 17, 2026 • edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

rustbot commented Jun 17, 2026

Uh oh!

rustbot commented Jun 17, 2026

Uh oh!

This comment has been minimized.

mu001999 commented Jun 18, 2026

Uh oh!

zjp-CN commented Jun 19, 2026

Uh oh!

mati865 commented Jun 19, 2026

Uh oh!

Uh oh!

This comment has been minimized.

rustbot commented Jul 6, 2026

Uh oh!

Dnreikronos commented Jul 14, 2026

Uh oh!

GuillaumeGomez commented Jul 15, 2026

Uh oh!

nnethercote commented Jul 16, 2026

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Dnreikronos commented Jul 17, 2026

Uh oh!

petrochenkov Jul 17, 2026 • edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Dnreikronos Jul 18, 2026

Choose a reason for hiding this comment

Uh oh!

petrochenkov Jul 17, 2026 • edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Dnreikronos Jul 18, 2026

Choose a reason for hiding this comment

Uh oh!

petrochenkov commented Jul 17, 2026

Uh oh!

rustbot commented Jul 17, 2026

Uh oh!

Dnreikronos commented Jul 18, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

12 participants

Dnreikronos commented Jun 17, 2026 •

edited by rustbot

Loading

petrochenkov Jul 17, 2026 •

edited by rustbot

Loading

petrochenkov Jul 17, 2026 •

edited by rustbot

Loading