@fmease and I decided to delay this PR for a bit until more diagnostic infra for attrs lands (hopefully next week) to make the duplicate error a warning to be consistent with current master.

r=fmease,bjorn3 once that PR lands and you can downgrade the error to a lint warning again.

@bors delegate+

✌️ @jdonszelmann, you can now approve this pull request!

If @fmease told you to "r=me" after making some further change, please make that change, then do @bors r=@fmease

Hi @jdonszelmann and @fmease, #137687 has reached beta so it would be great if we could resolve that via a beta-backport of this PR. Do you think it's possible to resolve the review feedback and merge this PR in the next week or so?

I can probably pitch in to help if necessary 🙂

Hi there. We wanted to delay this until attribute diagnostics. Something that should not be a lot of work but I have not worked as much on recently as I maybe should. I can't to this tomorrow, but likely next week. The pr has been reviewed but there was a bit of an issue around incremental, which I now know how to solve but just haven't yet. Is that a reasonable timeframe? I am pretty busy with organising rust week atm, but knowing the solution I guess the only important thing is that it gets quick reviews? Let me know how that sounds

Just to clarify, will this PR then depend on the attribute diagnostics work? (Is that #138164?)

Generally, for backports, we try to keep the backport as small as possible so if this PR can be made to work independently of that PR (possibly even with a degraded diagnostics experience), that would be highly preferred.

No. We decided to delay this because it's relatively low prio and any nice and permanent solution for this depends on that. I'll make a temp fix that at least doesn't ice separately then, that sounds better for now. I don't mind doing it, I know the problem now and then I also know how to fix it permanently later. You'll hear from me

Note that #137687 actually has two separate problems/subissues:

1. A problem (lower priority) involving the #[crate_name] attribute.
2. A problem (higher priority, found in a crater run) involving user-defined macro_rules and derive macros.

This PR only appears to address the first problem. The second problem would probably need to have a separate fix.

ok this is weird, I've copied just the tests over to master to fix it in a temporary way, but can no longer reporoduce the issue. Something else must have solved it in the meantime. Let me see what.

(I know I've said this in the other PR too, but just in case)

Just a heads up: I split #137687 into two issues:

• ICE: expr in place where literal is expected (builtin attr parsing) #137687 is used to track Matthias's fuzzed regression (the #[crate_name = concat!("Cloneb")] one).
• regression: ICE: expr in place where literal is expected (builtin attr parsing) #140612 is used to track the crater regressions (known to affect user macros)

Amazing work, thank you!

@bors r+ rollup

📌 Commit 9a7d66d has been approved by fmease

It is now in the queue for this repository.

merge conflicts

@bors r-

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.

@bors r=fmease

📌 Commit 48a4e2d has been approved by fmease

It is now in the queue for this repository.

⌛ Testing commit 48a4e2d with merge 93edf9f...

☀️ Test successful - checks-actions
Approved by: fmease
Pushing 93edf9f to master...

Comparing 4eedad3 (parent) -> 93edf9f (this PR)

Test differences

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 93edf9f9b0bf284d8f8cbe52af5d0569d0cf5850 --output-dir test-dashboard

Job duration changes

1. dist-aarch64-linux: 6292.7s -> 9447.7s (50.1%)
2. pr-check-1: 1377.3s -> 1612.4s (17.1%)
3. i686-gnu-2: 5542.5s -> 6348.7s (14.5%)
4. aarch64-gnu-llvm-19-1: 3303.4s -> 3771.2s (14.2%)
5. x86_64-gnu-miri: 4523.6s -> 5090.9s (12.5%)
6. dist-apple-various: 4610.1s -> 4043.7s (-12.3%)
7. dist-aarch64-apple: 6558.8s -> 5792.5s (-11.7%)
8. x86_64-gnu-llvm-19: 2518.5s -> 2800.5s (11.2%)
9. x86_64-gnu-stable: 6924.7s -> 7649.4s (10.5%)
10. x86_64-rust-for-linux: 2590.4s -> 2855.4s (10.2%)

yay, finally!

Finished benchmarking commit (93edf9f): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

Max RSS (memory usage)

Cycles

Binary size

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

Bootstrap: 467.477s -> 468.299s (0.18%)
Artifact size: 378.32 MiB -> 378.33 MiB (0.00%)