Remove ATTRIBUTE_ORDER

[JonathanBrouwer]

r? @jdonszelmann

There's only a few attributes that use KeepInnermost and I think I like the consistency of just making them all KeepOutermost
This will soft-conflict with all attribute-related PRs, if you send r=me I'll rebase & merge it at a safe time

[rustbot]

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann

[JonathanBrouwer]

This order was inconsistent with the order in Warn and WarnButFutureError

[jdonszelmann]

Aren't these technically breaking changes?

[JonathanBrouwer]

Why is this a breaking change? I think erroring/warning on a different attribute should be fine right?

[jdonszelmann]

Well in the cases where it warns, it compiles. Let's say there are two inline attributes, one says always the other never. It will warn about the innermost, apply the outermost, and be inlined. If we make the attribute keep the innermost, it warns about the outermost and not inline

[JonathanBrouwer]

Ooh right, yeah you're right, good catch.
I'll think about this a little bit but will probably just submit it to T-lang

[JonathanBrouwer]

@bors try

[rust-bors]

☀️ Try build successful (CI)
Build commit: 54bb9bb (54bb9bb1bbe87f59b5a2e9afea4c8cedcf5e0b47, parent: 0028f344ce9f64766259577c998a1959ca1f6a0b)

[JonathanBrouwer]

@craterbot check

[craterbot]

👌 Experiment pr-153041 created and queued.
🤖 Automatically detected try build 54bb9bb
⚠️ Try build based on commit 6bafe7f, but latest commit is 698abd4. Did you forget to make a new try build?
🔍 You can check out the queue and this experiment's details.

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[craterbot]

🚧 Experiment pr-153041 is now running

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

[rustbot]

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.

[craterbot]

🎉 Experiment pr-153041 is completed!
📊 4 regressed and 3 fixed (827089 total)
📊 2463 spurious results on the retry-regressed-list.txt, consider a retry¹ if this is a significant amount.
📰 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

Footnotes

1. re-run the experiment with crates=https://crater-reports.s3.amazonaws.com/pr-153041/retry-regressed-list.txt ↩

[JonathanBrouwer]

All 4 regressed and 3 fixed are spurious.

@rust-lang/lang Previously when multiple of the same attribute were present, we would FCW and then sometimes pick the first (outermost) and sometimes pick the second (innermost) attribute to keep, depending on the exact attribute. Most attributes already picked the first (outermost) attribute to keep, a minority picked the second (innermost).

This PR makes this consistent, always keeping the first (outermost) and warning on the second (innermost) attribute.
This is technically a breaking change because if the attribute has arguments, we may now pick the other attribute with different arguments.

For example, this PR changes the meaning of this program, previously we would pick exported_symbol_name2, we will now pick exported_symbol_name

#[export_name = "exported_symbol_name"]
#[export_name = "exported_symbol_name2"]
fn ...

This affects the following non-rustc attributes:

• export_name
• link_name
• link_section
• instruction_set
• must_not_suspend