Add #![unstable_removed(..)] attribute to track removed features by Ozzy1423 · Pull Request #153335 · rust-lang/rust

Ozzy1423 · 2026-03-03T08:34:57Z

Adds the #![unstable_removed(..)] attribute to enable tracking removed library features.
Produce an error when a removed attribute is used.
Add a test that it works.

For #141617

r? @jyn514

rustbot · 2026-03-03T08:35:00Z

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

cc @jdonszelmann, @JonathanBrouwer

Some changes occurred in compiler/rustc_hir/src/attrs

cc @jdonszelmann, @JonathanBrouwer

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann, @JonathanBrouwer

rustbot · 2026-03-03T08:35:01Z

Failed to set assignee to jyn514: invalid assignee

Note: Only org members with at least the repository "read" role, users with write permissions, or people who have commented on the PR may be assigned.

jyn514

neat! can you add one or two examples of real features that were removed so i can see what it looks like?

this looks fine to me from a compiler side, i'd love to have someone from @rust-lang/libs review though.

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jdonszelmann

this is the one thing I'd like to see

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rustbot · 2026-03-03T15:21:00Z

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

Ozzy1423 · 2026-03-07T14:01:35Z

I've now provided an example, moving the concat_idents feature removal tracking to the new attribute in the second commit.
@rustbot ready
Unsure where you would like these unstable_removed attributes to live. (At their old impl site? All in one place?)

jdonszelmann · 2026-03-09T09:03:28Z

r=me on behalf of compiler after @nia-e brings it up with T-libs on wednesday. Ping me if you need the r+

nia-e · 2026-03-09T09:12:33Z

It would be worth checking if there's any in-tree dev docs on (removing) unstable features and updating them to mention this also

jyn514 · 2026-03-12T07:26:04Z

@rustbot author

rustbot · 2026-03-14T09:52:25Z

The rustc-dev-guide subtree was changed. If this PR only touches the dev guide consider submitting a PR directly to rust-lang/rustc-dev-guide otherwise thank you for updating the dev guide with your changes.

cc @BoxyUwU, @tshepang

Ozzy1423 · 2026-03-14T09:54:28Z

Added docs on renaming and removing library features, changed "issue" field to "link" to be more general.

jyn514 · 2026-03-15T07:09:28Z

@rustbot ready

nia-e · 2026-03-18T16:33:58Z

We discussed this in the @rust-lang/libs meeting today and we're happy to see this ^^ thanks!

@rustbot label -I-libs-nominated

jyn514 · 2026-03-18T19:42:28Z

r? @jdonszelmann

reddevilmidzy · 2026-03-31T04:47:20Z

@rustbot author

jdonszelmann · 2026-04-05T10:23:47Z

@jyn514 r=me on rebase

Move concat_idents to use the unstable_removed attribute

rustbot · 2026-04-12T10:19:09Z

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.

Ozzy1423 · 2026-04-12T10:34:53Z

@rustbot ready
Resolved conflicts and updated code due to recent refactors

jdonszelmann · 2026-04-13T11:22:18Z

@bors r+

rust-bors · 2026-04-13T11:22:21Z

📌 Commit 25a92d2 has been approved by jdonszelmann

It is now in the queue for this repository.

…uwer Rollup of 10 pull requests Successful merges: - #155227 (`rust-analyzer` subtree update) - #153335 (Add #![unstable_removed(..)] attribute to track removed features) - #154932 (Handle RTN projections in assoc type restriction diagnostics) - #155096 (delegation: support proper interaction of user-specified args and impl Traits) - #155106 (cg_llvm: scalable vectors with `simd_cast` and `simd_select`) - #155140 (add regression test for OpenOptionsExt downstream compat) - #155182 (Make the expansion of guard metavars begin guard non-terminals) - #155226 (delegation: revert execution of hir_crate_items before delayed lowering) - #153997 (Use closures more consistently in `dep_graph.rs`.) - #155003 (update thin-vec)

@jyn514

Rollup merge of #153335 - Ozzy1423:removed-features, r=jdonszelmann Add #![unstable_removed(..)] attribute to track removed features Adds the #![unstable_removed(..)] attribute to enable tracking removed library features. Produce an error when a removed attribute is used. Add a test that it works. For #141617 r? @jyn514

…uwer Rollup of 10 pull requests Successful merges: - rust-lang/rust#155227 (`rust-analyzer` subtree update) - rust-lang/rust#153335 (Add #![unstable_removed(..)] attribute to track removed features) - rust-lang/rust#154932 (Handle RTN projections in assoc type restriction diagnostics) - rust-lang/rust#155096 (delegation: support proper interaction of user-specified args and impl Traits) - rust-lang/rust#155106 (cg_llvm: scalable vectors with `simd_cast` and `simd_select`) - rust-lang/rust#155140 (add regression test for OpenOptionsExt downstream compat) - rust-lang/rust#155182 (Make the expansion of guard metavars begin guard non-terminals) - rust-lang/rust#155226 (delegation: revert execution of hir_crate_items before delayed lowering) - rust-lang/rust#153997 (Use closures more consistently in `dep_graph.rs`.) - rust-lang/rust#155003 (update thin-vec)

bjorn3 reviewed Mar 3, 2026

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Comment thread library/core/src/lib.rs Outdated

jyn514 reviewed Mar 3, 2026

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Comment thread tests/ui/attributes/malformed-unstable-removed.rs

Comment thread compiler/rustc_passes/src/stability.rs Outdated

jdonszelmann requested changes Mar 3, 2026

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Comment thread compiler/rustc_attr_parsing/src/attributes/stability.rs Outdated

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Ozzy1423 force-pushed the removed-features branch from c384f06 to 4966708 Compare March 6, 2026 19:33

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mejrs reviewed Mar 7, 2026

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Comment thread compiler/rustc_hir/src/attrs/data_structures.rs Outdated

Ozzy1423 force-pushed the removed-features branch from 4966708 to e4908ff Compare March 7, 2026 13:56

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Ozzy1423 force-pushed the removed-features branch from e4908ff to 4fe9116 Compare March 14, 2026 09:52

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Add #![unstable_removed(..)] attribute to track removed features

25a92d2

Move concat_idents to use the unstable_removed attribute

Ozzy1423 force-pushed the removed-features branch from 4fe9116 to 25a92d2 Compare April 12, 2026 10:19

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 Apr 12, 2026

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JonathanBrouwer mentioned this pull request Apr 13, 2026

Rollup of 10 pull requests #155239

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rust-bors Bot merged commit d4037f7 into rust-lang:main Apr 13, 2026
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rustbot added this to the 1.97.0 milestone Apr 13, 2026

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