Add `AcceptContext::expect_key_value` by scrabsha · Pull Request #155831 · rust-lang/rust

scrabsha · 2026-04-26T15:41:55Z

This PR adds AcceptContext::expect_name_value that takes any name-value-ish node and returns what's in it (it depends on the type of the node). It follows the same style as AcceptContext::expect_list and AcceptContext::single introduced in #155696.

Having expect_name_value taking care of all the error emission allowed me to remove every call to AttributeDiagnosticContext::expected_name_value from outside rustc_attr_parsing::context and mark it as private. as_name_value is still used in places in which we want to emit our own error messages.

r? JonathanBrouwer

Oracle changes

While reviewing the uses of expected_name_value, I found quite a few of these:

let Some(value_str) = name_value.value_as_str() else {
    cx.adcx().expected_name_value(/* ... */);
    return None;
};

I believe emitting an "expected a name-value pair" error message is misleading because in this situation we already have asserted that the name-value is... a name-value. I replaced these with calls to expected_string_literal. This alters the oracles a bit.

I also made MetaItemParser::expect_name_value slightly smarter than what ~most of the code was doing before, as it is able to assert that the name is a single word (and not an arbitrary path) and that the argument is an = value (and not a list, or nothing) in one go and potentially emit two errors instead of just ones. This too alters oracles.

scrabsha · 2026-04-28T08:30:41Z

   | ^^^^^^^^^^^^^^^^^-------^^^^^^^^^^
   |                  |
-   |                  expected this to be of the form `enable = "..."`
+   |                  the only valid argument here is `enable`


The change here is caused by the change expected_name_value -> expected_specific_argument when checking that the argument is enable in compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs.

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scrabsha · 2026-04-28T08:33:04Z

+error[E0539]: malformed `cfg` attribute input
+  --> $DIR/cfg-target-compact-errors.rs:5:1
+   |
+LL | #[cfg(target(o::o))]
+   | ^^^^^^^^^^^^^----^^^
+   |              |
+   |              expected a valid identifier here
+   |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+help: must be of the form
+   |
+LL - #[cfg(target(o::o))]
+LL + #[cfg(predicate)]
+   |
+


This error is added because MetaItemOrLitParser::expect_key_value checks both that the argument is a single word (here it is a path) and that the argument is a key-value (next error in this oracle) before returning.

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scrabsha · 2026-04-28T08:36:12Z

+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-^^
+   |                                                             |
+   |                                                             expected a string literal here


This change is caused by replacing expected_key_value -> expected_string_literal in compiler/rustc_attr_parsing/src/attributes/link_attrs.rs.

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rustbot · 2026-04-28T08:41:47Z

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann, @JonathanBrouwer

Some changes occurred to diagnostic attributes.

cc @mejrs

rustbot · 2026-04-29T18:01:28Z

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.

JonathanBrouwer · 2026-04-29T18:01:33Z

^ Rebased
@bors r+ rollup

rust-bors · 2026-04-29T18:01:36Z

📌 Commit 7724d13 has been approved by JonathanBrouwer

It is now in the queue for this repository.

…thanBrouwer Add `AcceptContext::expect_key_value`

…uwer Rollup of 22 pull requests Successful merges: - #154149 (resolve: Extend `ambiguous_import_visibilities` deprecation lint to glob-vs-glob ambiguities) - #155189 (simd_reduce_min/max: remove float support) - #155453 (apply Cortex-A53 errata 843419 mitigation to the AArch64 Linux targets) - #155562 (Add a missing `GenericTypeVisitable`, and avoid having interner traits for `FnSigKind` and `Abi`) - #155608 (rustc_middle: Implement the `partial_cmp` operation for `DefId`s) - #155721 (When archive format is wrong produce an error instead of ICE) - #155794 (privacy: share effective visibility initialization) - #155832 (c-variadic: more precise compatibility check in const-eval) - #155856 (std_detect: support detecting more features on aarch64 Windows) - #155861 (Suggest `[const] Trait` bounds in more places) - #155899 (`dlltool`: Set the working directory to workaround `--temp-prefix` bug) - #155916 (Update with new LLVM 22 target for `wasm32-wali-linux-musl` target) - #155935 (remap OUT_DIR paths to fix build script path leakage in crate metadata. ) - #155950 (use the new `//@ needs-asm-mnemonic: ret` more) - #155958 (ci(free-disk-space): remove more tools and fix warnings) - #155966 (miri subtree update) - #155711 (bump curl-sys and openssl-sys to support OpenSSL 4.0.x) - #155831 (Add `AcceptContext::expect_key_value`) - #155877 (Avoid misleading return-type note for foreign `Fn` callees) - #155949 (Update `opt_ast_lowering_delayed_lints` query to allow "stealing" lints, allowing to use `FnOnce` instead of `Fn`) - #155951 (Make `FlatMapInPlaceVec` an unsafe trait.) - #155967 (Fix `doc_cfg` feature for extern items)

…uwer Rollup of 21 pull requests Successful merges: - #155966 (miri subtree update) - #154149 (resolve: Extend `ambiguous_import_visibilities` deprecation lint to glob-vs-glob ambiguities) - #155189 (simd_reduce_min/max: remove float support) - #155562 (Add a missing `GenericTypeVisitable`, and avoid having interner traits for `FnSigKind` and `Abi`) - #155608 (rustc_middle: Implement the `partial_cmp` operation for `DefId`s) - #155721 (When archive format is wrong produce an error instead of ICE) - #155794 (privacy: share effective visibility initialization) - #155832 (c-variadic: more precise compatibility check in const-eval) - #155856 (std_detect: support detecting more features on aarch64 Windows) - #155861 (Suggest `[const] Trait` bounds in more places) - #155899 (`dlltool`: Set the working directory to workaround `--temp-prefix` bug) - #155916 (Update with new LLVM 22 target for `wasm32-wali-linux-musl` target) - #155935 (remap OUT_DIR paths to fix build script path leakage in crate metadata. ) - #155950 (use the new `//@ needs-asm-mnemonic: ret` more) - #155958 (ci(free-disk-space): remove more tools and fix warnings) - #155711 (bump curl-sys and openssl-sys to support OpenSSL 4.0.x) - #155831 (Add `AcceptContext::expect_key_value`) - #155877 (Avoid misleading return-type note for foreign `Fn` callees) - #155949 (Update `opt_ast_lowering_delayed_lints` query to allow "stealing" lints, allowing to use `FnOnce` instead of `Fn`) - #155951 (Make `FlatMapInPlaceVec` an unsafe trait.) - #155967 (Fix `doc_cfg` feature for extern items)

Rollup merge of #155831 - scrabsha:push-pqrumlqtlsyk, r=JonathanBrouwer Add `AcceptContext::expect_key_value`

…uwer Rollup of 21 pull requests Successful merges: - rust-lang/rust#155966 (miri subtree update) - rust-lang/rust#154149 (resolve: Extend `ambiguous_import_visibilities` deprecation lint to glob-vs-glob ambiguities) - rust-lang/rust#155189 (simd_reduce_min/max: remove float support) - rust-lang/rust#155562 (Add a missing `GenericTypeVisitable`, and avoid having interner traits for `FnSigKind` and `Abi`) - rust-lang/rust#155608 (rustc_middle: Implement the `partial_cmp` operation for `DefId`s) - rust-lang/rust#155721 (When archive format is wrong produce an error instead of ICE) - rust-lang/rust#155794 (privacy: share effective visibility initialization) - rust-lang/rust#155832 (c-variadic: more precise compatibility check in const-eval) - rust-lang/rust#155856 (std_detect: support detecting more features on aarch64 Windows) - rust-lang/rust#155861 (Suggest `[const] Trait` bounds in more places) - rust-lang/rust#155899 (`dlltool`: Set the working directory to workaround `--temp-prefix` bug) - rust-lang/rust#155916 (Update with new LLVM 22 target for `wasm32-wali-linux-musl` target) - rust-lang/rust#155935 (remap OUT_DIR paths to fix build script path leakage in crate metadata. ) - rust-lang/rust#155950 (use the new `//@ needs-asm-mnemonic: ret` more) - rust-lang/rust#155958 (ci(free-disk-space): remove more tools and fix warnings) - rust-lang/rust#155711 (bump curl-sys and openssl-sys to support OpenSSL 4.0.x) - rust-lang/rust#155831 (Add `AcceptContext::expect_key_value`) - rust-lang/rust#155877 (Avoid misleading return-type note for foreign `Fn` callees) - rust-lang/rust#155949 (Update `opt_ast_lowering_delayed_lints` query to allow "stealing" lints, allowing to use `FnOnce` instead of `Fn`) - rust-lang/rust#155951 (Make `FlatMapInPlaceVec` an unsafe trait.) - rust-lang/rust#155967 (Fix `doc_cfg` feature for extern items)

rustbot added A-attributes Area: Attributes (`#[…]`, `#![…]`) S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Apr 26, 2026

scrabsha commented Apr 26, 2026

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scrabsha force-pushed the push-pqrumlqtlsyk branch from 5c6f7cf to 27cefb8 Compare April 26, 2026 16:20

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scrabsha commented Apr 28, 2026

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scrabsha marked this pull request as ready for review April 28, 2026 08:41

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JonathanBrouwer approved these changes Apr 29, 2026

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Add AcceptContext::expect_key_value

7724d13

JonathanBrouwer force-pushed the push-pqrumlqtlsyk branch from c92e28d to 7724d13 Compare April 29, 2026 18:01

rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Apr 29, 2026

JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Apr 29, 2026

Rollup merge of rust-lang#155831 - scrabsha:push-pqrumlqtlsyk, r=Jona…

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…thanBrouwer Add `AcceptContext::expect_key_value`

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Rollup of 10 pull requests #155975

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Rollup merge of rust-lang#155831 - scrabsha:push-pqrumlqtlsyk, r=Jona…

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…thanBrouwer Add `AcceptContext::expect_key_value`

JonathanBrouwer mentioned this pull request Apr 29, 2026

Rollup of 22 pull requests #155976

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Rollup of 21 pull requests #155979

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rust-bors Bot merged commit 344cc3e into rust-lang:main Apr 30, 2026
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Unrolled build for #155831

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Rollup merge of #155831 - scrabsha:push-pqrumlqtlsyk, r=JonathanBrouwer Add `AcceptContext::expect_key_value`

scrabsha deleted the push-pqrumlqtlsyk branch April 30, 2026 07:22

cuviper added this to the 1.97.0 milestone Apr 30, 2026

scrabsha mentioned this pull request May 1, 2026

Add AcceptContext::expect_no_args #156037

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