2300 Commits

Author SHA1 Message Date
bohan
f99cdf8b1c explain ImportData::imported_module 2025-06-29 00:23:35 +08:00
Matthias Krüger
190a1a7f74
Rollup merge of #142730 - bend-n:suggest_declaring_modules_when_file_found_but_module_not_defined, r=petrochenkov
suggest declaring modules when file found but module not defined

suggests declaring modules when a module is found but not defined, i.e
```
├── main.rs: `use thing::thang;`
└── thing.rs: `struct thang`
```
or
```
├── main.rs: `use thing::thang;`
└── thing
    └── mod.rs: `struct thang`
```
which currently is just
```rust
error[E0432]: unresolved import `yeah`
 --> src/main.rs:1:1
  |
1 | use thing::thang;
  |     ^^^^^ use of unresolved module or unlinked crate `thing`
  |
```
but now would have this nice help:
```text
= help: you may have forgotten to declare the module `thing`. use `mod thing` in this file to declare this module.
```
2025-06-27 22:13:02 +02:00
Matthias Krüger
2f8b715f10
Rollup merge of #142981 - compiler-errors:verbose-missing-suggestion, r=estebank
Make missing lifetime suggestion verbose

I keep seeing this suggestion when working on rustc, and it's annoying that it's inline. Part of https://github.com/rust-lang/rust/issues/141973. Feel free to close this if there's another PR already doing this.

r? ``@estebank``
2025-06-26 15:47:22 +02:00
Matthias Krüger
a05f2cc44d
Rollup merge of #142393 - compiler-errors:nofield, r=petrochenkov
Don't  give APITs names with macro expansion placeholder fragments in it

The `DefCollector` previously called `pprust::ty_to_string` to construct a name for APITs (arg-position impl traits). The `ast::Ty` that was being formatted however has already had its macro calls replaced with "placeholder fragments", which end up rendering like `!()` (or ICEing, in the case of rust-lang/rust#140333, since it led to a placeholder struct field with no name).

Instead, collect the name of the APIT *before* we visit its macros and replace them with placeholders in the macro expander. This makes the implementation a bit more involved, but AFAICT there's no better way to do this since we can't do a reverse mapping from placeholder fragment -> original macro call AST.

Fixes rust-lang/rust#140333
2025-06-26 15:47:20 +02:00
Matthias Krüger
cbcf183711
Rollup merge of #141648 - GuillaumeGomez:redundant_explicit_links-expansion, r=lolbinarycat
[rustdoc] Do not emit redundant_explicit_links lint if the doc comment comes from expansion

Fixes https://github.com/rust-lang/rust/issues/141553.

The problem was that we change the context for the attributes in some cases to get better error output, preventing us to detect if the attribute comes from expansion. Most of the changes are about keeping track of the "does this span comes from expansion" information.

r? ```@Manishearth```
2025-06-26 15:47:18 +02:00
Jana Dönszelmann
63c5a84b74
Rollup merge of #142724 - xizheyin:avoid_overwrite_args, r=oli-obk
Add runtime check to avoid overwrite arg in `Diag`

## Origin PR description
At first, I set up a `debug_assert` check for the arg method to make sure that `args` in `Diag` aren't easily overwritten, and I added the `remove_arg()` method, so that if you do need to overwrite an arg, then you can explicitly call `remove_arg()` to remove it first, then call `arg()` to overwrite it.

For the code before the rust-lang/rust#142015 change, it won't compile because it will report an error
```
arg `instance`already exists.
```

This PR also modifies all diagnostics that fail the check to pass the check. There are two cases of check failure:

1. ~~Between *the parent diagnostic and the subdiagnostic*, or *between the subdiagnostics* have the same field between them. In this case, I renamed the conflicting fields.~~
2. ~~For subdiagnostics stored in `Vec`, the rendering may iteratively write the same arg over and over again. In this case, I changed the auto-generation with `derive(SubDiagnostic)` to manually implementing `SubDiagnostic` and manually rendered it with `eagerly_translate()`, similar to https://github.com/rust-lang/rust/issues/142031#issuecomment-2984812090, and after rendering it I manually deleted useless arg with the newly added `remove_arg` method.~~

## Final Decision

After trying and discussing, we made a final decision.

For `#[derive(Subdiagnostic)]`, This PR made two changes:

1. After the subdiagnostic is rendered, remove all args of this subdiagnostic, which allows for usage like `Vec<Subdiag>`.
2. Store `diag.args` before setting arguments, so that you can restore the contents of the main diagnostic after deleting the arguments after subdiagnostic is rendered, to avoid deleting the main diagnostic's arg when they have the same name args.
2025-06-25 22:14:55 +02:00
Michael Goulet
8cd3fa04e2 Don't give APITs names with macro expansion placeholder fragments in it 2025-06-25 15:42:11 +00:00
xizheyin
d2d17c60bd
Add runtime check to avoid overwrite arg easily in diag and store and restore snapshot when set subdiag arg
Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>
2025-06-25 21:07:16 +08:00
Michael Goulet
250b5d204f Make missing lifetime suggestion verbose 2025-06-24 18:59:42 +00:00
Matthias Krüger
d7e10f083c
Rollup merge of #142805 - estebank:underscore-import, r=compiler-errors
Emit a single error when importing a path with `_`

When encountering `use _;`, `use _::*'` or similar, do not emit two errors for that single mistake. This also side-steps the issue of resolve errors suggesting adding a crate named `_` to `Cargo.toml`.

Fix rust-lang/rust#142662.
2025-06-24 20:46:04 +02:00
bendn
3583423536
suggest declaring modules when file found but module not defined 2025-06-25 01:12:15 +07:00
Esteban Küber
d82fb1e72d Emit a single error when importing a path with _
When encountering `use _;`, `use _::*'` or similar, do not emit two errors for that single mistake. This also side-steps the issue of resolve errors suggesting adding a crate named `_` to `Cargo.toml`.
2025-06-24 16:21:26 +00:00
Guillaume Gomez
3b5525bc42 Improve code and documentation 2025-06-23 16:12:49 +02:00
Guillaume Gomez
78cbcaffea Update tests to work with new DocFragment field and redundant_explicit_links new API 2025-06-23 16:02:34 +02:00
Guillaume Gomez
7e683cc4d1 Do not emit redundant_explicit_links rustdoc lint if the doc comment comes from expansion 2025-06-23 16:02:33 +02:00
bors
c2ec7532ee Auto merge of #142706 - fee1-dead-contrib:push-zsznlqyrzsqo, r=oli-obk
completely deduplicate `Visitor` and `MutVisitor`

r? oli-obk

This closes rust-lang/rust#127615.

### Discussion

> * Give every `MutVisitor::visit_*` method a corresponding `flat_map_*` method.

Not every AST node exists in a location where they can be mapped to multiple instances of themselves. Not every AST node exists in a location where they can be removed from existence (e.g. `filter_map_expr`). I don't think this is doable.

> * Give every `MutVisitor::visit_*` method a corresponding `Visitor` method and vice versa

The only three remaining method-level asymmetries after this PR are `visit_stmt` and `visit_nested_use_tree` (only on `Visitor`) and `visit_span` (only on `MutVisitor`).

`visit_stmt` doesn't seem applicable to `MutVisitor` because `walk_flat_map_stmt_kind` will ask `flat_map_item` / `filter_map_expr` to potentially turn a single `Stmt` to multiple based on what a visitor wants. So only using `flat_map_stmt` seems appropriate.

`visit_nested_use_tree` is used for `rustc_resolve` to track stuff. Not useful for `MutVisitor` for now.

`visit_span` is currently not used for `MutVisitor` already, it was just kept in case we want to revive rust-lang/rust#127241. cc `@cjgillot` maybe we could remove for now and re-insert later if we find a use-case? It does involve some extra effort to maintain.

* Remaining FIXMEs

`visit_lifetime` has an extra param for `Visitor` that's not in `MutVisitor`. This is again something only used by `rustc_resolve`. I think we can keep that symmetry for now.
2025-06-22 14:03:44 +00:00
David Tolnay
e51c37c34c
Add AttributeExt::doc_resolution_scope 2025-06-21 11:09:12 -07:00
Trevor Gross
44d50f9acf
Rollup merge of #142716 - nnethercote:adjust-with_generic_param_rib, r=petrochenkov
Adjust `with_generic_param_rib`.

Currently all of its call sites construct a `LifetimeRibKind::Generics` value, which `with_generic_param_rib` then deconstructs (and panics if it's a different `LifetimeRibKind` variant).

This commit makes the code simpler and shorter: the call sites just pass in the three values and `with_generic_param_rib` constructs the `LifetimeRibKind::Generics` value from them.

r? `@petrochenkov`
2025-06-20 23:25:57 -04:00
Jana Dönszelmann
75bcc9ca6e
remove equivalent new method on context 2025-06-20 07:50:11 +02:00
Nicholas Nethercote
41ca0cb020 Adjust with_generic_param_rib.
Currently all of its call sites construct a `LifetimeRibKind::Generics`
value, which `with_generic_param_rib` then deconstructs (and panics if
it's a different `LifetimeRibKind` variant).

This commit makes the code simpler and shorter: the call sites just pass
in the three values and `with_generic_param_rib` constructs the
`LifetimeRibKind::Generics` value from them.
2025-06-19 20:44:06 +10:00
Deadbeef
3da58e673a completely deduplicate Visitor and MutVisitor 2025-06-19 17:50:44 +08:00
Nicholas Nethercote
248b7a9490 Fix PathSource lifetimes.
It currently has two, which don't accurately capture what's happening --
the `TupleStruct` spans are allocated in `ResolverArenas`, which is
different to where the `Expr` is allocated -- and require some
"outlives" constraints to be used.

This commit adds another lifetime, renames the existing ones, and
removes the "outlives" constraints.
2025-06-16 10:33:00 +10:00
bors
d087f112b7 Auto merge of #134841 - estebank:serde-attr-4, r=wesleywiser
Look at proc-macro attributes when encountering unknown attribute

```
error: cannot find attribute `sede` in this scope
  --> $DIR/missing-derive-2.rs:22:7
   |
LL |     #[sede(untagged)]
   |       ^^^^
   |
help: the derive macros `Deserialize` and `Serialize` accept the similarly named `serde` attribute
   |
LL |     #[serde(untagged)]
   |         +

error: cannot find attribute `serde` in this scope
  --> $DIR/missing-derive-2.rs:16:7
   |
LL |     #[serde(untagged)]
   |       ^^^^^
   |
note: `serde` is imported here, but it is a crate, not an attribute
  --> $DIR/missing-derive-2.rs:5:1
   |
LL | extern crate serde;
   | ^^^^^^^^^^^^^^^^^^^
help: `serde` is an attribute that can be used by the derive macros `Serialize` and `Deserialize`, you might be missing a `derive` attribute
   |
LL + #[derive(Serialize, Deserialize)]
LL | enum B {
   |
```

Partially address #47608. This PR doesn't find [macros that haven't yet been imported by name](af945cb86e).
2025-06-13 22:59:24 +00:00
Matthias Krüger
fac011eb2d
Rollup merge of #142158 - xizheyin:141617, r=jdonszelmann
Tracking the old name of renamed unstable library features

This PR resolves the first problem of rust-lang/rust#141617 : tracking renamed unstable features. The first commit is to add a ui test, and the second one tracks the changes. I will comment on the code for clarification.

r? `@jdonszelmann`
There have been a lot of PR's reviewed by you lately, thanks for your time!

cc `@jyn514`
2025-06-13 05:16:56 +02:00
bors
bb3a3c530c Auto merge of #142438 - matthiaskrgr:rollup-u1jdnhz, r=matthiaskrgr
Rollup of 9 pull requests

Successful merges:

 - rust-lang/rust#134536 (Lint on fn pointers comparisons in external macros)
 - rust-lang/rust#141069 (Suggest mut when possbile for temporary value dropped while borrowed)
 - rust-lang/rust#141934 (resolve: Tweak `private_macro_use` lint to be compatible with upcoming macro prelude changes)
 - rust-lang/rust#142034 (Detect method not being present that is present in other tuple types)
 - rust-lang/rust#142402 (chore(doctest): Remove redundant blank lines)
 - rust-lang/rust#142406 (Note when enum variants shadow an associated function)
 - rust-lang/rust#142407 (Remove bootstrap adhoc group)
 - rust-lang/rust#142408 (Add myself (WaffleLapkin) to review rotation)
 - rust-lang/rust#142418 (Remove lower_arg_ty as all callers were passing `None`)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-06-12 23:05:49 +00:00
Esteban Küber
92a798dac0 Detect when attribute is provided by missing derive macro
```
error: cannot find attribute `empty_helper` in this scope
  --> $DIR/derive-helper-legacy-limits.rs:17:3
   |
LL | #[empty_helper]
   |   ^^^^^^^^^^^^
   |
help: `empty_helper` is an attribute that can be used by the derive macro `Empty`, you might be missing a `derive` attribute
   |
LL + #[derive(Empty)]
LL | struct S2;
   |
```

Look at proc-macro attributes when encountering unknown attribute

```
error: cannot find attribute `sede` in this scope
  --> src/main.rs:18:7
   |
18 |     #[sede(untagged)]
   |       ^^^^
   |
help: the derive macros `Serialize` and `Deserialize` accept the similarly named `serde` attribute
   |
18 |     #[serde(untagged)]
   |       ~~~~~

error: cannot find attribute `serde` in this scope
  --> src/main.rs:12:7
   |
12 |     #[serde(untagged)]
   |       ^^^^^
   |
   = note: `serde` is in scope, but it is a crate, not an attribute
help: `serde` is an attribute that can be used by the derive macros `Serialize` and `Deserialize`, you might be missing a `derive` attribute
   |
10 | #[derive(Serialize, Deserialize)]
   |
```
2025-06-12 21:28:49 +00:00
Matthias Krüger
8b6d55e782
Rollup merge of #141934 - petrochenkov:privmacuse, r=compiler-errors
resolve: Tweak `private_macro_use` lint to be compatible with upcoming macro prelude changes

Unblocks https://github.com/rust-lang/rust/pull/139493.
Zulip thread requesting help - [#t-compiler/help > Help requested for effects of #139493](https://rust-lang.zulipchat.com/#narrow/channel/182449-t-compiler.2Fhelp/topic/Help.20requested.20for.20effects.20of.20.23139493/with/514653911).

This PR by itself shouldn't cause any observable changes, its only observable effect is that the prelude changes from https://github.com/rust-lang/rust/pull/139493 will no longer cause regressions in tests like `tests/ui/imports/issue-119369.rs` or `tests/ui/extern/issue-80074.rs`.

This is achieved by moving the "is this thing in stdlib prelude" check from an early point (`fn process_macro_use_imports`) to a later point (`fn record_use_inner`), at which the stdlib prelude is already populated and can be inspected.
(The `is_builtin_macro` check is subsumed by the stdlib prelude check, all built-in macros go through the stdlib prelude anyway.)
2025-06-12 22:09:42 +02:00
xizheyin
b8066f94fd
Tracking the old name of renamed unstable library attribute
Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>
2025-06-12 19:24:11 +08:00
Jana Dönszelmann
6072207a11
introduce new lint infra
lint on duplicates during attribute parsing
To do this we stuff them in the diagnostic context to be emitted after
hir is constructed
2025-06-12 09:56:47 +02:00
Matthias Krüger
2d9513b98c
Rollup merge of #142157 - Enselic:trivial-anon-const-use-cases, r=compiler-errors
rustc_resolve: Improve `resolve_const_param_in_non_trivial_anon_const` wording

In some contexts, const expressions are OK. Add a `here` to the error message to clarify this.

Closes rust-lang/rust#79429 which has 15 x 👍
2025-06-12 03:14:51 +02:00
Martin Nordholts
4882ea4b3c rustc_resolve: Improve resolve_const_param_in_non_trivial_anon_const wording
In some contexts, const expressions are OK. Add a `here` to the error
message to clarify this.
2025-06-07 13:01:16 +02:00
Guillaume Gomez
2946ce29ed
Rollup merge of #142086 - fee1-dead-contrib:ast-visitor-dedup, r=oli-obk
duduplicate more AST visitor methods

r? oli-obk
2025-06-06 23:53:17 +02:00
Deadbeef
8a7262c426 deduplicate more walk_* methods in AST visit 2025-06-06 04:59:26 +00:00
bors
ccf3198de3 Auto merge of #138677 - shepmaster:consistent-elided-lifetime-syntax, r=traviscross,jieyouxu
Add a new `mismatched-lifetime-syntaxes` lint

The lang-team [discussed this](https://hackmd.io/nf4ZUYd7Rp6rq-1svJZSaQ) and I attempted to [summarize](https://github.com/rust-lang/rust/pull/120808#issuecomment-2701863833) their decision. The summary-of-the-summary is:

- Using two different kinds of syntax for elided lifetimes is confusing. In rare cases, it may even [lead to unsound code](https://github.com/rust-lang/rust/issues/48686)! Some examples:

    ```rust
    // Lint will warn about these
    fn(v: ContainsLifetime) -> ContainsLifetime<'_>;
    fn(&'static u8) -> &u8;
    ```

- Matching up references with no lifetime syntax, references with anonymous lifetime syntax, and paths with anonymous lifetime syntax is an exception to the simplest possible rule:

    ```rust
    // Lint will not warn about these
    fn(&u8) -> &'_ u8;
    fn(&'_ u8) -> &u8;
    fn(&u8) -> ContainsLifetime<'_>;
    ```

- Having a lint for consistent syntax of elided lifetimes will make the [future goal](https://github.com/rust-lang/rust/issues/91639) of warning-by-default for paths participating in elision much simpler.

---

This new lint attempts to accomplish the goal of enforcing consistent syntax. In the process, it supersedes and replaces the existing `elided-named-lifetimes` lint, which means it starts out life as warn-by-default.
2025-06-05 19:49:30 +00:00
Jake Goulding
d35ad94849 Replace elided_named_lifetimes with mismatched_lifetime_syntaxes 2025-06-04 10:40:04 -04:00
bors
2f176126aa Auto merge of #141954 - matthiaskrgr:rollup-zptd6t9, r=matthiaskrgr
Rollup of 9 pull requests

Successful merges:

 - rust-lang/rust#141554 (Improve documentation for codegen options)
 - rust-lang/rust#141817 (rustc_llvm: add Windows system libs only when cross-compiling from Wi…)
 - rust-lang/rust#141843 (Add `visit_id` to ast `Visitor`)
 - rust-lang/rust#141881 (Subtree update of `rust-analyzer`)
 - rust-lang/rust#141898 ([rustdoc-json] Implement PartialOrd and Ord for rustdoc_types::Id)
 - rust-lang/rust#141921 (Disable f64 minimum/maximum tests for arm 32)
 - rust-lang/rust#141930 (Enable triagebot `[concern]` functionality)
 - rust-lang/rust#141936 (Decouple "reporting in deps" from `FutureIncompatibilityReason`)
 - rust-lang/rust#141949 (move `test-float-parse` tool into `src/tools` dir)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-06-03 09:51:59 +00:00
Matthias Krüger
ad876cbe86
Rollup merge of #141843 - fee1-dead-contrib:ast_visitor_visit_id, r=oli-obk
Add `visit_id` to ast `Visitor`

This helps with efforts to deduplicate the `MutVisitor` and the `Visitor` code. All users of `Visitor`'s methods that have extra `NodeId` as parameters really just want to visit the id on its own.

Also includes some methods deduplicated and cleaned up as a result of this change.

r? oli-obk
2025-06-03 11:33:33 +02:00
Matthias Krüger
69ebe39cea
Rollup merge of #141876 - compiler-errors:missing-let-ty, r=SparrowLii
Don't declare variables in `ExprKind::Let` in invalid positions

Handle `let` expressions in invalid positions specially during resolve in order to avoid making destructuring-assignment expressions that reference (invalid) variables that have not yet been delcared yet.

See further explanation in test and comment in the source.

Fixes rust-lang/rust#141844
2025-06-03 07:03:44 +02:00
Matthias Krüger
8db6881620
Rollup merge of #141741 - nnethercote:overhaul-UsePath, r=petrochenkov
Overhaul `UsePath`

It currently uses `SmallVec<[Res; 3]>` which is really weird. Details in the individual commits.

r? `@petrochenkov`
2025-06-03 07:03:43 +02:00
Nicholas Nethercote
8747ccbcdf Overhaul UsePath.
`UsePath` contains a `SmallVec<[Res; 3]>`. This holds up to three `Res`
results, one per namespace (type, value, or macro). `lower_import_res`
takes a `PerNS<Option<Res<NodeId>>>` result and lowers it into the
`SmallVec`. This is pretty weird. The input `PerNS` makes it clear which
`Res` belongs to which namespace, but the `SmallVec` throws that
information away.

And code that operates on the `SmallVec` tends to use iteration (or even
just grabbing the first entry!) without knowing which namespace the
`Res` belongs to. Even weirder! Also, `SmallVec` is an overly flexible
type to use here, because it can contain any number of elements (even
though it's optimized for 3 in this case).

This commit changes `UsePath` so it also contains a
`PerNS<Option<Res<HirId>>>`. This type preserves more information and is
more self-documenting. The commit also changes a lot of the use sites to
access the result for a particular namespace. E.g. if you're looking up
a trait, it will be in the `Res` for the type namespace if it's present;
it's silly to look in the `Res` for the value namespace or macro
namespace. Overall I find the new code much easier to understand.

However, some use sites still iterate. These now use `present_items`
because that filters out the `None` results.

Also, `redundant_pub_crate.rs` gets a bigger change. A
`UseKind:ListStem` item gets no `Res` results, which means the old `all`
call in `is_not_macro_export` would succeed (because `all` succeeds on
an empty iterator) and the `ListStem` would be ignored. This is what we
want, but was more by luck than design. The new code detects `ListStem`
explicitly. The commit generalizes the name of that function
accordingly.

Finally, the commit also removes the `use_path` arena, because
`PerNS<Option<Res>>` impls `Copy` (unlike `SmallVec`) and it can be
allocated in the arena shared by all `Copy` types.
2025-06-03 08:23:21 +10:00
Vadim Petrochenkov
6a5bad36a8 resolve: Tweak private_macro_use lint to be compatible with upcoming macro prelude changes 2025-06-03 00:09:54 +03:00
yukang
7167e7ce06 Fix false positive lint error from no_implicit_prelude attr 2025-06-02 17:49:01 +08:00
Michael Goulet
d2d0f62f78 Don't declare variables in ExprKind::Let in invalid positions 2025-06-02 02:19:34 +00:00
Guillaume Gomez
d843809b9d
Rollup merge of #141666 - lolbinarycat:rustdoc-source_span_for_markdown_range-bug-141665, r=GuillaumeGomez
source_span_for_markdown_range: fix utf8 violation

it is non-trivial to reproduce this bug through rustdoc, which uses this function less than clippy, so the regression test was added as a unit test instead of an integration test.

fixes https://github.com/rust-lang/rust/issues/141665

r? ``@GuillaumeGomez``
2025-06-01 19:35:43 +02:00
Guillaume Gomez
cd0adc9d7b
Rollup merge of #140370 - WaffleLapkin:unqualified, r=jdonszelmann
Improve diagnostics for usage of qualified paths within tuple struct exprs/pats

For patterns the old diagnostic was just incorrect, but I also added machine applicable suggestions.

For context, this special cases errors for `<T as Trait>::Assoc(..)` patterns and expressions (latter is just a call). Tuple struct patterns and expressions both live in the value namespace, so they are not forwarded through associated *types*.

r? ``@jdonszelmann``

cc ``@petrochenkov`` in https://github.com/rust-lang/rust/pull/80080#issuecomment-800630582 you were wondering why it doesn't work for types, that's why — tuple patterns are resolved in the value namespace.
2025-06-01 19:35:41 +02:00
Deadbeef
c33b08552b Add visit_id to ast Visitor
This helps with efforts to deduplicate the `MutVisitor` and the
`Visitor` code. All users of `Visitor`'s methods that have extra
`NodeId` as parameters really just want to visit the id on its
own.

Also includes some methods deduplicated and cleaned up as
a result of this change.
2025-06-01 02:38:24 +00:00
binarycat
a8b5e706b7 source_span_for_markdown_range: fix utf8 violation
it is non-trivial to reproduce this bug through rustdoc,
which uses this function less than clippy,
so the regression test was added as a unit test
instead of an integration test.
2025-05-31 14:51:16 -05:00
Matthew Jasper
4a1843924e Fix spans for unsafe binders 2025-05-30 16:58:48 +00:00
Matthias Krüger
7aba37da44
Rollup merge of #133823 - estebank:issue-56328, r=petrochenkov
Use `cfg_attr_trace` in AST with a placeholder attribute for accurate suggestion

In rust-lang/rust#138515, we insert a placeholder attribute so that checks for attributes can still know about the placement of `cfg` attributes. When we suggest removing items with `cfg_attr`s (fix rust-lang/rust#56328) and make them verbose. We tweak the wording of the existing "unused `extern crate`" lint.

```
warning: unused `extern crate`
  --> $DIR/removing-extern-crate.rs:9:1
   |
LL | extern crate removing_extern_crate as foo;
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unused
   |
note: the lint level is defined here
  --> $DIR/removing-extern-crate.rs:6:9
   |
LL | #![warn(rust_2018_idioms)]
   |         ^^^^^^^^^^^^^^^^
   = note: `#[warn(unused_extern_crates)]` implied by `#[warn(rust_2018_idioms)]`
help: remove the unused `extern crate`
   |
LL - #[cfg_attr(test, macro_use)]
LL - extern crate removing_extern_crate as foo;
   |
```

r? `@petrochenkov`

try-job: x86_64-gnu-aux
2025-05-30 07:01:27 +02:00
Esteban Küber
f80e3ac4ed Use cfg_attr AST placeholder AST cfg_attr_trace for diagnostics
PR 138515, we insert a placeholder attribute so that checks for attributes can still know about the placement of `cfg` attributes. When we suggest removing items with `cfg_attr`s (fix Issue 56328) and make them verbose. We tweak the wording of the existing "unused `extern crate`" lint.

```
warning: unused extern crate
  --> $DIR/removing-extern-crate.rs:9:1
   |
LL | extern crate removing_extern_crate as foo;
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unused
   |
note: the lint level is defined here
  --> $DIR/removing-extern-crate.rs:6:9
   |
LL | #![warn(rust_2018_idioms)]
   |         ^^^^^^^^^^^^^^^^
   = note: `#[warn(unused_extern_crates)]` implied by `#[warn(rust_2018_idioms)]`
help: remove the unused `extern crate`
   |
LL - #[cfg_attr(test, macro_use)]
LL - extern crate removing_extern_crate as foo;
LL +
   |
```
2025-05-29 10:24:23 +00:00