When rustdoc lints were changed to be tool lints, the `rustdoc` group
was removed, leading to spurious warnings like
```
warning: unknown lint: `rustdoc`
```
The lint group still worked when rustdoc ran, since rustdoc added the group itself.
This renames the group to `rustdoc::all` for consistency with
`clippy::all` and the rest of the rustdoc lints.
Implement NOOP_METHOD_CALL lint
Implements the beginnings of https://github.com/rust-lang/lang-team/issues/67 - a lint for detecting noop method calls (e.g, calling `<&T as Clone>::clone()` when `T: !Clone`).
This PR does not fully realize the vision and has a few limitations that need to be addressed either before merging or in subsequent PRs:
* [ ] No UFCS support
* [ ] The warning message is pretty plain
* [ ] Doesn't work for `ToOwned`
The implementation uses [`Instance::resolve`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/instance/struct.Instance.html#method.resolve) which is normally later in the compiler. It seems that there are some invariants that this function relies on that we try our best to respect. For instance, it expects substitutions to have happened, which haven't yet performed, but we check first for `needs_subst` to ensure we're dealing with a monomorphic type.
Thank you to ```@davidtwco,``` ```@Aaron1011,``` and ```@wesleywiser``` for helping me at various points through out this PR ❤️.
Note that the FIXME was removed because this can't be fixed,
`register_renamed` calls LintId::of and there's no LintId for rustdoc
lints when rustc is running.
- Move MISSING_CRATE_LEVEL_DOCS to rustdoc directly
- Update documentation
This also takes the opportunity to make the `no-crate-level-doc-lint`
test more specific.
- Use `register_renamed` when rustdoc is running so the lint will still
be active and use a structured suggestion
- Test the behavior for rustc, not just for rustdoc (because it differs)
- Rename `broken_intra_doc_links` to `rustdoc::broken_intra_doc_links`
- Ensure that the old lint names still work and give deprecation errors
- Register lints even when running doctests
Otherwise, all `rustdoc::` lints would be ignored.
- Register all existing lints as removed
This unfortunately doesn't work with `register_renamed` because tool
lints have not yet been registered when rustc is running. For similar
reasons, `check_backwards_compat` doesn't work either. Call
`register_removed` directly instead.
- Fix fallout
+ Rustdoc lints for compiler/
+ Rustdoc lints for library/
Note that this does *not* suggest `rustdoc::broken_intra_doc_links` for
`rustdoc::intra_doc_link_resolution_failure`, since there was no time
when the latter was valid.
Apply lint restrictions from renamed lints
Previously, if you denied the old name of a renamed lint, it would warn
about using the new name, but otherwise do nothing. Now, it will behave
the same as if you'd used the new name.
Fixes https://github.com/rust-lang/rust/issues/82615.
r? `@ehuss`
Previously, if you denied the old name of a renamed lint, it would warn
about using the new name, but otherwise do nothing. Now, it will behave
the same as if you'd used the new name.
When token-based attribute handling is implemeneted in #80689,
we will need to access tokens from `HasAttrs` (to perform
cfg-stripping), and we will to access attributes from `HasTokens` (to
construct a `PreexpTokenStream`).
This PR merges the `HasAttrs` and `HasTokens` traits into a new
`AstLike` trait. The previous `HasAttrs` impls from `Vec<Attribute>` and `AttrVec`
are removed - they aren't attribute targets, so the impls never really
made sense.
Improve non_fmt_panic lint.
This change:
- fixes the span used by this lint in the case the panic argument is a single macro expansion (e.g. `panic!(a!())`);
- adds a suggestion for `panic!(format!(..))` to remove `format!()` instead of adding `"{}", ` or using `panic_any` like it does now; and
- fixes the incorrect suggestion to replace `panic![123]` by `panic_any(123]`.
Fixes#82109.
Fixes#82110.
Fixes#82111.
Example output:
```
warning: panic message is not a string literal
--> src/main.rs:8:12
|
8 | panic!(format!("error: {}", "oh no"));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `#[warn(non_fmt_panic)]` on by default
= note: this is no longer accepted in Rust 2021
= note: the panic!() macro supports formatting, so there's no need for the format!() macro here
help: remove the `format!(..)` macro call
|
8 | panic!("error: {}", "oh no");
| -- --
```
r? `@estebank`
Crate root is sufficiently different from `mod` items, at least at syntactic level.
Also remove customization point for "`mod` item or crate root" from AST visitors.
Add 'consider using' message to overflowing_literals
Fixes#79744.
Ironically, the `overflowing_literals` handler for binary or hex already
had this message! You would think it would be the other way around :)
cc ```@scottmcm```
Rename HIR UnOp variants
This renames the variants in HIR UnOp from
enum UnOp {
UnDeref,
UnNot,
UnNeg,
}
to
enum UnOp {
Deref,
Not,
Neg,
}
Motivations:
- This is more consistent with the rest of the code base where most enum
variants don't have a prefix.
- These variants are never used without the `UnOp` prefix so the extra
`Un` prefix doesn't help with readability. E.g. we don't have any
`UnDeref`s in the code, we only have `UnOp::UnDeref`.
- MIR `UnOp` type variants don't have a prefix so this is more
consistent with MIR types.
- "un" prefix reads like "inverse" or "reverse", so as a beginner in
rustc code base when I see "UnDeref" what comes to my mind is
something like `&*` instead of just `*`.
This renames the variants in HIR UnOp from
enum UnOp {
UnDeref,
UnNot,
UnNeg,
}
to
enum UnOp {
Deref,
Not,
Neg,
}
Motivations:
- This is more consistent with the rest of the code base where most enum
variants don't have a prefix.
- These variants are never used without the `UnOp` prefix so the extra
`Un` prefix doesn't help with readability. E.g. we don't have any
`UnDeref`s in the code, we only have `UnOp::UnDeref`.
- MIR `UnOp` type variants don't have a prefix so this is more
consistent with MIR types.
- "un" prefix reads like "inverse" or "reverse", so as a beginner in
rustc code base when I see "UnDeref" what comes to my mind is
something like "&*" instead of just "*".
This allows a build system to indicate a location in its own dependency
specification files (eg Cargo's `Cargo.toml`) which can be reported
along side any unused crate dependency.
This supports several types of location:
- 'json' - provide some json-structured data, which is included in the json diagnostics
in a `tool_metadata` field
- 'raw' - emit the provided string into the output. This also appears as a json string in
`tool_metadata`.
If no `--extern-location` is explicitly provided then a default json entry of the form
`"tool_metadata":{"name":<cratename>,"path":<cratepath>}` is emitted.
Add lint for `panic!(123)` which is not accepted in Rust 2021.
This extends the `panic_fmt` lint to warn for all cases where the first argument cannot be interpreted as a format string, as will happen in Rust 2021.
It suggests to add `"{}",` to format the message as a string. In the case of `std::panic!()`, it also suggests the recently stabilized
`std::panic::panic_any()` function as an alternative.
It renames the lint to `non_fmt_panic` to match the lint naming guidelines.
This is part of #80162.
r? ```@estebank```
introduce future-compatibility warning for forbidden lint groups
We used to ignore `forbid(group)` scenarios completely. This changed in #78864, but that led to a number of regressions (#80988, #81218).
This PR introduces a future compatibility warning for the case where a group is forbidden but then an individual lint within that group is allowed. We now issue a FCW when we see the "allow", but permit it to take effect.
r? ``@Mark-Simulacrum``
This extends the `panic_fmt` lint to warn for all cases where the first
argument cannot be interpreted as a format string, as will happen in
Rust 2021.
It suggests to add `"{}", ` to format the message as a string. In the
case of `std::panic!()`, it also suggests the recently stabilized
`std::panic::panic_any()` function as an alternative.
It renames the lint to `non_fmt_panic` to match the lint naming
guidelines.
We used to ignore `forbid(group)` scenarios completely. This changed
in #78864, but that led to a number of regressions (#80988, #81218).
This PR introduces a future compatibility warning for the case where
a group is forbidden but then an individual lint within that group
is allowed. We now issue a FCW when we see the "allow", but permit
it to take effect.
Fix early lints inside an async desugaring
Fixes#81531
When we buffer an early lint for a macro invocation,
we need to determine which NodeId to take the lint level from.
Currently, we use the NodeId of the closest def parent. However, if
the macro invocation is inside the desugared closure from an `async fn`
or async closure, that NodeId does not actually exist in the AST.
This commit uses the parent of a desugared closure when computing
`lint_node_id`, which is something that actually exists in the AST (an
`async fn` or async closure).
Fixes#81531
When we buffer an early lint for a macro invocation,
we need to determine which NodeId to take the lint level from.
Currently, we use the `NodeId` of the closest def parent. However, if
the macro invocation is inside the desugared closure from an `async fn`
or async closure, that `NodeId` does not actually exist in the AST.
This commit explicitly calls `check_lint` for the `NodeId`s of closures
desugared from async expressions, ensuring that we do not miss any
buffered lints.
Box the biggest ast::ItemKind variants
This PR is a different approach on https://github.com/rust-lang/rust/pull/81400, aiming to save memory in humongous ASTs.
The three affected item kind enums are:
- `ast::ItemKind` (208 -> 112 bytes)
- `ast::AssocItemKind` (176 -> 72 bytes)
- `ast::ForeignItemKind` (176 -> 72 bytes)
Implement Rust 2021 panic
This implements the Rust 2021 versions of `panic!()`. See https://github.com/rust-lang/rust/issues/80162 and https://github.com/rust-lang/rfcs/pull/3007.
It does so by replacing `{std, core}::panic!()` by a bulitin macro that expands to either `$crate::panic::panic_2015!(..)` or `$crate::panic::panic_2021!(..)` depending on the edition of the caller.
This does not yet make std's panic an alias for core's panic on Rust 2021 as the RFC proposes. That will be a separate change: c5273bdfb2 That change is blocked on figuring out what to do with https://github.com/rust-lang/rust/issues/80846 first.
clashing_extern_declarations: Use symbol interning to avoid string alloc.
Use symbol interning as a hack to avoid allocating a string for every symbol name we store in the seen set. This hopefully addresses the minor perf regression described in https://github.com/rust-lang/rust/pull/80009#issuecomment-763526902.
r? `@nagisa`
Improve safety of `LateContext::qpath_res`
This is my first rustc code change, inspired by hacking on clippy!
The first change is to clear cached `TypeckResults` from `LateContext` when visiting a nested item. I took a hint from [here](5e91c4ecc0/compiler/rustc_privacy/src/lib.rs (L1300)).
Clippy has a `qpath_res` util function to avoid a possible ICE in `LateContext::qpath_res`. But the docs of `LateContext::qpath_res` promise no ICE. So this updates the `LateContext` method to keep its promises, and removes the util function.
Related: rust-lang/rust-clippy#4545
CC ````````````@eddyb```````````` since you've done related work
CC ````````````@flip1995```````````` FYI
Refractor a few more types to `rustc_type_ir`
In the continuation of #79169, ~~blocked on that PR~~.
This PR:
- moves `IntVarValue`, `FloatVarValue`, `InferTy` (and friends) and `Variance`
- creates the `IntTy`, `UintTy` and `FloatTy` enums in `rustc_type_ir`, based on their `ast` and `chalk_ir` equilavents, and uses them for types in the rest of the compiler.
~~I will split up that commit to make this easier to review and to have a better commit history.~~
EDIT: done, I split the PR in commits of 200-ish lines each
r? `````@nikomatsakis````` cc `````@jackh726`````
Fix <unknown> queries and add more timing info to render_html
Closes https://github.com/rust-lang/rust/issues/81251.
## Fix `<unknown>` queries
This happened because `alloc_query_strings` was never called.
## Add more timing info to render_html
This still has some issues I'm not sure how to work out:
- `create_renderer` and `renderer_after_krate` aren't shown by default.
I want something like `verbose_generic_activity_with_arg`, but it doesn't exist.
I'm also not sure how to show activities that aren't on by default - I
tried `-Z self-profile -Z self-profile-args=all`, but it didn't show up.
r? `@wesleywiser`
Gracefully handle loop labels missing leading `'` in different positions
Fix#81192.
* Account for labels when suggesting `loop` instead of `while true`
* Suggest `'a` when given `a` only when appropriate
* Add loop head span to hir
* Tweak error for invalid `break expr`
* Add more misspelled label tests
* Avoid emitting redundant "unused label" lint
* Parse loop labels missing a leading `'`
Each commit can be reviewed in isolation.
Fix formatting for removed lints
- Don't add backticks for the reason a lint was removed. This is almost
never a code block, and when it is the backticks should be in the reason
itself.
- Don't assume clippy is the only tool that needs to be checked for
backwards compatibility
I split this out of https://github.com/rust-lang/rust/pull/80527/ because it kept causing tests to fail, and it's a good change to have anyway.
r? `@flip1995`
Prevents LateContext::maybe_typeck_results() from returning data in a
nested item without a body. Consequently, LateContext::qpath_res is less
likely to ICE when called in a nested item. Would have prevented
rust-lang/rust-clippy#4545, presumably.
- Don't add backticks for the reason a lint was removed. This is almost
never a code block, and when it is the backticks should be in the reason
itself.
- Don't assume clippy is the only tool that needs to be checked for
backwards compatibility
This copies the unknown_lints code clippy uses for its
unknown_clippy_lints lint to rustc. The unknown_clippy_lints code is
more advanced, because it doesn't suggest renamed or removed lints and
correctly suggest lower casing lints.
Previously, clippy (and any other tool emitting lints) had to have their
own separate UNKNOWN_LINTS pass, because the compiler assumed any tool
lint could be valid. Now, as long as any lint starting with the tool
prefix exists, the compiler will warn when an unknown lint is present.
Separate out a `hir::Impl` struct
This makes it possible to pass the `Impl` directly to functions, instead
of having to pass each of the many fields one at a time. It also
simplifies matches in many cases.
See `rustc_save_analysis::dump_visitor::process_impl` or `rustdoc::clean::clean_impl` for a good example of how this makes `impl`s easier to work with.
r? `@petrochenkov` maybe?
This makes it possible to pass the `Impl` directly to functions, instead
of having to pass each of the many fields one at a time. It also
simplifies matches in many cases.
Add `#[track_caller]` to `bug!` and `register_renamed`
Before:
```
thread 'rustc' panicked at 'compiler/rustc_lint/src/context.rs:267:18: invalid lint renaming of broken_intra_doc_links to rustdoc::broken_intra_doc_links', compiler/rustc_middle/src/util/bug.rs:34:26
```
After:
```
thread 'rustc' panicked at 'src/librustdoc/core.rs:455:24: invalid lint renaming of broken_intra_doc_links to rustdoc::broken_intra_doc_links', compiler/rustc_middle/src/util/bug.rs:35:26
```
The reason I added it to `register_renamed` too is that any panic in
that function will be the caller's fault.
Before:
```
thread 'rustc' panicked at 'compiler/rustc_lint/src/context.rs:267:18: invalid lint renaming of broken_intra_doc_links to rustdoc::broken_intra_doc_links', compiler/rustc_middle/src/util/bug.rs:34:26
```
After:
```
thread 'rustc' panicked at 'src/librustdoc/core.rs:455:24: invalid lint renaming of broken_intra_doc_links to rustdoc::broken_intra_doc_links', compiler/rustc_middle/src/util/bug.rs:35:26
```
The reason I added it to `register_renamed` too is that any panic in
that function will be the caller's fault.
Rename rustc_middle::lint::LintSource
Rename [`rustc_middle::lint::LintSource`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/lint/enum.LintSource.html) to `rustc_middle::lint::LintLevelSource`.
This enum represents the source of a *lint level*, not a lint. This should improve code readability.
Update: Also documents `rustc_middle::lint::LevelSource` to clarify.
Rename `overlapping_patterns` lint
As discussed in https://github.com/rust-lang/rust/issues/65477. I also tweaked a few things along the way.
r? `@varkor`
`@rustbot` modify labels: +A-exhaustiveness-checking
Use true previous lint level when detecting overriden forbids
Previously, cap-lints was ignored when checking the previous forbid level, which
meant that it was a hard error to do so. This is different from the normal
behavior of lints, which are silenced by cap-lints; if the forbid would not take
effect regardless, there is not much point in complaining about the fact that we
are reducing its level.
It might be considered a bug that even `--cap-lints deny` would suffice to
silence the error on overriding forbid, depending on if one cares about failing
the build or precisely forbid being set. But setting cap-lints to deny is quite
odd and not really done in practice, so we don't try to handle it specially.
This also unifies the code paths for nested and same-level scopes. However, the
special case for CLI lint flags is left in place (introduced by #70918) to fix
the regression noted in #70819. That means that CLI flags do not lint on forbid
being overridden by a non-forbid level. It is unclear whether this is a bug or a
desirable feature, but it is certainly inconsistent. CLI flags are a
sufficiently different "type" of place though that this is deemed out of scope
for this commit.
r? `@pnkfelix` perhaps?
cc #77713 -- not marking as "Fixes" because of the lack of proper unused attribute handling in this PR
This preserves the current lint behavior for now.
Linting after item statements currently prevents the compiler from bootstrapping.
Fixing this is blocked on fixing this upstream in Cargo, and bumping the Cargo
submodule.
rustc_ast currently has a few dependencies on rustc_lexer. Ideally, an AST
would not have any dependency its lexer, for minimizing unnecessarily
design-time dependencies. Breaking this dependency would also have practical
benefits, since modifying rustc_lexer would not trigger a rebuild of rustc_ast.
This commit does not remove the rustc_ast --> rustc_lexer dependency,
but it does remove one of the sources of this dependency, which is the
code that handles fuzzy matching between symbol names for making suggestions
in diagnostics. Since that code depends only on Symbol, it is easy to move
it to rustc_span. It might even be best to move it to a separate crate,
since other tools such as Cargo use the same algorithm, and have simply
contain a duplicate of the code.
This changes the signature of find_best_match_for_name so that it is no
longer generic over its input. I checked the optimized binaries, and this
function was duplicated at nearly every call site, because most call sites
used short-lived iterator chains, generic over Map and such. But there's
no good reason for a function like this to be generic, since all it does
is immediately convert the generic input (the Iterator impl) to a concrete
Vec<Symbol>. This has all of the costs of generics (duplicated method bodies)
with no benefit.
Changing find_best_match_for_name to be non-generic removed about 10KB of
code from the optimized binary. I know it's a drop in the bucket, but we have
to start reducing binary size, and beginning to tame over-use of generics
is part of that.
lint: Do not provide suggestions for non standard characters
Fixes#77273
Only provide suggestions if the case-fixed result is different than the original.
Previously, cap-lints was ignored when checking the previous forbid level, which
meant that it was a hard error to do so. This is different from the normal
behavior of lints, which are silenced by cap-lints; if the forbid would not take
effect regardless, there is not much point in complaining about the fact that we
are reducing its level.
It might be considered a bug that even `--cap-lints deny` would suffice to
silence the error on overriding forbid, depending on if one cares about failing
the build or precisely forbid being set. But setting cap-lints to deny is quite
odd and not really done in practice, so we don't try to handle it specially.
This also unifies the code paths for nested and same-level scopes. However, the
special case for CLI lint flags is left in place (introduced by #70918) to fix
the regression noted in #70819. That means that CLI flags do not lint on forbid
being overridden by a non-forbid level. It is unclear whether this is a bug or a
desirable feature, but it is certainly inconsistent. CLI flags are a
sufficiently different "type" of place though that this is deemed out of scope
for this commit.
rustc_ast: Do not panic by default when visiting macro calls
Panicking by default made sense when we didn't have HIR or MIR and everything worked on AST, but now all AST visitors run early and majority of them have to deal with macro calls, often by ignoring them.
The second commit renames `visit_mac` to `visit_mac_call`, the corresponding structures were renamed earlier in https://github.com/rust-lang/rust/pull/69589.
Fix ICE when a future-incompat-report has its command-line level capped
Fixes#78660
With PR https://github.com/rust-lang/rust/pull/75534 merged, we now run
more lint-related code for future-incompat-report, even when their final
level is Allow. Some lint-related code was not expecting `Level::Allow`,
and had an explicit panic.
This PR explicitly tracks the lint level set on the command line before
`--cap-lints` is applied. This is used to emit a more precise error
note (e.g. we don't say that `-W lint-name` was specified on the
command line just because a lint was capped to Warn). As a result, we
can now correctly emit a note that `-A` was used if we got
`Level::Allow` from the command line (before the cap is applied).
See https://github.com/rust-lang/rust/issues/61733#issuecomment-716188981
We now preserve the trailing semicolon in a macro invocation, even if
the macro expands to nothing. As a result, the following code no longer
compiles:
```rust
macro_rules! empty {
() => { }
}
fn foo() -> bool { //~ ERROR mismatched
{ true } //~ ERROR mismatched
empty!();
}
```
Previously, `{ true }` would be considered the trailing expression, even
though there's a semicolon in `empty!();`
This makes macro expansion more token-based.
Fixes#78660
With PR https://github.com/rust-lang/rust/pull/75534 merged, we now run
more lint-related code for future-incompat-report, even when their final
level is Allow. Some lint-related code was not expecting `Level::Allow`,
and had an explicit panic.
This PR explicitly tracks the lint level set on the command line before
`--cap-lints` is applied. This is used to emit a more precise error
note (e.g. we don't say that `-W lint-name` was specified on the
command line just because a lint was capped to Warn). As a result, we
can now correctly emit a note that `-A` was used if we got
`Level::Allow` from the command line (before the cap is applied).
Implement rustc side of report-future-incompat
cc https://github.com/rust-lang/rust/issues/71249
This is an alternative to `@pnkfelix's` initial implementation in https://github.com/pnkfelix/rust/commits/prototype-rustc-side-of-report-future-incompat (mainly because I started working before seeing that branch 😄 ).
My approach outputs the entire original `Diagnostic`, in a way that is compatible with incremental compilation. This is not yet integrated with compiletest, but can be used manually by passing `-Z emit-future-incompat-report` to `rustc`.
Several changes are made to support this feature:
* The `librustc_session/lint` module is moved to a new crate `librustc_lint_defs` (name bikesheddable). This allows accessing lint definitions from `librustc_errors`.
* The `Lint` struct is extended with an `Option<FutureBreakage>`. When present, it indicates that we should display a lint in the future-compat report. `FutureBreakage` contains additional information that we may want to display in the report (currently, a `date` field indicating when the crate will stop compiling).
* A new variant `rustc_error::Level::Allow` is added. This is used when constructing a diagnostic for a future-breakage lint that is marked as allowed (via `#[allow]` or `--cap-lints`). This allows us to capture any future-breakage diagnostics in one place, while still discarding them before they are passed to the `Emitter`.
* `DiagnosticId::Lint` is extended with a `has_future_breakage` field, indicating whether or not the `Lint` has future breakage information (and should therefore show up in the report).
* `Session` is given access to the `LintStore` via a new `SessionLintStore` trait (since `librustc_session` cannot directly reference `LintStore` without a cyclic dependency). We use this to turn a string `DiagnosticId::Lint` back into a `Lint`, to retrieve the `FutureBreakage` data.
Currently, `FutureBreakage.date` is always set to `None`. However, this could potentially be interpreted by Cargo in the future.
I've enabled the future-breakage report for the `ARRAY_INTO_ITER` lint, which can be used to test out this PR. The intent is to use the field to allow Cargo to determine the date of future breakage (as described in [RFC 2834](https://github.com/rust-lang/rfcs/blob/master/text/2834-cargo-report-future-incompat.md)) without needing to parse the diagnostic itself.
cc `@pnkfelix`
Dogfood {exclusive,half-open} ranges in compiler (nfc)
In particular, this allows us to write more explicit matches that
avoid the pitfalls of using a fully general fall-through case, yet
remain fairly ergonomic. Less logic is in guard cases, more is in
the actual exhaustive case analysis.
No functional changes.
In particular, this allows us to write more explicit matches that
avoid the pitfalls of using a fully general fall-through case, yet
remain fairly ergonomic. Less logic is in guard cases, more is in
the actual exhaustive case analysis.
No functional changes.
When the 'early' and 'late' visitors visit an attribute target, they
activate any lint attributes (e.g. `#[allow]`) that apply to it.
This can affect warnings emitted on sibiling attributes. For example,
the following code does not produce an `unused_attributes` for
`#[inline]`, since the sibiling `#[allow(unused_attributes)]` suppressed
the warning.
```rust
trait Foo {
#[allow(unused_attributes)] #[inline] fn first();
#[inline] #[allow(unused_attributes)] fn second();
}
```
However, we do not do this for statements - instead, the lint attributes
only become active when we visit the struct nested inside `StmtKind`
(e.g. `Item`).
Currently, this is difficult to observe due to another issue - the
`HasAttrs` impl for `StmtKind` ignores attributes for `StmtKind::Item`.
As a result, the `unused_doc_comments` lint will never see attributes on
item statements.
This commit makes two interrelated fixes to the handling of inert
(non-proc-macro) attributes on statements:
* The `HasAttr` impl for `StmtKind` now returns attributes for
`StmtKind::Item`, treating it just like every other `StmtKind`
variant. The only place relying on the old behavior was macro
which has been updated to explicitly ignore attributes on item
statements. This allows the `unused_doc_comments` lint to fire for
item statements.
* The `early` and `late` lint visitors now activate lint attributes when
invoking the callback for `Stmt`. This ensures that a lint
attribute (e.g. `#[allow(unused_doc_comments)]`) can be applied to
sibiling attributes on an item statement.
For now, the `unused_doc_comments` lint is explicitly disabled on item
statements, which preserves the current behavior. The exact locatiosn
where this lint should fire are being discussed in PR #78306
