Clippy subtree update

Cargo.lock

@@ -660,7 +660,7 @@ checksum = "a1d728cc89cf3aee9ff92b05e62b19ee65a02b5702cff7d5a377e32c6ae29d8d"
 
 [[package]]
 name = "clippy"
-version = "0.1.97"
+version = "0.1.98"
 dependencies = [
  "anstream",
  "askama",
@@ -687,7 +687,7 @@ dependencies = [
 
 [[package]]
 name = "clippy_config"
-version = "0.1.97"
+version = "0.1.98"
 dependencies = [
  "clippy_utils",
  "itertools",
@@ -711,7 +711,7 @@ dependencies = [
 
 [[package]]
 name = "clippy_lints"
-version = "0.1.97"
+version = "0.1.98"
 dependencies = [
  "arrayvec",
  "cargo_metadata 0.23.1",
@@ -743,7 +743,7 @@ dependencies = [
 
 [[package]]
 name = "clippy_utils"
-version = "0.1.97"
+version = "0.1.98"
 dependencies = [
  "arrayvec",
  "itertools",
@@ -1148,7 +1148,7 @@ checksum = "a0afaad2b26fa326569eb264b1363e8ae3357618c43982b3f285f0774ce76b69"
 
 [[package]]
 name = "declare_clippy_lint"
-version = "0.1.97"
+version = "0.1.98"
 
 [[package]]
 name = "derive-where"

src/tools/clippy/CHANGELOG.md

@@ -6947,6 +6947,7 @@ Released 2018-09-13
 [`map_err_ignore`]: https://rust-lang.github.io/rust-clippy/master/index.html#map_err_ignore
 [`map_flatten`]: https://rust-lang.github.io/rust-clippy/master/index.html#map_flatten
 [`map_identity`]: https://rust-lang.github.io/rust-clippy/master/index.html#map_identity
+[`map_or_identity`]: https://rust-lang.github.io/rust-clippy/master/index.html#map_or_identity
 [`map_unwrap_or`]: https://rust-lang.github.io/rust-clippy/master/index.html#map_unwrap_or
 [`map_with_unused_argument_over_ranges`]: https://rust-lang.github.io/rust-clippy/master/index.html#map_with_unused_argument_over_ranges
 [`match_as_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_as_ref
@@ -7375,6 +7376,7 @@ Released 2018-09-13
 [`unstable_as_mut_slice`]: https://rust-lang.github.io/rust-clippy/master/index.html#unstable_as_mut_slice
 [`unstable_as_slice`]: https://rust-lang.github.io/rust-clippy/master/index.html#unstable_as_slice
 [`unused_async`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_async
+[`unused_async_trait_impl`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_async_trait_impl
 [`unused_collect`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_collect
 [`unused_enumerate_index`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_enumerate_index
 [`unused_format_specs`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_format_specs

src/tools/clippy/CONTRIBUTING.md

@@ -93,20 +93,9 @@ an AST expression).
 ## Getting code-completion for rustc internals to work
 
 ### RustRover
-Unfortunately, [`RustRover`][RustRover_homepage] does not (yet?) understand how Clippy uses compiler-internals
-using `extern crate` and it also needs to be able to read the source files of the rustc-compiler which are not
-available via a `rustup` component at the time of writing.
-To work around this, you need to have a copy of the [rustc-repo][rustc_repo] available which can be obtained via
-`git clone https://github.com/rust-lang/rust/`.
-Then you can run a `cargo dev` command to automatically make Clippy use the rustc-repo via path-dependencies
-which `RustRover` will be able to understand.
-Run `cargo dev setup intellij --repo-path <repo-path>` where `<repo-path>` is a path to the rustc repo
-you just cloned.
-The command will add path-dependencies pointing towards rustc-crates inside the rustc repo to
-Clippy's `Cargo.toml`s and should allow `RustRover` to understand most of the types that Clippy uses.
-Just make sure to remove the dependencies again before finally making a pull request!
-
-[rustc_repo]: https://github.com/rust-lang/rust/
+Since [`RustRover`][RustRover_homepage] 2026.1, no additional setup is required.
+Just open the project in RustRover as usual.
+
 [RustRover_homepage]: https://www.jetbrains.com/rust/
 
 ### Rust Analyzer

src/tools/clippy/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "clippy"
-version = "0.1.97"
+version = "0.1.98"
 description = "A bunch of helpful lints to avoid common pitfalls in Rust"
 repository = "https://github.com/rust-lang/rust-clippy"
 readme = "README.md"

src/tools/clippy/book/src/configuration.md

@@ -123,7 +123,13 @@ fn main() {
 You can also omit the patch version when specifying the MSRV, so `msrv = 1.30`
 is equivalent to `msrv = 1.30.0`.
 
-Note: `custom_inner_attributes` is an unstable feature, so it has to be enabled explicitly.
+> **Note:** Some lints change their behavior depending on the configured MSRV.
+> In some cases, Clippy may suppress a lint entirely to avoid suggesting APIs or
+> syntax unavailable for the configured MSRV.
+> In other cases, Clippy may emit the lint but choose an older compatible suggestion.
+
+> **Note:** `custom_inner_attributes` is an unstable feature, so it has to be
+> enabled explicitly.
 
 Lints that recognize this configuration option can be
 found [here](https://rust-lang.github.io/rust-clippy/master/index.html#msrv)

src/tools/clippy/book/src/development/emitting_lints.md

@@ -88,6 +88,8 @@ LL |     for _ in 1..1 + 1 {}
    |              ^^^^^^^^ help: use: `1..=1`
 ```
 
+### Applicability
+
 **Not all suggestions are always right**, some of them require human
 supervision, that's why we have [Applicability][applicability].
 
@@ -105,23 +107,26 @@ impl<'tcx> LateLintPass<'tcx> for LintName {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>)  {
         // Imagine that `some_lint_expr_logic` checks for requirements for emitting the lint
         if some_lint_expr_logic(expr) {
-            span_lint_and_sugg( // < Note this change
+            span_lint_and_then( // < Note this change
                 cx,
                 LINT_NAME,
-                span,
+                expr.span,
                 "message on why the lint is emitted",
-                "use",
-                format!("foo + {} * bar", snippet(cx, expr.span, "<default>")), // < Suggestion
-                Applicability::MachineApplicable,
+                |diag| {
+                    // v Build and emit the suggestion
+                    let mut app = Applicability::MachineApplicable;
+                    let expr_snippet = snippet_with_applicability(cx, expr.span, "_", &mut app);
+                    let sugg = format!("foo + {expr_snippet} * bar");
+                    diag.span_suggestion(expr.span, "use", sugg, app);
+                }
             );
         }
     }
 }
 ```
 
 Suggestions generally use the [`format!`][format_macro] macro to interpolate the
-old values with the new ones. To get code snippets, use one of the `snippet*`
-functions from `clippy_utils::source`.
+old values with the new ones. For information on getting code snippets, see [Snippets](emitting_lints.md#snippets).
 
 ## How to choose between notes, help messages and suggestions
 
@@ -183,13 +188,50 @@ error: This `.fold` can be more succinctly expressed as `.any`
     |
 ```
 
-### Snippets
+## Snippets
 
 Snippets are pieces of the source code (as a string), they are extracted
-generally using the [`snippet`][snippet_fn] function.
+generally using the various `snippet_*` functions from [`clippy_utils::source`][].
+
+If you're using the snippets _not_ to build a suggestion, it's usually
+enough to use [`snippet`][snippet_fn] -- it accepts the span of the item, and
+also a fallback string (see [Fallback string](emitting_lints.md#fallback-string)).
 
 For example, if you want to know how an item looks (and you know the item's
-span), you could use `snippet(cx, span, "..")`.
+span), you could use `snippet(cx, span, "_")`.
+
+If you do use the snippet for a suggestion, it's recommended to use
+[`snippet_with_applicability`] instead. This is so that Clippy can reduce the
+[applicability](emitting_lints.md#applicability) of the suggestion in case it couldn't extract
+the snippet "cleanly" -- see the function's documentation for more information.
+
+It's often necessary to create multiple snippets to build a suggestion, in which
+case you'll have the following pattern:
+
+```rust
+// inside `span_lint_and_then`
+
+// 1. Create initial applicability.
+let mut app = Applicability::MachineApplicable;
+
+// 2. Use it to create all the snippets
+let foo_snippet = snippet_with_applicability(cx, foo.span, "_", &mut app);
+let bar_snippet = snippet_with_applicability(cx, bar.span, "_", &mut app);
+let sugg = format!("{foo_snippet} + {bar_snippet}"); // or whatever
+
+// 3. Use it to emit the final suggestion
+diag.span_suggestion(span, msg, sugg, app);
+```
+
+### Fallback string
+This is the string that is used for the snippet when the source code that the
+span points to is unavailable. That mostly only happens when proc-macros
+mishandle spans -- see [the section on proc-macros][proc-macro-spans].
+
+Most of the time, the snippets in a suggestion come from a (span of a) single
+expression, and so `"_"` is an appropriate fallback string. If you instead
+find yourself suggesting to insert multiple statements, or a block--basically
+anything "big"--then consider using `".."` instead.
 
 ## Final: Run UI Tests to Emit the Lint
 
@@ -210,8 +252,11 @@ cover in the next chapters.
 [`span_lint_and_help`]: https://doc.rust-lang.org/nightly/nightly-rustc/clippy_utils/diagnostics/fn.span_lint_and_help.html
 [`span_lint_and_sugg`]: https://doc.rust-lang.org/nightly/nightly-rustc/clippy_utils/diagnostics/fn.span_lint_and_sugg.html
 [`span_lint_and_then`]: https://doc.rust-lang.org/beta/nightly-rustc/clippy_utils/diagnostics/fn.span_lint_and_then.html
+[`clippy_utils::source`]: https://doc.rust-lang.org/nightly/nightly-rustc/clippy_utils/source/index.html
 [range_plus_one]: https://rust-lang.github.io/rust-clippy/master/index.html#range_plus_one
 [inclusive_range]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html
 [applicability]: https://doc.rust-lang.org/beta/nightly-rustc/rustc_errors/enum.Applicability.html
 [snippet_fn]: https://doc.rust-lang.org/beta/nightly-rustc/clippy_utils/source/fn.snippet.html
+[`snippet_with_applicability`]: https://doc.rust-lang.org/beta/nightly-rustc/clippy_utils/source/fn.snippet_with_applicability.html
+[proc-macro-spans]: macro_expansions.html#the-is_from_proc_macro-function
 [format_macro]: https://doc.rust-lang.org/std/macro.format.html

src/tools/clippy/clippy_config/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "clippy_config"
-version = "0.1.97"
+version = "0.1.98"
 edition = "2024"
 publish = false
 

src/tools/clippy/clippy_lints/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "clippy_lints"
-version = "0.1.97"
+version = "0.1.98"
 description = "A bunch of helpful lints to avoid common pitfalls in Rust"
 repository = "https://github.com/rust-lang/rust-clippy"
 readme = "README.md"

src/tools/clippy/clippy_lints/src/attrs/useless_attribute.rs

@@ -15,7 +15,7 @@ pub(super) fn check(cx: &EarlyContext<'_>, item: &Item, attrs: &[Attribute]) {
             return;
         }
         if let Some(lint_list) = &attr.meta_item_list()
-            && attr.name().is_some_and(|name| is_lint_level(name))
+            && attr.name().is_some_and(is_lint_level)
         {
             for lint in lint_list {
                 match item.kind {

src/tools/clippy/clippy_lints/src/booleans.rs

@@ -612,7 +612,12 @@ impl<'tcx> NonminimalBoolVisitor<'_, 'tcx> {
                 }
             }
             let nonminimal_bool_lint = |mut suggestions: Vec<_>| {
-                if !self.cx.tcx.lint_level_spec_at_node(NONMINIMAL_BOOL, e.hir_id).is_allow() {
+                if !self
+                    .cx
+                    .tcx
+                    .lint_level_spec_at_node(NONMINIMAL_BOOL, e.hir_id)
+                    .is_allow()
+                {
                     suggestions.sort();
                     span_lint_hir_and_then(
                         self.cx,

src/tools/clippy/clippy_lints/src/collapsible_if.rs

@@ -140,6 +140,8 @@ impl CollapsibleIf {
 
                     // Prevent "elseif"
                     // Check that the "else" is followed by whitespace
+                    // Note: We intentionally use char::is_whitespace instead of rustc_lexer::is_whitespace here to
+                    // avoid visual issues with zero-width spaces. See ui tests.
                     let requires_space = snippet(cx, up_to_else, "..").ends_with(|c: char| !c.is_whitespace());
                     let mut applicability = Applicability::MachineApplicable;
                     diag.span_suggestion(

src/tools/clippy/clippy_lints/src/dbg_macro.rs

@@ -75,53 +75,51 @@ impl LateLintPass<'_> for DbgMacro {
                 "the `dbg!` macro is intended as a debugging tool",
                 |diag| {
                     let mut applicability = Applicability::MachineApplicable;
-                    let (sugg_span, suggestion) = match is_async_move_desugar(expr)
-                        .unwrap_or(expr)
-                        .peel_drop_temps()
-                        .kind
-                    {
-                        // dbg!()
-                        ExprKind::Block(..) => {
-                            // If the `dbg!` macro is a "free" statement and not contained within other expressions,
-                            // remove the whole statement.
-                            if let Node::Stmt(_) = cx.tcx.parent_hir_node(expr.hir_id)
-                                && let Some(semi_span) = cx.sess().source_map().mac_call_stmt_semi_span(macro_call.span)
-                            {
-                                (macro_call.span.to(semi_span), String::new())
-                            } else {
-                                (macro_call.span, String::from("()"))
-                            }
-                        },
-                        // dbg!(1)
-                        ExprKind::Match(val, ..) => (
-                            macro_call.span,
-                            snippet_with_applicability(cx, val.span.source_callsite(), "..", &mut applicability)
-                                .to_string(),
-                        ),
-                        // dbg!(2, 3)
-                        ExprKind::Tup(
-                            [
-                                Expr {
-                                    kind: ExprKind::Match(first, ..),
-                                    ..
-                                },
-                                ..,
-                                Expr {
-                                    kind: ExprKind::Match(last, ..),
-                                    ..
-                                },
-                            ],
-                        ) => {
-                            let snippet = snippet_with_applicability(
-                                cx,
-                                first.span.source_callsite().to(last.span.source_callsite()),
-                                "..",
-                                &mut applicability,
-                            );
-                            (macro_call.span, format!("({snippet})"))
-                        },
-                        _ => unreachable!(),
-                    };
+                    let (sugg_span, suggestion) =
+                        match is_async_move_desugar(expr).unwrap_or(expr).peel_drop_temps().kind {
+                            // dbg!()
+                            ExprKind::Block(..) => {
+                                // If the `dbg!` macro is a "free" statement and not contained within other expressions,
+                                // remove the whole statement.
+                                if let Node::Stmt(_) = cx.tcx.parent_hir_node(expr.hir_id)
+                                    && let Some(semi_span) =
+                                        cx.sess().source_map().mac_call_stmt_semi_span(macro_call.span)
+                                {
+                                    (macro_call.span.to(semi_span), String::new())
+                                } else {
+                                    (macro_call.span, String::from("()"))
+                                }
+                            },
+                            // dbg!(1)
+                            ExprKind::Match(val, ..) => (
+                                macro_call.span,
+                                snippet_with_applicability(cx, val.span.source_callsite(), "..", &mut applicability)
+                                    .to_string(),
+                            ),
+                            // dbg!(2, 3)
+                            ExprKind::Tup(
+                                [
+                                    Expr {
+                                        kind: ExprKind::Match(first, ..),
+                                        ..
+                                    },
+                                    ..,
+                                    Expr {
+                                        kind: ExprKind::Match(last, ..),
+                                        ..
+                                    },
+                                ],
+                            ) => {
+                                let snippet = snippet_with_applicability(
+                                    cx,
+                                    first.span.source_callsite().to(last.span.source_callsite()),
+                                    "..",
+                                    &mut applicability,
+                                );
+                                (macro_call.span, format!("({snippet})"))
+                            },
+                            _ => unreachable!(),
+                        };
 
                     diag.span_suggestion(
                         sugg_span,

src/tools/clippy/clippy_lints/src/declared_lints.rs

@@ -435,6 +435,7 @@ pub static LINTS: &[&::declare_clippy_lint::LintInfo] = &[
     crate::methods::MAP_ERR_IGNORE_INFO,
     crate::methods::MAP_FLATTEN_INFO,
     crate::methods::MAP_IDENTITY_INFO,
+    crate::methods::MAP_OR_IDENTITY_INFO,
     crate::methods::MAP_UNWRAP_OR_INFO,
     crate::methods::MAP_WITH_UNUSED_ARGUMENT_OVER_RANGES_INFO,
     crate::methods::MUT_MUTEX_LOCK_INFO,
@@ -783,6 +784,7 @@ pub static LINTS: &[&::declare_clippy_lint::LintInfo] = &[
     crate::unnested_or_patterns::UNNESTED_OR_PATTERNS_INFO,
     crate::unsafe_removed_from_name::UNSAFE_REMOVED_FROM_NAME_INFO,
     crate::unused_async::UNUSED_ASYNC_INFO,
+    crate::unused_async::UNUSED_ASYNC_TRAIT_IMPL_INFO,
     crate::unused_io_amount::UNUSED_IO_AMOUNT_INFO,
     crate::unused_peekable::UNUSED_PEEKABLE_INFO,
     crate::unused_result_ok::UNUSED_RESULT_OK_INFO,