[beta] Clippy backports for ICE fixes

src/tools/clippy/clippy_lints/src/arc_with_non_send_sync.rs

@@ -1,12 +1,12 @@
-use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::last_path_segment;
 use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
-use if_chain::if_chain;
-
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::LateContext;
 use rustc_lint::LateLintPass;
 use rustc_middle::ty;
+use rustc_middle::ty::print::with_forced_trimmed_paths;
+use rustc_middle::ty::GenericArgKind;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::symbol::sym;
 
@@ -15,58 +15,65 @@ declare_clippy_lint! {
     /// This lint warns when you use `Arc` with a type that does not implement `Send` or `Sync`.
     ///
     /// ### Why is this bad?
-    /// Wrapping a type in Arc doesn't add thread safety to the underlying data, so data races
-    /// could occur when touching the underlying data.
+    /// `Arc<T>` is only `Send`/`Sync` when `T` is [both `Send` and `Sync`](https://doc.rust-lang.org/std/sync/struct.Arc.html#impl-Send-for-Arc%3CT%3E),
+    /// either `T` should be made `Send + Sync` or an `Rc` should be used instead of an `Arc`
     ///
     /// ### Example
     /// ```rust
     /// # use std::cell::RefCell;
     /// # use std::sync::Arc;
     ///
     /// fn main() {
-    ///     // This is safe, as `i32` implements `Send` and `Sync`.
+    ///     // This is fine, as `i32` implements `Send` and `Sync`.
     ///     let a = Arc::new(42);
     ///
-    ///     // This is not safe, as `RefCell` does not implement `Sync`.
+    ///     // `RefCell` is `!Sync`, so either the `Arc` should be replaced with an `Rc`
+    ///     // or the `RefCell` replaced with something like a `RwLock`
     ///     let b = Arc::new(RefCell::new(42));
     /// }
     /// ```
     #[clippy::version = "1.72.0"]
     pub ARC_WITH_NON_SEND_SYNC,
-    correctness,
+    suspicious,
     "using `Arc` with a type that does not implement `Send` or `Sync`"
 }
 declare_lint_pass!(ArcWithNonSendSync => [ARC_WITH_NON_SEND_SYNC]);
 
 impl LateLintPass<'_> for ArcWithNonSendSync {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
         let ty = cx.typeck_results().expr_ty(expr);
-        if_chain! {
-            if is_type_diagnostic_item(cx, ty, sym::Arc);
-            if let ExprKind::Call(func, [arg]) = expr.kind;
-            if let ExprKind::Path(func_path) = func.kind;
-            if last_path_segment(&func_path).ident.name == sym::new;
-            if let arg_ty = cx.typeck_results().expr_ty(arg);
-            if !matches!(arg_ty.kind(), ty::Param(_));
-            if !cx.tcx
-                .lang_items()
-                .sync_trait()
-                .map_or(false, |id| implements_trait(cx, arg_ty, id, &[])) ||
-                !cx.tcx
-                .get_diagnostic_item(sym::Send)
-                .map_or(false, |id| implements_trait(cx, arg_ty, id, &[]));
+        if is_type_diagnostic_item(cx, ty, sym::Arc)
+            && let ExprKind::Call(func, [arg]) = expr.kind
+            && let ExprKind::Path(func_path) = func.kind
+            && last_path_segment(&func_path).ident.name == sym::new
+            && let arg_ty = cx.typeck_results().expr_ty(arg)
+            // make sure that the type is not and does not contain any type parameters
+            && arg_ty.walk().all(|arg| {
+                !matches!(arg.unpack(), GenericArgKind::Type(ty) if matches!(ty.kind(), ty::Param(_)))
+            })
+            && let Some(send) = cx.tcx.get_diagnostic_item(sym::Send)
+            && let Some(sync) = cx.tcx.lang_items().sync_trait()
+            && let [is_send, is_sync] = [send, sync].map(|id| implements_trait(cx, arg_ty, id, &[]))
+            && !(is_send && is_sync)
+        {
+            span_lint_and_then(
+                cx,
+                ARC_WITH_NON_SEND_SYNC,
+                expr.span,
+                "usage of an `Arc` that is not `Send` or `Sync`",
+                |diag| with_forced_trimmed_paths!({
+                    if !is_send {
+                        diag.note(format!("the trait `Send` is not implemented for `{arg_ty}`"));
+                    }
+                    if !is_sync {
+                        diag.note(format!("the trait `Sync` is not implemented for `{arg_ty}`"));
+                    }
+
+                    diag.note(format!("required for `{ty}` to implement `Send` and `Sync`"));
 
-            then {
-                span_lint_and_help(
-                    cx,
-                    ARC_WITH_NON_SEND_SYNC,
-                    expr.span,
-                    "usage of `Arc<T>` where `T` is not `Send` or `Sync`",
-                    None,
-                    "consider using `Rc<T>` instead or wrapping `T` in a std::sync type like \
-                    `Mutex<T>`",
-                );
-            }
+                    diag.help("consider using an `Rc` instead or wrapping the inner type with a `Mutex`");
+                }
+            ));
         }
     }
 }

src/tools/clippy/clippy_lints/src/dereference.rs

@@ -1296,8 +1296,8 @@ fn referent_used_exactly_once<'tcx>(
     possible_borrowers: &mut Vec<(LocalDefId, PossibleBorrowerMap<'tcx, 'tcx>)>,
     reference: &Expr<'tcx>,
 ) -> bool {
-    let mir = enclosing_mir(cx.tcx, reference.hir_id);
-    if let Some(local) = expr_local(cx.tcx, reference)
+    if let Some(mir) = enclosing_mir(cx.tcx, reference.hir_id)
+        && let Some(local) = expr_local(cx.tcx, reference)
         && let [location] = *local_assignments(mir, local).as_slice()
         && let Some(statement) = mir.basic_blocks[location.block].statements.get(location.statement_index)
         && let StatementKind::Assign(box (_, Rvalue::Ref(_, _, place))) = statement.kind

src/tools/clippy/clippy_lints/src/methods/unnecessary_literal_unwrap.rs

@@ -2,6 +2,8 @@ use clippy_utils::{diagnostics::span_lint_and_then, is_res_lang_ctor, last_path_
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_lint::LateContext;
+use rustc_middle::ty;
+use rustc_middle::ty::print::with_forced_trimmed_paths;
 
 use super::UNNECESSARY_LITERAL_UNWRAP;
 
@@ -21,6 +23,7 @@ fn get_ty_from_args<'a>(args: Option<&'a [hir::GenericArg<'a>]>, index: usize) -
     }
 }
 
+#[expect(clippy::too_many_lines)]
 pub(super) fn check(
     cx: &LateContext<'_>,
     expr: &hir::Expr<'_>,
@@ -62,6 +65,34 @@ pub(super) fn check(
                 (expr.span.with_hi(args[0].span.lo()), "panic!(".to_string()),
                 (expr.span.with_lo(args[0].span.hi()), ")".to_string()),
             ]),
+            ("None", "unwrap_or_default", _) => {
+                let ty = cx.typeck_results().expr_ty(expr);
+                let default_ty_string = if let ty::Adt(def, ..) = ty.kind() {
+                    with_forced_trimmed_paths!(format!("{}", cx.tcx.def_path_str(def.did())))
+                } else {
+                    "Default".to_string()
+                };
+                Some(vec![(expr.span, format!("{default_ty_string}::default()"))])
+            },
+            ("None", "unwrap_or", _) => Some(vec![
+                (expr.span.with_hi(args[0].span.lo()), String::new()),
+                (expr.span.with_lo(args[0].span.hi()), String::new()),
+            ]),
+            ("None", "unwrap_or_else", _) => match args[0].kind {
+                hir::ExprKind::Closure(hir::Closure {
+                    fn_decl:
+                        hir::FnDecl {
+                            output: hir::FnRetTy::DefaultReturn(span) | hir::FnRetTy::Return(hir::Ty { span, .. }),
+                            ..
+                        },
+                    ..
+                }) => Some(vec![
+                    (expr.span.with_hi(span.hi()), String::new()),
+                    (expr.span.with_lo(args[0].span.hi()), String::new()),
+                ]),
+                _ => None,
+            },
+            _ if call_args.is_empty() => None,
             (_, _, Some(_)) => None,
             ("Ok", "unwrap_err", None) | ("Err", "unwrap", None) => Some(vec![
                 (

src/tools/clippy/clippy_lints/src/missing_fields_in_debug.rs

@@ -207,11 +207,10 @@ impl<'tcx> LateLintPass<'tcx> for MissingFieldsInDebug {
         if let ItemKind::Impl(Impl { of_trait: Some(trait_ref), self_ty, items, .. }) = item.kind
             && let Res::Def(DefKind::Trait, trait_def_id) = trait_ref.path.res
             && let TyKind::Path(QPath::Resolved(_, self_path)) = &self_ty.kind
-            // don't trigger if self is a generic parameter, e.g. `impl<T> Debug for T`
-            // this can only happen in core itself, where the trait is defined,
-            // but it caused ICEs in the past:
-            // https://github.com/rust-lang/rust-clippy/issues/10887
-            && !matches!(self_path.res, Res::Def(DefKind::TyParam, _))
+            // make sure that the self type is either a struct, an enum or a union
+            // this prevents ICEs such as when self is a type parameter or a primitive type
+            // (see #10887, #11063)
+            && let Res::Def(DefKind::Struct | DefKind::Enum | DefKind::Union, self_path_did) = self_path.res
             && cx.match_def_path(trait_def_id, &[sym::core, sym::fmt, sym::Debug])
             // don't trigger if this impl was derived
             && !cx.tcx.has_attr(item.owner_id, sym::automatically_derived)
@@ -222,7 +221,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingFieldsInDebug {
             && let body = cx.tcx.hir().body(*body_id)
             && let ExprKind::Block(block, _) = body.value.kind
             // inspect `self`
-            && let self_ty = cx.tcx.type_of(self_path.res.def_id()).skip_binder().peel_refs()
+            && let self_ty = cx.tcx.type_of(self_path_did).skip_binder().peel_refs()
             && let Some(self_adt) = self_ty.ty_adt_def()
             && let Some(self_def_id) = self_adt.did().as_local()
             && let Some(Node::Item(self_item)) = cx.tcx.hir().find_by_def_id(self_def_id)

src/tools/clippy/clippy_lints/src/redundant_type_annotations.rs

@@ -1,6 +1,8 @@
 use clippy_utils::diagnostics::span_lint;
+use clippy_utils::is_lint_allowed;
 use rustc_ast::LitKind;
 use rustc_hir as hir;
+use rustc_hir::def::DefKind;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::Ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -45,8 +47,8 @@ fn is_same_type<'tcx>(cx: &LateContext<'tcx>, ty_resolved_path: hir::def::Res, f
         return primty.name() == func_return_type_sym;
     }
 
-    // type annotation is any other non generic type
-    if let hir::def::Res::Def(_, defid) = ty_resolved_path
+    // type annotation is a non generic type
+    if let hir::def::Res::Def(DefKind::Struct | DefKind::Union | DefKind::Enum, defid) = ty_resolved_path
         && let Some(annotation_ty) = cx.tcx.type_of(defid).no_bound_vars()
     {
         return annotation_ty == func_return_type;
@@ -130,8 +132,9 @@ fn extract_primty(ty_kind: &hir::TyKind<'_>) -> Option<hir::PrimTy> {
 
 impl LateLintPass<'_> for RedundantTypeAnnotations {
     fn check_local<'tcx>(&mut self, cx: &LateContext<'tcx>, local: &'tcx rustc_hir::Local<'tcx>) {
-        // type annotation part
-        if !local.span.from_expansion()
+        if !is_lint_allowed(cx, REDUNDANT_TYPE_ANNOTATIONS, local.hir_id)
+            // type annotation part
+            && !local.span.from_expansion()
             && let Some(ty) = &local.ty
 
             // initialization part

src/tools/clippy/clippy_lints/src/tuple_array_conversions.rs

@@ -31,7 +31,7 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.72.0"]
     pub TUPLE_ARRAY_CONVERSIONS,
-    complexity,
+    nursery,
     "checks for tuple<=>array conversions that are not done with `.into()`"
 }
 impl_lint_pass!(TupleArrayConversions => [TUPLE_ARRAY_CONVERSIONS]);

src/tools/clippy/clippy_lints/src/useless_conversion.rs

@@ -6,6 +6,7 @@ use clippy_utils::ty::{is_copy, is_type_diagnostic_item, same_type_and_consts};
 use clippy_utils::{get_parent_expr, is_trait_method, match_def_path, path_to_local, paths};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
+use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
 use rustc_hir::{BindingAnnotation, Expr, ExprKind, HirId, MatchSource, Node, PatKind};
 use rustc_lint::{LateContext, LateLintPass};
@@ -40,6 +41,7 @@ declare_clippy_lint! {
 #[derive(Default)]
 pub struct UselessConversion {
     try_desugar_arm: Vec<HirId>,
+    expn_depth: u32,
 }
 
 impl_lint_pass!(UselessConversion => [USELESS_CONVERSION]);
@@ -106,6 +108,7 @@ fn into_iter_deep_call<'hir>(cx: &LateContext<'_>, mut expr: &'hir Expr<'hir>) -
 impl<'tcx> LateLintPass<'tcx> for UselessConversion {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
         if e.span.from_expansion() {
+            self.expn_depth += 1;
             return;
         }
 
@@ -151,9 +154,14 @@ impl<'tcx> LateLintPass<'tcx> for UselessConversion {
                 {
                     if let Some(parent) = get_parent_expr(cx, e) {
                         let parent_fn = match parent.kind {
-                            ExprKind::Call(recv, args) if let ExprKind::Path(ref qpath) = recv.kind => {
-                                cx.qpath_res(qpath, recv.hir_id).opt_def_id()
-                                    .map(|did| (did, args, MethodOrFunction::Function))
+                            ExprKind::Call(recv, args)
+                                if let ExprKind::Path(ref qpath) = recv.kind
+                                    && let Some(did) = cx.qpath_res(qpath, recv.hir_id).opt_def_id()
+                                    // make sure that the path indeed points to a fn-like item, so that
+                                    // `fn_sig` does not ICE. (see #11065)
+                                    && cx.tcx.opt_def_kind(did).is_some_and(DefKind::is_fn_like) =>
+                            {
+                                    Some((did, args, MethodOrFunction::Function))
                             }
                             ExprKind::MethodCall(.., args, _) => {
                                 cx.typeck_results().type_dependent_def_id(parent.hir_id)
@@ -169,6 +177,7 @@ impl<'tcx> LateLintPass<'tcx> for UselessConversion {
                             && let Some(&into_iter_param) = sig.inputs().get(kind.param_pos(arg_pos))
                             && let ty::Param(param) = into_iter_param.kind()
                             && let Some(span) = into_iter_bound(cx, parent_fn_did, into_iter_did, param.index)
+                            && self.expn_depth == 0
                         {
                             // Get the "innermost" `.into_iter()` call, e.g. given this expression:
                             // `foo.into_iter().into_iter()`
@@ -304,5 +313,8 @@ impl<'tcx> LateLintPass<'tcx> for UselessConversion {
         if Some(&e.hir_id) == self.try_desugar_arm.last() {
             self.try_desugar_arm.pop();
         }
+        if e.span.from_expansion() {
+            self.expn_depth -= 1;
+        }
     }
 }

src/tools/clippy/clippy_utils/src/mir/mod.rs

@@ -101,21 +101,26 @@ pub fn used_exactly_once(mir: &rustc_middle::mir::Body<'_>, local: rustc_middle:
 
 /// Returns the `mir::Body` containing the node associated with `hir_id`.
 #[allow(clippy::module_name_repetitions)]
-pub fn enclosing_mir(tcx: TyCtxt<'_>, hir_id: HirId) -> &Body<'_> {
+pub fn enclosing_mir(tcx: TyCtxt<'_>, hir_id: HirId) -> Option<&Body<'_>> {
     let body_owner_local_def_id = tcx.hir().enclosing_body_owner(hir_id);
-    tcx.optimized_mir(body_owner_local_def_id.to_def_id())
+    if tcx.hir().body_owner_kind(body_owner_local_def_id).is_fn_or_closure() {
+        Some(tcx.optimized_mir(body_owner_local_def_id.to_def_id()))
+    } else {
+        None
+    }
 }
 
 /// Tries to determine the `Local` corresponding to `expr`, if any.
 /// This function is expensive and should be used sparingly.
 pub fn expr_local(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> Option<Local> {
-    let mir = enclosing_mir(tcx, expr.hir_id);
-    mir.local_decls.iter_enumerated().find_map(|(local, local_decl)| {
-        if local_decl.source_info.span == expr.span {
-            Some(local)
-        } else {
-            None
-        }
+    enclosing_mir(tcx, expr.hir_id).and_then(|mir| {
+        mir.local_decls.iter_enumerated().find_map(|(local, local_decl)| {
+            if local_decl.source_info.span == expr.span {
+                Some(local)
+            } else {
+                None
+            }
+        })
     })
 }
 

src/tools/clippy/tests/ui/arc_with_non_send_sync.rs

@@ -7,11 +7,18 @@ fn foo<T>(x: T) {
     // Should not lint - purposefully ignoring generic args.
     let a = Arc::new(x);
 }
+fn issue11076<T>() {
+    let a: Arc<Vec<T>> = Arc::new(Vec::new());
+}
 
 fn main() {
-    // This is safe, as `i32` implements `Send` and `Sync`.
-    let a = Arc::new(42);
+    let _ = Arc::new(42);
 
-    // This is not safe, as `RefCell` does not implement `Sync`.
-    let b = Arc::new(RefCell::new(42));
+    // !Sync
+    let _ = Arc::new(RefCell::new(42));
+    let mutex = Mutex::new(1);
+    // !Send
+    let _ = Arc::new(mutex.lock().unwrap());
+    // !Send + !Sync
+    let _ = Arc::new(&42 as *const i32);
 }

src/tools/clippy/tests/ui/arc_with_non_send_sync.stderr

@@ -1,11 +1,34 @@
-error: usage of `Arc<T>` where `T` is not `Send` or `Sync`
-  --> $DIR/arc_with_non_send_sync.rs:16:13
+error: usage of an `Arc` that is not `Send` or `Sync`
+  --> $DIR/arc_with_non_send_sync.rs:18:13
    |
-LL |     let b = Arc::new(RefCell::new(42));
+LL |     let _ = Arc::new(RefCell::new(42));
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: consider using `Rc<T>` instead or wrapping `T` in a std::sync type like `Mutex<T>`
+   = note: the trait `Sync` is not implemented for `RefCell<i32>`
+   = note: required for `Arc<RefCell<i32>>` to implement `Send` and `Sync`
+   = help: consider using an `Rc` instead or wrapping the inner type with a `Mutex`
    = note: `-D clippy::arc-with-non-send-sync` implied by `-D warnings`
 
-error: aborting due to previous error
+error: usage of an `Arc` that is not `Send` or `Sync`
+  --> $DIR/arc_with_non_send_sync.rs:21:13
+   |
+LL |     let _ = Arc::new(mutex.lock().unwrap());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the trait `Send` is not implemented for `MutexGuard<'_, i32>`
+   = note: required for `Arc<MutexGuard<'_, i32>>` to implement `Send` and `Sync`
+   = help: consider using an `Rc` instead or wrapping the inner type with a `Mutex`
+
+error: usage of an `Arc` that is not `Send` or `Sync`
+  --> $DIR/arc_with_non_send_sync.rs:23:13
+   |
+LL |     let _ = Arc::new(&42 as *const i32);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the trait `Send` is not implemented for `*const i32`
+   = note: the trait `Sync` is not implemented for `*const i32`
+   = note: required for `Arc<*const i32>` to implement `Send` and `Sync`
+   = help: consider using an `Rc` instead or wrapping the inner type with a `Mutex`
+
+error: aborting due to 3 previous errors