Auto merge of #13630 - samueltardieu:push-qrnxuykslnsl, r=y21

Use match ergonomics compatible with editions 2021 and 2024

This PR contains the minimal changes needed to make Clippy match ergonomics work with both Rust 2021 and Rust 2024.

changelog: none

clippy_lints/src/checked_conversions.rs

@@ -232,7 +232,7 @@ fn get_types_from_cast<'a>(
     // or `to_type::MAX as from_type`
     let call_from_cast: Option<(&Expr<'_>, &str)> = if let ExprKind::Cast(limit, from_type) = &expr.kind
         // to_type::max_value(), from_type
-        && let TyKind::Path(ref from_type_path) = &from_type.kind
+        && let TyKind::Path(from_type_path) = &from_type.kind
         && let Some(from_sym) = int_ty_to_sym(from_type_path)
     {
         Some((limit, from_sym))
@@ -245,7 +245,7 @@ fn get_types_from_cast<'a>(
         if let ExprKind::Call(from_func, [limit]) = &expr.kind
             // `from_type::from, to_type::max_value()`
             // `from_type::from`
-            && let ExprKind::Path(ref path) = &from_func.kind
+            && let ExprKind::Path(path) = &from_func.kind
             && let Some(from_sym) = get_implementing_type(path, INTS, "from")
         {
             Some((limit, from_sym))

clippy_lints/src/copy_iterator.rs

@@ -37,7 +37,7 @@
 impl<'tcx> LateLintPass<'tcx> for CopyIterator {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
         if let ItemKind::Impl(Impl {
-            of_trait: Some(ref trait_ref),
+            of_trait: Some(trait_ref),
             ..
         }) = item.kind
             && let ty = cx.tcx.type_of(item.owner_id).instantiate_identity()

clippy_lints/src/derivable_impls.rs

@@ -187,7 +187,7 @@ fn check_enum<'tcx>(cx: &LateContext<'tcx>, item: &'tcx Item<'_>, func_expr: &Ex
 impl<'tcx> LateLintPass<'tcx> for DerivableImpls {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
         if let ItemKind::Impl(Impl {
-            of_trait: Some(ref trait_ref),
+            of_trait: Some(trait_ref),
             items: [child],
             self_ty,
             ..

clippy_lints/src/derive.rs

@@ -202,7 +202,7 @@
 impl<'tcx> LateLintPass<'tcx> for Derive {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
         if let ItemKind::Impl(Impl {
-            of_trait: Some(ref trait_ref),
+            of_trait: Some(trait_ref),
             ..
         }) = item.kind
         {

clippy_lints/src/disallowed_script_idents.rs

@@ -80,7 +80,7 @@ fn check_crate(&mut self, cx: &EarlyContext<'_>, _: &ast::Crate) {
         let mut symbols: Vec<_> = symbols.iter().collect();
         symbols.sort_unstable_by_key(|k| k.1);
 
-        for (symbol, &span) in &symbols {
+        for &(symbol, &span) in &symbols {
             // Note: `symbol.as_str()` is an expensive operation, thus should not be called
             // more than once for a single symbol.
             let symbol_str = symbol.as_str();

clippy_lints/src/empty_drop.rs

@@ -36,7 +36,7 @@
 impl LateLintPass<'_> for EmptyDrop {
     fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
         if let ItemKind::Impl(Impl {
-            of_trait: Some(ref trait_ref),
+            of_trait: Some(trait_ref),
             items: [child],
             ..
         }) = item.kind

clippy_lints/src/len_zero.rs

@@ -629,7 +629,7 @@ fn has_is_empty_impl(cx: &LateContext<'_>, id: DefId) -> bool {
                 .filter_by_name_unhygienic(is_empty)
                 .any(|item| is_is_empty(cx, item))
         }),
-        ty::Alias(ty::Projection, ref proj) => has_is_empty_impl(cx, proj.def_id),
+        ty::Alias(ty::Projection, proj) => has_is_empty_impl(cx, proj.def_id),
         ty::Adt(id, _) => has_is_empty_impl(cx, id.did()),
         ty::Array(..) | ty::Slice(..) | ty::Str => true,
         _ => false,

clippy_lints/src/lifetimes.rs

@@ -425,7 +425,7 @@ fn visit_ty(&mut self, ty: &'tcx Ty<'_>) {
                 self.visit_opaque_ty(opaque);
                 self.lts.truncate(len);
                 self.lts.extend(bounds.iter().filter_map(|bound| match bound {
-                    GenericArg::Lifetime(&l) => Some(l),
+                    &GenericArg::Lifetime(l) => Some(l),
                     _ => None,
                 }));
             },

clippy_lints/src/manual_async_fn.rs

@@ -169,7 +169,7 @@ fn captures_all_lifetimes(inputs: &[Ty<'_>], output_lifetimes: &[LifetimeName])
 }
 
 fn desugared_async_block<'tcx>(cx: &LateContext<'tcx>, block: &'tcx Block<'tcx>) -> Option<&'tcx Body<'tcx>> {
-    if let Some(Expr {
+    if let Some(&Expr {
         kind: ExprKind::Closure(&Closure { kind, body, .. }),
         ..
     }) = block.expr

clippy_lints/src/matches/match_like_matches.rs

@@ -148,7 +148,7 @@ fn find_bool_lit(ex: &ExprKind<'_>) -> Option<bool> {
         }) => Some(*b),
         ExprKind::Block(
             rustc_hir::Block {
-                stmts: &[],
+                stmts: [],
                 expr: Some(exp),
                 ..
             },

clippy_lints/src/matches/redundant_pattern_match.rs

@@ -319,10 +319,9 @@ fn found_good_method<'tcx>(
     node: (&PatKind<'_>, &PatKind<'_>),
 ) -> Option<(&'static str, Option<&'tcx Expr<'tcx>>)> {
     match node {
-        (
-            PatKind::TupleStruct(ref path_left, patterns_left, _),
-            PatKind::TupleStruct(ref path_right, patterns_right, _),
-        ) if patterns_left.len() == 1 && patterns_right.len() == 1 => {
+        (PatKind::TupleStruct(path_left, patterns_left, _), PatKind::TupleStruct(path_right, patterns_right, _))
+            if patterns_left.len() == 1 && patterns_right.len() == 1 =>
+        {
             if let (PatKind::Wild, PatKind::Wild) = (&patterns_left[0].kind, &patterns_right[0].kind) {
                 find_good_method_for_match(
                     cx,
@@ -350,8 +349,8 @@ fn found_good_method<'tcx>(
                 None
             }
         },
-        (PatKind::TupleStruct(ref path_left, patterns, _), PatKind::Path(ref path_right))
-        | (PatKind::Path(ref path_left), PatKind::TupleStruct(ref path_right, patterns, _))
+        (PatKind::TupleStruct(path_left, patterns, _), PatKind::Path(path_right))
+        | (PatKind::Path(path_left), PatKind::TupleStruct(path_right, patterns, _))
             if patterns.len() == 1 =>
         {
             if let PatKind::Wild = patterns[0].kind {
@@ -381,14 +380,14 @@ fn found_good_method<'tcx>(
                 None
             }
         },
-        (PatKind::TupleStruct(ref path_left, patterns, _), PatKind::Wild) if patterns.len() == 1 => {
+        (PatKind::TupleStruct(path_left, patterns, _), PatKind::Wild) if patterns.len() == 1 => {
             if let PatKind::Wild = patterns[0].kind {
                 get_good_method(cx, arms, path_left)
             } else {
                 None
             }
         },
-        (PatKind::Path(ref path_left), PatKind::Wild) => get_good_method(cx, arms, path_left),
+        (PatKind::Path(path_left), PatKind::Wild) => get_good_method(cx, arms, path_left),
         _ => None,
     }
 }

clippy_lints/src/methods/filter_map.rs

@@ -21,8 +21,8 @@ fn is_method(cx: &LateContext<'_>, expr: &Expr<'_>, method_name: Symbol) -> bool
         ExprKind::Path(QPath::TypeRelative(_, mname)) => mname.ident.name == method_name,
         ExprKind::Path(QPath::Resolved(_, segments)) => segments.segments.last().unwrap().ident.name == method_name,
         ExprKind::MethodCall(segment, _, _, _) => segment.ident.name == method_name,
-        ExprKind::Closure(&Closure { body, .. }) => {
-            let body = cx.tcx.hir().body(body);
+        ExprKind::Closure(Closure { body, .. }) => {
+            let body = cx.tcx.hir().body(*body);
             let closure_expr = peel_blocks(body.value);
             match closure_expr.kind {
                 ExprKind::MethodCall(PathSegment { ident, .. }, receiver, ..) => {

clippy_lints/src/needless_late_init.rs

@@ -347,7 +347,7 @@ fn check_local(&mut self, cx: &LateContext<'tcx>, local: &'tcx LetStmt<'tcx>) {
         if let LetStmt {
             init: None,
             pat:
-                &Pat {
+                Pat {
                     kind: PatKind::Binding(BindingMode::NONE, binding_id, _, None),
                     ..
                 },
@@ -357,7 +357,7 @@ fn check_local(&mut self, cx: &LateContext<'tcx>, local: &'tcx LetStmt<'tcx>) {
             && let Some((_, Node::Stmt(local_stmt))) = parents.next()
             && let Some((_, Node::Block(block))) = parents.next()
         {
-            check(cx, local, local_stmt, block, binding_id);
+            check(cx, local, local_stmt, block, *binding_id);
         }
     }
 }

clippy_lints/src/needless_pass_by_ref_mut.rs

@@ -183,7 +183,7 @@ fn check_fn(
             .iter()
             .zip(fn_sig.inputs())
             .zip(body.params)
-            .filter(|((&input, &ty), arg)| !should_skip(cx, input, ty, arg))
+            .filter(|&((&input, &ty), arg)| !should_skip(cx, input, ty, arg))
             .peekable();
         if it.peek().is_none() {
             return;

clippy_lints/src/partialeq_ne_impl.rs

@@ -34,7 +34,7 @@
 impl<'tcx> LateLintPass<'tcx> for PartialEqNeImpl {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
         if let ItemKind::Impl(Impl {
-            of_trait: Some(ref trait_ref),
+            of_trait: Some(trait_ref),
             items: impl_items,
             ..
         }) = item.kind

clippy_lints/src/question_mark.rs

@@ -93,7 +93,7 @@ enum IfBlockType<'hir> {
 
 fn find_let_else_ret_expression<'hir>(block: &'hir Block<'hir>) -> Option<&'hir Expr<'hir>> {
     if let Block {
-        stmts: &[],
+        stmts: [],
         expr: Some(els),
         ..
     } = block

clippy_lints/src/ref_option_ref.rs

@@ -39,7 +39,7 @@ impl<'tcx> LateLintPass<'tcx> for RefOptionRef {
     fn check_ty(&mut self, cx: &LateContext<'tcx>, ty: &'tcx Ty<'tcx>) {
         if let TyKind::Ref(_, ref mut_ty) = ty.kind
             && mut_ty.mutbl == Mutability::Not
-            && let TyKind::Path(ref qpath) = &mut_ty.ty.kind
+            && let TyKind::Path(qpath) = &mut_ty.ty.kind
             && let last = last_path_segment(qpath)
             && let Some(def_id) = last.res.opt_def_id()
             && cx.tcx.is_diagnostic_item(sym::Option, def_id)

clippy_lints/src/returns.rs

@@ -347,7 +347,7 @@ fn check_final_expr<'tcx>(
     let peeled_drop_expr = expr.peel_drop_temps();
     match &peeled_drop_expr.kind {
         // simple return is always "bad"
-        ExprKind::Ret(ref inner) => {
+        ExprKind::Ret(inner) => {
             // check if expr return nothing
             let ret_span = if inner.is_none() && replacement == RetReplacement::Empty {
                 extend_span_to_previous_non_ws(cx, peeled_drop_expr.span)

clippy_lints/src/serde_api.rs

@@ -26,7 +26,7 @@
 impl<'tcx> LateLintPass<'tcx> for SerdeApi {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
         if let ItemKind::Impl(Impl {
-            of_trait: Some(ref trait_ref),
+            of_trait: Some(trait_ref),
             items,
             ..
         }) = item.kind

clippy_lints/src/single_component_path_imports.rs

@@ -174,7 +174,7 @@ fn track_uses(
         }
 
         match &item.kind {
-            ItemKind::Mod(_, ModKind::Loaded(ref items, ..)) => {
+            ItemKind::Mod(_, ModKind::Loaded(items, ..)) => {
                 self.check_mod(items);
             },
             ItemKind::MacroDef(MacroDef { macro_rules: true, .. }) => {

clippy_lints/src/suspicious_operation_groupings.rs

@@ -334,7 +334,7 @@ fn strip_non_ident_wrappers(expr: &Expr) -> &Expr {
     let mut output = expr;
     loop {
         output = match &output.kind {
-            ExprKind::Paren(ref inner) | ExprKind::Unary(_, ref inner) => inner,
+            ExprKind::Paren(inner) | ExprKind::Unary(_, inner) => inner,
             _ => {
                 return output;
             },
@@ -348,13 +348,13 @@ fn extract_related_binops(kind: &ExprKind) -> Option<Vec<BinaryOp<'_>>> {
 
 fn if_statement_binops(kind: &ExprKind) -> Option<Vec<BinaryOp<'_>>> {
     match kind {
-        ExprKind::If(ref condition, _, _) => chained_binops(&condition.kind),
-        ExprKind::Paren(ref e) => if_statement_binops(&e.kind),
-        ExprKind::Block(ref block, _) => {
+        ExprKind::If(condition, _, _) => chained_binops(&condition.kind),
+        ExprKind::Paren(e) => if_statement_binops(&e.kind),
+        ExprKind::Block(block, _) => {
             let mut output = None;
             for stmt in &block.stmts {
-                match stmt.kind {
-                    StmtKind::Expr(ref e) | StmtKind::Semi(ref e) => {
+                match &stmt.kind {
+                    StmtKind::Expr(e) | StmtKind::Semi(e) => {
                         output = append_opt_vecs(output, if_statement_binops(&e.kind));
                     },
                     _ => {},
@@ -383,7 +383,7 @@ fn append_opt_vecs<A>(target_opt: Option<Vec<A>>, source_opt: Option<Vec<A>>) ->
 fn chained_binops(kind: &ExprKind) -> Option<Vec<BinaryOp<'_>>> {
     match kind {
         ExprKind::Binary(_, left_outer, right_outer) => chained_binops_helper(left_outer, right_outer),
-        ExprKind::Paren(ref e) | ExprKind::Unary(_, ref e) => chained_binops(&e.kind),
+        ExprKind::Paren(e) | ExprKind::Unary(_, e) => chained_binops(&e.kind),
         _ => None,
     }
 }
@@ -391,16 +391,14 @@ fn chained_binops(kind: &ExprKind) -> Option<Vec<BinaryOp<'_>>> {
 fn chained_binops_helper<'expr>(left_outer: &'expr Expr, right_outer: &'expr Expr) -> Option<Vec<BinaryOp<'expr>>> {
     match (&left_outer.kind, &right_outer.kind) {
         (
-            ExprKind::Paren(ref left_e) | ExprKind::Unary(_, ref left_e),
-            ExprKind::Paren(ref right_e) | ExprKind::Unary(_, ref right_e),
+            ExprKind::Paren(left_e) | ExprKind::Unary(_, left_e),
+            ExprKind::Paren(right_e) | ExprKind::Unary(_, right_e),
         ) => chained_binops_helper(left_e, right_e),
-        (ExprKind::Paren(ref left_e) | ExprKind::Unary(_, ref left_e), _) => chained_binops_helper(left_e, right_outer),
-        (_, ExprKind::Paren(ref right_e) | ExprKind::Unary(_, ref right_e)) => {
-            chained_binops_helper(left_outer, right_e)
-        },
+        (ExprKind::Paren(left_e) | ExprKind::Unary(_, left_e), _) => chained_binops_helper(left_e, right_outer),
+        (_, ExprKind::Paren(right_e) | ExprKind::Unary(_, right_e)) => chained_binops_helper(left_outer, right_e),
         (
-            ExprKind::Binary(Spanned { node: left_op, .. }, ref left_left, ref left_right),
-            ExprKind::Binary(Spanned { node: right_op, .. }, ref right_left, ref right_right),
+            ExprKind::Binary(Spanned { node: left_op, .. }, left_left, left_right),
+            ExprKind::Binary(Spanned { node: right_op, .. }, right_left, right_right),
         ) => match (
             chained_binops_helper(left_left, left_right),
             chained_binops_helper(right_left, right_right),

clippy_lints/src/swap.rs

@@ -392,7 +392,7 @@ fn is_used_after_swap(&mut self, idx_ident: Ident) -> bool {
         for stmt in self.block.stmts {
             match stmt.kind {
                 StmtKind::Expr(expr) | StmtKind::Semi(expr) => v.visit_expr(expr),
-                StmtKind::Let(LetStmt { ref init, .. }) => {
+                StmtKind::Let(LetStmt { init, .. }) => {
                     if let Some(init) = init.as_ref() {
                         v.visit_expr(init);
                     }

clippy_lints/src/trait_bounds.rs

@@ -124,7 +124,7 @@ fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx TraitItem<'tc
         let mut self_bounds_map = FxHashMap::default();
 
         for predicate in item.generics.predicates {
-            if let WherePredicate::BoundPredicate(ref bound_predicate) = predicate
+            if let WherePredicate::BoundPredicate(bound_predicate) = predicate
                 && bound_predicate.origin != PredicateOrigin::ImplTrait
                 && !bound_predicate.span.from_expansion()
                 && let TyKind::Path(QPath::Resolved(_, Path { segments, .. })) = bound_predicate.bounded_ty.kind
@@ -268,7 +268,7 @@ impl Eq for SpanlessTy<'_, '_> {}
         let mut map: UnhashMap<SpanlessTy<'_, '_>, Vec<&GenericBound<'_>>> = UnhashMap::default();
         let mut applicability = Applicability::MaybeIncorrect;
         for bound in generics.predicates {
-            if let WherePredicate::BoundPredicate(ref p) = bound
+            if let WherePredicate::BoundPredicate(p) = bound
                 && p.origin != PredicateOrigin::ImplTrait
                 && p.bounds.len() as u64 <= self.max_trait_bounds
                 && !p.span.from_expansion()

clippy_lints/src/undocumented_unsafe_blocks.rs

@@ -295,7 +295,7 @@ fn expr_has_unnecessary_safety_comment<'tcx>(
     if cx.tcx.hir().parent_iter(expr.hir_id).any(|(_, ref node)| {
         matches!(
             node,
-            Node::Block(&Block {
+            Node::Block(Block {
                 rules: BlockCheckMode::UnsafeBlock(UnsafeSource::UserProvided),
                 ..
             }),

clippy_lints/src/unit_types/let_unit_value.rs

@@ -194,7 +194,7 @@ fn needs_inferred_result_ty(
     let (id, receiver, args) = match e.kind {
         ExprKind::Call(
             Expr {
-                kind: ExprKind::Path(ref path),
+                kind: ExprKind::Path(path),
                 hir_id,
                 ..
             },

clippy_lints/src/unit_types/unit_arg.rs

@@ -149,7 +149,7 @@ fn is_empty_block(expr: &Expr<'_>) -> bool {
         expr.kind,
         ExprKind::Block(
             Block {
-                stmts: &[],
+                stmts: [],
                 expr: None,
                 ..
             },

clippy_lints/src/unused_io_amount.rs

@@ -244,7 +244,7 @@ fn unpack_call_chain<'a>(mut expr: &'a hir::Expr<'a>) -> &'a hir::Expr<'a> {
 }
 
 fn unpack_try<'a>(mut expr: &'a hir::Expr<'a>) -> &'a hir::Expr<'a> {
-    while let ExprKind::Call(func, [ref arg_0]) = expr.kind
+    while let ExprKind::Call(func, [arg_0]) = expr.kind
         && matches!(
             func.kind,
             ExprKind::Path(hir::QPath::LangItem(hir::LangItem::TryTraitBranch, ..))
@@ -266,7 +266,7 @@ fn unpack_match<'a>(mut expr: &'a hir::Expr<'a>) -> &'a hir::Expr<'a> {
 /// waited on.  Otherwise return None.
 fn unpack_await<'a>(expr: &'a hir::Expr<'a>) -> &'a hir::Expr<'a> {
     if let ExprKind::Match(expr, _, hir::MatchSource::AwaitDesugar) = expr.kind {
-        if let ExprKind::Call(func, [ref arg_0]) = expr.kind {
+        if let ExprKind::Call(func, [arg_0]) = expr.kind {
             if matches!(
                 func.kind,
                 ExprKind::Path(hir::QPath::LangItem(hir::LangItem::IntoFutureIntoFuture, ..))

clippy_lints/src/utils/author.rs

@@ -396,7 +396,7 @@ macro_rules! kind {
                 self.pat(field!(let_expr.pat));
                 // Does what ExprKind::Cast does, only adds a clause for the type
                 // if it's a path
-                if let Some(TyKind::Path(ref qpath)) = let_expr.value.ty.as_ref().map(|ty| &ty.kind) {
+                if let Some(TyKind::Path(qpath)) = let_expr.value.ty.as_ref().map(|ty| &ty.kind) {
                     bind!(self, qpath);
                     chain!(self, "let TyKind::Path(ref {qpath}) = {let_expr}.ty.kind");
                     self.qpath(qpath);

clippy_lints/src/utils/internal_lints/collapsible_calls.rs

@@ -79,7 +79,7 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
 
         if let ExprKind::Call(func, [call_cx, call_lint, call_sp, call_msg, call_f]) = expr.kind
             && is_expr_path_def_path(cx, func, &["clippy_utils", "diagnostics", "span_lint_and_then"])
-            && let ExprKind::Closure(&Closure { body, .. }) = &call_f.kind
+            && let ExprKind::Closure(&Closure { body, .. }) = call_f.kind
             && let body = cx.tcx.hir().body(body)
             && let only_expr = peel_blocks_with_stmt(body.value)
             && let ExprKind::MethodCall(ps, recv, span_call_args, _) = &only_expr.kind

clippy_lints/src/utils/internal_lints/lint_without_lint_pass.rs

@@ -123,7 +123,7 @@ fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
                     .expect("lints must have a description field");
 
                 if let ExprKind::Lit(Spanned {
-                    node: LitKind::Str(ref sym, _),
+                    node: LitKind::Str(sym, _),
                     ..
                 }) = field.expr.kind
                 {
@@ -249,7 +249,7 @@ fn check_invalid_clippy_version_attribute(cx: &LateContext<'_>, item: &'_ Item<'
 pub(super) fn extract_clippy_version_value(cx: &LateContext<'_>, item: &'_ Item<'_>) -> Option<Symbol> {
     let attrs = cx.tcx.hir().attrs(item.hir_id());
     attrs.iter().find_map(|attr| {
-        if let ast::AttrKind::Normal(ref attr_kind) = &attr.kind
+        if let ast::AttrKind::Normal(attr_kind) = &attr.kind
             // Identify attribute
             && let [tool_name, attr_name] = &attr_kind.item.path.segments[..]
             && tool_name.ident.name == sym::clippy

clippy_utils/src/higher.rs

@@ -103,7 +103,7 @@ impl<'hir> IfLet<'hir> {
     /// Parses an `if let` expression
     pub fn hir(cx: &LateContext<'_>, expr: &Expr<'hir>) -> Option<Self> {
         if let ExprKind::If(
-            Expr {
+            &Expr {
                 kind:
                     ExprKind::Let(&hir::LetExpr {
                         pat: let_pat,
@@ -381,12 +381,12 @@ impl<'hir> WhileLet<'hir> {
     /// Parses a desugared `while let` loop
     pub const fn hir(expr: &Expr<'hir>) -> Option<Self> {
         if let ExprKind::Loop(
-            Block {
+            &Block {
                 expr:
-                    Some(Expr {
+                    Some(&Expr {
                         kind:
                             ExprKind::If(
-                                Expr {
+                                &Expr {
                                     kind:
                                         ExprKind::Let(&hir::LetExpr {
                                             pat: let_pat,

clippy_utils/src/hir_utils.rs

@@ -1189,11 +1189,11 @@ pub fn hash_tykind(&mut self, ty: &TyKind<'_>) {
                 self.hash_ty(ty);
                 self.hash_pat(pat);
             },
-            TyKind::Ptr(ref mut_ty) => {
+            TyKind::Ptr(mut_ty) => {
                 self.hash_ty(mut_ty.ty);
                 mut_ty.mutbl.hash(&mut self.s);
             },
-            TyKind::Ref(lifetime, ref mut_ty) => {
+            TyKind::Ref(lifetime, mut_ty) => {
                 self.hash_lifetime(lifetime);
                 self.hash_ty(mut_ty.ty);
                 mut_ty.mutbl.hash(&mut self.s);
@@ -1218,7 +1218,7 @@ pub fn hash_tykind(&mut self, ty: &TyKind<'_>) {
                     self.hash_ty(ty);
                 }
             },
-            TyKind::Path(ref qpath) => self.hash_qpath(qpath),
+            TyKind::Path(qpath) => self.hash_qpath(qpath),
             TyKind::OpaqueDef(_, arg_list) => {
                 self.hash_generic_args(arg_list);
             },

clippy_utils/src/lib.rs

@@ -689,11 +689,11 @@ pub fn find_crates(tcx: TyCtxt<'_>, name: Symbol) -> Vec<Res> {
 ///
 /// This function is expensive and should be used sparingly.
 pub fn def_path_res(tcx: TyCtxt<'_>, path: &[&str]) -> Vec<Res> {
-    let (base, path) = match *path {
+    let (base, path) = match path {
         [primitive] => {
             return vec![PrimTy::from_name(Symbol::intern(primitive)).map_or(Res::Err, Res::PrimTy)];
         },
-        [base, ref path @ ..] => (base, path),
+        [base, path @ ..] => (base, path),
         _ => return Vec::new(),
     };
 
@@ -935,7 +935,7 @@ pub fn is_default_equivalent(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
             }
         },
         ExprKind::Call(repl_func, []) => is_default_equivalent_call(cx, repl_func),
-        ExprKind::Call(from_func, [ref arg]) => is_default_equivalent_from(cx, from_func, arg),
+        ExprKind::Call(from_func, [arg]) => is_default_equivalent_from(cx, from_func, arg),
         ExprKind::Path(qpath) => is_res_lang_ctor(cx, cx.qpath_res(qpath, e.hir_id), OptionNone),
         ExprKind::AddrOf(rustc_hir::BorrowKind::Ref, _, expr) => matches!(expr.kind, ExprKind::Array([])),
         _ => false,
@@ -948,7 +948,7 @@ fn is_default_equivalent_from(cx: &LateContext<'_>, from_func: &Expr<'_>, arg: &
     {
         match arg.kind {
             ExprKind::Lit(hir::Lit {
-                node: LitKind::Str(ref sym, _),
+                node: LitKind::Str(sym, _),
                 ..
             }) => return sym.is_empty() && is_path_lang_item(cx, ty, LangItem::String),
             ExprKind::Array([]) => return is_path_diagnostic_item(cx, ty, sym::Vec),
@@ -3460,7 +3460,7 @@ fn maybe_get_relative_path(from: &DefPath, to: &DefPath, max_super: usize) -> St
 pub fn is_parent_stmt(cx: &LateContext<'_>, id: HirId) -> bool {
     matches!(
         cx.tcx.parent_hir_node(id),
-        Node::Stmt(..) | Node::Block(Block { stmts: &[], .. })
+        Node::Stmt(..) | Node::Block(Block { stmts: [], .. })
     )
 }