diff --git a/compiler/rustc_abi/src/lib.rs b/compiler/rustc_abi/src/lib.rs
index 76765c8a0aa38..b0c0ee942ea8f 100644
--- a/compiler/rustc_abi/src/lib.rs
+++ b/compiler/rustc_abi/src/lib.rs
@@ -1176,7 +1176,7 @@ impl FieldsShape {
 
     /// Gets source indices of the fields by increasing offsets.
     #[inline]
-    pub fn index_by_increasing_offset<'a>(&'a self) -> impl Iterator<Item = usize> + 'a {
+    pub fn index_by_increasing_offset(&self) -> impl Iterator<Item = usize> + '_ {
         let mut inverse_small = [0u8; 64];
         let mut inverse_big = IndexVec::new();
         let use_small = self.count() <= inverse_small.len();
diff --git a/compiler/rustc_arena/src/lib.rs b/compiler/rustc_arena/src/lib.rs
index 4fae5ef845f7d..345e058e1134a 100644
--- a/compiler/rustc_arena/src/lib.rs
+++ b/compiler/rustc_arena/src/lib.rs
@@ -22,6 +22,7 @@
 #![feature(strict_provenance)]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
+#![allow(clippy::mut_from_ref)] // Arena allocators are one of the places where this pattern is fine.
 
 use smallvec::SmallVec;
 
@@ -568,7 +569,9 @@ pub macro declare_arena([$($a:tt $name:ident: $ty:ty,)*]) {
     }
 
     pub trait ArenaAllocatable<'tcx, C = rustc_arena::IsNotCopy>: Sized {
+        #[allow(clippy::mut_from_ref)]
         fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self;
+        #[allow(clippy::mut_from_ref)]
         fn allocate_from_iter<'a>(
             arena: &'a Arena<'tcx>,
             iter: impl ::std::iter::IntoIterator<Item = Self>,
@@ -578,10 +581,12 @@ pub macro declare_arena([$($a:tt $name:ident: $ty:ty,)*]) {
     // Any type that impls `Copy` can be arena-allocated in the `DroplessArena`.
     impl<'tcx, T: Copy> ArenaAllocatable<'tcx, rustc_arena::IsCopy> for T {
         #[inline]
+        #[allow(clippy::mut_from_ref)]
         fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self {
             arena.dropless.alloc(self)
         }
         #[inline]
+        #[allow(clippy::mut_from_ref)]
         fn allocate_from_iter<'a>(
             arena: &'a Arena<'tcx>,
             iter: impl ::std::iter::IntoIterator<Item = Self>,
@@ -601,6 +606,7 @@ pub macro declare_arena([$($a:tt $name:ident: $ty:ty,)*]) {
             }
 
             #[inline]
+            #[allow(clippy::mut_from_ref)]
             fn allocate_from_iter<'a>(
                 arena: &'a Arena<'tcx>,
                 iter: impl ::std::iter::IntoIterator<Item = Self>,
@@ -616,12 +622,14 @@ pub macro declare_arena([$($a:tt $name:ident: $ty:ty,)*]) {
 
     impl<'tcx> Arena<'tcx> {
         #[inline]
+        #[allow(clippy::mut_from_ref)]
         pub fn alloc<T: ArenaAllocatable<'tcx, C>, C>(&self, value: T) -> &mut T {
             value.allocate_on(self)
         }
 
         // Any type that impls `Copy` can have slices be arena-allocated in the `DroplessArena`.
         #[inline]
+        #[allow(clippy::mut_from_ref)]
         pub fn alloc_slice<T: ::std::marker::Copy>(&self, value: &[T]) -> &mut [T] {
             if value.is_empty() {
                 return &mut [];
@@ -629,6 +637,7 @@ pub macro declare_arena([$($a:tt $name:ident: $ty:ty,)*]) {
             self.dropless.alloc_slice(value)
         }
 
+        #[allow(clippy::mut_from_ref)]
         pub fn alloc_from_iter<'a, T: ArenaAllocatable<'tcx, C>, C>(
             &'a self,
             iter: impl ::std::iter::IntoIterator<Item = T>,
diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs
index 236ebd04ae88d..1389acabfcbd5 100644
--- a/compiler/rustc_ast_passes/src/ast_validation.rs
+++ b/compiler/rustc_ast_passes/src/ast_validation.rs
@@ -691,7 +691,7 @@ fn validate_generic_param_order(
                 GenericParamKind::Lifetime => (),
                 GenericParamKind::Const { ty: _, kw_span: _, default: Some(default) } => {
                     ordered_params += " = ";
-                    ordered_params += &pprust::expr_to_string(&*default.value);
+                    ordered_params += &pprust::expr_to_string(&default.value);
                 }
                 GenericParamKind::Const { ty: _, kw_span: _, default: None } => (),
             }
diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs
index b3923b651eb3b..007d64f681f76 100644
--- a/compiler/rustc_ast_passes/src/feature_gate.rs
+++ b/compiler/rustc_ast_passes/src/feature_gate.rs
@@ -404,11 +404,14 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                     );
                 } else {
                     // And if it isn't, cancel the early-pass warning.
-                    self.sess
+                    if let Some(err) = self
+                        .sess
                         .parse_sess
                         .span_diagnostic
                         .steal_diagnostic(e.span, StashKey::EarlySyntaxWarning)
-                        .map(|err| err.cancel());
+                    {
+                        err.cancel()
+                    }
                 }
             }
             ast::ExprKind::TryBlock(_) => {
diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
index 80c451d675355..1f6838a027844 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -686,7 +686,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
     fn bclose_maybe_open(&mut self, span: rustc_span::Span, empty: bool, close_box: bool) {
         let has_comment = self.maybe_print_comment(span.hi());
         if !empty || has_comment {
-            self.break_offset_if_not_bol(1, -(INDENT_UNIT as isize));
+            self.break_offset_if_not_bol(1, -INDENT_UNIT);
         }
         self.word("}");
         if close_box {
@@ -988,7 +988,9 @@ impl<'a> State<'a> {
 
     pub fn print_assoc_constraint(&mut self, constraint: &ast::AssocConstraint) {
         self.print_ident(constraint.ident);
-        constraint.gen_args.as_ref().map(|args| self.print_generic_args(args, false));
+        if let Some(args) = constraint.gen_args.as_ref() {
+            self.print_generic_args(args, false)
+        }
         self.space();
         match &constraint.kind {
             ast::AssocConstraintKind::Equality { term } => {
diff --git a/compiler/rustc_data_structures/src/graph/implementation/mod.rs b/compiler/rustc_data_structures/src/graph/implementation/mod.rs
index 1aa7ac024d94e..9ff401c3c7aad 100644
--- a/compiler/rustc_data_structures/src/graph/implementation/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/implementation/mod.rs
@@ -206,17 +206,11 @@ impl<N: Debug, E: Debug> Graph<N, E> {
         AdjacentEdges { graph: self, direction, next: first_edge }
     }
 
-    pub fn successor_nodes<'a>(
-        &'a self,
-        source: NodeIndex,
-    ) -> impl Iterator<Item = NodeIndex> + 'a {
+    pub fn successor_nodes(&self, source: NodeIndex) -> impl Iterator<Item = NodeIndex> + '_ {
         self.outgoing_edges(source).targets()
     }
 
-    pub fn predecessor_nodes<'a>(
-        &'a self,
-        target: NodeIndex,
-    ) -> impl Iterator<Item = NodeIndex> + 'a {
+    pub fn predecessor_nodes(&self, target: NodeIndex) -> impl Iterator<Item = NodeIndex> + '_ {
         self.incoming_edges(target).sources()
     }
 
diff --git a/compiler/rustc_data_structures/src/memmap.rs b/compiler/rustc_data_structures/src/memmap.rs
index 1556873f59765..ef37a606f313e 100644
--- a/compiler/rustc_data_structures/src/memmap.rs
+++ b/compiler/rustc_data_structures/src/memmap.rs
@@ -40,7 +40,7 @@ impl Deref for Mmap {
 
 impl AsRef<[u8]> for Mmap {
     fn as_ref(&self) -> &[u8] {
-        &*self.0
+        &self.0
     }
 }
 
diff --git a/compiler/rustc_data_structures/src/profiling.rs b/compiler/rustc_data_structures/src/profiling.rs
index 58a0609e29655..1ed584eafad30 100644
--- a/compiler/rustc_data_structures/src/profiling.rs
+++ b/compiler/rustc_data_structures/src/profiling.rs
@@ -778,7 +778,7 @@ pub fn print_time_passes_entry(
                 "rss_start": start_rss,
                 "rss_end": end_rss,
             });
-            eprintln!("time: {}", json.to_string());
+            eprintln!("time: {json}");
             return;
         }
         TimePassesFormat::Text => (),
diff --git a/compiler/rustc_data_structures/src/sharded.rs b/compiler/rustc_data_structures/src/sharded.rs
index f88c055a9b569..bd7a86f67800f 100644
--- a/compiler/rustc_data_structures/src/sharded.rs
+++ b/compiler/rustc_data_structures/src/sharded.rs
@@ -140,6 +140,7 @@ pub fn make_hash<K: Hash + ?Sized>(val: &K) -> u64 {
 /// `hash` can be computed with any hasher, so long as that hasher is used
 /// consistently for each `Sharded` instance.
 #[inline]
+#[allow(clippy::modulo_one)]
 pub fn get_shard_index_by_hash(hash: u64) -> usize {
     let hash_len = mem::size_of::<usize>();
     // Ignore the top 7 bits as hashbrown uses these and get the next SHARD_BITS highest bits.
diff --git a/compiler/rustc_data_structures/src/stable_hasher.rs b/compiler/rustc_data_structures/src/stable_hasher.rs
index de9842156d61f..3ed1de1bc3ca1 100644
--- a/compiler/rustc_data_structures/src/stable_hasher.rs
+++ b/compiler/rustc_data_structures/src/stable_hasher.rs
@@ -312,14 +312,14 @@ impl<CTX> HashStable<CTX> for ::std::num::NonZeroUsize {
 
 impl<CTX> HashStable<CTX> for f32 {
     fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
-        let val: u32 = unsafe { ::std::mem::transmute(*self) };
+        let val: u32 = self.to_bits();
         val.hash_stable(ctx, hasher);
     }
 }
 
 impl<CTX> HashStable<CTX> for f64 {
     fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
-        let val: u64 = unsafe { ::std::mem::transmute(*self) };
+        let val: u64 = self.to_bits();
         val.hash_stable(ctx, hasher);
     }
 }
diff --git a/compiler/rustc_data_structures/src/stack.rs b/compiler/rustc_data_structures/src/stack.rs
index 3bdd67512321b..7ff1339c5ab34 100644
--- a/compiler/rustc_data_structures/src/stack.rs
+++ b/compiler/rustc_data_structures/src/stack.rs
@@ -5,7 +5,7 @@ const RED_ZONE: usize = 100 * 1024; // 100k
 
 // Only the first stack that is pushed, grows exponentially (2^n * STACK_PER_RECURSION) from then
 // on. This flag has performance relevant characteristics. Don't set it too high.
-const STACK_PER_RECURSION: usize = 1 * 1024 * 1024; // 1MB
+const STACK_PER_RECURSION: usize = 1024 * 1024; // 1MB
 
 /// Grows the stack on demand to prevent stack overflow. Call this in strategic locations
 /// to "break up" recursive calls. E.g. almost any call to `visit_expr` or equivalent can benefit
diff --git a/compiler/rustc_data_structures/src/sync/vec.rs b/compiler/rustc_data_structures/src/sync/vec.rs
index aefaa8519d536..1783b4b357257 100644
--- a/compiler/rustc_data_structures/src/sync/vec.rs
+++ b/compiler/rustc_data_structures/src/sync/vec.rs
@@ -84,7 +84,7 @@ impl<T: Copy> AppendOnlyVec<T> {
     }
 
     pub fn iter(&self) -> impl Iterator<Item = T> + '_ {
-        (0..).map(|i| self.get(i)).take_while(|o| o.is_some()).filter_map(|o| o)
+        (0..).map(|i| self.get(i)).take_while(|o| o.is_some()).flatten()
     }
 }
 
diff --git a/compiler/rustc_data_structures/src/unord.rs b/compiler/rustc_data_structures/src/unord.rs
index 5c2435a0122eb..6c8d541463158 100644
--- a/compiler/rustc_data_structures/src/unord.rs
+++ b/compiler/rustc_data_structures/src/unord.rs
@@ -224,7 +224,7 @@ impl<V: Eq + Hash> UnordSet<V> {
     }
 
     #[inline]
-    pub fn items<'a>(&'a self) -> UnordItems<&'a V, impl Iterator<Item = &'a V>> {
+    pub fn items(&self) -> UnordItems<&V, impl Iterator<Item = &V>> {
         UnordItems(self.inner.iter())
     }
 
@@ -415,7 +415,7 @@ impl<K: Eq + Hash, V> UnordMap<K, V> {
     }
 
     #[inline]
-    pub fn items<'a>(&'a self) -> UnordItems<(&'a K, &'a V), impl Iterator<Item = (&'a K, &'a V)>> {
+    pub fn items(&self) -> UnordItems<(&K, &V), impl Iterator<Item = (&K, &V)>> {
         UnordItems(self.inner.iter())
     }
 
diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index 9ed8ab67431c0..e09ef34b93dbc 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -956,7 +956,7 @@ impl Diagnostic {
     // Exact iteration order of diagnostic arguments shouldn't make a difference to output because
     // they're only used in interpolation.
     #[allow(rustc::potential_query_instability)]
-    pub fn args<'a>(&'a self) -> impl Iterator<Item = DiagnosticArg<'a, 'static>> {
+    pub fn args(&self) -> impl Iterator<Item = DiagnosticArg<'_, 'static>> {
         self.args.iter()
     }
 
diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index 4b1ff0e1df941..81e8bcbf7cd54 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -1407,7 +1407,7 @@ impl EmitterWriter {
                 // Account for newlines to align output to its label.
                 for (line, text) in normalize_whitespace(&text).lines().enumerate() {
                     buffer.append(
-                        0 + line,
+                        line,
                         &format!(
                             "{}{}",
                             if line == 0 { String::new() } else { " ".repeat(label_width) },
@@ -1918,7 +1918,7 @@ impl EmitterWriter {
                         let last_line = unhighlighted_lines.pop();
                         let first_line = unhighlighted_lines.drain(..).next();
 
-                        first_line.map(|(p, l)| {
+                        if let Some((p, l)) = first_line {
                             self.draw_code_line(
                                 &mut buffer,
                                 &mut row_num,
@@ -1930,12 +1930,12 @@ impl EmitterWriter {
                                 &file_lines,
                                 is_multiline,
                             )
-                        });
+                        }
 
                         buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
                         row_num += 1;
 
-                        last_line.map(|(p, l)| {
+                        if let Some((p, l)) = last_line {
                             self.draw_code_line(
                                 &mut buffer,
                                 &mut row_num,
@@ -1947,7 +1947,7 @@ impl EmitterWriter {
                                 &file_lines,
                                 is_multiline,
                             )
-                        });
+                        }
                     }
                 }
 
diff --git a/compiler/rustc_expand/src/config.rs b/compiler/rustc_expand/src/config.rs
index a78dc0678d5da..4ff8e409d88e3 100644
--- a/compiler/rustc_expand/src/config.rs
+++ b/compiler/rustc_expand/src/config.rs
@@ -466,7 +466,7 @@ impl<'a> StripUnconfigured<'a> {
         //
         // N.B., this is intentionally not part of the visit_expr() function
         //     in order for filter_map_expr() to be able to avoid this check
-        if let Some(attr) = expr.attrs().iter().find(|a| is_cfg(*a)) {
+        if let Some(attr) = expr.attrs().iter().find(|a| is_cfg(a)) {
             self.sess.emit_err(RemoveExprNotSupported { span: attr.span });
         }
 
diff --git a/compiler/rustc_expand/src/mbe/metavar_expr.rs b/compiler/rustc_expand/src/mbe/metavar_expr.rs
index de34df0114a74..fb3a00d86d4f7 100644
--- a/compiler/rustc_expand/src/mbe/metavar_expr.rs
+++ b/compiler/rustc_expand/src/mbe/metavar_expr.rs
@@ -41,7 +41,7 @@ impl MetaVarExpr {
         };
         check_trailing_token(&mut tts, sess)?;
         let mut iter = args.trees();
-        let rslt = match &*ident.as_str() {
+        let rslt = match ident.as_str() {
             "count" => parse_count(&mut iter, sess, ident.span)?,
             "ignore" => MetaVarExpr::Ignore(parse_ident(&mut iter, sess, ident.span)?),
             "index" => MetaVarExpr::Index(parse_depth(&mut iter, sess, ident.span)?),
diff --git a/compiler/rustc_hir/src/lang_items.rs b/compiler/rustc_hir/src/lang_items.rs
index eac8fd2942931..8f91a96f964ab 100644
--- a/compiler/rustc_hir/src/lang_items.rs
+++ b/compiler/rustc_hir/src/lang_items.rs
@@ -49,7 +49,7 @@ impl LanguageItems {
         self.get(it).ok_or_else(|| LangItemError(it))
     }
 
-    pub fn iter<'a>(&'a self) -> impl Iterator<Item = (LangItem, DefId)> + 'a {
+    pub fn iter(&self) -> impl Iterator<Item = (LangItem, DefId)> + '_ {
         self.items
             .iter()
             .enumerate()
diff --git a/compiler/rustc_hir_analysis/src/coherence/inherent_impls_overlap.rs b/compiler/rustc_hir_analysis/src/coherence/inherent_impls_overlap.rs
index 7bca4edcc8c96..ad76e2bed2023 100644
--- a/compiler/rustc_hir_analysis/src/coherence/inherent_impls_overlap.rs
+++ b/compiler/rustc_hir_analysis/src/coherence/inherent_impls_overlap.rs
@@ -302,7 +302,7 @@ impl<'tcx> InherentOverlapChecker<'tcx> {
                         .iter()
                         .flatten()
                         .map(|r| r.impl_blocks.len() as isize - avg as isize)
-                        .map(|v| v.abs() as usize)
+                        .map(|v| v.unsigned_abs())
                         .sum::<usize>();
                     s / connected_regions.len()
                 },
diff --git a/compiler/rustc_hir_pretty/src/lib.rs b/compiler/rustc_hir_pretty/src/lib.rs
index 4f27c01fad2c9..74f5b359021d2 100644
--- a/compiler/rustc_hir_pretty/src/lib.rs
+++ b/compiler/rustc_hir_pretty/src/lib.rs
@@ -242,7 +242,7 @@ pub fn enum_def_to_string(
 impl<'a> State<'a> {
     pub fn bclose_maybe_open(&mut self, span: rustc_span::Span, close_box: bool) {
         self.maybe_print_comment(span.hi());
-        self.break_offset_if_not_bol(1, -(INDENT_UNIT as isize));
+        self.break_offset_if_not_bol(1, -INDENT_UNIT);
         self.word("}");
         if close_box {
             self.end(); // close the outer-box
diff --git a/compiler/rustc_hir_typeck/src/_match.rs b/compiler/rustc_hir_typeck/src/_match.rs
index 035ccf30b2462..6c2ce62722a54 100644
--- a/compiler/rustc_hir_typeck/src/_match.rs
+++ b/compiler/rustc_hir_typeck/src/_match.rs
@@ -538,8 +538,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 // FIXME(rpitit): This will need to be fixed when we move to associated types
                                 assert!(matches!(
                                     *trait_pred.trait_ref.self_ty().kind(),
-                                    ty::Alias(_, ty::AliasTy { def_id, substs, .. })
-                                    if def_id == rpit_def_id && substs == substs
+                                    ty::Alias(_, ty::AliasTy { def_id, substs: alias_substs, .. })
+                                    if def_id == rpit_def_id && substs == alias_substs
                                 ));
                                 ty::PredicateKind::Clause(ty::Clause::Trait(
                                     trait_pred.with_self_ty(self.tcx, ty),
@@ -548,8 +548,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             ty::PredicateKind::Clause(ty::Clause::Projection(mut proj_pred)) => {
                                 assert!(matches!(
                                     *proj_pred.projection_ty.self_ty().kind(),
-                                    ty::Alias(_, ty::AliasTy { def_id, substs, .. })
-                                    if def_id == rpit_def_id && substs == substs
+                                    ty::Alias(_, ty::AliasTy { def_id, substs: alias_substs, .. })
+                                    if def_id == rpit_def_id && substs == alias_substs
                                 ));
                                 proj_pred = proj_pred.with_self_ty(self.tcx, ty);
                                 ty::PredicateKind::Clause(ty::Clause::Projection(proj_pred))
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/adjust_fulfillment_errors.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/adjust_fulfillment_errors.rs
index 7534e432f1198..3e0c2bf2a5538 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/adjust_fulfillment_errors.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/adjust_fulfillment_errors.rs
@@ -242,8 +242,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let Some(arg) = segment
             .args()
             .args
-            .iter()
-            .nth(index) else { return false; };
+            .get(index) else { return false; };
         error.obligation.cause.span = arg
             .span()
             .find_ancestor_in_same_ctxt(error.obligation.cause.span)
diff --git a/compiler/rustc_hir_typeck/src/generator_interior/drop_ranges/cfg_build.rs b/compiler/rustc_hir_typeck/src/generator_interior/drop_ranges/cfg_build.rs
index 1eeb7d984ee04..3e9a9ce1b3114 100644
--- a/compiler/rustc_hir_typeck/src/generator_interior/drop_ranges/cfg_build.rs
+++ b/compiler/rustc_hir_typeck/src/generator_interior/drop_ranges/cfg_build.rs
@@ -526,8 +526,9 @@ impl DropRangesBuilder {
         let mut next = <_>::from(0u32);
         for value in tracked_values {
             for_each_consumable(hir, value, |value| {
-                if !tracked_value_map.contains_key(&value) {
-                    tracked_value_map.insert(value, next);
+                if let std::collections::hash_map::Entry::Vacant(e) = tracked_value_map.entry(value)
+                {
+                    e.insert(next);
                     next = next + 1;
                 }
             });
diff --git a/compiler/rustc_hir_typeck/src/generator_interior/mod.rs b/compiler/rustc_hir_typeck/src/generator_interior/mod.rs
index 84ed8f3780e17..5faa6ab13dd7d 100644
--- a/compiler/rustc_hir_typeck/src/generator_interior/mod.rs
+++ b/compiler/rustc_hir_typeck/src/generator_interior/mod.rs
@@ -313,8 +313,7 @@ pub fn resolve_interior<'a, 'tcx>(
     // Extract type components to build the witness type.
     let type_list = fcx.tcx.mk_type_list_from_iter(type_causes.iter().map(|cause| cause.ty));
     let bound_vars = fcx.tcx.mk_bound_variable_kinds(&bound_vars);
-    let witness =
-        fcx.tcx.mk_generator_witness(ty::Binder::bind_with_vars(type_list, bound_vars.clone()));
+    let witness = fcx.tcx.mk_generator_witness(ty::Binder::bind_with_vars(type_list, bound_vars));
 
     drop(typeck_results);
     // Store the generator types and spans into the typeck results for this generator.
diff --git a/compiler/rustc_hir_typeck/src/method/probe.rs b/compiler/rustc_hir_typeck/src/method/probe.rs
index 0092bd2c6e641..8388d0f94c8a9 100644
--- a/compiler/rustc_hir_typeck/src/method/probe.rs
+++ b/compiler/rustc_hir_typeck/src/method/probe.rs
@@ -1755,7 +1755,6 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
     fn probe_for_similar_candidate(&mut self) -> Result<Option<ty::AssocItem>, MethodError<'tcx>> {
         debug!("probing for method names similar to {:?}", self.method_name);
 
-        let steps = self.steps.clone();
         self.probe(|_| {
             let mut pcx = ProbeContext::new(
                 self.fcx,
@@ -1763,8 +1762,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                 self.mode,
                 self.method_name,
                 self.return_type,
-                &self.orig_steps_var_values,
-                steps,
+                self.orig_steps_var_values,
+                self.steps,
                 self.scope_expr_id,
             );
             pcx.allow_similar_names = true;
diff --git a/compiler/rustc_index/src/bit_set.rs b/compiler/rustc_index/src/bit_set.rs
index eba5b3ed882a1..271ab830694bb 100644
--- a/compiler/rustc_index/src/bit_set.rs
+++ b/compiler/rustc_index/src/bit_set.rs
@@ -1850,7 +1850,7 @@ impl<R: Idx, C: Idx> SparseBitMatrix<R, C> {
 
     /// Iterates through all the columns set to true in a given row of
     /// the matrix.
-    pub fn iter<'a>(&'a self, row: R) -> impl Iterator<Item = C> + 'a {
+    pub fn iter(&self, row: R) -> impl Iterator<Item = C> + '_ {
         self.row(row).into_iter().flat_map(|r| r.iter())
     }
 
diff --git a/compiler/rustc_index/src/vec.rs b/compiler/rustc_index/src/vec.rs
index 009602382dd07..ae2f52c513e9f 100644
--- a/compiler/rustc_index/src/vec.rs
+++ b/compiler/rustc_index/src/vec.rs
@@ -201,18 +201,15 @@ impl<I: Idx, T> IndexVec<I, T> {
     }
 
     #[inline]
-    pub fn drain<'a, R: RangeBounds<usize>>(
-        &'a mut self,
-        range: R,
-    ) -> impl Iterator<Item = T> + 'a {
+    pub fn drain<R: RangeBounds<usize>>(&mut self, range: R) -> impl Iterator<Item = T> + '_ {
         self.raw.drain(range)
     }
 
     #[inline]
-    pub fn drain_enumerated<'a, R: RangeBounds<usize>>(
-        &'a mut self,
+    pub fn drain_enumerated<R: RangeBounds<usize>>(
+        &mut self,
         range: R,
-    ) -> impl Iterator<Item = (I, T)> + 'a {
+    ) -> impl Iterator<Item = (I, T)> + '_ {
         let begin = match range.start_bound() {
             std::ops::Bound::Included(i) => *i,
             std::ops::Bound::Excluded(i) => i.checked_add(1).unwrap(),
diff --git a/compiler/rustc_lint/src/levels.rs b/compiler/rustc_lint/src/levels.rs
index a76229dd3524b..a2a7c93a7ca95 100644
--- a/compiler/rustc_lint/src/levels.rs
+++ b/compiler/rustc_lint/src/levels.rs
@@ -266,12 +266,12 @@ impl LintLevelsProvider for QueryMapExpectationsWrapper<'_> {
         let LintExpectationId::Stable { attr_id: Some(attr_id), hir_id, attr_index, .. } = id else { bug!("unstable expectation id should already be mapped") };
         let key = LintExpectationId::Unstable { attr_id, lint_index: None };
 
-        if !self.unstable_to_stable_ids.contains_key(&key) {
-            self.unstable_to_stable_ids.insert(
-                key,
-                LintExpectationId::Stable { hir_id, attr_index, lint_index: None, attr_id: None },
-            );
-        }
+        self.unstable_to_stable_ids.entry(key).or_insert(LintExpectationId::Stable {
+            hir_id,
+            attr_index,
+            lint_index: None,
+            attr_id: None,
+        });
 
         self.expectations.push((id.normalize(), expectation));
     }
diff --git a/compiler/rustc_llvm/src/lib.rs b/compiler/rustc_llvm/src/lib.rs
index 8542dcf5bf0fe..ec3cf34d7109f 100644
--- a/compiler/rustc_llvm/src/lib.rs
+++ b/compiler/rustc_llvm/src/lib.rs
@@ -30,7 +30,7 @@ pub unsafe extern "C" fn LLVMRustStringWriteImpl(
     ptr: *const c_char,
     size: size_t,
 ) {
-    let slice = slice::from_raw_parts(ptr as *const u8, size as usize);
+    let slice = slice::from_raw_parts(ptr as *const u8, size);
 
     sr.bytes.borrow_mut().extend_from_slice(slice);
 }
diff --git a/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs b/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
index 9b91627883a8d..4540ded0f41a3 100644
--- a/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
+++ b/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
@@ -119,7 +119,7 @@ impl DiagnosticDeriveBuilder {
 impl<'a> DiagnosticDeriveVariantBuilder<'a> {
     /// Generates calls to `code` and similar functions based on the attributes on the type or
     /// variant.
-    pub fn preamble<'s>(&mut self, variant: &VariantInfo<'s>) -> TokenStream {
+    pub fn preamble(&mut self, variant: &VariantInfo<'_>) -> TokenStream {
         let ast = variant.ast();
         let attrs = &ast.attrs;
         let preamble = attrs.iter().map(|attr| {
@@ -133,7 +133,7 @@ impl<'a> DiagnosticDeriveVariantBuilder<'a> {
 
     /// Generates calls to `span_label` and similar functions based on the attributes on fields or
     /// calls to `set_arg` when no attributes are present.
-    pub fn body<'s>(&mut self, variant: &VariantInfo<'s>) -> TokenStream {
+    pub fn body(&mut self, variant: &VariantInfo<'_>) -> TokenStream {
         let mut body = quote! {};
         // Generate `set_arg` calls first..
         for binding in variant.bindings().iter().filter(|bi| should_generate_set_arg(bi.ast())) {
diff --git a/compiler/rustc_macros/src/diagnostics/fluent.rs b/compiler/rustc_macros/src/diagnostics/fluent.rs
index 9f96a04148792..607d51f5608d3 100644
--- a/compiler/rustc_macros/src/diagnostics/fluent.rs
+++ b/compiler/rustc_macros/src/diagnostics/fluent.rs
@@ -100,7 +100,7 @@ pub(crate) fn fluent_messages(input: proc_macro::TokenStream) -> proc_macro::Tok
             Diagnostic::spanned(
                 resource_span,
                 Level::Error,
-                format!("could not open Fluent resource: {}", e.to_string()),
+                format!("could not open Fluent resource: {e}"),
             )
             .emit();
             return failed(&crate_name);
diff --git a/compiler/rustc_metadata/src/locator.rs b/compiler/rustc_metadata/src/locator.rs
index 2515269ea2ff2..c6af8d6328983 100644
--- a/compiler/rustc_metadata/src/locator.rs
+++ b/compiler/rustc_metadata/src/locator.rs
@@ -762,14 +762,14 @@ impl<'a> CrateLocator<'a> {
     }
 
     pub(crate) fn into_error(self, root: Option<CratePaths>) -> CrateError {
-        CrateError::LocatorCombined(CombinedLocatorError {
+        CrateError::LocatorCombined(Box::new(CombinedLocatorError {
             crate_name: self.crate_name,
             root,
             triple: self.triple,
             dll_prefix: self.target.dll_prefix.to_string(),
             dll_suffix: self.target.dll_suffix.to_string(),
             crate_rejections: self.crate_rejections,
-        })
+        }))
     }
 }
 
@@ -958,7 +958,7 @@ pub(crate) enum CrateError {
     StableCrateIdCollision(Symbol, Symbol),
     DlOpen(String),
     DlSym(String),
-    LocatorCombined(CombinedLocatorError),
+    LocatorCombined(Box<CombinedLocatorError>),
     NonDylibPlugin(Symbol),
 }
 
diff --git a/compiler/rustc_middle/src/hir/map/mod.rs b/compiler/rustc_middle/src/hir/map/mod.rs
index 89a485b47ca8c..9d97a75a2fa6f 100644
--- a/compiler/rustc_middle/src/hir/map/mod.rs
+++ b/compiler/rustc_middle/src/hir/map/mod.rs
@@ -74,18 +74,17 @@ impl<'hir> Iterator for ParentHirIterator<'hir> {
         if self.current_id == CRATE_HIR_ID {
             return None;
         }
-        loop {
-            // There are nodes that do not have entries, so we need to skip them.
-            let parent_id = self.map.parent_id(self.current_id);
 
-            if parent_id == self.current_id {
-                self.current_id = CRATE_HIR_ID;
-                return None;
-            }
+        // There are nodes that do not have entries, so we need to skip them.
+        let parent_id = self.map.parent_id(self.current_id);
 
-            self.current_id = parent_id;
-            return Some(parent_id);
+        if parent_id == self.current_id {
+            self.current_id = CRATE_HIR_ID;
+            return None;
         }
+
+        self.current_id = parent_id;
+        return Some(parent_id);
     }
 }
 
diff --git a/compiler/rustc_middle/src/mir/interpret/allocation.rs b/compiler/rustc_middle/src/mir/interpret/allocation.rs
index 2f2c7b154165a..1a8e48264471c 100644
--- a/compiler/rustc_middle/src/mir/interpret/allocation.rs
+++ b/compiler/rustc_middle/src/mir/interpret/allocation.rs
@@ -109,26 +109,34 @@ const MAX_HASHED_BUFFER_LEN: usize = 2 * MAX_BYTES_TO_HASH;
 // large.
 impl hash::Hash for Allocation {
     fn hash<H: hash::Hasher>(&self, state: &mut H) {
+        let Self {
+            bytes,
+            provenance,
+            init_mask,
+            align,
+            mutability,
+            extra: (), // don't bother hashing ()
+        } = self;
+
         // Partially hash the `bytes` buffer when it is large. To limit collisions with common
         // prefixes and suffixes, we hash the length and some slices of the buffer.
-        let byte_count = self.bytes.len();
+        let byte_count = bytes.len();
         if byte_count > MAX_HASHED_BUFFER_LEN {
             // Hash the buffer's length.
             byte_count.hash(state);
 
             // And its head and tail.
-            self.bytes[..MAX_BYTES_TO_HASH].hash(state);
-            self.bytes[byte_count - MAX_BYTES_TO_HASH..].hash(state);
+            bytes[..MAX_BYTES_TO_HASH].hash(state);
+            bytes[byte_count - MAX_BYTES_TO_HASH..].hash(state);
         } else {
-            self.bytes.hash(state);
+            bytes.hash(state);
         }
 
         // Hash the other fields as usual.
-        self.provenance.hash(state);
-        self.init_mask.hash(state);
-        self.align.hash(state);
-        self.mutability.hash(state);
-        self.extra.hash(state);
+        provenance.hash(state);
+        init_mask.hash(state);
+        align.hash(state);
+        mutability.hash(state);
     }
 }
 
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index 0fad30973db71..56755e588cb45 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -915,7 +915,7 @@ pub enum LocalInfo<'tcx> {
 
 impl<'tcx> LocalDecl<'tcx> {
     pub fn local_info(&self) -> &LocalInfo<'tcx> {
-        &**self.local_info.as_ref().assert_crate_local()
+        &self.local_info.as_ref().assert_crate_local()
     }
 
     /// Returns `true` only if local is a binding that can itself be
diff --git a/compiler/rustc_middle/src/mir/patch.rs b/compiler/rustc_middle/src/mir/patch.rs
index b898e85fa71b9..f62853c3e7403 100644
--- a/compiler/rustc_middle/src/mir/patch.rs
+++ b/compiler/rustc_middle/src/mir/patch.rs
@@ -133,21 +133,21 @@ impl<'tcx> MirPatch<'tcx> {
         let mut new_decl = LocalDecl::new(ty, span).internal();
         **new_decl.local_info.as_mut().assert_crate_local() = local_info;
         self.new_locals.push(new_decl);
-        Local::new(index as usize)
+        Local::new(index)
     }
 
     pub fn new_temp(&mut self, ty: Ty<'tcx>, span: Span) -> Local {
         let index = self.next_local;
         self.next_local += 1;
         self.new_locals.push(LocalDecl::new(ty, span));
-        Local::new(index as usize)
+        Local::new(index)
     }
 
     pub fn new_internal(&mut self, ty: Ty<'tcx>, span: Span) -> Local {
         let index = self.next_local;
         self.next_local += 1;
         self.new_locals.push(LocalDecl::new(ty, span).internal());
-        Local::new(index as usize)
+        Local::new(index)
     }
 
     pub fn new_block(&mut self, data: BasicBlockData<'tcx>) -> BasicBlock {
diff --git a/compiler/rustc_middle/src/mir/tcx.rs b/compiler/rustc_middle/src/mir/tcx.rs
index 0092401470f56..4f00abf7fabc1 100644
--- a/compiler/rustc_middle/src/mir/tcx.rs
+++ b/compiler/rustc_middle/src/mir/tcx.rs
@@ -98,7 +98,7 @@ impl<'tcx> PlaceTy<'tcx> {
                     ty::Array(inner, _) if !from_end => tcx.mk_array(*inner, (to - from) as u64),
                     ty::Array(inner, size) if from_end => {
                         let size = size.eval_target_usize(tcx, param_env);
-                        let len = size - (from as u64) - (to as u64);
+                        let len = size - from - to;
                         tcx.mk_array(*inner, len)
                     }
                     _ => bug!("cannot subslice non-array type: `{:?}`", self),
diff --git a/compiler/rustc_middle/src/mir/traversal.rs b/compiler/rustc_middle/src/mir/traversal.rs
index 62cdf794b1e91..7d247eeb656c2 100644
--- a/compiler/rustc_middle/src/mir/traversal.rs
+++ b/compiler/rustc_middle/src/mir/traversal.rs
@@ -178,17 +178,7 @@ impl<'a, 'tcx> Postorder<'a, 'tcx> {
         // When we yield `B` and call `traverse_successor`, we push `C` to the stack, but
         // since we've already visited `E`, that child isn't added to the stack. The last
         // two iterations yield `C` and finally `A` for a final traversal of [E, D, B, C, A]
-        loop {
-            let bb = if let Some(&mut (_, ref mut iter)) = self.visit_stack.last_mut() {
-                if let Some(bb) = iter.next() {
-                    bb
-                } else {
-                    break;
-                }
-            } else {
-                break;
-            };
-
+        while let Some(&mut (_, ref mut iter)) = self.visit_stack.last_mut() && let Some(bb) = iter.next() {
             if self.visited.insert(bb) {
                 if let Some(term) = &self.basic_blocks[bb].terminator {
                     self.visit_stack.push((bb, term.successors()));
diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs
index 833402abfc479..6a8ae525069c0 100644
--- a/compiler/rustc_middle/src/traits/mod.rs
+++ b/compiler/rustc_middle/src/traits/mod.rs
@@ -923,7 +923,7 @@ impl ObjectSafetyViolation {
                 }
             }
             ObjectSafetyViolation::SupertraitNonLifetimeBinder(_) => {
-                format!("where clause cannot reference non-lifetime `for<...>` variables").into()
+                "where clause cannot reference non-lifetime `for<...>` variables".into()
             }
             ObjectSafetyViolation::Method(name, MethodViolationCode::StaticMethod(_), _) => {
                 format!("associated function `{}` has no `self` parameter", name).into()
diff --git a/compiler/rustc_middle/src/traits/solve.rs b/compiler/rustc_middle/src/traits/solve.rs
index 0d6f9813e7673..9c350fb5a137c 100644
--- a/compiler/rustc_middle/src/traits/solve.rs
+++ b/compiler/rustc_middle/src/traits/solve.rs
@@ -105,7 +105,7 @@ impl<'tcx> std::ops::Deref for ExternalConstraints<'tcx> {
     type Target = ExternalConstraintsData<'tcx>;
 
     fn deref(&self) -> &Self::Target {
-        &*self.0
+        &self.0
     }
 }
 
diff --git a/compiler/rustc_middle/src/ty/consts/int.rs b/compiler/rustc_middle/src/ty/consts/int.rs
index a7f38884ebcc4..c0e557d480d3d 100644
--- a/compiler/rustc_middle/src/ty/consts/int.rs
+++ b/compiler/rustc_middle/src/ty/consts/int.rs
@@ -337,7 +337,7 @@ impl ScalarInt {
     /// Fails if the size of the `ScalarInt` is not equal to `Size { raw: 16 }`
     /// and returns the `ScalarInt`s size in that case.
     pub fn try_to_i128(self) -> Result<i128, Size> {
-        self.try_to_int(Size::from_bits(128)).map(|v| i128::try_from(v).unwrap())
+        self.try_to_int(Size::from_bits(128))
     }
 }
 
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 2ef6180c4cbd2..c312aaf6819aa 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -924,7 +924,7 @@ impl<'tcx> TyCtxt<'tcx> {
             crate_name,
             // Don't print the whole stable crate id. That's just
             // annoying in debug output.
-            stable_crate_id.to_u64() >> 8 * 6,
+            stable_crate_id.to_u64() >> (8 * 6),
             self.def_path(def_id).to_string_no_crate_verbose()
         )
     }
@@ -2379,7 +2379,7 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn in_scope_traits(self, id: HirId) -> Option<&'tcx [TraitCandidate]> {
         let map = self.in_scope_traits_map(id.owner)?;
         let candidates = map.get(&id.local_id)?;
-        Some(&*candidates)
+        Some(candidates)
     }
 
     pub fn named_bound_var(self, id: HirId) -> Option<resolve_bound_vars::ResolvedArg> {
diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index 0e2e2a956ec7b..5bbd396d6f3b0 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -1891,7 +1891,7 @@ impl<'tcx> Ty<'tcx> {
                         // The way we evaluate the `N` in `[T; N]` here only works since we use
                         // `simd_size_and_type` post-monomorphization. It will probably start to ICE
                         // if we use it in generic code. See the `simd-array-trait` ui test.
-                        (f0_len.eval_target_usize(tcx, ParamEnv::empty()) as u64, *f0_elem_ty)
+                        (f0_len.eval_target_usize(tcx, ParamEnv::empty()), *f0_elem_ty)
                     }
                     // Otherwise, the fields of this Adt are the SIMD components (and we assume they
                     // all have the same type).
diff --git a/compiler/rustc_parse/src/lexer/mod.rs b/compiler/rustc_parse/src/lexer/mod.rs
index 4a7da11a09784..e41d0f7047b3b 100644
--- a/compiler/rustc_parse/src/lexer/mod.rs
+++ b/compiler/rustc_parse/src/lexer/mod.rs
@@ -558,8 +558,8 @@ impl<'a> StringReader<'a> {
         }
 
         if let Some(possible_offset) = possible_offset {
-            let lo = start + BytePos(possible_offset as u32);
-            let hi = lo + BytePos(found_terminators as u32);
+            let lo = start + BytePos(possible_offset);
+            let hi = lo + BytePos(found_terminators);
             let span = self.mk_sp(lo, hi);
             err.span_suggestion(
                 span,
diff --git a/compiler/rustc_parse/src/lexer/unicode_chars.rs b/compiler/rustc_parse/src/lexer/unicode_chars.rs
index d4f971d5bc84f..1f027c08fc3b5 100644
--- a/compiler/rustc_parse/src/lexer/unicode_chars.rs
+++ b/compiler/rustc_parse/src/lexer/unicode_chars.rs
@@ -336,8 +336,8 @@ const ASCII_ARRAY: &[(&str, &str, Option<token::TokenKind>)] = &[
     ("\"", "Quotation Mark", None),
 ];
 
-pub(super) fn check_for_substitution<'a>(
-    reader: &StringReader<'a>,
+pub(super) fn check_for_substitution(
+    reader: &StringReader<'_>,
     pos: BytePos,
     ch: char,
     count: usize,
diff --git a/compiler/rustc_parse/src/parser/generics.rs b/compiler/rustc_parse/src/parser/generics.rs
index 8d0f168e09d7e..f8ef1307c988e 100644
--- a/compiler/rustc_parse/src/parser/generics.rs
+++ b/compiler/rustc_parse/src/parser/generics.rs
@@ -53,7 +53,7 @@ impl<'a> Parser<'a> {
                 let snapshot = self.create_snapshot_for_diagnostic();
                 match self.parse_ty() {
                     Ok(p) => {
-                        if let TyKind::ImplTrait(_, bounds) = &(*p).kind {
+                        if let TyKind::ImplTrait(_, bounds) = &p.kind {
                             let span = impl_span.to(self.token.span.shrink_to_lo());
                             let mut err = self.struct_span_err(
                                 span,
diff --git a/compiler/rustc_query_system/src/query/caches.rs b/compiler/rustc_query_system/src/query/caches.rs
index 3ac8a852a4e77..29f6a07e81beb 100644
--- a/compiler/rustc_query_system/src/query/caches.rs
+++ b/compiler/rustc_query_system/src/query/caches.rs
@@ -136,7 +136,9 @@ where
     }
 
     fn iter(&self, f: &mut dyn FnMut(&Self::Key, &Self::Value, DepNodeIndex)) {
-        self.cache.lock().as_ref().map(|value| f(&(), &value.0, value.1));
+        if let Some(value) = self.cache.lock().as_ref() {
+            f(&(), &value.0, value.1)
+        }
     }
 }
 
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index b3f66c4ba3354..31ac3f1c151ee 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -1224,7 +1224,7 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
             lifetime_ribs: Vec::new(),
             lifetime_elision_candidates: None,
             current_trait_ref: None,
-            diagnostic_metadata: Box::new(DiagnosticMetadata::default()),
+            diagnostic_metadata: Default::default(),
             // errors at module scope should always be reported
             in_func_body: false,
             lifetime_uses: Default::default(),
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index de0ddb53fa402..d4eba495dcdcd 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -1426,7 +1426,7 @@ pub fn rustc_short_optgroups() -> Vec<RustcOptGroup> {
         opt::opt_s(
             "",
             "edition",
-            &*EDITION_STRING,
+            &EDITION_STRING,
             EDITION_NAME_LIST,
         ),
         opt::multi_s(
diff --git a/compiler/rustc_session/src/parse.rs b/compiler/rustc_session/src/parse.rs
index 002ae1e3165ac..15e27952cf50f 100644
--- a/compiler/rustc_session/src/parse.rs
+++ b/compiler/rustc_session/src/parse.rs
@@ -84,12 +84,12 @@ impl SymbolGallery {
 
 /// Construct a diagnostic for a language feature error due to the given `span`.
 /// The `feature`'s `Symbol` is the one you used in `active.rs` and `rustc_span::symbols`.
-pub fn feature_err<'a>(
-    sess: &'a ParseSess,
+pub fn feature_err(
+    sess: &ParseSess,
     feature: Symbol,
     span: impl Into<MultiSpan>,
     explain: impl Into<DiagnosticMessage>,
-) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
     feature_err_issue(sess, feature, span, GateIssue::Language, explain)
 }
 
@@ -98,20 +98,21 @@ pub fn feature_err<'a>(
 /// This variant allows you to control whether it is a library or language feature.
 /// Almost always, you want to use this for a language feature. If so, prefer `feature_err`.
 #[track_caller]
-pub fn feature_err_issue<'a>(
-    sess: &'a ParseSess,
+pub fn feature_err_issue(
+    sess: &ParseSess,
     feature: Symbol,
     span: impl Into<MultiSpan>,
     issue: GateIssue,
     explain: impl Into<DiagnosticMessage>,
-) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
     let span = span.into();
 
     // Cancel an earlier warning for this same error, if it exists.
     if let Some(span) = span.primary_span() {
-        sess.span_diagnostic
-            .steal_diagnostic(span, StashKey::EarlySyntaxWarning)
-            .map(|err| err.cancel());
+        if let Some(err) = sess.span_diagnostic.steal_diagnostic(span, StashKey::EarlySyntaxWarning)
+        {
+            err.cancel()
+        }
     }
 
     let mut err = sess.create_err(FeatureGateError { span, explain: explain.into() });
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 11cd5811be8b9..aa8859ed1a358 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -1353,16 +1353,16 @@ impl Clone for SourceFile {
         Self {
             name: self.name.clone(),
             src: self.src.clone(),
-            src_hash: self.src_hash.clone(),
+            src_hash: self.src_hash,
             external_src: Lock::new(self.external_src.borrow().clone()),
-            start_pos: self.start_pos.clone(),
-            end_pos: self.end_pos.clone(),
+            start_pos: self.start_pos,
+            end_pos: self.end_pos,
             lines: Lock::new(self.lines.borrow().clone()),
             multibyte_chars: self.multibyte_chars.clone(),
             non_narrow_chars: self.non_narrow_chars.clone(),
             normalized_pos: self.normalized_pos.clone(),
-            name_hash: self.name_hash.clone(),
-            cnum: self.cnum.clone(),
+            name_hash: self.name_hash,
+            cnum: self.cnum,
         }
     }
 }
@@ -2051,13 +2051,13 @@ pub type FileLinesResult = Result<FileLines, SpanLinesError>;
 
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub enum SpanLinesError {
-    DistinctSources(DistinctSources),
+    DistinctSources(Box<DistinctSources>),
 }
 
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub enum SpanSnippetError {
     IllFormedSpan(Span),
-    DistinctSources(DistinctSources),
+    DistinctSources(Box<DistinctSources>),
     MalformedForSourcemap(MalformedSourceMapPositions),
     SourceNotAvailable { filename: FileName },
 }
diff --git a/compiler/rustc_span/src/source_map.rs b/compiler/rustc_span/src/source_map.rs
index ee895f53eba9b..88e3674f89943 100644
--- a/compiler/rustc_span/src/source_map.rs
+++ b/compiler/rustc_span/src/source_map.rs
@@ -542,10 +542,10 @@ impl SourceMap {
         let hi = self.lookup_char_pos(sp.hi());
         trace!(?hi);
         if lo.file.start_pos != hi.file.start_pos {
-            return Err(SpanLinesError::DistinctSources(DistinctSources {
+            return Err(SpanLinesError::DistinctSources(Box::new(DistinctSources {
                 begin: (lo.file.name.clone(), lo.file.start_pos),
                 end: (hi.file.name.clone(), hi.file.start_pos),
-            }));
+            })));
         }
         Ok((lo, hi))
     }
@@ -603,10 +603,10 @@ impl SourceMap {
         let local_end = self.lookup_byte_offset(sp.hi());
 
         if local_begin.sf.start_pos != local_end.sf.start_pos {
-            Err(SpanSnippetError::DistinctSources(DistinctSources {
+            Err(SpanSnippetError::DistinctSources(Box::new(DistinctSources {
                 begin: (local_begin.sf.name.clone(), local_begin.sf.start_pos),
                 end: (local_end.sf.name.clone(), local_end.sf.start_pos),
-            }))
+            })))
         } else {
             self.ensure_source_file_source_present(local_begin.sf.clone());
 
diff --git a/compiler/rustc_target/src/spec/abi.rs b/compiler/rustc_target/src/spec/abi.rs
index d4f7ed31b895c..5582d909f6b10 100644
--- a/compiler/rustc_target/src/spec/abi.rs
+++ b/compiler/rustc_target/src/spec/abi.rs
@@ -324,8 +324,6 @@ impl Abi {
 
 impl fmt::Display for Abi {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            abi => write!(f, "\"{}\"", abi.name()),
-        }
+        write!(f, "\"{}\"", self.name())
     }
 }
diff --git a/compiler/rustc_transmute/src/lib.rs b/compiler/rustc_transmute/src/lib.rs
index 4b4a8ebd079fc..a93a42987ed53 100644
--- a/compiler/rustc_transmute/src/lib.rs
+++ b/compiler/rustc_transmute/src/lib.rs
@@ -149,7 +149,7 @@ mod rustc {
                     .iter()
                     .enumerate()
                     .find(|(_, field_def)| name == field_def.name)
-                    .expect(&format!("There were no fields named `{name}`."));
+                    .unwrap_or_else(|| panic!("There were no fields named `{name}`."));
                 fields[field_idx].unwrap_leaf() == ScalarInt::TRUE
             };