diff --git a/compiler/rustc_abi/src/layout.rs b/compiler/rustc_abi/src/layout.rs
index 11e7b80f85e..9c2cf58efed 100644
--- a/compiler/rustc_abi/src/layout.rs
+++ b/compiler/rustc_abi/src/layout.rs
@@ -354,7 +354,7 @@ fn layout_of_struct_or_enum<'a, V: Idx, F: Deref<Target = &'a LayoutS<V>> + Debu
                 if !always_sized { StructKind::MaybeUnsized } else { StructKind::AlwaysSized }
             };
 
-            let mut st = self.univariant(dl, &variants[v], &repr, kind)?;
+            let mut st = self.univariant(dl, &variants[v], repr, kind)?;
             st.variants = Variants::Single { index: v };
 
             if is_unsafe_cell {
@@ -457,7 +457,7 @@ struct TmpLayout<V: Idx> {
             let mut variant_layouts = variants
                 .iter_enumerated()
                 .map(|(j, v)| {
-                    let mut st = self.univariant(dl, v, &repr, StructKind::AlwaysSized)?;
+                    let mut st = self.univariant(dl, v, repr, StructKind::AlwaysSized)?;
                     st.variants = Variants::Single { index: j };
 
                     align = align.max(st.align);
@@ -647,8 +647,8 @@ struct TmpLayout<V: Idx> {
             .map(|(i, field_layouts)| {
                 let mut st = self.univariant(
                     dl,
-                    &field_layouts,
-                    &repr,
+                    field_layouts,
+                    repr,
                     StructKind::Prefixed(min_ity.size(), prefix_align),
                 )?;
                 st.variants = Variants::Single { index: i };
@@ -755,7 +755,7 @@ struct TmpLayout<V: Idx> {
             // Try to use a ScalarPair for all tagged enums.
             let mut common_prim = None;
             let mut common_prim_initialized_in_all_variants = true;
-            for (field_layouts, layout_variant) in iter::zip(&*variants, &layout_variants) {
+            for (field_layouts, layout_variant) in iter::zip(variants, &layout_variants) {
                 let FieldsShape::Arbitrary { ref offsets, .. } = layout_variant.fields else {
                     panic!();
                 };
diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index 6a2f1f0c574..6df00411ab3 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -1179,7 +1179,7 @@ pub fn to_bound(&self) -> Option<GenericBound> {
     pub fn peel_parens(&self) -> &Expr {
         let mut expr = self;
         while let ExprKind::Paren(inner) = &expr.kind {
-            expr = &inner;
+            expr = inner;
         }
         expr
     }
@@ -2027,7 +2027,7 @@ impl Ty {
     pub fn peel_refs(&self) -> &Self {
         let mut final_ty = self;
         while let TyKind::Rptr(_, MutTy { ty, .. }) = &final_ty.kind {
-            final_ty = &ty;
+            final_ty = ty;
         }
         final_ty
     }
diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs
index cb3c54fa03c..a81d8b2360d 100644
--- a/compiler/rustc_ast/src/mut_visit.rs
+++ b/compiler/rustc_ast/src/mut_visit.rs
@@ -740,8 +740,7 @@ pub fn visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
             return; // Avoid visiting the span for the second time.
         }
         token::Interpolated(nt) => {
-            let mut nt = Lrc::make_mut(nt);
-            visit_nonterminal(&mut nt, vis);
+            visit_nonterminal(Lrc::make_mut(nt), vis);
         }
         _ => {}
     }
diff --git a/compiler/rustc_ast/src/tokenstream.rs b/compiler/rustc_ast/src/tokenstream.rs
index 58c6d397ea2..482c302950f 100644
--- a/compiler/rustc_ast/src/tokenstream.rs
+++ b/compiler/rustc_ast/src/tokenstream.rs
@@ -64,7 +64,7 @@ pub fn eq_unspanned(&self, other: &TokenTree) -> bool {
         match (self, other) {
             (TokenTree::Token(token, _), TokenTree::Token(token2, _)) => token.kind == token2.kind,
             (TokenTree::Delimited(_, delim, tts), TokenTree::Delimited(_, delim2, tts2)) => {
-                delim == delim2 && tts.eq_unspanned(&tts2)
+                delim == delim2 && tts.eq_unspanned(tts2)
             }
             _ => false,
         }
@@ -402,7 +402,7 @@ pub fn eq_unspanned(&self, other: &TokenStream) -> bool {
         let mut t1 = self.trees();
         let mut t2 = other.trees();
         for (t1, t2) in iter::zip(&mut t1, &mut t2) {
-            if !t1.eq_unspanned(&t2) {
+            if !t1.eq_unspanned(t2) {
                 return false;
             }
         }
@@ -475,7 +475,7 @@ fn flatten_token(token: &Token, spacing: Spacing) -> TokenTree {
             token::Interpolated(nt) => TokenTree::Delimited(
                 DelimSpan::from_single(token.span),
                 Delimiter::Invisible,
-                TokenStream::from_nonterminal_ast(&nt).flattened(),
+                TokenStream::from_nonterminal_ast(nt).flattened(),
             ),
             _ => TokenTree::Token(token.clone(), spacing),
         }
@@ -511,7 +511,7 @@ fn can_skip(stream: &TokenStream) -> bool {
     fn try_glue_to_last(vec: &mut Vec<TokenTree>, tt: &TokenTree) -> bool {
         if let Some(TokenTree::Token(last_tok, Spacing::Joint)) = vec.last()
             && let TokenTree::Token(tok, spacing) = tt
-            && let Some(glued_tok) = last_tok.glue(&tok)
+            && let Some(glued_tok) = last_tok.glue(tok)
         {
             // ...then overwrite the last token tree in `vec` with the
             // glued token, and skip the first token tree from `stream`.
diff --git a/compiler/rustc_ast/src/util/comments.rs b/compiler/rustc_ast/src/util/comments.rs
index c96474ccb42..35454c3a670 100644
--- a/compiler/rustc_ast/src/util/comments.rs
+++ b/compiler/rustc_ast/src/util/comments.rs
@@ -110,7 +110,7 @@ fn get_horizontal_trim<'a>(lines: &'a [&str], kind: CommentKind) -> Option<Strin
         } else {
             &mut lines
         };
-        if let Some(horizontal) = get_horizontal_trim(&lines, kind) {
+        if let Some(horizontal) = get_horizontal_trim(lines, kind) {
             changes = true;
             // remove a "[ \t]*\*" block from each line, if possible
             for line in lines.iter_mut() {
@@ -147,7 +147,7 @@ fn all_whitespace(s: &str, col: CharPos) -> Option<usize> {
 
 fn trim_whitespace_prefix(s: &str, col: CharPos) -> &str {
     let len = s.len();
-    match all_whitespace(&s, col) {
+    match all_whitespace(s, col) {
         Some(col) => {
             if col < len {
                 &s[col..]
diff --git a/compiler/rustc_ast/src/util/literal.rs b/compiler/rustc_ast/src/util/literal.rs
index 1d6e7914f3a..f6f186b5107 100644
--- a/compiler/rustc_ast/src/util/literal.rs
+++ b/compiler/rustc_ast/src/util/literal.rs
@@ -52,14 +52,14 @@ pub fn from_token_lit(lit: token::Lit) -> Result<LitKind, LitError> {
                 // new symbol because the string in the LitKind is different to the
                 // string in the token.
                 let s = symbol.as_str();
-                let symbol = if s.contains(&['\\', '\r']) {
+                let symbol = if s.contains(['\\', '\r']) {
                     let mut buf = String::with_capacity(s.len());
                     let mut error = Ok(());
                     // Force-inlining here is aggressive but the closure is
                     // called on every char in the string, so it can be
                     // hot in programs with many long strings.
                     unescape_literal(
-                        &s,
+                        s,
                         Mode::Str,
                         &mut #[inline(always)]
                         |_, unescaped_char| match unescaped_char {
@@ -85,7 +85,7 @@ pub fn from_token_lit(lit: token::Lit) -> Result<LitKind, LitError> {
                     if s.contains('\r') {
                         let mut buf = String::with_capacity(s.len());
                         let mut error = Ok(());
-                        unescape_literal(&s, Mode::RawStr, &mut |_, unescaped_char| {
+                        unescape_literal(s, Mode::RawStr, &mut |_, unescaped_char| {
                             match unescaped_char {
                                 Ok(c) => buf.push(c),
                                 Err(err) => {
@@ -106,7 +106,7 @@ pub fn from_token_lit(lit: token::Lit) -> Result<LitKind, LitError> {
                 let s = symbol.as_str();
                 let mut buf = Vec::with_capacity(s.len());
                 let mut error = Ok(());
-                unescape_literal(&s, Mode::ByteStr, &mut |_, c| match c {
+                unescape_literal(s, Mode::ByteStr, &mut |_, c| match c {
                     Ok(c) => buf.push(byte_from_char(c)),
                     Err(err) => {
                         if err.is_fatal() {
@@ -122,7 +122,7 @@ pub fn from_token_lit(lit: token::Lit) -> Result<LitKind, LitError> {
                 let bytes = if s.contains('\r') {
                     let mut buf = Vec::with_capacity(s.len());
                     let mut error = Ok(());
-                    unescape_literal(&s, Mode::RawByteStr, &mut |_, c| match c {
+                    unescape_literal(s, Mode::RawByteStr, &mut |_, c| match c {
                         Ok(c) => buf.push(byte_from_char(c)),
                         Err(err) => {
                             if err.is_fatal() {
diff --git a/compiler/rustc_ast/src/util/parser.rs b/compiler/rustc_ast/src/util/parser.rs
index f65f1f069cb..819f1884a06 100644
--- a/compiler/rustc_ast/src/util/parser.rs
+++ b/compiler/rustc_ast/src/util/parser.rs
@@ -384,7 +384,7 @@ pub fn contains_exterior_struct_lit(value: &ast::Expr) -> bool {
         | ast::ExprKind::AssignOp(_, lhs, rhs)
         | ast::ExprKind::Binary(_, lhs, rhs) => {
             // X { y: 1 } + X { y: 2 }
-            contains_exterior_struct_lit(&lhs) || contains_exterior_struct_lit(&rhs)
+            contains_exterior_struct_lit(lhs) || contains_exterior_struct_lit(rhs)
         }
         ast::ExprKind::Await(x)
         | ast::ExprKind::Unary(_, x)
@@ -393,12 +393,12 @@ pub fn contains_exterior_struct_lit(value: &ast::Expr) -> bool {
         | ast::ExprKind::Field(x, _)
         | ast::ExprKind::Index(x, _) => {
             // &X { y: 1 }, X { y: 1 }.y
-            contains_exterior_struct_lit(&x)
+            contains_exterior_struct_lit(x)
         }
 
         ast::ExprKind::MethodCall(box ast::MethodCall { receiver, .. }) => {
             // X { y: 1 }.bar(...)
-            contains_exterior_struct_lit(&receiver)
+            contains_exterior_struct_lit(receiver)
         }
 
         _ => false,
diff --git a/compiler/rustc_ast/src/util/unicode.rs b/compiler/rustc_ast/src/util/unicode.rs
index f009f7b300c..0eae791b25e 100644
--- a/compiler/rustc_ast/src/util/unicode.rs
+++ b/compiler/rustc_ast/src/util/unicode.rs
@@ -17,7 +17,7 @@ pub fn contains_text_flow_control_chars(s: &str) -> bool {
     // U+2069 - E2 81 A9
     let mut bytes = s.as_bytes();
     loop {
-        match core::slice::memchr::memchr(0xE2, &bytes) {
+        match core::slice::memchr::memchr(0xE2, bytes) {
             Some(idx) => {
                 // bytes are valid UTF-8 -> E2 must be followed by two bytes
                 let ch = &bytes[idx..idx + 3];
diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
index ebe55a4b771..d3d8431c163 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -519,7 +519,7 @@ fn print_meta_item(&mut self, item: &ast::MetaItem) {
             ast::MetaItemKind::List(items) => {
                 self.print_path(&item.path, false, 0);
                 self.popen();
-                self.commasep(Consistent, &items, |s, i| s.print_meta_list_item(i));
+                self.commasep(Consistent, items, |s, i| s.print_meta_list_item(i));
                 self.pclose();
             }
         }
@@ -536,7 +536,7 @@ fn print_meta_item(&mut self, item: &ast::MetaItem) {
     fn print_tt(&mut self, tt: &TokenTree, convert_dollar_crate: bool) {
         match tt {
             TokenTree::Token(token, _) => {
-                let token_str = self.token_to_string_ext(&token, convert_dollar_crate);
+                let token_str = self.token_to_string_ext(token, convert_dollar_crate);
                 self.word(token_str);
                 if let token::DocComment(..) = token.kind {
                     self.hardbreak()
@@ -998,7 +998,7 @@ pub fn print_assoc_constraint(&mut self, constraint: &ast::AssocConstraint) {
             ast::AssocConstraintKind::Bound { bounds } => {
                 if !bounds.is_empty() {
                     self.word_nbsp(":");
-                    self.print_type_bounds(&bounds);
+                    self.print_type_bounds(bounds);
                 }
             }
         }
@@ -1035,7 +1035,7 @@ pub fn print_type(&mut self, ty: &ast::Ty) {
             }
             ast::TyKind::Tup(elts) => {
                 self.popen();
-                self.commasep(Inconsistent, &elts, |s, ty| s.print_type(ty));
+                self.commasep(Inconsistent, elts, |s, ty| s.print_type(ty));
                 if elts.len() == 1 {
                     self.word(",");
                 }
@@ -1254,7 +1254,7 @@ enum AsmArg<'a> {
 
         self.popen();
         self.commasep(Consistent, &args, |s, arg| match arg {
-            AsmArg::Template(template) => s.print_string(&template, ast::StrStyle::Cooked),
+            AsmArg::Template(template) => s.print_string(template, ast::StrStyle::Cooked),
             AsmArg::Operand(op) => {
                 let print_reg_or_class = |s: &mut Self, r: &InlineAsmRegOrRegClass| match r {
                     InlineAsmRegOrRegClass::Reg(r) => s.print_symbol(*r, ast::StrStyle::Cooked),
@@ -1424,11 +1424,11 @@ pub(crate) fn print_pat(&mut self, pat: &ast::Pat) {
                     self.print_path(path, true, 0);
                 }
                 self.popen();
-                self.commasep(Inconsistent, &elts, |s, p| s.print_pat(p));
+                self.commasep(Inconsistent, elts, |s, p| s.print_pat(p));
                 self.pclose();
             }
             PatKind::Or(pats) => {
-                self.strsep("|", true, Inconsistent, &pats, |s, p| s.print_pat(p));
+                self.strsep("|", true, Inconsistent, pats, |s, p| s.print_pat(p));
             }
             PatKind::Path(None, path) => {
                 self.print_path(path, true, 0);
@@ -1450,7 +1450,7 @@ pub(crate) fn print_pat(&mut self, pat: &ast::Pat) {
                 }
                 self.commasep_cmnt(
                     Consistent,
-                    &fields,
+                    fields,
                     |s, f| {
                         s.cbox(INDENT_UNIT);
                         if !f.is_shorthand {
@@ -1475,7 +1475,7 @@ pub(crate) fn print_pat(&mut self, pat: &ast::Pat) {
             }
             PatKind::Tuple(elts) => {
                 self.popen();
-                self.commasep(Inconsistent, &elts, |s, p| s.print_pat(p));
+                self.commasep(Inconsistent, elts, |s, p| s.print_pat(p));
                 if elts.len() == 1 {
                     self.word(",");
                 }
@@ -1498,7 +1498,7 @@ pub(crate) fn print_pat(&mut self, pat: &ast::Pat) {
                     self.print_pat(inner);
                 }
             }
-            PatKind::Lit(e) => self.print_expr(&**e),
+            PatKind::Lit(e) => self.print_expr(e),
             PatKind::Range(begin, end, Spanned { node: end_kind, .. }) => {
                 if let Some(e) = begin {
                     self.print_expr(e);
@@ -1514,7 +1514,7 @@ pub(crate) fn print_pat(&mut self, pat: &ast::Pat) {
             }
             PatKind::Slice(elts) => {
                 self.word("[");
-                self.commasep(Inconsistent, &elts, |s, p| s.print_pat(p));
+                self.commasep(Inconsistent, elts, |s, p| s.print_pat(p));
                 self.word("]");
             }
             PatKind::Rest => self.word(".."),
@@ -1600,7 +1600,7 @@ pub(crate) fn print_generic_params(&mut self, generic_params: &[ast::GenericPara
 
         self.word("<");
 
-        self.commasep(Inconsistent, &generic_params, |s, param| {
+        self.commasep(Inconsistent, generic_params, |s, param| {
             s.print_outer_attributes_inline(&param.attrs);
 
             match &param.kind {
diff --git a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
index 81483ac30d1..7a2146bc9b3 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
@@ -305,10 +305,10 @@ pub(super) fn print_expr_outer_attr_style(&mut self, expr: &ast::Expr, is_inline
                 self.print_expr_tup(exprs);
             }
             ast::ExprKind::Call(func, args) => {
-                self.print_expr_call(func, &args);
+                self.print_expr_call(func, args);
             }
             ast::ExprKind::MethodCall(box ast::MethodCall { seg, receiver, args, .. }) => {
-                self.print_expr_method_call(seg, &receiver, &args);
+                self.print_expr_method_call(seg, receiver, args);
             }
             ast::ExprKind::Binary(op, lhs, rhs) => {
                 self.print_expr_binary(*op, lhs, rhs);
@@ -605,7 +605,7 @@ fn print_closure_binder(&mut self, binder: &ast::ClosureBinder) {
         match binder {
             ast::ClosureBinder::NotPresent => {}
             ast::ClosureBinder::For { generic_params, .. } => {
-                self.print_formal_generic_params(&generic_params)
+                self.print_formal_generic_params(generic_params)
             }
         }
     }
diff --git a/compiler/rustc_data_structures/src/intern.rs b/compiler/rustc_data_structures/src/intern.rs
index 11cbff8ea6a..76a1288e6d3 100644
--- a/compiler/rustc_data_structures/src/intern.rs
+++ b/compiler/rustc_data_structures/src/intern.rs
@@ -72,7 +72,7 @@ fn partial_cmp(&self, other: &Interned<'a, T>) -> Option<Ordering> {
         if ptr::eq(self.0, other.0) {
             Some(Ordering::Equal)
         } else {
-            let res = self.0.partial_cmp(&other.0);
+            let res = self.0.partial_cmp(other.0);
             debug_assert_ne!(res, Some(Ordering::Equal));
             res
         }
@@ -86,7 +86,7 @@ fn cmp(&self, other: &Interned<'a, T>) -> Ordering {
         if ptr::eq(self.0, other.0) {
             Ordering::Equal
         } else {
-            let res = self.0.cmp(&other.0);
+            let res = self.0.cmp(other.0);
             debug_assert_ne!(res, Ordering::Equal);
             res
         }
diff --git a/compiler/rustc_data_structures/src/memmap.rs b/compiler/rustc_data_structures/src/memmap.rs
index 917416df6b8..b95c1af3c26 100644
--- a/compiler/rustc_data_structures/src/memmap.rs
+++ b/compiler/rustc_data_structures/src/memmap.rs
@@ -36,7 +36,7 @@ impl Deref for Mmap {
 
     #[inline]
     fn deref(&self) -> &[u8] {
-        &*self.0
+        &self.0
     }
 }
 
@@ -96,13 +96,13 @@ impl Deref for MmapMut {
 
     #[inline]
     fn deref(&self) -> &[u8] {
-        &*self.0
+        &self.0
     }
 }
 
 impl DerefMut for MmapMut {
     #[inline]
     fn deref_mut(&mut self) -> &mut [u8] {
-        &mut *self.0
+        &mut self.0
     }
 }
diff --git a/compiler/rustc_data_structures/src/profiling.rs b/compiler/rustc_data_structures/src/profiling.rs
index ba1960805d8..aa7a01eed15 100644
--- a/compiler/rustc_data_structures/src/profiling.rs
+++ b/compiler/rustc_data_structures/src/profiling.rs
@@ -192,7 +192,7 @@ fn cold_call<F>(profiler_ref: &SelfProfilerRef, f: F) -> TimingGuard<'_>
             F: for<'a> FnOnce(&'a SelfProfiler) -> TimingGuard<'a>,
         {
             let profiler = profiler_ref.profiler.as_ref().unwrap();
-            f(&**profiler)
+            f(profiler)
         }
 
         if self.event_filter_mask.contains(event_filter) {
@@ -466,7 +466,7 @@ fn instant_query_event(
 
     pub fn with_profiler(&self, f: impl FnOnce(&SelfProfiler)) {
         if let Some(profiler) = &self.profiler {
-            f(&profiler)
+            f(profiler)
         }
     }
 
@@ -733,7 +733,7 @@ fn drop(&mut self) {
         if let Some((start_time, start_rss, ref message)) = self.start_and_message {
             let end_rss = get_resident_set_size();
             let dur = start_time.elapsed();
-            print_time_passes_entry(&message, dur, start_rss, end_rss);
+            print_time_passes_entry(message, dur, start_rss, end_rss);
         }
     }
 }
diff --git a/compiler/rustc_data_structures/src/stable_hasher.rs b/compiler/rustc_data_structures/src/stable_hasher.rs
index ce859173418..c287e8eb982 100644
--- a/compiler/rustc_data_structures/src/stable_hasher.rs
+++ b/compiler/rustc_data_structures/src/stable_hasher.rs
@@ -366,7 +366,7 @@ fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
 impl<T: HashStable<CTX>, CTX> HashStable<CTX> for Vec<T> {
     #[inline]
     fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
-        (&self[..]).hash_stable(ctx, hasher);
+        self[..].hash_stable(ctx, hasher);
     }
 }
 
@@ -405,7 +405,7 @@ fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
 {
     #[inline]
     fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
-        (&self[..]).hash_stable(ctx, hasher);
+        self[..].hash_stable(ctx, hasher);
     }
 }
 
@@ -440,7 +440,7 @@ fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
 impl<CTX> HashStable<CTX> for String {
     #[inline]
     fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
-        (&self[..]).hash_stable(hcx, hasher);
+        self[..].hash_stable(hcx, hasher);
     }
 }
 
diff --git a/compiler/rustc_data_structures/src/sync.rs b/compiler/rustc_data_structures/src/sync.rs
index c550f246e09..e4f47b22ac3 100644
--- a/compiler/rustc_data_structures/src/sync.rs
+++ b/compiler/rustc_data_structures/src/sync.rs
@@ -201,7 +201,7 @@ impl<T> Deref for WorkerLocal<T> {
 
             #[inline(always)]
             fn deref(&self) -> &T {
-                &*self.0
+                &self.0
             }
         }
 
diff --git a/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs b/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs
index c450c276366..d8879bf70ed 100644
--- a/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs
+++ b/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs
@@ -39,7 +39,7 @@ fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
     }
 
     fn fallback_fluent_bundle(&self) -> &FluentBundle {
-        &**self.fallback_bundle
+        &self.fallback_bundle
     }
 }
 
@@ -49,7 +49,7 @@ fn emit_diagnostic(&mut self, diag: &Diagnostic) {
         let fluent_args = to_fluent_args(diag.args());
 
         let mut children = diag.children.clone();
-        let (mut primary_span, suggestions) = self.primary_span_formatted(&diag, &fluent_args);
+        let (mut primary_span, suggestions) = self.primary_span_formatted(diag, &fluent_args);
 
         self.fix_multispans_in_extern_macros_and_render_macro_backtrace(
             &mut primary_span,
@@ -65,7 +65,7 @@ fn emit_diagnostic(&mut self, diag: &Diagnostic) {
             &diag.code,
             &primary_span,
             &children,
-            &suggestions,
+            suggestions,
         );
     }
 
diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index 7d5e4723a6d..06bb5edc090 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -292,7 +292,7 @@ pub fn update_unstable_expectation_id(
             let lint_index = expectation_id.get_lint_index();
             expectation_id.set_lint_index(None);
             let mut stable_id = unstable_to_stable
-                .get(&expectation_id)
+                .get(expectation_id)
                 .expect("each unstable `LintExpectationId` must have a matching stable id")
                 .normalize();
 
diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index 1fabe15ff83..db595df8ec1 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -283,7 +283,7 @@ fn primary_span_formatted<'a>(
                         if self
                             .source_map()
                             .map(|sm| is_case_difference(
-                                &**sm,
+                                sm,
                                 substitution,
                                 sugg.substitutions[0].parts[0].span,
                             ))
@@ -525,7 +525,7 @@ fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
     }
 
     fn fallback_fluent_bundle(&self) -> &FluentBundle {
-        &**self.fallback_bundle
+        &self.fallback_bundle
     }
 }
 
@@ -538,7 +538,7 @@ fn emit_diagnostic(&mut self, diag: &Diagnostic) {
         let fluent_args = to_fluent_args(diag.args());
 
         let mut children = diag.children.clone();
-        let (mut primary_span, suggestions) = self.primary_span_formatted(&diag, &fluent_args);
+        let (mut primary_span, suggestions) = self.primary_span_formatted(diag, &fluent_args);
         debug!("emit_diagnostic: suggestions={:?}", suggestions);
 
         self.fix_multispans_in_extern_macros_and_render_macro_backtrace(
@@ -555,7 +555,7 @@ fn emit_diagnostic(&mut self, diag: &Diagnostic) {
             &diag.code,
             &primary_span,
             &children,
-            &suggestions,
+            suggestions,
             self.track_diagnostics.then_some(&diag.emitted_at),
         );
     }
@@ -801,7 +801,7 @@ fn render_source_line(
         }
 
         let source_string = match file.get_line(line.line_index - 1) {
-            Some(s) => normalize_whitespace(&*s),
+            Some(s) => normalize_whitespace(&s),
             None => return Vec::new(),
         };
 
@@ -1148,7 +1148,7 @@ fn render_source_line(
                 (pos + 2, annotation.start_col.saturating_sub(left))
             };
             if let Some(ref label) = annotation.label {
-                buffer.puts(line_offset + pos, code_offset + col, &label, style);
+                buffer.puts(line_offset + pos, code_offset + col, label, style);
             }
         }
 
@@ -1358,7 +1358,7 @@ fn emit_message_default(
             // only render error codes, not lint codes
             if let Some(DiagnosticId::Error(ref code)) = *code {
                 buffer.append(0, "[", Style::Level(*level));
-                buffer.append(0, &code, Style::Level(*level));
+                buffer.append(0, code, Style::Level(*level));
                 buffer.append(0, "]", Style::Level(*level));
                 label_width += 2 + code.len();
             }
@@ -1683,7 +1683,7 @@ fn emit_suggestion_default(
         };
 
         // Render the replacements for each suggestion
-        let suggestions = suggestion.splice_lines(&**sm);
+        let suggestions = suggestion.splice_lines(sm);
         debug!("emit_suggestion_default: suggestions={:?}", suggestions);
 
         if suggestions.is_empty() {
@@ -1784,7 +1784,7 @@ fn emit_suggestion_default(
                     buffer.puts(
                         row_num - 1 + line - line_start,
                         max_line_num_len + 3,
-                        &normalize_whitespace(&*file_lines.file.get_line(line - 1).unwrap()),
+                        &normalize_whitespace(&file_lines.file.get_line(line - 1).unwrap()),
                         Style::Removal,
                     );
                 }
@@ -1926,7 +1926,7 @@ fn emit_suggestion_default(
                             buffer.putc(
                                 row_num,
                                 (padding as isize + p) as usize,
-                                if part.is_addition(&sm) { '+' } else { '~' },
+                                if part.is_addition(sm) { '+' } else { '~' },
                                 Style::Addition,
                             );
                         }
@@ -1973,7 +1973,7 @@ fn emit_suggestion_default(
             buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
         } else if notice_capitalization {
             let msg = "notice the capitalization difference";
-            buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
+            buffer.puts(row_num, max_line_num_len + 3, msg, Style::NoStyle);
         }
         emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
         Ok(())
@@ -2028,7 +2028,7 @@ fn emit_messages_default(
                     for child in children {
                         let span = child.render_span.as_ref().unwrap_or(&child.span);
                         if let Err(err) = self.emit_message_default(
-                            &span,
+                            span,
                             &child.message,
                             args,
                             &None,
@@ -2113,7 +2113,7 @@ fn draw_code_line(
                 *row_num - 1,
                 max_line_num_len + 3,
                 &normalize_whitespace(
-                    &*file_lines.file.get_line(file_lines.lines[line_pos].line_index).unwrap(),
+                    &file_lines.file.get_line(file_lines.lines[line_pos].line_index).unwrap(),
                 ),
                 Style::NoStyle,
             );
diff --git a/compiler/rustc_errors/src/json.rs b/compiler/rustc_errors/src/json.rs
index c4498eafa4e..a37073d8fa3 100644
--- a/compiler/rustc_errors/src/json.rs
+++ b/compiler/rustc_errors/src/json.rs
@@ -136,7 +136,7 @@ fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
     }
 
     fn fallback_fluent_bundle(&self) -> &FluentBundle {
-        &**self.fallback_bundle
+        &self.fallback_bundle
     }
 }
 
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 2be36a6eeb4..6176120b301 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -1328,7 +1328,7 @@ fn emit_diagnostic(&mut self, diagnostic: &mut Diagnostic) -> Option<ErrorGuaran
 
             diagnostic.children.drain_filter(already_emitted_sub).for_each(|_| {});
 
-            self.emitter.emit_diagnostic(&diagnostic);
+            self.emitter.emit_diagnostic(diagnostic);
             if diagnostic.is_error() {
                 self.deduplicated_err_count += 1;
             } else if let Warning(_) = diagnostic.level {
diff --git a/compiler/rustc_errors/src/translation.rs b/compiler/rustc_errors/src/translation.rs
index a452fac0747..afd660ff1bf 100644
--- a/compiler/rustc_errors/src/translation.rs
+++ b/compiler/rustc_errors/src/translation.rs
@@ -59,13 +59,13 @@ fn translate_message<'a>(
         trace!(?message, ?args);
         let (identifier, attr) = match message {
             DiagnosticMessage::Str(msg) | DiagnosticMessage::Eager(msg) => {
-                return Cow::Borrowed(&msg);
+                return Cow::Borrowed(msg);
             }
             DiagnosticMessage::FluentIdentifier(identifier, attr) => (identifier, attr),
         };
 
         let translate_with_bundle = |bundle: &'a FluentBundle| -> Option<(Cow<'_, str>, Vec<_>)> {
-            let message = bundle.get_message(&identifier)?;
+            let message = bundle.get_message(identifier)?;
             let value = match attr {
                 Some(attr) => message.get_attribute(attr)?.value(),
                 None => message.value()?,
@@ -73,7 +73,7 @@ fn translate_message<'a>(
             debug!(?message, ?value);
 
             let mut errs = vec![];
-            let translated = bundle.format_pattern(value, Some(&args), &mut errs);
+            let translated = bundle.format_pattern(value, Some(args), &mut errs);
             debug!(?translated, ?errs);
             Some((translated, errs))
         };
diff --git a/compiler/rustc_fs_util/src/lib.rs b/compiler/rustc_fs_util/src/lib.rs
index 63998bb6b00..a7dfce3b9b8 100644
--- a/compiler/rustc_fs_util/src/lib.rs
+++ b/compiler/rustc_fs_util/src/lib.rs
@@ -65,7 +65,7 @@ pub enum LinkOrCopy {
 pub fn link_or_copy<P: AsRef<Path>, Q: AsRef<Path>>(p: P, q: Q) -> io::Result<LinkOrCopy> {
     let p = p.as_ref();
     let q = q.as_ref();
-    match fs::remove_file(&q) {
+    match fs::remove_file(q) {
         Ok(()) => (),
         Err(err) if err.kind() == io::ErrorKind::NotFound => (),
         Err(err) => return Err(err),
diff --git a/compiler/rustc_graphviz/src/lib.rs b/compiler/rustc_graphviz/src/lib.rs
index 401d3f6689c..1f8268cc17c 100644
--- a/compiler/rustc_graphviz/src/lib.rs
+++ b/compiler/rustc_graphviz/src/lib.rs
@@ -410,7 +410,7 @@ pub fn new<Name: Into<Cow<'a, str>>>(name: Name) -> Result<Id<'a>, ()> {
     }
 
     pub fn as_slice(&'a self) -> &'a str {
-        &*self.name
+        &self.name
     }
 }
 
@@ -515,7 +515,7 @@ fn escape_str(s: &str) -> String {
     pub fn to_dot_string(&self) -> String {
         match *self {
             LabelStr(ref s) => format!("\"{}\"", s.escape_default()),
-            EscStr(ref s) => format!("\"{}\"", LabelText::escape_str(&s)),
+            EscStr(ref s) => format!("\"{}\"", LabelText::escape_str(s)),
             HtmlStr(ref s) => format!("<{}>", s),
         }
     }
@@ -529,7 +529,7 @@ fn pre_escaped_content(self) -> Cow<'a, str> {
             EscStr(s) => s,
             LabelStr(s) => {
                 if s.contains('\\') {
-                    (&*s).escape_default().to_string().into()
+                    s.escape_default().to_string().into()
                 } else {
                     s
                 }
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index 81aedcce877..658d4fd6c21 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -2431,7 +2431,7 @@ pub fn as_generic_param(&self) -> Option<(DefId, Ident)> {
     pub fn peel_refs(&self) -> &Self {
         let mut final_ty = self;
         while let TyKind::Rptr(_, MutTy { ty, .. }) = &final_ty.kind {
-            final_ty = &ty;
+            final_ty = ty;
         }
         final_ty
     }
diff --git a/compiler/rustc_hir/src/hir_id.rs b/compiler/rustc_hir/src/hir_id.rs
index 33f02a115ef..93613ef27d4 100644
--- a/compiler/rustc_hir/src/hir_id.rs
+++ b/compiler/rustc_hir/src/hir_id.rs
@@ -116,7 +116,7 @@ fn cmp(&self, other: &Self) -> std::cmp::Ordering {
 
 impl PartialOrd for HirId {
     fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        Some(self.cmp(&other))
+        Some(self.cmp(other))
     }
 }
 
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
index 957f8c1058e..d4c4875850d 100644
--- a/compiler/rustc_hir/src/intravisit.rs
+++ b/compiler/rustc_hir/src/intravisit.rs
@@ -448,7 +448,7 @@ fn visit_inline_asm(&mut self, asm: &'v InlineAsm<'v>, id: HirId) {
 
 pub fn walk_param<'v, V: Visitor<'v>>(visitor: &mut V, param: &'v Param<'v>) {
     visitor.visit_id(param.hir_id);
-    visitor.visit_pat(&param.pat);
+    visitor.visit_pat(param.pat);
 }
 
 pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item<'v>) {
@@ -470,7 +470,7 @@ pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item<'v>) {
         }
         ItemKind::Fn(ref sig, ref generics, body_id) => visitor.visit_fn(
             FnKind::ItemFn(item.ident, generics, sig.header),
-            &sig.decl,
+            sig.decl,
             body_id,
             item.span,
             item.hir_id(),
@@ -544,7 +544,7 @@ pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item<'v>) {
 
 pub fn walk_body<'v, V: Visitor<'v>>(visitor: &mut V, body: &'v Body<'v>) {
     walk_list!(visitor, visit_param, body.params);
-    visitor.visit_expr(&body.value);
+    visitor.visit_expr(body.value);
 }
 
 pub fn walk_ident<'v, V: Visitor<'v>>(visitor: &mut V, ident: Ident) {
@@ -580,7 +580,7 @@ pub fn walk_local<'v, V: Visitor<'v>>(visitor: &mut V, local: &'v Local<'v>) {
     // dominates the local's definition.
     walk_list!(visitor, visit_expr, &local.init);
     visitor.visit_id(local.hir_id);
-    visitor.visit_pat(&local.pat);
+    visitor.visit_pat(local.pat);
     if let Some(els) = local.els {
         visitor.visit_block(els);
     }
@@ -606,7 +606,7 @@ pub fn walk_stmt<'v, V: Visitor<'v>>(visitor: &mut V, statement: &'v Stmt<'v>) {
 
 pub fn walk_arm<'v, V: Visitor<'v>>(visitor: &mut V, arm: &'v Arm<'v>) {
     visitor.visit_id(arm.hir_id);
-    visitor.visit_pat(&arm.pat);
+    visitor.visit_pat(arm.pat);
     if let Some(ref g) = arm.guard {
         match g {
             Guard::If(ref e) => visitor.visit_expr(e),
@@ -615,7 +615,7 @@ pub fn walk_arm<'v, V: Visitor<'v>>(visitor: &mut V, arm: &'v Arm<'v>) {
             }
         }
     }
-    visitor.visit_expr(&arm.body);
+    visitor.visit_expr(arm.body);
 }
 
 pub fn walk_pat<'v, V: Visitor<'v>>(visitor: &mut V, pattern: &'v Pat<'v>) {
@@ -660,7 +660,7 @@ pub fn walk_pat<'v, V: Visitor<'v>>(visitor: &mut V, pattern: &'v Pat<'v>) {
 pub fn walk_pat_field<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v PatField<'v>) {
     visitor.visit_id(field.hir_id);
     visitor.visit_ident(field.ident);
-    visitor.visit_pat(&field.pat)
+    visitor.visit_pat(field.pat)
 }
 
 pub fn walk_array_len<'v, V: Visitor<'v>>(visitor: &mut V, len: &'v ArrayLen) {
@@ -799,7 +799,7 @@ pub fn walk_let_expr<'v, V: Visitor<'v>>(visitor: &mut V, let_expr: &'v Let<'v>)
 pub fn walk_expr_field<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v ExprField<'v>) {
     visitor.visit_id(field.hir_id);
     visitor.visit_ident(field.ident);
-    visitor.visit_expr(&field.expr)
+    visitor.visit_expr(field.expr)
 }
 
 pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) {
@@ -807,10 +807,10 @@ pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) {
 
     match typ.kind {
         TyKind::Slice(ref ty) => visitor.visit_ty(ty),
-        TyKind::Ptr(ref mutable_type) => visitor.visit_ty(&mutable_type.ty),
+        TyKind::Ptr(ref mutable_type) => visitor.visit_ty(mutable_type.ty),
         TyKind::Rptr(ref lifetime, ref mutable_type) => {
             visitor.visit_lifetime(lifetime);
-            visitor.visit_ty(&mutable_type.ty)
+            visitor.visit_ty(mutable_type.ty)
         }
         TyKind::Never => {}
         TyKind::Tup(tuple_element_types) => {
@@ -818,7 +818,7 @@ pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) {
         }
         TyKind::BareFn(ref function_declaration) => {
             walk_list!(visitor, visit_generic_param, function_declaration.generic_params);
-            visitor.visit_fn_decl(&function_declaration.decl);
+            visitor.visit_fn_decl(function_declaration.decl);
         }
         TyKind::Path(ref qpath) => {
             visitor.visit_qpath(qpath, typ.hir_id, typ.span);
@@ -948,8 +948,8 @@ pub fn walk_trait_item<'v, V: Visitor<'v>>(visitor: &mut V, trait_item: &'v Trai
     let TraitItem { ident, generics, ref defaultness, ref kind, span, owner_id: _ } = *trait_item;
     let hir_id = trait_item.hir_id();
     visitor.visit_ident(ident);
-    visitor.visit_generics(&generics);
-    visitor.visit_defaultness(&defaultness);
+    visitor.visit_generics(generics);
+    visitor.visit_defaultness(defaultness);
     match *kind {
         TraitItemKind::Const(ref ty, default) => {
             visitor.visit_id(hir_id);
@@ -958,13 +958,13 @@ pub fn walk_trait_item<'v, V: Visitor<'v>>(visitor: &mut V, trait_item: &'v Trai
         }
         TraitItemKind::Fn(ref sig, TraitFn::Required(param_names)) => {
             visitor.visit_id(hir_id);
-            visitor.visit_fn_decl(&sig.decl);
+            visitor.visit_fn_decl(sig.decl);
             for &param_name in param_names {
                 visitor.visit_ident(param_name);
             }
         }
         TraitItemKind::Fn(ref sig, TraitFn::Provided(body_id)) => {
-            visitor.visit_fn(FnKind::Method(ident, sig), &sig.decl, body_id, span, hir_id);
+            visitor.visit_fn(FnKind::Method(ident, sig), sig.decl, body_id, span, hir_id);
         }
         TraitItemKind::Type(bounds, ref default) => {
             visitor.visit_id(hir_id);
@@ -1006,7 +1006,7 @@ pub fn walk_impl_item<'v, V: Visitor<'v>>(visitor: &mut V, impl_item: &'v ImplIt
         ImplItemKind::Fn(ref sig, body_id) => {
             visitor.visit_fn(
                 FnKind::Method(impl_item.ident, sig),
-                &sig.decl,
+                sig.decl,
                 body_id,
                 impl_item.span,
                 impl_item.hir_id(),
@@ -1039,7 +1039,7 @@ pub fn walk_impl_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, impl_item_ref: &'
 
 pub fn walk_trait_ref<'v, V: Visitor<'v>>(visitor: &mut V, trait_ref: &'v TraitRef<'v>) {
     visitor.visit_id(trait_ref.hir_ref_id);
-    visitor.visit_path(&trait_ref.path, trait_ref.hir_ref_id)
+    visitor.visit_path(trait_ref.path, trait_ref.hir_ref_id)
 }
 
 pub fn walk_param_bound<'v, V: Visitor<'v>>(visitor: &mut V, bound: &'v GenericBound<'v>) {
@@ -1071,7 +1071,7 @@ pub fn walk_struct_def<'v, V: Visitor<'v>>(
 pub fn walk_field_def<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v FieldDef<'v>) {
     visitor.visit_id(field.hir_id);
     visitor.visit_ident(field.ident);
-    visitor.visit_ty(&field.ty);
+    visitor.visit_ty(field.ty);
 }
 
 pub fn walk_enum_def<'v, V: Visitor<'v>>(
diff --git a/compiler/rustc_macros/src/diagnostics/diagnostic.rs b/compiler/rustc_macros/src/diagnostics/diagnostic.rs
index be9821c00f5..684835d8c5c 100644
--- a/compiler/rustc_macros/src/diagnostics/diagnostic.rs
+++ b/compiler/rustc_macros/src/diagnostics/diagnostic.rs
@@ -29,8 +29,8 @@ pub(crate) fn into_tokens(self) -> TokenStream {
         let DiagnosticDerive { mut structure, mut builder } = self;
 
         let implementation = builder.each_variant(&mut structure, |mut builder, variant| {
-            let preamble = builder.preamble(&variant);
-            let body = builder.body(&variant);
+            let preamble = builder.preamble(variant);
+            let body = builder.body(variant);
 
             let diag = &builder.parent.diag;
             let DiagnosticDeriveKind::Diagnostic { handler } = &builder.parent.kind else {
@@ -39,7 +39,7 @@ pub(crate) fn into_tokens(self) -> TokenStream {
             let init = match builder.slug.value_ref() {
                 None => {
                     span_err(builder.span, "diagnostic slug not specified")
-                        .help(&format!(
+                        .help(format!(
                             "specify the slug as the first argument to the `#[diag(...)]` \
                             attribute, such as `#[diag(hir_analysis_example_error)]`",
                         ))
@@ -48,10 +48,10 @@ pub(crate) fn into_tokens(self) -> TokenStream {
                 }
                 Some(slug) if let Some( Mismatch { slug_name, crate_name, slug_prefix }) = Mismatch::check(slug) => {
                     span_err(slug.span().unwrap(), "diagnostic slug and crate name do not match")
-                        .note(&format!(
+                        .note(format!(
                             "slug is `{slug_name}` but the crate name is `{crate_name}`"
                         ))
-                        .help(&format!(
+                        .help(format!(
                             "expected a slug starting with `{slug_prefix}_...`"
                         ))
                         .emit();
@@ -113,8 +113,8 @@ pub(crate) fn into_tokens(self) -> TokenStream {
         let LintDiagnosticDerive { mut structure, mut builder } = self;
 
         let implementation = builder.each_variant(&mut structure, |mut builder, variant| {
-            let preamble = builder.preamble(&variant);
-            let body = builder.body(&variant);
+            let preamble = builder.preamble(variant);
+            let body = builder.body(variant);
 
             let diag = &builder.parent.diag;
             let formatting_init = &builder.formatting_init;
@@ -128,28 +128,28 @@ pub(crate) fn into_tokens(self) -> TokenStream {
 
         let msg = builder.each_variant(&mut structure, |mut builder, variant| {
             // Collect the slug by generating the preamble.
-            let _ = builder.preamble(&variant);
+            let _ = builder.preamble(variant);
 
             match builder.slug.value_ref() {
                 None => {
                     span_err(builder.span, "diagnostic slug not specified")
-                        .help(&format!(
+                        .help(format!(
                             "specify the slug as the first argument to the attribute, such as \
                             `#[diag(compiletest_example)]`",
                         ))
                         .emit();
-                    return DiagnosticDeriveError::ErrorHandled.to_compile_error();
+                    DiagnosticDeriveError::ErrorHandled.to_compile_error()
                 }
                 Some(slug) if let Some( Mismatch { slug_name, crate_name, slug_prefix }) = Mismatch::check(slug) => {
                     span_err(slug.span().unwrap(), "diagnostic slug and crate name do not match")
-                        .note(&format!(
+                        .note(format!(
                             "slug is `{slug_name}` but the crate name is `{crate_name}`"
                         ))
-                        .help(&format!(
+                        .help(format!(
                             "expected a slug starting with `{slug_prefix}_...`"
                         ))
                         .emit();
-                    return DiagnosticDeriveError::ErrorHandled.to_compile_error();
+                    DiagnosticDeriveError::ErrorHandled.to_compile_error()
                 }
                 Some(slug) => {
                     quote! {
diff --git a/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs b/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
index 3ea83fd09c7..9f2ac5112f1 100644
--- a/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
+++ b/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
@@ -100,7 +100,7 @@ pub fn each_variant<'s, F>(&mut self, structure: &mut Structure<'s>, f: F) -> To
                 _ => variant.ast().ident.span().unwrap(),
             };
             let builder = DiagnosticDeriveVariantBuilder {
-                parent: &self,
+                parent: self,
                 span,
                 field_map: build_field_mapping(variant),
                 formatting_init: TokenStream::new(),
@@ -211,7 +211,7 @@ fn generate_structure_code_for_attr(
                     nested_iter.next();
                 }
                 Some(NestedMeta::Meta(Meta::NameValue { .. })) => {}
-                Some(nested_attr) => throw_invalid_nested_attr!(attr, &nested_attr, |diag| diag
+                Some(nested_attr) => throw_invalid_nested_attr!(attr, nested_attr, |diag| diag
                     .help("a diagnostic slug is required as the first argument")),
                 None => throw_invalid_attr!(attr, &meta, |diag| diag
                     .help("a diagnostic slug is required as the first argument")),
@@ -227,13 +227,13 @@ fn generate_structure_code_for_attr(
                         ..
                     })) => (value, path),
                     NestedMeta::Meta(Meta::Path(_)) => {
-                        invalid_nested_attr(attr, &nested_attr)
+                        invalid_nested_attr(attr, nested_attr)
                             .help("diagnostic slug must be the first argument")
                             .emit();
                         continue;
                     }
                     _ => {
-                        invalid_nested_attr(attr, &nested_attr).emit();
+                        invalid_nested_attr(attr, nested_attr).emit();
                         continue;
                     }
                 };
@@ -251,7 +251,7 @@ fn generate_structure_code_for_attr(
                             #diag.code(rustc_errors::DiagnosticId::Error(#code.to_string()));
                         });
                     }
-                    _ => invalid_nested_attr(attr, &nested_attr)
+                    _ => invalid_nested_attr(attr, nested_attr)
                         .help("only `code` is a valid nested attributes following the slug")
                         .emit(),
                 }
@@ -427,9 +427,9 @@ fn generate_inner_field_code(
                 Ok(self.add_spanned_subdiagnostic(binding, &fn_ident, slug))
             }
             SubdiagnosticKind::Note | SubdiagnosticKind::Help | SubdiagnosticKind::Warn => {
-                if type_matches_path(&info.ty, &["rustc_span", "Span"]) {
+                if type_matches_path(info.ty, &["rustc_span", "Span"]) {
                     Ok(self.add_spanned_subdiagnostic(binding, &fn_ident, slug))
-                } else if type_is_unit(&info.ty) {
+                } else if type_is_unit(info.ty) {
                     Ok(self.add_subdiagnostic(&fn_ident, slug))
                 } else {
                     report_type_error(attr, "`Span` or `()`")?
diff --git a/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs b/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
index fa0ca5a5242..446aebe4f83 100644
--- a/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
+++ b/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
@@ -409,7 +409,7 @@ fn generate_field_code_inner_list(
                 let mut code = None;
                 for nested_attr in list.nested.iter() {
                     let NestedMeta::Meta(ref meta) = nested_attr else {
-                        throw_invalid_nested_attr!(attr, &nested_attr);
+                        throw_invalid_nested_attr!(attr, nested_attr);
                     };
 
                     let span = meta.span().unwrap();
@@ -427,7 +427,7 @@ fn generate_field_code_inner_list(
                             );
                             code.set_once((code_field, formatting_init), span);
                         }
-                        _ => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
+                        _ => throw_invalid_nested_attr!(attr, nested_attr, |diag| {
                             diag.help("`code` is the only valid nested attribute")
                         }),
                     }
diff --git a/compiler/rustc_macros/src/diagnostics/utils.rs b/compiler/rustc_macros/src/diagnostics/utils.rs
index dff088b9bdf..da90233523c 100644
--- a/compiler/rustc_macros/src/diagnostics/utils.rs
+++ b/compiler/rustc_macros/src/diagnostics/utils.rs
@@ -80,7 +80,7 @@ fn report_error_if_not_applied_to_ty(
     path: &[&str],
     ty_name: &str,
 ) -> Result<(), DiagnosticDeriveError> {
-    if !type_matches_path(&info.ty, path) {
+    if !type_matches_path(info.ty, path) {
         report_type_error(attr, ty_name)?;
     }
 
@@ -105,8 +105,8 @@ pub(crate) fn report_error_if_not_applied_to_span(
     attr: &Attribute,
     info: &FieldInfo<'_>,
 ) -> Result<(), DiagnosticDeriveError> {
-    if !type_matches_path(&info.ty, &["rustc_span", "Span"])
-        && !type_matches_path(&info.ty, &["rustc_errors", "MultiSpan"])
+    if !type_matches_path(info.ty, &["rustc_span", "Span"])
+        && !type_matches_path(info.ty, &["rustc_errors", "MultiSpan"])
     {
         report_type_error(attr, "`Span` or `MultiSpan`")?;
     }
@@ -686,7 +686,7 @@ pub(super) fn from_attr(
             let meta = match nested_attr {
                 NestedMeta::Meta(ref meta) => meta,
                 NestedMeta::Lit(_) => {
-                    invalid_nested_attr(attr, &nested_attr).emit();
+                    invalid_nested_attr(attr, nested_attr).emit();
                     continue;
                 }
             };
@@ -698,7 +698,7 @@ pub(super) fn from_attr(
             let string_value = match meta {
                 Meta::NameValue(MetaNameValue { lit: syn::Lit::Str(value), .. }) => Some(value),
 
-                Meta::Path(_) => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
+                Meta::Path(_) => throw_invalid_nested_attr!(attr, nested_attr, |diag| {
                     diag.help("a diagnostic slug must be the first argument to the attribute")
                 }),
                 _ => None,
@@ -720,7 +720,7 @@ pub(super) fn from_attr(
                     | SubdiagnosticKind::MultipartSuggestion { ref mut applicability, .. },
                 ) => {
                     let Some(value) = string_value else {
-                        invalid_nested_attr(attr, &nested_attr).emit();
+                        invalid_nested_attr(attr, nested_attr).emit();
                         continue;
                     };
 
@@ -736,7 +736,7 @@ pub(super) fn from_attr(
                     | SubdiagnosticKind::MultipartSuggestion { .. },
                 ) => {
                     let Some(value) = string_value else {
-                        invalid_nested_attr(attr, &nested_attr).emit();
+                        invalid_nested_attr(attr, nested_attr).emit();
                         continue;
                     };
 
@@ -752,19 +752,19 @@ pub(super) fn from_attr(
 
                 // Invalid nested attribute
                 (_, SubdiagnosticKind::Suggestion { .. }) => {
-                    invalid_nested_attr(attr, &nested_attr)
+                    invalid_nested_attr(attr, nested_attr)
                         .help(
                             "only `style`, `code` and `applicability` are valid nested attributes",
                         )
                         .emit();
                 }
                 (_, SubdiagnosticKind::MultipartSuggestion { .. }) => {
-                    invalid_nested_attr(attr, &nested_attr)
+                    invalid_nested_attr(attr, nested_attr)
                         .help("only `style` and `applicability` are valid nested attributes")
                         .emit()
                 }
                 _ => {
-                    invalid_nested_attr(attr, &nested_attr).emit();
+                    invalid_nested_attr(attr, nested_attr).emit();
                 }
             }
         }
diff --git a/compiler/rustc_session/src/cgu_reuse_tracker.rs b/compiler/rustc_session/src/cgu_reuse_tracker.rs
index 2336d99363f..8703e575465 100644
--- a/compiler/rustc_session/src/cgu_reuse_tracker.rs
+++ b/compiler/rustc_session/src/cgu_reuse_tracker.rs
@@ -121,7 +121,7 @@ pub fn check_expected_reuse(&self, sess: &Session) {
                         let at_least = if at_least { 1 } else { 0 };
                         IncorrectCguReuseType {
                             span: error_span.0,
-                            cgu_user_name: &cgu_user_name,
+                            cgu_user_name,
                             actual_reuse,
                             expected_reuse,
                             at_least,
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 927810351e9..d8c4b0845d0 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -622,7 +622,7 @@ pub fn path(&self, flavor: OutputType) -> PathBuf {
     /// should be placed on disk.
     pub fn output_path(&self, flavor: OutputType) -> PathBuf {
         let extension = flavor.extension();
-        self.with_directory_and_extension(&self.out_directory, &extension)
+        self.with_directory_and_extension(&self.out_directory, extension)
     }
 
     /// Gets the path where a compilation artifact of the given type for the
@@ -659,7 +659,7 @@ pub fn temp_path_ext(&self, ext: &str, codegen_unit_name: Option<&str>) -> PathB
 
         let temps_directory = self.temps_directory.as_ref().unwrap_or(&self.out_directory);
 
-        self.with_directory_and_extension(&temps_directory, &extension)
+        self.with_directory_and_extension(temps_directory, &extension)
     }
 
     pub fn with_extension(&self, extension: &str) -> PathBuf {
@@ -1159,7 +1159,7 @@ fn fill_well_known_values(&mut self) {
                 values_target_family
                     .extend(target.options.families.iter().map(|family| Symbol::intern(family)));
                 values_target_arch.insert(Symbol::intern(&target.arch));
-                values_target_endian.insert(Symbol::intern(&target.options.endian.as_str()));
+                values_target_endian.insert(Symbol::intern(target.options.endian.as_str()));
                 values_target_env.insert(Symbol::intern(&target.options.env));
                 values_target_abi.insert(Symbol::intern(&target.options.abi));
                 values_target_vendor.insert(Symbol::intern(&target.options.vendor));
@@ -1846,7 +1846,7 @@ pub fn parse_target_triple(
     match matches.opt_str("target") {
         Some(target) if target.ends_with(".json") => {
             let path = Path::new(&target);
-            TargetTriple::from_path(&path).unwrap_or_else(|_| {
+            TargetTriple::from_path(path).unwrap_or_else(|_| {
                 early_error(error_format, &format!("target file {path:?} does not exist"))
             })
         }
@@ -1992,7 +1992,7 @@ fn parse_native_lib_modifiers(
 ) -> (NativeLibKind, Option<bool>) {
     let mut verbatim = None;
     for modifier in modifiers.split(',') {
-        let (modifier, value) = match modifier.strip_prefix(&['+', '-']) {
+        let (modifier, value) = match modifier.strip_prefix(['+', '-']) {
             Some(m) => (m, modifier.starts_with('+')),
             None => early_error(
                 error_format,
@@ -2421,7 +2421,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
 
     let mut search_paths = vec![];
     for s in &matches.opt_strs("L") {
-        search_paths.push(SearchPath::from_cli_opt(&s, error_format));
+        search_paths.push(SearchPath::from_cli_opt(s, error_format));
     }
 
     let libs = parse_libs(matches, error_format);
diff --git a/compiler/rustc_session/src/errors.rs b/compiler/rustc_session/src/errors.rs
index 2f7055e3cc5..a580a996c5c 100644
--- a/compiler/rustc_session/src/errors.rs
+++ b/compiler/rustc_session/src/errors.rs
@@ -321,7 +321,7 @@ fn fix_base_capitalisation(s: &str) -> Option<String> {
         LitError::InvalidIntSuffix => {
             let suf = suffix.expect("suffix error with no suffix");
             let suf = suf.as_str();
-            if looks_like_width_suffix(&['i', 'u'], &suf) {
+            if looks_like_width_suffix(&['i', 'u'], suf) {
                 // If it looks like a width, try to be helpful.
                 sess.emit_err(InvalidIntLiteralWidth { span, width: suf[1..].into() });
             } else if let Some(fixed) = fix_base_capitalisation(suf) {
diff --git a/compiler/rustc_span/src/analyze_source_file.rs b/compiler/rustc_span/src/analyze_source_file.rs
index 47aa4dfba42..d3c2c5113bc 100644
--- a/compiler/rustc_span/src/analyze_source_file.rs
+++ b/compiler/rustc_span/src/analyze_source_file.rs
@@ -247,7 +247,7 @@ fn analyze_source_file_generic(
             // The slow path:
             // This is either ASCII control character "DEL" or the beginning of
             // a multibyte char. Just decode to `char`.
-            let c = (&src[i..]).chars().next().unwrap();
+            let c = src[i..].chars().next().unwrap();
             char_len = c.len_utf8();
 
             let pos = BytePos::from_usize(i) + output_offset;
diff --git a/compiler/rustc_span/src/caching_source_map_view.rs b/compiler/rustc_span/src/caching_source_map_view.rs
index fdabf404a37..886112769a9 100644
--- a/compiler/rustc_span/src/caching_source_map_view.rs
+++ b/compiler/rustc_span/src/caching_source_map_view.rs
@@ -165,7 +165,7 @@ pub fn span_data_to_lines_and_cols(
             Some(new_file_and_idx)
         } else {
             let file = &self.line_cache[oldest].file;
-            if !file_contains(&file, span_data.hi) {
+            if !file_contains(file, span_data.hi) {
                 return None;
             }
 
diff --git a/compiler/rustc_span/src/hygiene.rs b/compiler/rustc_span/src/hygiene.rs
index 99a8b03fa39..038699154c7 100644
--- a/compiler/rustc_span/src/hygiene.rs
+++ b/compiler/rustc_span/src/hygiene.rs
@@ -381,7 +381,7 @@ pub(crate) fn new(edition: Edition) -> Self {
     }
 
     pub fn with<T, F: FnOnce(&mut HygieneData) -> T>(f: F) -> T {
-        with_session_globals(|session_globals| f(&mut *session_globals.hygiene_data.borrow_mut()))
+        with_session_globals(|session_globals| f(&mut session_globals.hygiene_data.borrow_mut()))
     }
 
     #[inline]
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 1065cd384a9..cef4c6f79ce 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -238,7 +238,7 @@ pub fn into_local_path(self) -> Option<PathBuf> {
     pub fn remapped_path_if_available(&self) -> &Path {
         match self {
             RealFileName::LocalPath(p)
-            | RealFileName::Remapped { local_path: _, virtual_name: p } => &p,
+            | RealFileName::Remapped { local_path: _, virtual_name: p } => p,
         }
     }
 
diff --git a/compiler/rustc_span/src/span_encoding.rs b/compiler/rustc_span/src/span_encoding.rs
index b3de6741594..f0e91e5a6a9 100644
--- a/compiler/rustc_span/src/span_encoding.rs
+++ b/compiler/rustc_span/src/span_encoding.rs
@@ -166,5 +166,5 @@ fn intern(&mut self, span_data: &SpanData) -> u32 {
 // If an interner exists, return it. Otherwise, prepare a fresh one.
 #[inline]
 fn with_span_interner<T, F: FnOnce(&mut SpanInterner) -> T>(f: F) -> T {
-    crate::with_session_globals(|session_globals| f(&mut *session_globals.span_interner.lock()))
+    crate::with_session_globals(|session_globals| f(&mut session_globals.span_interner.lock()))
 }
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 739716cfce3..240c28b5888 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -1876,7 +1876,7 @@ impl<S: Encoder> Encodable<S> for Symbol {
 impl<D: Decoder> Decodable<D> for Symbol {
     #[inline]
     default fn decode(d: &mut D) -> Symbol {
-        Symbol::intern(&d.read_str())
+        Symbol::intern(d.read_str())
     }
 }
 
diff --git a/compiler/rustc_target/src/abi/call/sparc64.rs b/compiler/rustc_target/src/abi/call/sparc64.rs
index ec8f20fe692..c8b6ac5ae25 100644
--- a/compiler/rustc_target/src/abi/call/sparc64.rs
+++ b/compiler/rustc_target/src/abi/call/sparc64.rs
@@ -78,7 +78,7 @@ fn arg_scalar_pair<C>(
 where
     C: HasDataLayout,
 {
-    data = arg_scalar(cx, &scalar1, offset, data);
+    data = arg_scalar(cx, scalar1, offset, data);
     match (scalar1.primitive(), scalar2.primitive()) {
         (abi::F32, _) => offset += Reg::f32().size,
         (_, abi::F64) => offset += Reg::f64().size,
@@ -90,7 +90,7 @@ fn arg_scalar_pair<C>(
     if (offset.bytes() % 4) != 0 && scalar2.primitive().is_float() {
         offset += Size::from_bytes(4 - (offset.bytes() % 4));
     }
-    data = arg_scalar(cx, &scalar2, offset, data);
+    data = arg_scalar(cx, scalar2, offset, data);
     return data;
 }
 
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index 0f8cfd7f538..5163d4f6f2a 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -2746,7 +2746,7 @@ fn load_file(path: &Path) -> Result<(Target, TargetWarnings), String> {
 
                 // Additionally look in the sysroot under `lib/rustlib/<triple>/target.json`
                 // as a fallback.
-                let rustlib_path = crate::target_rustlib_path(&sysroot, &target_triple);
+                let rustlib_path = crate::target_rustlib_path(sysroot, target_triple);
                 let p = PathBuf::from_iter([
                     Path::new(sysroot),
                     Path::new(&rustlib_path),