Cut some needless muts in compiler

compiler/rustc_ast_lowering/src/block.rs

@@ -114,7 +114,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.arena.alloc(hir::LetStmt { hir_id, super_, ty, pat, init, els, span, source })
     }
 
-    fn lower_block_check_mode(&mut self, b: &BlockCheckMode) -> hir::BlockCheckMode {
+    fn lower_block_check_mode(&self, b: &BlockCheckMode) -> hir::BlockCheckMode {
         match *b {
             BlockCheckMode::Default => hir::BlockCheckMode::DefaultBlock,
             BlockCheckMode::Unsafe(u) => {

compiler/rustc_ast_lowering/src/delegation.rs

@@ -122,7 +122,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         })
     }
 
-    fn lower_delegation_generics(&mut self, span: Span) -> &'hir hir::Generics<'hir> {
+    fn lower_delegation_generics(&self, span: Span) -> &'hir hir::Generics<'hir> {
         self.arena.alloc(hir::Generics {
             params: &[],
             predicates: &[],
@@ -179,7 +179,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     fn lower_delegation_sig(
-        &mut self,
+        &self,
         sig_id: DefId,
         decl: &'hir hir::FnDecl<'hir>,
         span: Span,

compiler/rustc_ast_lowering/src/expr.rs

@@ -424,7 +424,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         })
     }
 
-    pub(crate) fn lower_lit(&mut self, token_lit: &token::Lit, span: Span) -> hir::Lit {
+    pub(crate) fn lower_lit(&self, token_lit: &token::Lit, span: Span) -> hir::Lit {
         let lit_kind = match LitKind::from_token_lit(*token_lit) {
             Ok(lit_kind) => lit_kind,
             Err(err) => {
@@ -435,19 +435,19 @@ impl<'hir> LoweringContext<'_, 'hir> {
         respan(self.lower_span(span), lit_kind)
     }
 
-    fn lower_unop(&mut self, u: UnOp) -> hir::UnOp {
+    fn lower_unop(&self, u: UnOp) -> hir::UnOp {
         match u {
             UnOp::Deref => hir::UnOp::Deref,
             UnOp::Not => hir::UnOp::Not,
             UnOp::Neg => hir::UnOp::Neg,
         }
     }
 
-    fn lower_binop(&mut self, b: BinOp) -> BinOp {
+    fn lower_binop(&self, b: BinOp) -> BinOp {
         Spanned { node: b.node, span: self.lower_span(b.span) }
     }
 
-    fn lower_assign_op(&mut self, a: AssignOp) -> AssignOp {
+    fn lower_assign_op(&self, a: AssignOp) -> AssignOp {
         Spanned { node: a.node, span: self.lower_span(a.span) }
     }
 
@@ -681,7 +681,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         hir::Arm { hir_id, pat, guard, body, span }
     }
 
-    fn lower_capture_clause(&mut self, capture_clause: CaptureBy) -> CaptureBy {
+    fn lower_capture_clause(&self, capture_clause: CaptureBy) -> CaptureBy {
         match capture_clause {
             CaptureBy::Ref => CaptureBy::Ref,
             CaptureBy::Use { use_kw } => CaptureBy::Use { use_kw: self.lower_span(use_kw) },
@@ -1103,7 +1103,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     fn closure_movability_for_fn(
-        &mut self,
+        &self,
         decl: &FnDecl,
         fn_decl_span: Span,
         coroutine_kind: Option<hir::CoroutineKind>,
@@ -1133,7 +1133,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     fn lower_closure_binder<'c>(
-        &mut self,
+        &self,
         binder: &'c ClosureBinder,
     ) -> (hir::ClosureBinder, &'c [GenericParam]) {
         let (binder, params) = match binder {
@@ -1283,7 +1283,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     /// if they are not tuple structs.
     /// Type checking will take care of the full validation later.
     fn extract_tuple_struct_path<'a>(
-        &mut self,
+        &self,
         expr: &'a Expr,
     ) -> Option<(&'a Option<Box<QSelf>>, &'a Path)> {
         if let ExprKind::Path(qself, path) = &expr.kind {
@@ -1305,7 +1305,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     /// if they are not unit structs.
     /// Type checking will take care of the full validation later.
     fn extract_unit_struct_path<'a>(
-        &mut self,
+        &self,
         expr: &'a Expr,
     ) -> Option<(&'a Option<Box<QSelf>>, &'a Path)> {
         if let ExprKind::Path(qself, path) = &expr.kind {
@@ -1589,7 +1589,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         Some(Label { ident: self.lower_ident(label.ident) })
     }
 
-    fn lower_loop_destination(&mut self, destination: Option<(NodeId, Label)>) -> hir::Destination {
+    fn lower_loop_destination(&self, destination: Option<(NodeId, Label)>) -> hir::Destination {
         let target_id = match destination {
             Some((id, _)) => {
                 if let Some(loop_id) = self.resolver.get_label_res(id) {
@@ -1610,7 +1610,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         hir::Destination { label, target_id }
     }
 
-    fn lower_jump_destination(&mut self, id: NodeId, opt_label: Option<Label>) -> hir::Destination {
+    fn lower_jump_destination(&self, id: NodeId, opt_label: Option<Label>) -> hir::Destination {
         if self.is_in_loop_condition && opt_label.is_none() {
             hir::Destination {
                 label: None,

compiler/rustc_ast_lowering/src/item.rs

@@ -685,7 +685,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         self.arena.alloc(item)
     }
 
-    fn lower_foreign_item_ref(&mut self, i: &ForeignItem) -> hir::ForeignItemId {
+    fn lower_foreign_item_ref(&self, i: &ForeignItem) -> hir::ForeignItemId {
         hir::ForeignItemId { owner_id: self.owner_id(i.id) }
     }
 
@@ -951,7 +951,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         self.arena.alloc(item)
     }
 
-    fn lower_trait_item_ref(&mut self, i: &AssocItem) -> hir::TraitItemId {
+    fn lower_trait_item_ref(&self, i: &AssocItem) -> hir::TraitItemId {
         hir::TraitItemId { owner_id: self.owner_id(i.id) }
     }
 
@@ -1135,7 +1135,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         self.arena.alloc(item)
     }
 
-    fn lower_impl_item_ref(&mut self, i: &AssocItem) -> hir::ImplItemId {
+    fn lower_impl_item_ref(&self, i: &AssocItem) -> hir::ImplItemId {
         hir::ImplItemId { owner_id: self.owner_id(i.id) }
     }
 
@@ -1582,7 +1582,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     pub(super) fn lower_fn_header(
-        &mut self,
+        &self,
         h: FnHeader,
         default_safety: hir::Safety,
         attrs: &[hir::Attribute],
@@ -1613,7 +1613,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         }
     }
 
-    pub(super) fn lower_abi(&mut self, abi_str: StrLit) -> ExternAbi {
+    pub(super) fn lower_abi(&self, abi_str: StrLit) -> ExternAbi {
         let ast::StrLit { symbol_unescaped, span, .. } = abi_str;
         let extern_abi = symbol_unescaped.as_str().parse().unwrap_or_else(|_| {
             self.error_on_invalid_abi(abi_str);
@@ -1645,7 +1645,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         extern_abi
     }
 
-    pub(super) fn lower_extern(&mut self, ext: Extern) -> ExternAbi {
+    pub(super) fn lower_extern(&self, ext: Extern) -> ExternAbi {
         match ext {
             Extern::None => ExternAbi::Rust,
             Extern::Implicit(_) => ExternAbi::FALLBACK,
@@ -1670,7 +1670,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         });
     }
 
-    pub(super) fn lower_constness(&mut self, c: Const) -> hir::Constness {
+    pub(super) fn lower_constness(&self, c: Const) -> hir::Constness {
         match c {
             Const::Yes(_) => hir::Constness::Const,
             Const::No => hir::Constness::NotConst,

compiler/rustc_ast_lowering/src/lib.rs

@@ -732,7 +732,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     }
 
     #[instrument(level = "trace", skip(self))]
-    fn lower_res(&mut self, res: Res<NodeId>) -> Res {
+    fn lower_res(&self, res: Res<NodeId>) -> Res {
         let res: Result<Res, ()> = res.apply_id(|id| {
             let owner = self.current_hir_id_owner;
             let local_id = self.ident_and_label_to_local_id.get(&id).copied().ok_or(())?;
@@ -748,11 +748,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         res.unwrap_or(Res::Err)
     }
 
-    fn expect_full_res(&mut self, id: NodeId) -> Res<NodeId> {
+    fn expect_full_res(&self, id: NodeId) -> Res<NodeId> {
         self.resolver.get_partial_res(id).map_or(Res::Err, |pr| pr.expect_full_res())
     }
 
-    fn lower_import_res(&mut self, id: NodeId, span: Span) -> PerNS<Option<Res>> {
+    fn lower_import_res(&self, id: NodeId, span: Span) -> PerNS<Option<Res>> {
         let per_ns = self.resolver.get_import_res(id);
         let per_ns = per_ns.map(|res| res.map(|res| self.lower_res(res)));
         if per_ns.is_empty() {
@@ -1595,7 +1595,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }))
     }
 
-    fn lower_fn_params_to_idents(&mut self, decl: &FnDecl) -> &'hir [Option<Ident>] {
+    fn lower_fn_params_to_idents(&self, decl: &FnDecl) -> &'hir [Option<Ident>] {
         self.arena.alloc_from_iter(decl.inputs.iter().map(|param| match param.pat.kind {
             PatKind::Missing => None,
             PatKind::Ident(_, ident, _) => Some(self.lower_ident(ident)),
@@ -2365,15 +2365,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }))
     }
 
-    fn lower_unsafe_source(&mut self, u: UnsafeSource) -> hir::UnsafeSource {
+    fn lower_unsafe_source(&self, u: UnsafeSource) -> hir::UnsafeSource {
         match u {
             CompilerGenerated => hir::UnsafeSource::CompilerGenerated,
             UserProvided => hir::UnsafeSource::UserProvided,
         }
     }
 
     fn lower_trait_bound_modifiers(
-        &mut self,
+        &self,
         modifiers: TraitBoundModifiers,
     ) -> hir::TraitBoundModifiers {
         let constness = match modifiers.constness {

compiler/rustc_ast_lowering/src/pat.rs

@@ -331,13 +331,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
     }
 
-    fn pat_wild_with_node_id_of(&mut self, p: &Pat, hir_id: hir::HirId) -> &'hir hir::Pat<'hir> {
+    fn pat_wild_with_node_id_of(&self, p: &Pat, hir_id: hir::HirId) -> &'hir hir::Pat<'hir> {
         self.arena.alloc(self.pat_with_node_id_of(p, hir::PatKind::Wild, hir_id))
     }
 
     /// Construct a `Pat` with the `HirId` of `p.id` already lowered.
     fn pat_with_node_id_of(
-        &mut self,
+        &self,
         p: &Pat,
         kind: hir::PatKind<'hir>,
         hir_id: hir::HirId,
@@ -360,7 +360,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         hir::PatKind::Wild
     }
 
-    fn lower_range_end(&mut self, e: &RangeEnd, has_end: bool) -> hir::RangeEnd {
+    fn lower_range_end(&self, e: &RangeEnd, has_end: bool) -> hir::RangeEnd {
         match *e {
             RangeEnd::Excluded if has_end => hir::RangeEnd::Excluded,
             // No end; so `X..` behaves like `RangeFrom`.

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -142,7 +142,7 @@ impl<'a> AstValidator<'a> {
     }
 
     fn check_type_alias_where_clause_location(
-        &mut self,
+        &self,
         ty_alias: &TyAlias,
     ) -> Result<(), errors::WhereClauseBeforeTypeAlias> {
         if ty_alias.ty.is_none() || !ty_alias.where_clauses.before.has_where_token {

compiler/rustc_attr_parsing/src/attributes/cfg.rs

@@ -90,7 +90,7 @@ fn parse_cfg_entry<S: Stage>(
 }
 
 fn parse_cfg_entry_version<S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
+    cx: &AcceptContext<'_, '_, S>,
     list: &MetaItemListParser<'_>,
     meta_span: Span,
 ) -> Option<CfgEntry> {
@@ -119,7 +119,7 @@ fn parse_cfg_entry_version<S: Stage>(
 }
 
 fn parse_cfg_entry_target<S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
+    cx: &AcceptContext<'_, '_, S>,
     list: &MetaItemListParser<'_>,
     meta_span: Span,
 ) -> Option<CfgEntry> {
@@ -169,7 +169,7 @@ fn parse_name_value<S: Stage>(
     name_span: Span,
     value: Option<&NameValueParser>,
     span: Span,
-    cx: &mut AcceptContext<'_, '_, S>,
+    cx: &AcceptContext<'_, '_, S>,
 ) -> Option<CfgEntry> {
     try_gate_cfg(name, span, cx.sess(), cx.features_option());
 

compiler/rustc_attr_parsing/src/attributes/proc_macro_attrs.rs

@@ -66,7 +66,7 @@ impl<S: Stage> SingleAttributeParser<S> for RustcBuiltinMacroParser {
 }
 
 fn parse_derive_like<S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
+    cx: &AcceptContext<'_, '_, S>,
     args: &ArgParser<'_>,
     trait_name_mandatory: bool,
 ) -> Option<(Option<Symbol>, ThinVec<Symbol>)> {

compiler/rustc_attr_parsing/src/attributes/prototype.rs

@@ -67,7 +67,7 @@ impl<S: Stage> SingleAttributeParser<S> for CustomMirParser {
 }
 
 fn extract_value<S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
+    cx: &AcceptContext<'_, '_, S>,
     key: Symbol,
     arg: &ArgParser<'_>,
     span: Span,
@@ -96,7 +96,7 @@ fn extract_value<S: Stage>(
 }
 
 fn parse_dialect<S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
+    cx: &AcceptContext<'_, '_, S>,
     dialect: Option<(Symbol, Span)>,
     failed: &mut bool,
 ) -> Option<(MirDialect, Span)> {
@@ -118,7 +118,7 @@ fn parse_dialect<S: Stage>(
 }
 
 fn parse_phase<S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
+    cx: &AcceptContext<'_, '_, S>,
     phase: Option<(Symbol, Span)>,
     failed: &mut bool,
 ) -> Option<(MirPhase, Span)> {

compiler/rustc_attr_parsing/src/context.rs

@@ -1199,7 +1199,7 @@ pub(crate) const ALL_TARGETS: &'static [MaybeWarn] = &[
 /// `cx` is the context given to the attribute.
 /// `args` is the parser for the attribute arguments.
 pub(crate) fn parse_single_integer<S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
+    cx: &AcceptContext<'_, '_, S>,
     args: &ArgParser<'_>,
 ) -> Option<u128> {
     let Some(list) = args.list() else {

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -3833,7 +3833,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         self.buffer_error(err);
     }
 
-    fn explain_deref_coercion(&mut self, loan: &BorrowData<'tcx>, err: &mut Diag<'_>) {
+    fn explain_deref_coercion(&self, loan: &BorrowData<'tcx>, err: &mut Diag<'_>) {
         let tcx = self.infcx.tcx;
         if let Some(Terminator { kind: TerminatorKind::Call { call_source, fn_span, .. }, .. }) =
             &self.body[loan.reserve_location.block].terminator

compiler/rustc_borrowck/src/diagnostics/find_use.rs

@@ -15,7 +15,7 @@ pub(crate) fn find<'tcx>(
     region_vid: RegionVid,
     start_point: Location,
 ) -> Option<Cause> {
-    let mut uf = UseFinder { body, regioncx, tcx, region_vid, start_point };
+    let uf = UseFinder { body, regioncx, tcx, region_vid, start_point };
 
     uf.find()
 }
@@ -29,7 +29,7 @@ struct UseFinder<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> UseFinder<'a, 'tcx> {
-    fn find(&mut self) -> Option<Cause> {
+    fn find(&self) -> Option<Cause> {
         let mut queue = VecDeque::new();
         let mut visited = FxIndexSet::default();
 

compiler/rustc_borrowck/src/diagnostics/move_errors.rs

@@ -293,15 +293,15 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         self.buffer_error(err);
     }
 
-    fn has_ambiguous_copy(&mut self, ty: Ty<'tcx>) -> bool {
+    fn has_ambiguous_copy(&self, ty: Ty<'tcx>) -> bool {
         let Some(copy_def_id) = self.infcx.tcx.lang_items().copy_trait() else { return false };
 
         // Avoid bogus move errors because of an incoherent `Copy` impl.
         self.infcx.type_implements_trait(copy_def_id, [ty], self.infcx.param_env).may_apply()
             && self.infcx.tcx.coherent_trait(copy_def_id).is_err()
     }
 
-    fn report_cannot_move_from_static(&mut self, place: Place<'tcx>, span: Span) -> Diag<'infcx> {
+    fn report_cannot_move_from_static(&self, place: Place<'tcx>, span: Span) -> Diag<'infcx> {
         let description = if place.projection.len() == 1 {
             format!("static item {}", self.describe_any_place(place.as_ref()))
         } else {

compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs

@@ -160,7 +160,7 @@ impl OutlivesSuggestionBuilder {
 
     /// Emit an intermediate note on the given `Diag` if the involved regions are suggestable.
     pub(crate) fn intermediate_suggestion(
-        &mut self,
+        &self,
         mbcx: &MirBorrowckCtxt<'_, '_, '_>,
         errci: &ErrorConstraintInfo<'_>,
         diag: &mut Diag<'_>,