resolve: Change &mut Resolver to &Resolver when possible

Author: petrochenkov

compiler/rustc_expand/src/base.rs

@@ -1042,7 +1042,7 @@ pub trait ResolverExpand {
     fn next_node_id(&mut self) -> NodeId;
     fn invocation_parent(&self, id: LocalExpnId) -> LocalDefId;
 
-    fn resolve_dollar_crates(&mut self);
+    fn resolve_dollar_crates(&self);
     fn visit_ast_fragment_with_placeholders(
         &mut self,
         expn_id: LocalExpnId,

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -85,7 +85,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
     /// Reachable macros with block module parents exist due to `#[macro_export] macro_rules!`,
     /// but they cannot use def-site hygiene, so the assumption holds
     /// (<https://github.com/rust-lang/rust/pull/77984#issuecomment-712445508>).
-    pub(crate) fn get_nearest_non_block_module(&mut self, mut def_id: DefId) -> Module<'ra> {
+    pub(crate) fn get_nearest_non_block_module(&self, mut def_id: DefId) -> Module<'ra> {
         loop {
             match self.get_module(def_id) {
                 Some(module) => return module,
@@ -94,14 +94,14 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         }
     }
 
-    pub(crate) fn expect_module(&mut self, def_id: DefId) -> Module<'ra> {
+    pub(crate) fn expect_module(&self, def_id: DefId) -> Module<'ra> {
         self.get_module(def_id).expect("argument `DefId` is not a module")
     }
 
     /// If `def_id` refers to a module (in resolver's sense, i.e. a module item, crate root, enum,
     /// or trait), then this function returns that module's resolver representation, otherwise it
     /// returns `None`.
-    pub(crate) fn get_module(&mut self, def_id: DefId) -> Option<Module<'ra>> {
+    pub(crate) fn get_module(&self, def_id: DefId) -> Option<Module<'ra>> {
         match def_id.as_local() {
             Some(local_def_id) => self.local_module_map.get(&local_def_id).copied(),
             None => {
@@ -134,7 +134,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         }
     }
 
-    pub(crate) fn expn_def_scope(&mut self, expn_id: ExpnId) -> Module<'ra> {
+    pub(crate) fn expn_def_scope(&self, expn_id: ExpnId) -> Module<'ra> {
         match expn_id.expn_data().macro_def_id {
             Some(def_id) => self.macro_def_scope(def_id),
             None => expn_id
@@ -144,7 +144,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         }
     }
 
-    pub(crate) fn macro_def_scope(&mut self, def_id: DefId) -> Module<'ra> {
+    pub(crate) fn macro_def_scope(&self, def_id: DefId) -> Module<'ra> {
         if let Some(id) = def_id.as_local() {
             self.local_macro_def_scopes[&id]
         } else {
@@ -406,7 +406,7 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
         self.r.field_visibility_spans.insert(def_id, field_vis);
     }
 
-    fn block_needs_anonymous_module(&mut self, block: &Block) -> bool {
+    fn block_needs_anonymous_module(&self, block: &Block) -> bool {
         // If any statements are items, we need to create an anonymous module
         block
             .stmts
@@ -1130,7 +1130,7 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
     }
 
     /// Returns `true` if this attribute list contains `macro_use`.
-    fn contains_macro_use(&mut self, attrs: &[ast::Attribute]) -> bool {
+    fn contains_macro_use(&self, attrs: &[ast::Attribute]) -> bool {
         for attr in attrs {
             if attr.has_name(sym::macro_escape) {
                 let inner_attribute = matches!(attr.style, ast::AttrStyle::Inner);

compiler/rustc_resolve/src/diagnostics.rs

@@ -2151,7 +2151,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
     }
 
     pub(crate) fn find_similarly_named_module_or_crate(
-        &mut self,
+        &self,
         ident: Symbol,
         current_module: Module<'ra>,
     ) -> Option<Symbol> {
@@ -2445,7 +2445,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
     }
 
     fn undeclared_module_suggest_declare(
-        &mut self,
+        &self,
         ident: Ident,
         path: std::path::PathBuf,
     ) -> Option<(Vec<(Span, String)>, String, Applicability)> {
@@ -2460,7 +2460,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         ))
     }
 
-    fn undeclared_module_exists(&mut self, ident: Ident) -> Option<std::path::PathBuf> {
+    fn undeclared_module_exists(&self, ident: Ident) -> Option<std::path::PathBuf> {
         let map = self.tcx.sess.source_map();
 
         let src = map.span_to_filename(ident.span).into_local_path()?;
@@ -2781,12 +2781,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
     }
 
     /// Finds a cfg-ed out item inside `module` with the matching name.
-    pub(crate) fn find_cfg_stripped(
-        &mut self,
-        err: &mut Diag<'_>,
-        segment: &Symbol,
-        module: DefId,
-    ) {
+    pub(crate) fn find_cfg_stripped(&self, err: &mut Diag<'_>, segment: &Symbol, module: DefId) {
         let local_items;
         let symbols = if module.is_local() {
             local_items = self
@@ -2812,7 +2807,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             }
 
             fn comes_from_same_module_for_glob(
-                r: &mut Resolver<'_, '_>,
+                r: &Resolver<'_, '_>,
                 parent_module: DefId,
                 module: DefId,
                 visited: &mut FxHashMap<DefId, bool>,

compiler/rustc_resolve/src/effective_visibilities.rs

@@ -38,11 +38,11 @@ pub(crate) struct EffectiveVisibilitiesVisitor<'a, 'ra, 'tcx> {
 }
 
 impl Resolver<'_, '_> {
-    fn nearest_normal_mod(&mut self, def_id: LocalDefId) -> LocalDefId {
+    fn nearest_normal_mod(&self, def_id: LocalDefId) -> LocalDefId {
         self.get_nearest_non_block_module(def_id.to_def_id()).nearest_parent_mod().expect_local()
     }
 
-    fn private_vis_import(&mut self, binding: NameBinding<'_>) -> Visibility {
+    fn private_vis_import(&self, binding: NameBinding<'_>) -> Visibility {
         let NameBindingKind::Import { import, .. } = binding.kind else { unreachable!() };
         Visibility::Restricted(
             import
@@ -52,7 +52,7 @@ impl Resolver<'_, '_> {
         )
     }
 
-    fn private_vis_def(&mut self, def_id: LocalDefId) -> Visibility {
+    fn private_vis_def(&self, def_id: LocalDefId) -> Visibility {
         // For mod items `nearest_normal_mod` returns its argument, but we actually need its parent.
         let normal_mod_id = self.nearest_normal_mod(def_id);
         if normal_mod_id == def_id {

compiler/rustc_resolve/src/ident.rs

@@ -885,7 +885,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             );
         }
 
-        let check_usable = |this: &mut Self, binding: NameBinding<'ra>| {
+        let check_usable = |this: &Self, binding: NameBinding<'ra>| {
             let usable = this.is_accessible_from(binding.vis, parent_scope.module);
             if usable { Ok(binding) } else { Err((Determined, Weak::No)) }
         };

compiler/rustc_resolve/src/imports.rs

@@ -443,7 +443,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         f: F,
     ) -> T
     where
-        F: FnOnce(&mut Resolver<'ra, 'tcx>, &mut NameResolution<'ra>) -> T,
+        F: FnOnce(&Resolver<'ra, 'tcx>, &mut NameResolution<'ra>) -> T,
     {
         // Ensure that `resolution` isn't borrowed when defining in the module's glob importers,
         // during which the resolution might end up getting re-defined via a glob cycle.

compiler/rustc_resolve/src/late.rs

@@ -2491,7 +2491,7 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
 
     /// Searches the current set of local scopes for labels. Returns the `NodeId` of the resolved
     /// label and reports an error if the label is not found or is unreachable.
-    fn resolve_label(&mut self, mut label: Ident) -> Result<(NodeId, Span), ResolutionError<'ra>> {
+    fn resolve_label(&self, mut label: Ident) -> Result<(NodeId, Span), ResolutionError<'ra>> {
         let mut suggestion = None;
 
         for i in (0..self.label_ribs.len()).rev() {

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -937,7 +937,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
     }
 
     fn suggest_trait_and_bounds(
-        &mut self,
+        &self,
         err: &mut Diag<'_>,
         source: PathSource<'_, '_, '_>,
         res: Option<Res>,
@@ -1138,7 +1138,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
 
     /// Emit special messages for unresolved `Self` and `self`.
     fn suggest_self_ty(
-        &mut self,
+        &self,
         err: &mut Diag<'_>,
         source: PathSource<'_, '_, '_>,
         path: &[Segment],
@@ -1254,7 +1254,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
     }
 
     fn detect_missing_binding_available_from_pattern(
-        &mut self,
+        &self,
         err: &mut Diag<'_>,
         path: &[Segment],
         following_seg: Option<&Segment>,
@@ -1300,11 +1300,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         }
     }
 
-    fn suggest_at_operator_in_slice_pat_with_range(
-        &mut self,
-        err: &mut Diag<'_>,
-        path: &[Segment],
-    ) {
+    fn suggest_at_operator_in_slice_pat_with_range(&self, err: &mut Diag<'_>, path: &[Segment]) {
         let Some(pat) = self.diag_metadata.current_pat else { return };
         let (bound, side, range) = match &pat.kind {
             ast::PatKind::Range(Some(bound), None, range) => (bound, Side::Start, range),
@@ -1365,7 +1361,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
     }
 
     fn explain_functions_in_pattern(
-        &mut self,
+        &self,
         err: &mut Diag<'_>,
         res: Option<Res>,
         source: PathSource<'_, '_, '_>,
@@ -1377,7 +1373,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
     }
 
     fn suggest_changing_type_to_const_param(
-        &mut self,
+        &self,
         err: &mut Diag<'_>,
         res: Option<Res>,
         source: PathSource<'_, '_, '_>,
@@ -1427,7 +1423,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
     }
 
     fn suggest_pattern_match_with_let(
-        &mut self,
+        &self,
         err: &mut Diag<'_>,
         source: PathSource<'_, '_, '_>,
         span: Span,
@@ -1482,7 +1478,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
     }
 
     /// Given `where <T as Bar>::Baz: String`, suggest `where T: Bar<Baz = String>`.
-    fn restrict_assoc_type_in_where_clause(&mut self, span: Span, err: &mut Diag<'_>) -> bool {
+    fn restrict_assoc_type_in_where_clause(&self, span: Span, err: &mut Diag<'_>) -> bool {
         // Detect that we are actually in a `where` predicate.
         let (bounded_ty, bounds, where_span) = if let Some(ast::WherePredicate {
             kind:
@@ -1630,7 +1626,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         let ns = source.namespace();
         let is_expected = &|res| source.is_expected(res);
 
-        let path_sep = |this: &mut Self, err: &mut Diag<'_>, expr: &Expr, kind: DefKind| {
+        let path_sep = |this: &Self, err: &mut Diag<'_>, expr: &Expr, kind: DefKind| {
             const MESSAGE: &str = "use the path separator to refer to an item";
 
             let (lhs_span, rhs_span) = match &expr.kind {
@@ -2582,7 +2578,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
 
     // try to give a suggestion for this pattern: `name = blah`, which is common in other languages
     // suggest `let name = blah` to introduce a new binding
-    fn let_binding_suggestion(&mut self, err: &mut Diag<'_>, ident_span: Span) -> bool {
+    fn let_binding_suggestion(&self, err: &mut Diag<'_>, ident_span: Span) -> bool {
         if ident_span.from_expansion() {
             return false;
         }

compiler/rustc_resolve/src/lib.rs

@@ -1614,7 +1614,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
     }
 
     fn new_extern_module(
-        &mut self,
+        &self,
         parent: Option<Module<'ra>>,
         kind: ModuleKind,
         expn_id: ExpnId,
@@ -2011,7 +2011,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         }
     }
 
-    fn resolve_crate_root(&mut self, ident: Ident) -> Module<'ra> {
+    fn resolve_crate_root(&self, ident: Ident) -> Module<'ra> {
         debug!("resolve_crate_root({:?})", ident);
         let mut ctxt = ident.span.ctxt();
         let mark = if ident.name == kw::DollarCrate {
@@ -2084,7 +2084,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         module
     }
 
-    fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'ra>) -> Module<'ra> {
+    fn resolve_self(&self, ctxt: &mut SyntaxContext, module: Module<'ra>) -> Module<'ra> {
         let mut module = self.expect_module(module.nearest_parent_mod());
         while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
             let parent = module.parent.unwrap_or_else(|| self.expn_def_scope(ctxt.remove_mark()));

compiler/rustc_resolve/src/macros.rs

@@ -171,7 +171,7 @@ impl<'ra, 'tcx> ResolverExpand for Resolver<'ra, 'tcx> {
         self.invocation_parents[&id].parent_def
     }
 
-    fn resolve_dollar_crates(&mut self) {
+    fn resolve_dollar_crates(&self) {
         hygiene::update_dollar_crate_names(|ctxt| {
             let ident = Ident::new(kw::DollarCrate, DUMMY_SP.with_ctxt(ctxt));
             match self.resolve_crate_root(ident).kind {
@@ -826,7 +826,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
     }
 
     pub(crate) fn finalize_macro_resolutions(&mut self, krate: &Crate) {
-        let check_consistency = |this: &mut Self,
+        let check_consistency = |this: &Self,
                                  path: &[Segment],
                                  span,
                                  kind: MacroKind,