make import.vis is not mutable

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -283,6 +283,7 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
                     parent_scope,
                     finalize.then(|| Finalize::new(id, path.span)),
                     None,
+                    None,
                 ) {
                     PathResult::Module(ModuleOrUniformRoot::Module(module)) => {
                         let res = module.res().expect("visibility resolved to unnamed block");
@@ -372,7 +373,7 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
             has_attributes: !item.attrs.is_empty(),
             root_span,
             root_id,
-            vis: Cell::new(Some(vis)),
+            vis,
             used: Default::default(),
         });
 
@@ -888,7 +889,7 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
             root_span: item.span,
             span: item.span,
             module_path: Vec::new(),
-            vis: Cell::new(Some(vis)),
+            vis,
             used: Cell::new(used.then_some(Used::Other)),
         });
         self.r.potentially_unused_imports.push(import);
@@ -1089,7 +1090,7 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
                 root_span: span,
                 span,
                 module_path: Vec::new(),
-                vis: Cell::new(Some(ty::Visibility::Restricted(CRATE_DEF_ID))),
+                vis: ty::Visibility::Restricted(CRATE_DEF_ID),
                 used: Default::default(),
             })
         };
@@ -1125,6 +1126,7 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
                     ident,
                     MacroNS,
                     &self.parent_scope,
+                    None,
                 );
                 if let Ok(binding) = result {
                     let import = macro_use_import(self, ident.span, false);
@@ -1253,7 +1255,7 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
                     root_span: span,
                     span,
                     module_path: Vec::new(),
-                    vis: Cell::new(Some(vis)),
+                    vis,
                     used: Cell::new(Some(Used::Other)),
                 });
                 let import_binding = self.r.import(binding, import);

compiler/rustc_resolve/src/check_unused.rs

@@ -382,7 +382,7 @@ impl Resolver<'_, '_> {
         for import in self.potentially_unused_imports.iter() {
             match import.kind {
                 _ if import.used.get().is_some()
-                    || import.expect_vis().is_public()
+                    || import.vis.is_public()
                     || import.span.is_dummy() =>
                 {
                     if let ImportKind::MacroUse { .. } = import.kind {

compiler/rustc_resolve/src/diagnostics.rs

@@ -1052,6 +1052,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                                 parent_scope,
                                 false,
                                 false,
+                                None,
                             ) {
                                 suggestions.extend(
                                     ext.helper_attrs
@@ -1506,6 +1507,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                 None,
                 false,
                 None,
+                None,
             ) {
                 let desc = match binding.res() {
                     Res::Def(DefKind::Macro(MacroKind::Bang), _) => {
@@ -1983,6 +1985,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
         parent_scope: &ParentScope<'a>,
         ribs: Option<&PerNS<Vec<Rib<'a>>>>,
         ignore_binding: Option<NameBinding<'a>>,
+        ignore_import: Option<Import<'a>>,
         module: Option<ModuleOrUniformRoot<'a>>,
         failed_segment_idx: usize,
         ident: Ident,
@@ -2066,11 +2069,13 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                         parent_scope,
                         None,
                         ignore_binding,
+                        ignore_import,
                     )
                     .ok()
                 } else if let Some(ribs) = ribs
                     && let Some(TypeNS | ValueNS) = opt_ns
                 {
+                    assert!(ignore_import.is_none());
                     match self.resolve_ident_in_lexical_scope(
                         ident,
                         ns_to_try,
@@ -2091,6 +2096,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                         None,
                         false,
                         ignore_binding,
+                        ignore_import,
                     )
                     .ok()
                 };
@@ -2132,6 +2138,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
         } else if ident.name.as_str().chars().next().is_some_and(|c| c.is_ascii_uppercase()) {
             // Check whether the name refers to an item in the value namespace.
             let binding = if let Some(ribs) = ribs {
+                assert!(ignore_import.is_none());
                 self.resolve_ident_in_lexical_scope(
                     ident,
                     ValueNS,
@@ -2206,6 +2213,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                 None,
                 false,
                 ignore_binding,
+                ignore_import,
             ) {
                 let descr = binding.res().descr();
                 (format!("{descr} `{ident}` is not a crate or module"), suggestion)
@@ -2259,7 +2267,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
     ) -> Option<(Vec<Segment>, Option<String>)> {
         // Replace first ident with `self` and check if that is valid.
         path[0].ident.name = kw::SelfLower;
-        let result = self.maybe_resolve_path(&path, None, parent_scope);
+        let result = self.maybe_resolve_path(&path, None, parent_scope, None);
         debug!("make_missing_self_suggestion: path={:?} result={:?}", path, result);
         if let PathResult::Module(..) = result { Some((path, None)) } else { None }
     }
@@ -2278,7 +2286,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
     ) -> Option<(Vec<Segment>, Option<String>)> {
         // Replace first ident with `crate` and check if that is valid.
         path[0].ident.name = kw::Crate;
-        let result = self.maybe_resolve_path(&path, None, parent_scope);
+        let result = self.maybe_resolve_path(&path, None, parent_scope, None);
         debug!("make_missing_crate_suggestion:  path={:?} result={:?}", path, result);
         if let PathResult::Module(..) = result {
             Some((
@@ -2309,7 +2317,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
     ) -> Option<(Vec<Segment>, Option<String>)> {
         // Replace first ident with `crate` and check if that is valid.
         path[0].ident.name = kw::Super;
-        let result = self.maybe_resolve_path(&path, None, parent_scope);
+        let result = self.maybe_resolve_path(&path, None, parent_scope, None);
         debug!("make_missing_super_suggestion:  path={:?} result={:?}", path, result);
         if let PathResult::Module(..) = result { Some((path, None)) } else { None }
     }
@@ -2343,7 +2351,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
         for name in extern_crate_names.into_iter() {
             // Replace first ident with a crate name and check if that is valid.
             path[0].ident.name = name;
-            let result = self.maybe_resolve_path(&path, None, parent_scope);
+            let result = self.maybe_resolve_path(&path, None, parent_scope, None);
             debug!(
                 "make_external_crate_suggestion: name={:?} path={:?} result={:?}",
                 name, path, result
@@ -2510,7 +2518,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
 
     /// Finds a cfg-ed out item inside `module` with the matching name.
     pub(crate) fn find_cfg_stripped(
-        &mut self,
+        &self,
         err: &mut Diag<'_>,
         segment: &Symbol,
         module: DefId,