change hack

Author: LorrensP-2158466

compiler/rustc_resolve/src/imports.rs

@@ -374,21 +374,16 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             module.underscore_disambiguator.update_unchecked(|d| d + 1);
             module.underscore_disambiguator.get()
         });
-        let tcx = self.tcx();
         // "Same res different import" ambiguity hack for macros introduced in #145108.
         // See related discussion for more info:
         // https://rust-lang.zulipchat.com/#narrow/channel/421156-gsoc/topic/Project.3A.20Parallel.20Macro.20Expansion/near/542057918.
-        if ns == MacroNS && binding.is_glob_import() {
-            if let Some(def_id) = res.opt_def_id() {
-                self.greatest_vis_map
-                    .entry(def_id)
-                    .and_modify(|vis| {
-                        if !vis.is_at_least(binding.vis, tcx) {
-                            *vis = binding.vis
-                        }
-                    })
-                    .or_insert(binding.vis);
-            }
+        if ns == MacroNS
+            && binding.is_glob_import()
+            && binding.vis.is_public() // is a glob that reexports a macro
+            && self.macro_use_prelude.contains_key(&ident.name) // which also lives in macro_use world
+            && let Some(def_id) = res.opt_def_id()
+        {
+            self.macro_vis_hack_map.insert(def_id);
         }
         self.update_local_resolution(module, key, warn_ambiguity, |this, resolution| {
             if let Some(old_binding) = resolution.best_binding() {
@@ -1678,14 +1673,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 }
 
                 let vis = match res.opt_def_id() {
-                    Some(def_id) => {
-                        let vis =
-                            self.greatest_vis_map.get(&def_id).copied().unwrap_or(binding.vis);
-                        // macros exported through `macro_export` are not placed in this map, so
-                        // hack the hack and make sure we still keep the best visibility.
-                        if !vis.is_at_least(binding.vis, self.tcx()) { binding.vis } else { vis }
-                    }
-                    None => binding.vis,
+                    Some(def_id) if self.macro_vis_hack_map.contains(&def_id) => Visibility::Public,
+                    Some(_) | None => binding.vis,
                 };
                 children.push(ModChild { ident: ident.0, res, vis, reexport_chain });
             }

compiler/rustc_resolve/src/lib.rs

@@ -1169,8 +1169,7 @@ pub struct Resolver<'ra, 'tcx> {
     /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
     macro_expanded_macro_export_errors: BTreeSet<(Span, Span)> = BTreeSet::new(),
 
-    // Hack
-    greatest_vis_map: FxIndexMap<DefId, Visibility<DefId>>,
+    macro_vis_hack_map: FxIndexSet<DefId>,
     /// When a type is re-exported that has an inaccessible constructor because it has fields that
     /// are inaccessible from the import's scope, we mark that as the type won't be able to be built
     /// through the re-export. We use this information to extend the existing diagnostic.
@@ -1595,7 +1594,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             glob_map: Default::default(),
             used_imports: FxHashSet::default(),
             maybe_unused_trait_imports: Default::default(),
-            greatest_vis_map: Default::default(),
+            macro_vis_hack_map: Default::default(),
             inaccessible_ctor_reexport: Default::default(),
 
             arenas,