hack for RustEmbed with updated test

Author: LorrensP-2158466

compiler/rustc_resolve/src/imports.rs

@@ -374,6 +374,22 @@ 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);
+            }
+        }
         self.update_local_resolution(module, key, warn_ambiguity, |this, resolution| {
             if let Some(old_binding) = resolution.best_binding() {
                 if res == Res::Err && old_binding.res() != Res::Err {
@@ -623,12 +639,12 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         for (import, side_effect) in import_resolutions {
             let SideEffect { imported_module, bindings: side_effect_bindings } = side_effect;
             let parent = import.parent_scope.module;
-
             match (&import.kind, side_effect_bindings) {
                 (
                     ImportKind::Single { target, bindings, .. },
                     SideEffectBindings::Single { import_bindings },
                 ) => {
+                    debug!("{import_bindings:#?}");
                     self.per_ns(|this, ns| {
                         match import_bindings[ns] {
                             Some(Some(binding)) => {
@@ -687,6 +703,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                             .resolution(import.parent_scope.module, key)
                             .and_then(|r| r.binding())
                             .is_some_and(|binding| binding.warn_ambiguity_recursive());
+                        debug!("defining binding from glob: {imported_binding:#?}");
                         let _ = self.try_define_local(
                             parent,
                             key.ident.0,
@@ -1662,7 +1679,13 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     next_binding = binding;
                 }
 
-                children.push(ModChild { ident: ident.0, res, vis: binding.vis, reexport_chain });
+                let vis = match res.opt_def_id() {
+                    Some(def_id) => {
+                        self.greatest_vis_map.get(&def_id).copied().unwrap_or(binding.vis)
+                    }
+                    None => binding.vis,
+                };
+                children.push(ModChild { ident: ident.0, res, vis, reexport_chain });
             }
         });
 

compiler/rustc_resolve/src/lib.rs

@@ -1169,6 +1169,8 @@ 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>>,
     /// 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.
@@ -1593,6 +1595,7 @@ 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(),
             inaccessible_ctor_reexport: Default::default(),
 
             arenas,

tests/ui/imports/same-res-ambigious.fail.stderr

@@ -1,10 +1,11 @@
+//@ check-pass
 //@ edition: 2018
 //@ revisions: fail pass
 //@[pass] aux-crate: ambigious_extern=same-res-ambigious-extern.rs
 //@[fail] aux-crate: ambigious_extern=same-res-ambigious-extern-fail.rs
 // see https://github.com/rust-lang/rust/pull/147196
 
-#[derive(ambigious_extern::Embed)] //~ ERROR: derive macro `Embed` is private
+#[derive(ambigious_extern::Embed)]
 struct Foo{}
 
 fn main(){}