resolve: Avoid finalizing extern prelude entries more than once

Author: petrochenkov

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -994,7 +994,7 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
             // Binding from `extern crate` item in source code can replace
             // a binding from `--extern` on command line here.
             if !entry.is_import() {
-                entry.binding.set(crate::EpeBinding::Item(imported_binding));
+                entry.binding.set(crate::EpeBinding::Item(imported_binding, false));
             } else if ident.name != kw::Underscore {
                 self.r.dcx().span_delayed_bug(
                     item.span,

compiler/rustc_resolve/src/lib.rs

@@ -1011,9 +1011,9 @@ impl<'ra> NameBindingData<'ra> {
 enum EpeBinding<'ra> {
     #[default]
     OptPending,
-    OptReadyOk(NameBinding<'ra>),
-    OptReadyErr,
-    Item(NameBinding<'ra>),
+    OptReadyOk(NameBinding<'ra>, bool),
+    OptReadyErr(bool),
+    Item(NameBinding<'ra>, bool),
 }
 
 #[derive(Default, Clone)]
@@ -2021,7 +2021,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             if used == Used::Scope {
                 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
                     if !entry.introduced_by_item
-                        && entry.binding.get() == EpeBinding::Item(used_binding)
+                        && matches!(entry.binding.get(), EpeBinding::Item(b, _) if b == used_binding)
                     {
                         return;
                     }
@@ -2187,23 +2187,23 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         let norm_ident = ident.normalize_to_macros_2_0();
         let entry = self.extern_prelude.get(&norm_ident).cloned();
         let binding = entry.map(|entry| match entry.binding.get() {
-            EpeBinding::Item(binding) => {
-                if finalize && entry.introduced_by_item {
+            EpeBinding::Item(binding, finalized) => {
+                if finalize && !finalized && entry.introduced_by_item {
                     self.record_use(ident, binding, Used::Other);
                 }
-                EpeBinding::Item(binding)
+                EpeBinding::Item(binding, finalize)
             }
-            EpeBinding::OptReadyOk(binding) => {
-                if finalize {
+            EpeBinding::OptReadyOk(binding, finalized) => {
+                if finalize && !finalized {
                     self.cstore_mut().process_path_extern(self.tcx, ident.name, ident.span);
                 }
-                EpeBinding::OptReadyOk(binding)
+                EpeBinding::OptReadyOk(binding, finalize)
             }
-            EpeBinding::OptReadyErr => {
-                if finalize {
+            EpeBinding::OptReadyErr(finalized) => {
+                if finalize && !finalized {
                     self.cstore_mut().process_path_extern(self.tcx, ident.name, ident.span);
                 }
-                EpeBinding::OptReadyErr
+                EpeBinding::OptReadyErr(finalize)
             }
             EpeBinding::OptPending => {
                 let crate_id = if finalize {
@@ -2213,19 +2213,19 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 };
                 let res = match crate_id {
                     Some(crate_id) => Res::Def(DefKind::Mod, crate_id.as_def_id()),
-                    None => return EpeBinding::OptReadyErr,
+                    None => return EpeBinding::OptReadyErr(finalize),
                 };
                 let binding = self.arenas.new_pub_res_binding(res, DUMMY_SP, LocalExpnId::ROOT);
-                EpeBinding::OptReadyOk(binding)
+                EpeBinding::OptReadyOk(binding, finalize)
             }
         });
 
         binding.and_then(|binding| {
             self.extern_prelude[&norm_ident].binding.set(binding);
             match binding {
-                EpeBinding::Item(binding) | EpeBinding::OptReadyOk(binding) => Some(binding),
-                EpeBinding::OptReadyErr if finalize => Some(self.dummy_binding),
-                EpeBinding::OptReadyErr => None,
+                EpeBinding::Item(binding, _) | EpeBinding::OptReadyOk(binding, _) => Some(binding),
+                EpeBinding::OptReadyErr(_) if finalize => Some(self.dummy_binding),
+                EpeBinding::OptReadyErr(_) => None,
                 EpeBinding::OptPending => unreachable!(),
             }
         })

tests/ui/crate-loading/invalid-rlib.rs

@@ -6,6 +6,3 @@
 #![no_std]
 use ::foo; //~ ERROR invalid metadata files for crate `foo`
 //~| NOTE failed to mmap file
-//~^^ ERROR invalid metadata files for crate `foo`
-//~| NOTE failed to mmap file
-//~| NOTE duplicate diagnostic

tests/ui/crate-loading/invalid-rlib.stderr

@@ -6,15 +6,6 @@ LL | use ::foo;
    |
    = note: failed to mmap file 'auxiliary/libfoo.rlib'
 
-error[E0786]: found invalid metadata files for crate `foo`
-  --> $DIR/invalid-rlib.rs:7:7
-   |
-LL | use ::foo;
-   |       ^^^
-   |
-   = note: failed to mmap file 'auxiliary/libfoo.rlib'
-   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
-
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0786`.