[NFC] [C++20] [Modules] Remove 'ModuleInterface' bit in Sema::ModuleS…

…cope

The 'ModuleInterface' in Sema::ModuleScope is confusing. It actually
means 'not implementation'. This patch removes that bit and extract the
information from the recorded clang::Module.

clang/include/clang/Sema/Sema.h

@@ -2303,7 +2303,6 @@ class Sema final {
   struct ModuleScope {
     SourceLocation BeginLoc;
     clang::Module *Module = nullptr;
-    bool ModuleInterface = false;
     VisibleModuleSet OuterVisibleModules;
   };
   /// The modules we're currently parsing.
@@ -2367,9 +2366,11 @@ class Sema final {
     return ModuleScopes.empty() ? nullptr : ModuleScopes.back().Module;
   }
 
-  /// Is the module scope we are an interface?
-  bool currentModuleIsInterface() const {
-    return ModuleScopes.empty() ? false : ModuleScopes.back().ModuleInterface;
+  /// Is the module scope we are an implementation unit?
+  bool currentModuleIsImplementation() const {
+    return ModuleScopes.empty()
+               ? false
+               : ModuleScopes.back().Module->isModuleImplementation();
   }
 
   /// Is the module scope we are in a C++ Header Unit?

clang/lib/Sema/SemaModule.cpp

@@ -125,7 +125,6 @@ void Sema::HandleStartOfHeaderUnit() {
   ModuleScopes.push_back({}); // No GMF
   ModuleScopes.back().BeginLoc = StartOfTU;
   ModuleScopes.back().Module = Mod;
-  ModuleScopes.back().ModuleInterface = true;
   VisibleModules.setVisible(Mod, StartOfTU);
 
   // From now on, we have an owning module for all declarations we see.
@@ -375,7 +374,6 @@ Sema::ActOnModuleDecl(SourceLocation StartLoc, SourceLocation ModuleLoc,
   // Switch from the global module fragment (if any) to the named module.
   ModuleScopes.back().BeginLoc = StartLoc;
   ModuleScopes.back().Module = Mod;
-  ModuleScopes.back().ModuleInterface = MDK != ModuleDeclKind::Implementation;
   VisibleModules.setVisible(Mod, ModuleLoc);
 
   // From now on, we have an owning module for all declarations we see.
@@ -470,7 +468,6 @@ Sema::ActOnPrivateModuleFragmentDecl(SourceLocation ModuleLoc,
   ModuleScopes.push_back({});
   ModuleScopes.back().BeginLoc = ModuleLoc;
   ModuleScopes.back().Module = PrivateModuleFragment;
-  ModuleScopes.back().ModuleInterface = true;
   VisibleModules.setVisible(PrivateModuleFragment, ModuleLoc);
 
   // All declarations created from now on are scoped to the private module
@@ -523,7 +520,7 @@ DeclResult Sema::ActOnModuleImport(SourceLocation StartLoc,
   if (getLangOpts().CPlusPlusModules && isCurrentModulePurview() &&
       getCurrentModule()->Name == ModuleName) {
     Diag(ImportLoc, diag::err_module_self_import_cxx20)
-        << ModuleName << !ModuleScopes.back().ModuleInterface;
+        << ModuleName << currentModuleIsImplementation();
     return true;
   }
 
@@ -609,10 +606,7 @@ DeclResult Sema::ActOnModuleImport(SourceLocation StartLoc,
       Mod->Kind == Module::ModuleKind::ModulePartitionImplementation) {
     Diag(ExportLoc, diag::err_export_partition_impl)
         << SourceRange(ExportLoc, Path.back().second);
-  } else if (!ModuleScopes.empty() &&
-             (ModuleScopes.back().ModuleInterface ||
-              (getLangOpts().CPlusPlusModules &&
-               ModuleScopes.back().Module->isGlobalModule()))) {
+  } else if (!ModuleScopes.empty() && !currentModuleIsImplementation()) {
     // Re-export the module if the imported module is exported.
     // Note that we don't need to add re-exported module to Imports field
     // since `Exports` implies the module is imported already.
@@ -772,7 +766,7 @@ Decl *Sema::ActOnStartExportDecl(Scope *S, SourceLocation ExportLoc,
     Diag(ExportLoc, diag::err_export_not_in_module_interface) << 0;
     D->setInvalidDecl();
     return D;
-  } else if (!ModuleScopes.back().ModuleInterface) {
+  } else if (currentModuleIsImplementation()) {
     Diag(ExportLoc, diag::err_export_not_in_module_interface) << 1;
     Diag(ModuleScopes.back().BeginLoc,
          diag::note_not_module_interface_add_export)
@@ -932,7 +926,6 @@ Module *Sema::PushGlobalModuleFragment(SourceLocation BeginLoc) {
 
   // Enter the scope of the global module.
   ModuleScopes.push_back({BeginLoc, TheGlobalModuleFragment,
-                          /*ModuleInterface=*/false,
                           /*OuterVisibleModules=*/{}});
   VisibleModules.setVisible(TheGlobalModuleFragment, BeginLoc);
 
@@ -959,7 +952,6 @@ Module *Sema::PushImplicitGlobalModuleFragment(SourceLocation BeginLoc,
 
   // Enter the scope of the global module.
   ModuleScopes.push_back({BeginLoc, *M,
-                          /*ModuleInterface=*/false,
                           /*OuterVisibleModules=*/{}});
   VisibleModules.setVisible(*M, BeginLoc);
   return *M;