[Sema] Special case the bridging header module to consider it as non-implicit

Author: xymus

lib/AST/Module.cpp

@@ -2461,6 +2461,12 @@ RestrictedImportKind SourceFile::getRestrictedImportKind(const ModuleDecl *modul
   if (imports.isImportedBy(module, getParentModule()))
     return RestrictedImportKind::None;
 
+  // Special case the __ObjC module. This module is implicitly imported but
+  // represents any clang module so we can consider it public.
+  if (importKind == RestrictedImportKind::Implicit &&
+      module->getName().str() == CLANG_HEADER_MODULE_NAME)
+    return RestrictedImportKind::None;
+
   return importKind;
 }