diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index fc97981..07812bd 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -1288,8 +1288,11 @@
     bool needsImportVisitation() const override { return true; }
 
     void visitImport(StringRef FileName) override {
-      if (!CI.ExplicitlyLoadedModuleFiles.insert(FileName).second)
+      if (!CI.ExplicitlyLoadedModuleFiles.insert(FileName).second) {
+        if (ModuleFileStack.size() == 0)
+          TopFileIsModule = true;
         return;
+      }
 
       ModuleFileStack.push_back(FileName);
       if (ASTReader::readASTFileControlBlock(FileName, CI.getFileManager(),