diff --git a/clang/include/clang/CrossTU/CrossTranslationUnit.h b/clang/include/clang/CrossTU/CrossTranslationUnit.h
--- a/clang/include/clang/CrossTU/CrossTranslationUnit.h
+++ b/clang/include/clang/CrossTU/CrossTranslationUnit.h
@@ -163,6 +163,7 @@
   void emitCrossTUDiagnostics(const IndexError &IE);
 
 private:
+  bool checkThresholdReached() const;
   void lazyInitImporterSharedSt(TranslationUnitDecl *ToTU);
   ASTImporter &getOrCreateASTImporter(ASTContext &From);
   template <typename T>
diff --git a/clang/lib/CrossTU/CrossTranslationUnit.cpp b/clang/lib/CrossTU/CrossTranslationUnit.cpp
--- a/clang/lib/CrossTU/CrossTranslationUnit.cpp
+++ b/clang/lib/CrossTU/CrossTranslationUnit.cpp
@@ -340,6 +340,14 @@
   }
 }
 
+bool CrossTranslationUnitContext::checkThresholdReached() const {
+  if (NumASTLoaded >= CTULoadThreshold) {
+    ++NumASTLoadThresholdReached;
+    return true;
+  }
+  return false;
+}
+
 llvm::Expected<ASTUnit *> CrossTranslationUnitContext::loadExternalAST(
     StringRef LookupName, StringRef CrossTUDir, StringRef IndexName,
     bool DisplayCTUProgress) {
@@ -348,11 +356,10 @@
   //        translation units contains decls with the same lookup name an
   //        error will be returned.
 
-  if (NumASTLoaded >= CTULoadThreshold) {
-    ++NumASTLoadThresholdReached;
+  // If import threshold is reached, don't import anything.
+  if (checkThresholdReached())
     return llvm::make_error<IndexError>(
         index_error_code::load_threshold_reached);
-  }
 
   ASTUnit *Unit = nullptr;
   auto NameUnitCacheEntry = NameASTUnitMap.find(LookupName);