diff --git a/src/clang_translation_unit.cc b/src/clang_translation_unit.cc
index eaa41577..1ad8e2e6 100644
--- a/src/clang_translation_unit.cc
+++ b/src/clang_translation_unit.cc
@@ -72,7 +72,7 @@ std::unique_ptr<ClangTranslationUnit> ClangTranslationUnit::Create(
     ClangIndex* index,
     const std::string& filepath,
     const std::vector<std::string>& arguments,
-    std::vector<CXUnsavedFile> unsaved_files,
+    std::vector<CXUnsavedFile>& unsaved_files,
     unsigned flags) {
   std::vector<const char*> args;
   for (const std::string& a : arguments)
diff --git a/src/clang_translation_unit.h b/src/clang_translation_unit.h
index 0c91f1cc..efeedc6c 100644
--- a/src/clang_translation_unit.h
+++ b/src/clang_translation_unit.h
@@ -17,7 +17,7 @@ struct ClangTranslationUnit {
       ClangIndex* index,
       const std::string& filepath,
       const std::vector<std::string>& arguments,
-      std::vector<CXUnsavedFile> unsaved_files,
+      std::vector<CXUnsavedFile>& unsaved_files,
       unsigned flags);
 
   static std::unique_ptr<ClangTranslationUnit> Reparse(