diff --git a/parser.h b/parser.h
index be4b7c6..e497912 100644
--- a/parser.h
+++ b/parser.h
@@ -92,7 +92,7 @@
   const std::string& Package() const { return package_; }
 
   void MakeDocument(const AidlLocation& location, const Comments& comments,
-                    std::vector<std::unique_ptr<AidlImport>> imports,
+                    std::set<std::string> imports,
                     std::vector<std::unique_ptr<AidlDefinedType>> defined_types);
 
  private: