diff --git a/rs_bindings_from_cc/importers/type_map_override.h b/rs_bindings_from_cc/importers/type_map_override.h
index 4dd13db..35d4ba1 100644
--- a/rs_bindings_from_cc/importers/type_map_override.h
+++ b/rs_bindings_from_cc/importers/type_map_override.h
@@ -17,7 +17,7 @@
  public:
   explicit TypeMapOverrideImporter(ImportContext& context)
       : DeclImporterBase(context) {}
-  std::optional<IR::Item> Import(clang::TypeDecl*);
+  std::optional<IR::Item> Import(clang::TypeDecl*) override;
 };
 
 }  // namespace crubit