diff --git a/src/vim9class.c b/src/vim9class.c
index fd0a122..92e3c63 100644
--- a/src/vim9class.c
+++ b/src/vim9class.c
@@ -681,8 +681,7 @@
 	    garray_T lines_to_free;
 	    ga_init2(&lines_to_free, sizeof(char_u *), 50);
 
-	    ufunc_T *nf = define_function(&fea, NULL, &lines_to_free,
-					   is_class ? CF_CLASS : CF_INTERFACE);
+	    ufunc_T *nf = define_function(&fea, NULL, &lines_to_free, CF_CLASS);
 
 	    ga_clear_strings(&lines_to_free);
 	    vim_free(fga.ga_data);