diff --git a/vlib/v/markused/markused.v b/vlib/v/markused/markused.v
index ec208303f5..5d583ebb85 100644
--- a/vlib/v/markused/markused.v
+++ b/vlib/v/markused/markused.v
@@ -31,6 +31,7 @@ pub fn mark_used(mut table ast.Table, pref &pref.Preferences, ast_files []ast.Fi
 		'isnil',
 		'opt_ok',
 		'error',
+		'__print_assert_failure',
 		// utf8_str_visible_length is used by c/str.v
 		'utf8_str_visible_length',
 		'compare_ints',