diff --git a/common.c b/common.c
index 4e87904..3f5cec9 100644
--- a/common.c
+++ b/common.c
@@ -1058,6 +1058,7 @@ config_token_name (enum config_token token)
 
 	default:
 		hard_assert (!"invalid token value");
+		return NULL;
 	}
 }