diff --git a/src/lib/CliUtil.php b/src/lib/CliUtil.php
index 1cb887c..bab1c63 100644
--- a/src/lib/CliUtil.php
+++ b/src/lib/CliUtil.php
@@ -6,7 +6,7 @@ class CliUtil
 {
     protected array $commands = [];
 
-    protected function usage($error = null): void {
+    protected function usage($error = null): never {
         global $argv;
 
         if (!is_null($error))
@@ -58,7 +58,7 @@ class CliUtil
         return $input;
     }
 
-    public static function die($error): void {
+    public static function die($error): never {
         self::error($error);
         exit(1);
     }