diff --git a/src/Parsing/ParserState.php b/src/Parsing/ParserState.php
index 0ac2e923..bb17133f 100644
--- a/src/Parsing/ParserState.php
+++ b/src/Parsing/ParserState.php
@@ -449,10 +449,8 @@ public function backtrack($iAmount)
 
     /**
      * @param string $sString
-     *
-     * @return int
      */
-    public function strlen($sString)
+    public function strlen($sString): int
     {
         if ($this->oParserSettings->bMultibyteSupport) {
             return mb_strlen($sString, $this->sCharset);