diff --git a/generator/src/Parameter.php b/generator/src/Parameter.php
index 24ff990d..a32eb13b 100644
--- a/generator/src/Parameter.php
+++ b/generator/src/Parameter.php
@@ -157,4 +157,9 @@ private function getInnerXml(\SimpleXMLElement $SimpleXMLElement): string
         $inner_xml = trim($inner_xml);
         return $inner_xml;
     }
+
+    public function isTypeable(): bool
+    {
+        return $this->getType() !== 'mixed' && $this->getType() !== 'resource' && \count(\explode("|", $this->getType())) < 2;
+    }
 }
diff --git a/generator/src/WritePhpFunction.php b/generator/src/WritePhpFunction.php
index 4399bf5b..47acd58f 100644
--- a/generator/src/WritePhpFunction.php
+++ b/generator/src/WritePhpFunction.php
@@ -142,7 +142,7 @@ private function displayParamsWithType(array $params): string
 
         foreach ($params as $param) {
             $paramAsString = '';
-            if ($param->getType() !== 'mixed' && $param->getType() !== 'resource') {
+            if ($param->isTypeable()) {
                 if ($param->isNullable()) {
                     $paramAsString .= '?';
                 }