diff --git a/ext/simplexml/simplexml.stub.php b/ext/simplexml/simplexml.stub.php
index d71e7c010c5a..9389e8e71102 100644
--- a/ext/simplexml/simplexml.stub.php
+++ b/ext/simplexml/simplexml.stub.php
@@ -42,8 +42,8 @@ public function __construct(string $data, int $options = 0, bool $dataIsURL = fa
     /** @return SimpleXMLElement|null */
     public function addChild(string $qualifiedName, ?string $value = null, ?string $namespace = null) {}
 
-    /** @return SimpleXMLElement|null */
-    public function addAttribute(string $qualifiedName, ?string $value = null, ?string $namespace = null) {}
+    /** @return void */
+    public function addAttribute(string $qualifiedName, string $value, ?string $namespace = null) {}
 
     /** @return string */
     public function getName() {}
diff --git a/ext/simplexml/simplexml_arginfo.h b/ext/simplexml/simplexml_arginfo.h
index 972dc4749a90..2001d1f79fd1 100644
--- a/ext/simplexml/simplexml_arginfo.h
+++ b/ext/simplexml/simplexml_arginfo.h
@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: 9d5e78ef2ea4e8bda025f9a9e7f0e07d2e9db702 */
+ * Stub hash: 03981bac1d9aef20ccf0adf36f75496c3da8e605 */
 
 ZEND_BEGIN_ARG_WITH_RETURN_OBJ_TYPE_MASK_EX(arginfo_simplexml_load_file, 0, 1, SimpleXMLElement, MAY_BE_FALSE)
 	ZEND_ARG_TYPE_INFO(0, filename, IS_STRING, 0)
@@ -67,7 +67,11 @@ ZEND_BEGIN_ARG_INFO_EX(arginfo_class_SimpleXMLElement_addChild, 0, 0, 1)
 	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, namespace, IS_STRING, 1, "null")
 ZEND_END_ARG_INFO()
 
-#define arginfo_class_SimpleXMLElement_addAttribute arginfo_class_SimpleXMLElement_addChild
+ZEND_BEGIN_ARG_INFO_EX(arginfo_class_SimpleXMLElement_addAttribute, 0, 0, 2)
+	ZEND_ARG_TYPE_INFO(0, qualifiedName, IS_STRING, 0)
+	ZEND_ARG_TYPE_INFO(0, value, IS_STRING, 0)
+	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, namespace, IS_STRING, 1, "null")
+ZEND_END_ARG_INFO()
 
 ZEND_BEGIN_ARG_INFO_EX(arginfo_class_SimpleXMLElement_getName, 0, 0, 0)
 ZEND_END_ARG_INFO()