diff --git a/ext/zend_test/test.c b/ext/zend_test/test.c
index 37b3f7a2c5e..af6c4c7d127 100644
--- a/ext/zend_test/test.c
+++ b/ext/zend_test/test.c
@@ -850,7 +850,7 @@ static zend_function *zend_test_class_method_get(zend_object **object, zend_stri
 	    }
 		memset(fptr, 0, sizeof(zend_internal_function));
 		fptr->type = ZEND_INTERNAL_FUNCTION;
-		fptr->num_args = 1;
+		fptr->num_args = 0;
 		fptr->scope = (*object)->ce;
 		fptr->fn_flags = ZEND_ACC_CALL_VIA_HANDLER;
 		fptr->function_name = zend_string_copy(name);
@@ -874,7 +874,7 @@ static zend_function *zend_test_class_static_method_get(zend_class_entry *ce, ze
 		}
 		memset(fptr, 0, sizeof(zend_internal_function));
 		fptr->type = ZEND_INTERNAL_FUNCTION;
-		fptr->num_args = 1;
+		fptr->num_args = 0;
 		fptr->scope = ce;
 		fptr->fn_flags = ZEND_ACC_CALL_VIA_HANDLER|ZEND_ACC_STATIC;
 		fptr->function_name = zend_string_copy(name);
diff --git a/ext/zend_test/tests/gh16266.phpt b/ext/zend_test/tests/gh16266.phpt
new file mode 100644
index 00000000000..44cb7ef807c
--- /dev/null
+++ b/ext/zend_test/tests/gh16266.phpt
@@ -0,0 +1,21 @@
+--TEST--
+GH-16266 (_ZendTestClass::test() segfaults on named parameter)
+--EXTENSIONS--
+zend_test
+--FILE--
+<?php
+try {
+    $o = new _ZendTestClass();
+    $o->test('a', 'b', c: 'c');
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+try {
+    _ZendTestClass::test('a', 'b', c: 'c');
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+?>
+--EXPECT--
+Unknown named parameter $c
+Unknown named parameter $c