diff --git a/webservice/soap/locallib.php b/webservice/soap/locallib.php
index 8ccd31757af..13862560acf 100644
--- a/webservice/soap/locallib.php
+++ b/webservice/soap/locallib.php
@@ -273,11 +273,6 @@ class webservice_soap_server extends webservice_zend_server {
      */
     protected function generate_simple_struct_class(external_single_structure $structdesc) {
         global $USER;
-        // let's use unique class name, there might be problem in unit tests
-        $classname = 'webservices_struct_class_000000';
-        while(class_exists($classname)) {
-            $classname++;
-        }
 
         $fields = array();
         foreach ($structdesc->keys as $name => $fieldsdesc) {
@@ -286,6 +281,12 @@ class webservice_soap_server extends webservice_zend_server {
                         '    public $'.$name.';';
         }
 
+        // We do this after the call to get_phpdoc_type() to avoid duplicate class creation.
+        $classname = 'webservices_struct_class_000000';
+        while (class_exists($classname)) {
+            $classname++;
+        }
+
         $code = '
 /**
  * Virtual struct class for web services for user id '.$USER->id.' in context '.$this->restricted_context->id.'.