diff --git a/calendar/tests/calendartype_test.php b/calendar/tests/calendartype_test.php
index 487010b2869..4b32999de5b 100644
--- a/calendar/tests/calendartype_test.php
+++ b/calendar/tests/calendartype_test.php
@@ -36,7 +36,6 @@ require_once($CFG->libdir . '/form/datetimeselector.php');
 // Used to test the user datetime profile field.
 require_once($CFG->dirroot . '/user/profile/lib.php');
 require_once($CFG->dirroot . '/user/profile/definelib.php');
-require_once($CFG->dirroot . '/user/profile/index_field_form.php');
 
 /**
  * Unit tests for the calendar type system.
@@ -275,10 +274,10 @@ class core_calendar_type_testcase extends advanced_testcase {
         $formdata['param2'] = $date['inputmaxyear'];
 
         // Mock submitting this.
-        field_form::mock_submit($formdata);
+        \core_user\form\profile_field_form::mock_submit($formdata);
 
         // Create the user datetime form.
-        $form = new field_form(null, 'datetime');
+        $form = new \core_user\form\profile_field_form(null, 'datetime');
 
         // Get the data from the submission.
         $submissiondata = $form->get_data();
diff --git a/user/profile/index_field_form.php b/user/classes/form/profile_field_form.php
similarity index 93%
rename from user/profile/index_field_form.php
rename to user/classes/form/profile_field_form.php
index 39d168c07f3..589c38964eb 100644
--- a/user/profile/index_field_form.php
+++ b/user/classes/form/profile_field_form.php
@@ -22,9 +22,11 @@
  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 
-if (!defined('MOODLE_INTERNAL')) {
-    die('Direct access to this script is forbidden.');    //  It must be included from a Moodle page.
-}
+namespace core_user\form;
+
+use profile_define_base;
+
+defined('MOODLE_INTERNAL') || die;
 
 require_once($CFG->dirroot.'/lib/formslib.php');
 
@@ -34,7 +36,7 @@ require_once($CFG->dirroot.'/lib/formslib.php');
  * @copyright  2007 onwards Shane Elliot {@link http://pukunui.com}
  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
-class field_form extends moodleform {
+class profile_field_form extends \moodleform {
 
     /** @var profile_define_base $field */
     public $field;
diff --git a/user/profile/definelib.php b/user/profile/definelib.php
index acf70709a68..ee654c6aa4c 100644
--- a/user/profile/definelib.php
+++ b/user/profile/definelib.php
@@ -575,8 +575,7 @@ function profile_edit_field($id, $datatype, $redirect) {
     $field->description = clean_text($field->description, $field->descriptionformat);
     $field->description = array('text' => $field->description, 'format' => $field->descriptionformat, 'itemid' => 0);
 
-    require_once($CFG->dirroot.'/user/profile/index_field_form.php');
-    $fieldform = new field_form(null, $field->datatype);
+    $fieldform = new \core_user\form\profile_field_form(null, $field->datatype);
 
     // Convert the data format for.
     if (is_array($fieldform->editors())) {