diff --git a/question/classes/local/bank/view_component.php b/question/classes/local/bank/view_component.php
index 3932e9647a4..a50397921e3 100644
--- a/question/classes/local/bank/view_component.php
+++ b/question/classes/local/bank/view_component.php
@@ -26,6 +26,9 @@ namespace core_question\local\bank;
  */
 abstract class view_component {
 
+    /** @var view Question bank view. */
+    protected $qbank;
+
     /**
      * Constructor.
      * @param view $qbank the question bank view we are helping to render.
diff --git a/question/format/xml/format.php b/question/format/xml/format.php
index b50dae39b1a..52d91796841 100644
--- a/question/format/xml/format.php
+++ b/question/format/xml/format.php
@@ -46,6 +46,12 @@ if (!class_exists('qformat_default')) {
  */
 class qformat_xml extends qformat_default {
 
+    /** @var array Array of files for question answers. */
+    protected $answerfiles = [];
+
+    /** @var array Array of files for feedback to question answers. */
+    protected $feedbackfiles = [];
+
     public function provide_import() {
         return true;
     }
@@ -1203,9 +1209,9 @@ class qformat_xml extends qformat_default {
                 $contextid, 'question', 'generalfeedback', $question->id);
         if (!empty($question->options->answers)) {
             foreach ($question->options->answers as $answer) {
-                $answer->answerfiles = $fs->get_area_files(
+                $this->answerfiles[$answer->id] = $fs->get_area_files(
                         $contextid, 'question', 'answer', $answer->id);
-                $answer->feedbackfiles = $fs->get_area_files(
+                $this->feedbackfiles[$answer->id] = $fs->get_area_files(
                         $contextid, 'question', 'answerfeedback', $answer->id);
             }
         }
@@ -1593,10 +1599,10 @@ class qformat_xml extends qformat_default {
         $output = '';
         $output .= "    <answer fraction=\"{$percent}\" {$this->format($answer->answerformat)}>\n";
         $output .= $this->writetext($answer->answer, 3);
-        $output .= $this->write_files($answer->answerfiles);
+        $output .= $this->write_files($this->answerfiles[$answer->id]);
         $output .= "      <feedback {$this->format($answer->feedbackformat)}>\n";
         $output .= $this->writetext($answer->feedback, 4);
-        $output .= $this->write_files($answer->feedbackfiles);
+        $output .= $this->write_files($this->feedbackfiles[$answer->id]);
         $output .= "      </feedback>\n";
         $output .= $extra;
         $output .= "    </answer>\n";
diff --git a/question/type/calculated/upgrade.txt b/question/type/calculated/upgrade.txt
new file mode 100644
index 00000000000..00ebecaf389
--- /dev/null
+++ b/question/type/calculated/upgrade.txt
@@ -0,0 +1,6 @@
+This file describes API changes in /question/type/calculated/*.
+
+=== 4.3 ===
+* \qtype_calculated answers are now of the type \qtype_calculated\qtype_calculated_answer which extends \qtype_numerical_answer.
+  Plugins extending \qtype_calculated and still reference \qtype_numerical_answer in their code (e.g. in test helper functions)
+  should update their code to reference \qtype_calculated\qtype_calculated_answer instead.
diff --git a/question/type/calculatedmulti/tests/helper.php b/question/type/calculatedmulti/tests/helper.php
index 25dddb1916a..92330cf2a92 100644
--- a/question/type/calculatedmulti/tests/helper.php
+++ b/question/type/calculatedmulti/tests/helper.php
@@ -64,9 +64,9 @@ class qtype_calculatedmulti_test_helper extends question_test_helper {
         $q->incorrectfeedbackformat = FORMAT_HTML;
         $q->shownumcorrect = 1;
         $q->answers = array(
-            13 => new question_answer(13, '{={a} + {b}}', 1.0, 'Very good.', FORMAT_HTML),
-            14 => new question_answer(14, '{={a} - {b}}', 0.0, 'Add. not subtract!', FORMAT_HTML),
-            17 => new question_answer(17, '{={a} + 2 * {b}}', 0.0, 'Just add.', FORMAT_HTML),
+            13 => new \qtype_calculated\qtype_calculated_answer(13, '{={a} + {b}}', 1.0, 'Very good.', FORMAT_HTML, 0),
+            14 => new \qtype_calculated\qtype_calculated_answer(14, '{={a} - {b}}', 0.0, 'Add. not subtract!', FORMAT_HTML, 0),
+            17 => new \qtype_calculated\qtype_calculated_answer(17, '{={a} + 2 * {b}}', 0.0, 'Just add.', FORMAT_HTML, 0),
         );
         $q->answers[13]->correctanswerlength = 2;
         $q->answers[13]->correctanswerformat = 1;
@@ -107,10 +107,10 @@ class qtype_calculatedmulti_test_helper extends question_test_helper {
         $q->incorrectfeedbackformat = FORMAT_HTML;
         $q->shownumcorrect = 1;
         $q->answers = array(
-                13 => new qtype_numerical_answer(13, '{a} + {b}!', 0.5, 'Good', FORMAT_HTML, 0),
-                14 => new qtype_numerical_answer(14, '{={a} + {b}}', 0.5, 'Good',
+                13 => new \qtype_calculated\qtype_calculated_answer(13, '{a} + {b}!', 0.5, 'Good', FORMAT_HTML, 0),
+                14 => new \qtype_calculated\qtype_calculated_answer(14, '{={a} + {b}}', 0.5, 'Good',
                         FORMAT_HTML, 0),
-                17 => new qtype_numerical_answer(17, '{={a} - {b}}', -0.5, 'Wrong.', FORMAT_HTML, 0),
+                17 => new \qtype_calculated\qtype_calculated_answer(17, '{={a} - {b}}', -0.5, 'Wrong.', FORMAT_HTML, 0),
         );
         $q->answers[13]->correctanswerlength = 2;
         $q->answers[13]->correctanswerformat = 1;
diff --git a/question/type/calculatedsimple/tests/helper.php b/question/type/calculatedsimple/tests/helper.php
index c3bca397d58..eaa3d6af1fe 100644
--- a/question/type/calculatedsimple/tests/helper.php
+++ b/question/type/calculatedsimple/tests/helper.php
@@ -54,10 +54,10 @@ class qtype_calculatedsimple_test_helper extends question_test_helper {
         $q->generalfeedback = 'Generalfeedback: {={a} + {b}} is the right answer.';
 
         $q->answers = array(
-            13 => new qtype_numerical_answer(13, '{a} + {b}', 1.0, 'Very good.', FORMAT_HTML, 0),
-            14 => new qtype_numerical_answer(14, '{a} - {b}', 0.0, 'Add. not subtract!.',
+            13 => new \qtype_calculated\qtype_calculated_answer(13, '{a} + {b}', 1.0, 'Very good.', FORMAT_HTML, 0),
+            14 => new \qtype_calculated\qtype_calculated_answer(14, '{a} - {b}', 0.0, 'Add. not subtract!.',
                     FORMAT_HTML, 0),
-            17 => new qtype_numerical_answer(17, '*', 0.0, 'Completely wrong.', FORMAT_HTML, 0),
+            17 => new \qtype_calculated\qtype_calculated_answer(17, '*', 0.0, 'Completely wrong.', FORMAT_HTML, 0),
         );
         foreach ($q->answers as $answer) {
             $answer->correctanswerlength = 2;