diff --git a/core/modules/forum/forum.module b/core/modules/forum/forum.module
index f5382163a363bdbeb00162e0da80b4a436db5261..3575bfd4edbb555218671d7a13c83cdb719ca760 100644
--- a/core/modules/forum/forum.module
+++ b/core/modules/forum/forum.module
@@ -594,7 +594,13 @@ function forum_form_alter(&$form, $form_state, $form_id) {
       $form['advanced']['parent']['#access'] = FALSE;
     }
   }
-  if (!empty($form['#node_edit_form']) && isset($form['taxonomy_forums'])) {
+}
+
+/**
+ * Implements hook_form_BASE_FORM_ID_alter().
+ */
+function forum_form_node_form_alter(&$form, &$form_state, $form_id) {
+  if (isset($form['taxonomy_forums'])) {
     $langcode = $form['taxonomy_forums']['#language'];
     // Make the vocabulary required for 'real' forum-nodes.
     $form['taxonomy_forums'][$langcode]['#required'] = TRUE;
diff --git a/core/modules/node/node.pages.inc b/core/modules/node/node.pages.inc
index c7b26e75cb210e9d4e329bb6df7ed18a3f69ea52..c6993b66c708bdc38eabc9870ede4681b4544f6d 100644
--- a/core/modules/node/node.pages.inc
+++ b/core/modules/node/node.pages.inc
@@ -106,10 +106,6 @@ function node_form($form, &$form_state, $node) {
     unset($node->in_preview);
   }
 
-  // Identify this as a node edit form.
-  // @todo D8: Remove. Modules can implement hook_form_BASE_FORM_ID_alter() now.
-  $form['#node_edit_form'] = TRUE;
-
   // Override the default CSS class name, since the user-defined node type name
   // in 'TYPE-node-form' potentially clashes with third-party class names.
   $form['#attributes']['class'][0] = drupal_html_class('node-' . $node->type . '-form');