reverted:
--- b/core/modules/field/field.module
+++ a/core/modules/field/field.module
@@ -334,17 +334,8 @@
  * required if there are any active fields of that type.
  */
 function field_system_info_alter(&$info, $file, $type) {
+  if ($type == 'module' && module_hook($file->name, 'field_info')) {
+    $fields = field_read_fields(array('module' => $file->name), array('include_deleted' => TRUE));
-  // module_hook() relies on the very function this is called from:
-  // system_rebuild_module_data().
-  $function = $file->name . '_field_info';
-  if ($type == 'module' && function_exists($function)) {
-    try {
-      $fields = field_read_fields(array('module' => $file->name), array('include_deleted' => TRUE));
-    }
-    catch (Exception $e) {
-      // The field_config table is not yet installed. Nothing to do.
-      return;
-    }
     if ($fields) {
       $info['required'] = TRUE;
 
@@ -358,8 +349,7 @@
         }
       }
       if ($non_deleted) {
+        if (module_exists('field_ui')) {
-        // Calling module_exists() here leads to infinite recursion.
-        if (config('system.module')->get('field_ui') !== NULL) {
           $explanation = t('Field type(s) in use - see <a href="@fields-page">Field list</a>', array('@fields-page' => url('admin/reports/fields')));
         }
         else {