diff --git a/modules/field/views_handler_field_field.inc b/modules/field/views_handler_field_field.inc
index 5b10970..1b8e7ee 100644
--- a/modules/field/views_handler_field_field.inc
+++ b/modules/field/views_handler_field_field.inc
@@ -651,10 +651,10 @@ class views_handler_field_field extends views_handler_field {
       // 'safe_value' which doesn't appear anywhere in the field definition
       // so we can't affect it. Other side effects could happen similarly.
       $data = FALSE;
-      foreach ($this->group_fields as $field => $column) {
+      foreach ($this->group_fields as $field_name => $column) {
         if (property_exists($values, $this->aliases[$column])) {
-          $base_value[$field] = $values->{$this->aliases[$column]};
-          if (isset($base_value[$field])) {
+          $base_value[$field_name] = $values->{$this->aliases[$column]};
+          if (isset($base_value[$field_name])) {
             $data = TRUE;
           }
         }