Notice in locale_languages_edit_form_validate

When a user enters a duplicate language prefix or domain, form validation fails because those values must be unique. The validation message contains the original language that uses this prefix or domain, but the reference to this language is wrong:

  if (!empty($form_state['values']['domain']) && $duplicate = db_query("SELECT language FROM {languages} WHERE domain = :domain AND language <> :language", array(':domain' => $form_state['values']['domain'], ':language' => $form_state['values']['langcode']))->fetchField()) {
    form_set_error('domain', t('The domain (%domain) is already tied to a language (%language).', array('%domain' => $form_state['values']['domain'], '%language' => $duplicate->language)));
  }

Because fetchField() is used, $duplicate is a string, not an object. This code fails with a message like:

Notice: Trying to get property of non-object in locale_languages_edit_form_validate()