$pane_form['returning_customer']['name']['#title']=$login_with_username?t('Email address or username'):t('Email address');
$pane_form['returning_customer']['name']['#description']=$login_with_username?t('Enter your email address or username.'):t('Enter your email address.');
$pane_form['returning_customer']['name']['#title']=$login_with_username?$this->t('Email address or username'):$this->t('Email address');
$pane_form['returning_customer']['name']['#description']=$login_with_username?$this->t('Enter your email address or username.'):$this->t('Enter your email address.');
$form_state->setError($name_element,$this->t('Unrecognized email address or password. <a href=":password">Forgot your password?</a>',[':url'=>$password_url]));
$form_state->setError($name_element,$this->t('Unrecognized email address or password. <a href=":password">Forgot your password?</a>',[':password'=>$password_url]));
// Adding return to avoid the parent error when password is empty.