public FormStateInterface::setMethod($method)

public FormStateInterface::setError(array &$element, $message

public FormStateInterface::isCached()

public FormBuilderInterface::getForm($form_arg)

public static FormStateDecoratorBase::hasAnyErrors()

public &FormStateDecoratorBase::getStorage()

public SubformStateInterface::getCompleteFormState()

public FormStateInterface::getResponse()

public FormState::getFormObject() Returns

The app root. Type: string File core/lib/Drupal/Core/Form/FormCache