public ErrorMessageList Merge(ErrorMessageList errors)
{
var result = this;
foreach (var error in errors.All <ErrorMessage>())
{
result = result.With(error);
}
return(result);
}
private IEnumerable <T> All <T>() where T : ErrorMessage
{
if (this != Empty)
{
if (head is T)
{
yield return((T)head);
}
foreach (T message in tail.All <T>())
{
yield return(message);
}
}
}