Can return one of the given types, decided at runtime. The syntax is to declare all the possible types in the return value, then you can return typeof(return)(...value...) to construct it.

It has an auto-generated constructor for each value it can hold.

MultipleResponses!(Redirection, string) getData(int how) {
	if(how & 1)
		return typeof(return)(Redirection("http://dpldocs.info/"));
	else
		return typeof(return)("hi there!");
}

If you have lots of returns, you could, inside the function, alias r = typeof(return); to shorten it a little.