Php Open API - get referenced class or type

Hello, 

Is there a way in Php open API to find the PHP class or type from the reference?

So for example when i have a PhpReference I would like to know if it refers to a class and which class it is.

What I discovered so far was doing something like this would give me the type

if(reference.getFirstPsiChild() instanceof PhpTypedElement) {
    PhpTypedElement typedElement = (PhpTypedElement) reference.getFirstPsiChild();
    PhpIndex.getInstance(reference.getProject())
        .getClassesByFQN(typedElement.getType().toString())
        .forEach(phpClazz -> {
            System.out.println(phpClazz.getFQN());
        });
}

This does however not work if there are multiple possible types, like in this example

/**
 * @return Test|User
 */
function createTest() : Test{
    return new Test();
}

So what I am looking for is a way to get all the known return types.