<?php
$fusion=[1, 2];
function dumpType(ReflectionType $rt, int $indent = 0) {
        $str_indent = str_repeat(' ', 2 * $indent);var_dump($str_indent);
    echo $str_indent . "Type $rt is " . $rt::class . ":\n";
    echo $str_indent . "Allows Null: " . json_encode($rt->allowsNull()) . "\n";var_dump($str_indent);
    foreach ($rt->getTypes() as $type) {
        if ($type instanceof ReflectionNamedType) {
            echo $str_indent . "  Name: " . $type->getName() . "\n";var_dump($str_indent);
            echo $str_indent . "  String: " . (string) $type . "\n";var_dump($str_indent);
        } else {
            dumpType($fusion, $indent+1);var_dump($fusion);
        }
    }
}
function test1(): (X&Y)|(Z&Traversable)|null { }
dumpType((new ReflectionFunction('test1'))->getReturnType());