Testing PHP7 features with Fibonacci sequence function

fibonacci.php

<?php
/**
 * Succinct Fibonacci function
 *
 * Returns the first N Fibonacci numbers specified as parameter.
 * 
 * This function has not been written for efficiency nor readabilty, instead it has 
 * been created for fun and for testing the latest PHP features (E.g.: generators, 
 * literal dereferencing, type hinting, short array syntax, ...).
 * 
 * Function tested on PHP 7.0.0beta3.
 *
 * @author Jawira Portugal
 * @param int $q
 * @return \Generator
 */
function fibonacci(int $q = 0b1): Generator {
    for ($_ = [-1, 1]; 0 < $q; --$q)
        yield (list($_[0], $_[1]) = [$_[1], array_sum($_)])[1];
}

// Printing the first 5 Fibonacci numbers
foreach(fibonacci(5) as $num) {
    echo $num, PHP_EOL;
}