<?php

function func_one(array $x) {}
function func_two(array $x = null) {}
function func_three(array $x = array()) {}
function func_four(array $x = false) {}

function func_five(callable $x) {}
function func_six(callable $x = null) {}
function func_seven(callable $x = false) {}

function func_eight(stdClass $x) {}
function func_nine(stdClass $x = null) {}
function func_ten(stdClass $x = array()) {}
~~~~~~~~~~
error:6:31
error:10:35
error:14:33