magic_invoke.php

<?php
/**
 * Bug in 5.3 __invoke() ?
 *
 * @see http://news.php.net/php.internals/49801
 */

class Hoge
{
    public function __invoke()
    {
        echo __CLASS__, PHP_EOL;
    }
}

class Fuga
{
    public $hoge;

    public function h()
    {
        // callable object as a property
        $this->hoge = new Hoge();
        var_dump(is_callable($this->hoge)); // => true
        call_user_func($this->hoge);        // => "Hoge"
        // $this->hoge();                   // => Fatal error:  Call to undefined method Fuga::hoge()

        unset($this->hoge);

        // in the case of closure
        $this->hoge = function ()
        {
            echo "closure", PHP_EOL;
        };
        var_dump(is_callable($this->hoge)); // => true
        call_user_func($this->hoge);        // => "closure"
        // $this->hoge();                   // => Fatal error:  Call to undefined method Fuga::hoge()
    }
}

$d = new Fuga();
$d->h();