Description:
------------
If a class has a magic __call() method, fields which are closure are not invoked.

The result being that the $args param to __call() exceeds memory limits due to nesting recursively (and, depending on recursion and memory limits does not report as a recursion limit reached).

On preliminary review, this may be related to the callable types and Classname::method() syntax:
https://github.com/php/php-src/commit/989a13608b5154672e6ab94f970e271f7d0ae502

Test script:
---------------
<?php
class CallableStub {
    protected $callback = null;
    public function setCallback(callable $callback) {
        $this->callback = $callback;
    }
    public function __call($name, $args) {
        if($this->callback == null || !is_callable($this->callback)) {
            throw new \LogicException("CallableStub requires a callback function to be callable.");
        }

        //$cb = $this->callback; // $cb(); use a locl variable instead and it works!
        return $this->callback($name, $args);
    }
} 

$s = new CallableStub();
$s->setCallback( function ($x, $y) { var_dump(func_get_args()); });
$s->frankfurt('rabbit stew');

Expected result:
----------------
--- expected ---
$this->callback($someArgs);// invoke the closure in $this->callback;


Actual result:
--------------
--- actual ---
$this->callback($someargs);// invokes __call('callback', [$someargs]);

Error:

Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 262144 bytes) in /in/cg4kJ on line 16

Process exited with code 255.