Description:
------------
$this->{$method}() calls fail with a "Method name must be a string" error, even if $method is a string (and an existing method too).

I've encountered this after assigning $method via sscanf(), so it might be a sscanf() issue, but it doesn't look like it ...

Test script:
---------------
<?php
class Foo {

	public function test()
	{
		sscanf('bar', '%s', $method);
		var_dump($method);
		$this->{$method}();
	}

	public function bar() {}

}

$bar = new Foo();
$bar->test();

Expected result:
----------------
string(3) "bar"

Actual result:
--------------
string(3) "bar"

Fatal error: Method name must be a string in %s on line 8