Update the package — I'm pretty sure this is a limitation of the parser that isn't likely to be fixed any time soon, but hopefully one of the guys who works on the parser can confirm that.

you don't need always use :: to call static method,  actually,  :: doesn't means 
calling static method all the time.

you could use $this->speaker->say($str).

anyway, I agree we can do some improvement here, assign to myself. I can solve 
this in the mean time of implement the instance function call FR

thanks

Just wanted to verify that I have noticed a similar behavior when accessing class constants in PHP 5.4.4. 

When accessing the constant via the class name, or via an object of the class that defines the constant, or via an object returned by a getter of a class that uses the object as a property the constant is properly returned. 

But when trying to access the constant by using $this->object::const produces a parsing error while assigning the object to a temporary variable and using $var::const works.

class one {
        const ALPHA = 0;

        function __construct() {}
}

class two {
        protected $oo1;

        public function __construct() {
                $this->oo1 = new one();
        }

        public function getOne() {
                return $this->oo1;
        }

        public function printAlphaDirectly() {
                //echo $this->oo1::ALPHA . PHP_EOL;
        }

        public function printAlphaTmp() {
                $tmp = $this->oo1;

                echo $tmp::ALPHA . PHP_EOL;

        }
}

echo one::ALPHA . PHP_EOL; // (Output= 0) It works as expected

$o1 = new one();
echo $o1::ALPHA . PHP_EOL; // (Output= 0) It works when passing an object

$t1 = new two();
$o2 = $t1->getOne();

echo $o2::ALPHA . PHP_EOL; // (Output= 0) It works when using an object returned from a getter

$t1->printAlphaDirectly(); // PHP Parse error:  syntax error, unexpected '::' (T_PAAMAYIM_NEKUDOTAYIM)

$t1->printAlphaTmp(); // (Output= 0) It works when using a tmp var to hold the object

Supported in PHP 7.