Description:
------------
Implementing an interface via a trait doesn't appear to allow optional parameters like implementing via a class.  That is, I can add optional parameters to the implementation method in a class and it still satisfies the interface.  Adding optional parameters via a trait, however, ends as a fatal 'compatibility' error.

It appears the expected behavior was working in at least 5.4.6, or (unlikely) that it works in a linux version but not a windows one.

(Bug #63177 may be indirectly related.)


Test script:
---------------
//file testWorks.php
interface IStringable {
	public function toString();
}
class MyTestWorks implements IStringable {
	public function toString($a = '', $b = NULL) {
		echo "My Test is instantiated", PHP_EOL;
	}
}
$obj = new MyTestWorks();
$obj->toString();

//file testBroken.php
interface IStringable
{
	public function toString();
}
trait TStringable
{
	public function toString($a = '', $b = NULL) {
		echo "My Test is instantiated", PHP_EOL;
	}
}
class MyTestWorks implements IStringable{
	use TStringable;
}
$obj = new MyTestWorks();
$obj->toString();


Expected result:
----------------
>php testWorks.php
My Test is instantiated

>php testBroken.php
My Test is instantiated


(This is the output from php 5.4.6 [linux])

Actual result:
--------------
>php testWorks.php
My Test is instantiated

>php testBroken.php
PHP Fatal error:  Declaration of TStringable::toString($a = '', $b = NULL) must be compatible with IStringable::toString() in [...]\testBroken.php on line 17

(This is the output from php 5.4.11 [windows])