Description:
------------
Implemented abstract function with additional parameter having default value
doesn't cause any error.


Will output:

I am the first arg. I am the additional arg.
I am the first arg. I am the additional arg default value.


If no default value the script crash.


Test script:
---------------
<?php

abstract class AbstractMother
{
    public abstract function methodWithOneArg( $arg );
}

class ConcreteChild extends AbstractMother
{
    public function methodWithOneArg($arg, $arg2="I am the additional arg default value.")
    {
        echo $arg." ".$arg2 ;
    }
}

$child = new ConcreteChild() ;

$child->methodWithOneArg( "I am the first arg.", "I am the additional arg.") ;

echo "<br>" ;

$child->methodWithOneArg("I am the first arg.") ;

Expected result:
----------------
FATAL ERROR thrown

Actual result:
--------------
Just works, addition of a third argument is ignored:

<?php

class ConcreteChild2 extends AbstractMother
{
    public function methodWithOneArg($arg, $arg2="I am the additional arg default value.", $arg3="I am another arg default value.")
    {
        echo $arg." ".$arg2." ".$arg3 ;
    }
}
echo "<br>" ;echo "<br>" ;

$child2 = new ConcreteChild2() ;

$child->methodWithOneArg( "I am the first arg.", "I am the additional arg.", "I am the other additional arg") ;
echo "<br>" ;
$child->methodWithOneArg( "I am the first arg.", "I am the additional arg.") ;
echo "<br>" ;
$child->methodWithOneArg("I am the first arg.") ;

?>

Will output:

I am the first arg. I am the additional arg.
I am the first arg. I am the additional arg.
I am the first arg. I am the additional arg default value.