Description:
------------
When using a echo/print with an object that has a __toString method defined it behaves strange depending on the usage.

echo $obj is fine
echo $obj."\n"  is not

Reproduce code:
---------------
class TestClass
{
   public $foo;

   public function __construct($foo) {
       $this->foo = $foo;
   }

   public function __toString() {
       return $this->foo;
   }
}

$n = new TestClass("test") ;
echo $n ;   // works - shows test
echo $n."\n" ;  // does not - show Object id #1

Expected result:
----------------
Test

Actual result:
--------------
Object id #1