Description:
------------
Due to some reasons we are not allowed to create property with empty name:

    $object = new stdClass();
    $object->{""} = 42;
    // Fatal error: Cannot access empty property

Ok. But type-cast `(object)` doesn't know about this restriction: http://3v4l.org/IU3GW . This inconsistency cause some problems.

All PHP/5 versions affected including PHP/5.5 and PHP/5.6.0beta3:
  Some features emits a notice, others aren't.
  Some features interacts with empty property, others aren't.
  (there are some different behaviours in very old versions)


Test script:
---------------
<?php
$object = (object) array(
    "foo" => 42,
    ""    => 37,
    "bar" => 19,
);

echo "+ object created:\n";
var_dump($object);

echo "\nenum properties:\n";
foreach ($object as $p => $v) {
    var_dump($p);
}

echo "\nget_object_vars()\n";
var_dump(get_object_vars($object));


Expected result:
----------------
Fatal error: Cannot access empty property
(or an Exception should be better)

Actual result:
--------------
+ object created:
object(stdClass)#1 (3) {
  ["foo"]=>
  int(42)

Notice: Illegal member variable name in ... on line 9
  [""]=>
  int(37)
  ["bar"]=>
  int(19)
}

enum properties:
string(3) "foo"

Notice: Illegal member variable name in ... on line 12
string(3) "bar"

get_object_vars()

Notice: Illegal member variable name in ... on line 17
array(2) {
  ["foo"]=>
  int(42)
  ["bar"]=>
  int(19)
}