Description:
------------
If we pass an expression by reference, it doesn't recognize the variable from the expression, but doesn't complain about that fact either.

As written in http://www.php.net/manual/en/language.references.pass.php, such statement is invalid. Strangely enough it worked up to 5.0.4 (and 5.0.5 perhaps) and stopped working after upgrade to 5.1.2.

Moreover, since both remaining examples from the documentation produce a fatal error, it would seem natural if that one would as well.

Reproduce code:
---------------
<?php

function inc(&$a)
{
  $a++;
}

// $b = 3;
// inc($b);
inc($b = 3);
echo $b ."\n";

?>

Expected result:
----------------
Either 4 or a fatal error, rather than silently doing nothing.

Actual result:
--------------
3