Description:
------------
Embedding a heredoc inside another heredoc fails to compile on 5.2.12.

(The same code successfully compiles on 5.2.4-ubuntu, but running it has the wrong output.)

Reproduce code:
---------------
<?php
$a = Array("b" => 1);

echo <<<ZZ
{$a[<<<B
b
B
]}
ZZ;
?>


Expected result:
----------------
1

Actual result:
--------------
Parse error: syntax error, unexpected $end in /home/thue/test.php on line 11