Description:
------------
When importing namespace in a script using the __halt_compiler() function, the imported script must use the same type of declaration (bracketed namespace or unbracketed namespace).


Test script:
---------------
a.php
----
<?php
namespace a;
require_once 'b.php';
echo 'ok',PHP_EOL;
__halt_compiler(); // Remove this line and the script will works.

b.php
----
<?php
namespace b\c {}
namespace b\d {}


Expected result:
----------------
ok

Actual result:
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Fatal error: Cannot mix bracketed namespace declarations with unbracketed namespace declarations in b.php on line 2