[PHP-BUG] Bug #73604 [NEW]: Excplicit type cast for class constants produces error

From:             anatoly dot pashin at gmail dot com
Operating system: 
PHP version:      7.0.13
Package:          PHP Language Specification
Bug Type:         Bug
Bug description:Excplicit type cast for class constants produces error

Description:
------------
Interpreter produces `PHP Fatal error:  Constant expression contains
invalid operations in…` because of explicit const value type cast.

But implicit is allowed and works as expected.

Yes, I undestand difference between `+` and `(int)` that `int` will cast
to integer and drop past-float part. But question why that's now allowed
is still present.

Casting plain value rather than array value doesn't work too. Even if
you cast integer to integer.

Test script:
---------------
class Barcode
{
    const BARCODE_TYPES = [
        (int)\Stickers::BARCODE_TYPE_MEGAORDER,
        +\Stickers::BARCODE_TYPE_SHOP_ORDER,
    ];
}

Expected result:
----------------
All is OK and array value became int casted.

Actual result:
--------------
PHP Fatal error:  Constant expression contains invalid operations in…

-- 
Edit bug report at https://bugs.php.net/bug.php?id=73604&edit=1
-- 
Try a snapshot (PHP 5.4):   https://bugs.php.net/fix.php?id=73604&r=trysnapshot54
Try a snapshot (PHP 5.5):   https://bugs.php.net/fix.php?id=73604&r=trysnapshot55
Try a snapshot (trunk):     https://bugs.php.net/fix.php?id=73604&r=trysnapshottrunk
Fixed in SVN:               https://bugs.php.net/fix.php?id=73604&r=fixed
Fixed in release:           https://bugs.php.net/fix.php?id=73604&r=alreadyfixed
Need backtrace:             https://bugs.php.net/fix.php?id=73604&r=needtrace
Need Reproduce Script:      https://bugs.php.net/fix.php?id=73604&r=needscript
Try newer version:          https://bugs.php.net/fix.php?id=73604&r=oldversion
Not developer issue:        https://bugs.php.net/fix.php?id=73604&r=support
Expected behavior:          https://bugs.php.net/fix.php?id=73604&r=notwrong
Not enough info:            https://bugs.php.net/fix.php?id=73604&r=notenoughinfo
Submitted twice:            https://bugs.php.net/fix.php?id=73604&r=submittedtwice
register_globals:           https://bugs.php.net/fix.php?id=73604&r=globals
PHP 4 support discontinued: https://bugs.php.net/fix.php?id=73604&r=php4
Daylight Savings:           https://bugs.php.net/fix.php?id=73604&r=dst
IIS Stability:              https://bugs.php.net/fix.php?id=73604&r=isapi
Install GNU Sed:            https://bugs.php.net/fix.php?id=73604&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=73604&r=float
No Zend Extensions:         https://bugs.php.net/fix.php?id=73604&r=nozend
MySQL Configuration Error:  https://bugs.php.net/fix.php?id=73604&r=mysqlcfg