[PHP-BUG] Req #70508 [NEW]: Support ::function similar to ::class

From:             andreas at dqxtech dot net
Operating system: Linux
PHP version:      7.0.0RC2
Package:          PHP Language Specification
Bug Type:         Feature/Change Request
Bug description:Support ::function similar to ::class

Description:
------------
Classes like ReflectionFunction, ReflectionMethod, or built-in functions
like array_filter() accept functions identified as strings.

This often leads to code like this, which is hard to analyse by the
IDE:

$callback = '\MyVendor\MyLibraray\MyClass::foo';

For classes, I already use the ::class language construct to make this
understandable to the IDE, and allow things like "Find usages", or to
let the IDE tell me that the class does not exist.

I suggest to introduce a similar construct for functions and methods,
::function.

Test script:
---------------
class C {
  function fooMethod() {}
}

function fooFunction() {}

print C::fooMethod::function . "\n";
print fooFunction::function . "\n";

Expected result:
----------------
C::fooMethod
fooFunction


Actual result:
--------------
Fatal error: syntax error, unexpected T_DOUBLE_COLON

-- 
Edit bug report at https://bugs.php.net/bug.php?id=70508&edit=1
-- 
Try a snapshot (PHP 5.4):   https://bugs.php.net/fix.php?id=70508&r=trysnapshot54
Try a snapshot (PHP 5.5):   https://bugs.php.net/fix.php?id=70508&r=trysnapshot55
Try a snapshot (trunk):     https://bugs.php.net/fix.php?id=70508&r=trysnapshottrunk
Fixed in SVN:               https://bugs.php.net/fix.php?id=70508&r=fixed
Fixed in release:           https://bugs.php.net/fix.php?id=70508&r=alreadyfixed
Need backtrace:             https://bugs.php.net/fix.php?id=70508&r=needtrace
Need Reproduce Script:      https://bugs.php.net/fix.php?id=70508&r=needscript
Try newer version:          https://bugs.php.net/fix.php?id=70508&r=oldversion
Not developer issue:        https://bugs.php.net/fix.php?id=70508&r=support
Expected behavior:          https://bugs.php.net/fix.php?id=70508&r=notwrong
Not enough info:            https://bugs.php.net/fix.php?id=70508&r=notenoughinfo
Submitted twice:            https://bugs.php.net/fix.php?id=70508&r=submittedtwice
register_globals:           https://bugs.php.net/fix.php?id=70508&r=globals
PHP 4 support discontinued: https://bugs.php.net/fix.php?id=70508&r=php4
Daylight Savings:           https://bugs.php.net/fix.php?id=70508&r=dst
IIS Stability:              https://bugs.php.net/fix.php?id=70508&r=isapi
Install GNU Sed:            https://bugs.php.net/fix.php?id=70508&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=70508&r=float
No Zend Extensions:         https://bugs.php.net/fix.php?id=70508&r=nozend
MySQL Configuration Error:  https://bugs.php.net/fix.php?id=70508&r=mysqlcfg