.. _interfaces-cantoverloadconstants:

.. _cant-overload-constants:

Cant Overload Constants
+++++++++++++++++++++++

  It was not possible to overload class constants within a class, when the constant was defined in an interface. This restriction was removed in PHP 8.1.

.. code-block:: php
   
   <?php
   
   interface i { 
       const A = 1;
   }
   
   //This lints, but doesn't executin in PHP 8.0 and older.
   class x implements i { 
       const A = 1;
   }
   
   ?>

See also `interface constants <https://www.php.net/manual/en/language.oop5.interfaces.php#language.oop5.interfaces.constants>`.

Related PHP errors 
-------------------

  + `Cannot inherit previously-inherited or override constant A from interface i <https://php-errors.readthedocs.io/en/latest/messages/cannot-inherit-previously-inherited-or-override-constant-%25s-from-interface-%25s.html>`_



Connex PHP features
-------------------

  + `interface <https://php-dictionary.readthedocs.io/en/latest/dictionary/interface.ini.html>`_
  + `class <https://php-dictionary.readthedocs.io/en/latest/dictionary/class.ini.html>`_


Suggestions
___________

* Avoid overloading constants
* Define the constants only in the classes




Specs
_____

+------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Short name       | Interfaces/CantOverloadConstants                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
+------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Rulesets         | :ref:`All <ruleset-All>`, :ref:`Changed Behavior <ruleset-Changed-Behavior>`, :ref:`CompatibilityPHP53 <ruleset-CompatibilityPHP53>`, :ref:`CompatibilityPHP54 <ruleset-CompatibilityPHP54>`, :ref:`CompatibilityPHP55 <ruleset-CompatibilityPHP55>`, :ref:`CompatibilityPHP56 <ruleset-CompatibilityPHP56>`, :ref:`CompatibilityPHP70 <ruleset-CompatibilityPHP70>`, :ref:`CompatibilityPHP71 <ruleset-CompatibilityPHP71>`, :ref:`CompatibilityPHP72 <ruleset-CompatibilityPHP72>`, :ref:`CompatibilityPHP73 <ruleset-CompatibilityPHP73>`, :ref:`CompatibilityPHP74 <ruleset-CompatibilityPHP74>`, :ref:`CompatibilityPHP80 <ruleset-CompatibilityPHP80>`, :ref:`LintButWontExec <ruleset-LintButWontExec>` |
+------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Exakat since     | 2.3.2                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
+------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Severity         | Minor                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
+------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Time To Fix      | Quick (30 mins)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
+------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Changed Behavior | PHP 8.1 - `More <https://php-changed-behaviors.readthedocs.io/en/latest/behavior/constantFromInterfaceVisibilityCheck.html>`__                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
+------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Precision        | High                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
+------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Note             | This issue may lint but will not run                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
+------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Available in     | `Entreprise Edition <https://www.exakat.io/entreprise-edition>`_, `Exakat Cloud <https://www.exakat.io/exakat-cloud/>`_                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+