.. _closures-in-constant-expressions-must-be-static: Closures in constant expressions must be static ----------------------------------------------- .. meta:: :description: Closures in constant expressions must be static: When defining a closure as a constant value, there cannot be any context value that are imported. :og:image: https://php-errors.readthedocs.io/en/latest/_static/logo.png :og:type: article :og:title: Closures in constant expressions must be static :og:description: When defining a closure as a constant value, there cannot be any context value that are imported :og:url: https://php-errors.readthedocs.io/en/latest/messages/closures-in-constant-expressions-must-be-static.html :og:locale: en :twitter:card: summary_large_image :twitter:site: @exakat :twitter:title: Closures in constant expressions must be static :twitter:description: Closures in constant expressions must be static: When defining a closure as a constant value, there cannot be any context value that are imported :twitter:creator: @exakat :twitter:image:src: https://php-errors.readthedocs.io/en/latest/_static/logo.png .. raw:: html Description ___________ When defining a closure as a constant value, there cannot be any context value that are imported. This includes the current object ``$this`` which is included by default in any closure. To avoid this, the ``static`` option must be added to the closure. Example _______ .. code-block:: php Solutions _________ + Add the static option to the closure. + Define the closure inside a method. Related Error Messages ______________________ + :ref:`cannot-use(...)-variables-in-constant-expression` Changed Behavior ________________ This error may appear following an evolution in behavior, in previous versions. See ` `_.