outOfClass.self

Code example

<?php declare(strict_types = 1);

echo self::FOO; // ERROR: Using self outside of class scope.

Why is it reported?

The keyword self refers to the class in which it is used. It can only be used inside a class definition (in methods, class constants, or property declarations). Using self outside of a class scope (for example, in a function or in the global scope) is a PHP error because there is no class to reference.

How to fix it

Use the fully qualified class name instead of self when outside a class:

 <?php declare(strict_types = 1);

-echo self::FOO;
+echo MyClass::FOO;

Or move the code inside a class method:

<?php declare(strict_types = 1);

class MyClass
{
	public const FOO = 'bar';

	public function doFoo(): void
	{
		echo self::FOO; // This works inside a class
	}
}