property.visibility

Code example

<?php declare(strict_types = 1);

class Base
{
	public string $name = 'hello';
}

class Child extends Base
{
	protected string $name = 'world'; // ERROR: Protected property Child::$name overriding public property Base::$name should also be public.
}

Why is it reported?

When a child class overrides a property from a parent class, it must not reduce the visibility of the property. A public property cannot become protected or private, and a protected property cannot become private. Reducing visibility violates the Liskov Substitution Principle -- code that accesses the property through the parent type expects the declared visibility level to be maintained.

How to fix it

Match or widen the visibility of the overriding property:

 <?php declare(strict_types = 1);

 class Base
 {
 	public string $name = 'hello';
 }

 class Child extends Base
 {
-	protected string $name = 'world';
+	public string $name = 'world';
 }