I am trying to understand the visibility rules for methods and properties in PHP when using traits and abstract classes. I noticed some behaviors that I would like to clarify:

1. Abstract Classes:

• I defined a public method and property in an abstract class and tried to override them in a child class. I got an error when trying to change the visibility from public to private for the method, which stated that I cannot change public to private. However, changing from private to public was allowed for the method.
• The same behavior was observed for properties. Changing the visibility from public to private for a property in a child class resulted in an error, but changing from private to public was allowed.

2. Traits:

• When using traits, I know that you can change the visibility of methods using the as keyword. However, when overriding methods directly in the class using the trait, I was able to change the visibility from public to private and vice versa.
• For properties defined in the trait, I was not able to change the visibility when overriding them in the class. Attempting to change a public property to private in the class using the trait resulted in an error.

I am aware of the Less Restrictive Visibility rule, but I am trying to understand why these differences exist between abstract classes and traits in PHP. Specifically:

• Why can methods have their visibility changed in traits but not in abstract classes when overriding?
• Why can properties not have their visibility changed in traits while methods can?

abstract class AbstractClass {
    public function publicMethod() {}
    private function privateMethod() {}
    public $publicProperty;
    private $privateProperty;
}

class ChildClass extends AbstractClass {
    // Error
    private function publicMethod() {}

    // Allowed
    public function privateMethod() {}
    
    // Error
    private $publicProperty;
    
    // Allowed
    public $privateProperty;

}

trait MyTrait {
    public function publicMethod() {}
    private function privateMethod() {}
    public $publicProperty;
    private $privateProperty;
}

class MyClass {
    use MyTrait;

    // Allowed
    private function publicMethod() {}
    
    // Allowed
    public function privateMethod() {}
    
    // Error
    private $publicProperty;
    
    // Error
    public $privateProperty;

}