Why will output Fatal Error?

Question

PHP

abstract class First {
    private $a = 5;

    abstract public function getVar();
}

class Second extends First{
    public function getVar()
    {
        return $this->a;
    }
}

$obj = new Second();
$obj->getVar();

I pass the test, there is such a question, the answer options are:

• 5
  
• Notice about trying to gain access to unknown authority
• nothing
• fatal error
  

The correct one is Fatal error .
I only thought of Notice .
Why Fatal?

Answer 1

The $this->a property is declared private. Therefore, it will not be available in child classes.
But in general it is Notice. At least on php 7.1 (I checked)

Answer 2

notice if a variable is declared. and fatal if there is no class property. And you have your own class property that is missing