when name of static method of class start with 'class' and number, syntax check is failure at the method be invoked code

example, the below code is correct code in php:

class A {
    const class1const = 1; //is correct

    public static function class2test() { //is correct
        echo 'test';
    }
    public function class2test2() {
        self::class1const;  //has syntax error message
        self::class2test(); //has syntax error message
    }

    public static function t2class2test2() {
    }
}

$a = new A();
$a->class2test2(); //is correct
A::class1const; //has syntax error message
A::class2test(); //has syntax error message
A::t2class2test(); //is correct