Generic unchecked cast in constructor, warning not warranted?

I have a Stack class implemented using Array, and I get an unchecked warning in my constructor. It seems unwarranted because any type is a subtype of Object hence an array type of Object should be able to be downcasted to ? or am I missing something?

public class StackArray<E> implements Stack<E> {
    int tos;
    E[] stack;

    public StackArray() {
        this(10);
    }       // default size is 10
    public StackArray(int maxdepth) {
        tos = 0;
        /*
         type safety check, doesn't know if Object and E array are fine together
         Casting a raw-type to a parameterized type gives unchecked conversion warning
         https://docs.oracle.com/javase/tutorial/java/generics/rawTypes.html
        */
        stack = (E[]) new Object[maxdepth];      //unchecked warning here
        // Cannot create instances of type parameters
        // https://docs.oracle.com/javase/tutorial/java/generics/restrictions.html#createObjects
        // stack = new E[maxdepth];    // won't compile, type E cannot be instantiated directly
    }
    @Override
    public void push(E element) {
        stack[tos++] = element;
    }
    @Override
    public E pop() {
        return tos>0 ? stack[--tos] : null;
    }
}