Why should it be it simply resides inside of a different namespace and can still be accessed.
Like shown in the following example:
class my_class;
bit [7:0] arr [10];
endclass
class my_class2 extends my_class;
bit [7:0] arr [15];
function ret_super_arr ();
$display("arr size in super.arr is %0d", $size(super.arr));
endfunction
endclass
module tb;
my_class obj;
my_class2 obj2;
initial begin
obj = new();
obj2 = new();
$display("arr size in obj is %0d", $size(obj.arr));
$display("arr size in obj2 is %0d", $size(obj2.arr));
obj2.ret_super_arr();
end
endmodule : tb