If you instantiate tr and type TF, the fastest way to do this is to search the given prompt (usually in double quotes), and you’ll find a very low-level error. The error report will tell you which lines are wrong
This error means that the corresponding signal cannot be found and needs to be modified
A signal cannot be found, you need to track whether the signal exists or whether the road stiffness has changed
The

the object at dereference depth 0 is being used before it was constructed allocated.
please make sure that the object is allocated before using it

The reason is that there is no new for the corresponding property or objec. If the following code exists in top_tb.sv, it should be commented out

initial begin
   my_driver drv;
   drv = new("drv", null);
   drv.main_phase(null);
   $finish();
end

1. cross-module reference resolution error