Inter-dependency between Constraints isn't Working as expected. Anything Missing?

SystemVerilog
1

Hello !

  1. I have the following below example of constraint code and trying to create some constraints with inter-dependency b/w constraints of two different classes.

`include "uvm_macros.svh"
 import uvm_pkg::*;

module nested_constraints;
    typedef struct {
        rand bit [31:0] blka_addr;
    } blka_var_s;
        
    typedef struct {
        rand bit [31:0] top_addr;
        rand blka_var_s blka_var; 
    } top_var_s;
    
    class policy_base#(type ITEM=uvm_object);
        ITEM item;
        
        virtual function void set_item(ITEM item);
            this.item = item;
        endfunction
   
        function pre_randomize();
            get_plusargs();
        endfunction: pre_randomize

        virtual function get_plusargs();
        endfunction: get_plusargs
    endclass: policy_base

    class policy_list#(type ITEM=uvm_object) extends policy_base #(ITEM);
        rand policy_base#(ITEM) policy[$];
        
        function void add(policy_base#(ITEM) pcy);
            policy.push_back(pcy);
        endfunction
        
        function void set_item(ITEM item);
            foreach(policy[i]) begin 
                policy[i].set_item(item);
            end    
        endfunction
    endclass: policy_list

    // Sub Block class with struct variable as random
    class blka_gen_base;
        rand policy_base #(blka_gen_base) blka_policy[$];
        
        rand blka_var_s blka_var; 

        function pre_randomize();
            foreach (blka_policy[i]) begin 
                blka_policy[i].set_item(this);
            end    
        endfunction: pre_randomize 
    endclass: blka_gen_base 

    // Adding a constraint for this block level address to be between 5 and 100
    class blka_addr_cstr extends policy_base #(blka_gen_base);
        constraint blka_addr_c {
            soft {item.blka_var.blka_addr > 5 && item.blka_var.blka_addr < 100};
        }    
    endclass: blka_addr_cstr 

    // A class where adding the above constraint to the policy 
    class blka_gen extends blka_gen_base;
        policy_list#(blka_gen_base) blka_pcy;

        function new();
            blka_addr_cstr  baac;
            
            blka_pcy = new;
            baac = new();

            blka_pcy.add(baac);
            blka_policy.push_back(blka_pcy);
        endfunction: new
    endclass: blka_gen

    // Top Level Class with top level struct variable, and also instanced the block blka class as rand to be randomized
    
    class top_gen_base;
        rand policy_base #(top_gen_base) top_policy[$];
        rand blka_gen blka_g; 
        
        rand top_var_s top_var; 
    
        function new();
            blka_g = new();
        endfunction: new

        function pre_randomize();
            foreach (top_policy[i]) begin 
                top_policy[i].set_item(this);
            end    
        endfunction: pre_randomize 
    
        function post_randomize();
            $display("top_var.blka_var = %0p, blka_g.blka_var = %0p\n", top_var.blka_var, blka_g.blka_var);
            top_var.blka_var = blka_g.blka_var;
        endfunction: post_randomize
    endclass: top_gen_base 

    // Adding a constraint for top level class variable where the top addr to be always 5
    class top_addr_cstr extends policy_base #(top_gen_base);
        constraint top_addr_c {
            // soft {item.top_var.top_addr > 5 && item.top_var.top_addr < 100};
            {item.top_var.top_addr == 5};
        }    
    endclass: top_addr_cstr 

    // Adding a constraint where if the top level addr is 5, wanted the block level address to be > 100 < 150.
    class top_mix_addr_cstr extends policy_base #(top_gen_base);
        constraint addr_mix_c {
            (item.top_var.top_addr == 5) -> (item.blka_g.blka_var.blka_addr > 100 && item.blka_g.blka_var.blka_addr < 150); 
            // if (item.top_var.top_addr == 5) (item.blka_g.blka_var.blka_addr > 100 && item.blka_g.blka_var.blka_addr < 150); 
        }
    endclass: top_mix_addr_cstr

    class top_gen extends top_gen_base;
        policy_list#(top_gen_base) top_pcy;

        function new();
            top_addr_cstr       tac;
            top_mix_addr_cstr   tmac;

            top_pcy = new;
            tac = new();
            tmac = new();

            top_pcy.add(tac);
            top_pcy.add(tmac);
            top_policy.push_back(top_pcy);
        endfunction: new
    endclass: top_gen

    initial begin 
        top_gen  tg = new();
        assert(tg.randomize());
        $display("tg = %0p\n", tg);
    end

endmodule: nested_constraints
  1. But when the above code is executed I get the following results

top_var.blka_var = '{blka_addr:'h35520161}, blka_g.blka_var = '{blka_addr:'h73}

tg = '{super:'{top_policy:'{nested_constraints.policy_base#(top_gen_base)@1807_1}, blka_g:nested_constraints.blka_gen@1802_1, top_var:'{top_addr:'h5, blka_var:'{blka_addr:'h73}}}, top_pcy:nested_constraints.policy_list#(top_gen_base)@1807_1}

Note:

  1. Main intent is lets say at the block level have created bunch of constraints using the policy.
  2. Wanted to re-use all the block level constraints at the top level and then use the values accordingly.

Any specific reason why the inter-depedency b/w the constraints i.e. top constraint vs the constraint inside the sub block class isn’t getting equated ? Please clarify.