multiple constant drivers for net erro

Lets me show a code that's work may be can help you to locate the probleme:

generate
        if(NUM_OF_TAPS == 4)
            assign final_result_temp = final_additions;
        else if (NUM_OF_TAPS == 8)
            assign final_result_temp = final_additions + final_additions;
        else if (NUM_OF_TAPS == 16)
            assign final_result_temp = final_additions + final_additions + final_additions + final_additions;
    endgenerate  // after 16 taps this should addition should be done with registered stages
    
    always @ (posedge clk or posedge reset)
    begin
        if (reset)
        begin
            final_result <= 0;
        end
        else if (clear == 1)
        begin
            final_result <= 0;
        end
        else
        begin
            final_result <= final_result_temp;
        end
    end

This code it work very well. The change that i need is to calculate the final_result_temp result using a genereic code. That's mean avoid the using of the if statement.

I hope that this code is more comprehensible.

Thanks