合成不支持多个单边下的分配

I have written this code:

我写了这段代码:

module Key_Schedule(
    subkey_tupple1,
    subkey_tupple2,
    generate_key_final_step,
    rst,clk
);

    reg [0:31] a1,b1,a2,b2;
    input [0:31] subkey_tupple1;
    input [0:31] subkey_tupple2;
    //input [31:0] subkey_A_swap;
    //input [31:0] subkey_B_swap;
    input clk,rst;
    output reg [0:63] generate_key_final_step;
    reg [0:63] temp;
    reg [0:63] round_sub_key_left;

    always @(posedge clk or negedge rst)
    begin
        if (!rst)
        begin
            temp<={64{1'b0}};
            round_sub_key_left<={64{1'b0}};
        end
        else
            temp<={subkey_tupple1[0:31],subkey_tupple2[0:31]};

//The error is below... line 49
        round_sub_key_left<={temp[8:15],temp[16:23],temp[24:31],temp[0:7],temp[40:47],temp[48:55],temp[56:63],temp[32:39]};
        a1={temp[8:15],temp[16:23],temp[24:31],temp[0:7]};
        b1={temp[40:47],temp[48:55],temp[56:63],temp[32:39]};
        a2=b1;
        b2=a1^b1;
        generate_key_final_step={a2,b2};
    end
endmodule
module K