module test; typedef packed struct { bit [9:-1][2:0] a; ///REQ-EXT-10001, REQ-EXT-10004 bit [3:0] b; } packed ST1; typedef struct { ST1 st1; ST1 st2[2:0]; } ST2; initial begin ST2 st2; st2 = '{2'b01, '{3'b1, 3'b0, 12'b1},'{4'b0011,'{3'b1,3'b0,12'b0},'{3'b1,3'b0,12'b0}}}; $display("st2 before:%0d '%h", st2.st2[0].b, st2.st2[0].a); ST2 st3=st2; st3.st2[0].b = st3.st2[0].b+1; $display("st2 after:%d '%h', st3: %0d '%h, %0d '%h", st2.st2[0].b, st2.st2[0].a, st3.st2[0].b, st3.st2[0].a, st3.st2[1].b, st3.st2[1].a);//CHECK-001:'{a:'h1}, st2:'{'a:'h1}, '{a:'h0},'{a:h1}}} end endmodule this piece of system verilog code, when compiled by vcs, it reports: Error-[SE] Syntax error Following verilog source has syntax error: "sc_assignment_pattern_048.sv", 29: token is 'st3' ST2 st3=st2; how should I modify this error?

The error message "token is 'st3'" indicates that there is a syntax error in the line where you declare and initialize the ST3 variable. To fix the error, you can use the "bit by bit" assignment operator ({}) to initialize the ST3 variable instead of using the "=" operator. Here is the modified code:

module test;
    typedef packed struct {
        bit [9:-1][2:0] a; ///REQ-EXT-10001, REQ-EXT-10004
        bit [3:0] b;
    } packed ST1;

    typedef struct {
        ST1 st1;
        ST1 st2[2:0];
    } ST2;

    initial begin
        ST2 st2;
        st2 = '{2'b01, '{3'b1, 3'b0, 12'b1},'{4'b0011,'{3'b1,3'b0,12'b0},'{3'b1,3'b0,12'b0}}};
        $display("st2 before:%0d '%h", st2.st2[0].b, st2.st2[0].a);

        ST2 st3 = '{st2.st1, '{st2.st2[0]}, '{st2.st2[1]}, '{st2.st2[2]}};
        st3.st2[0].b = st3.st2[0].b+1;
        $display("st2 after:%d '%h', st3: %0d '%h, %0d '%h", st2.st2[0].b, st2.st2[0].a, st3.st2[0].b, st3.st2[0].a, st3.st2[1].b, st3.st2[1].a);//CHECK-001:'{a:'h1}, st2:'{'a:'h1}, '{a:'h0},'{a:h1}}}
    end
endmodule

In this modified code, the ST3 variable is initialized using the bit by bit assignment operator {}, with each field of the variable being assigned separately. This should resolve the syntax error and allow the code to be compiled successfully.