module test; typedef struct packed { logic [9:-1][2:0] a; ///REQ-EXT-10001, REQ-EXT-10004 logic [3:0] b; } 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 how should I modify this piece of system verilog code so that it can be compiled successfully by vcs?

There are a few issues with the provided code that need to be fixed in order to compile successfully with VCS:

1. The packed struct declaration should be preceded by the keyword "packed" rather than "typedef packed struct".

2. The logic data type should be changed to bit.

3. The curly braces in the initial block should be closed properly.

4. The $display statement is missing a closing quotation mark.

Here's 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;
        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