initial generate block scoping support

- significant refactor of struct conversion
- significant refactor of typedef conversion
- scoping support in multipack conversion
- scoping support in typeof conversion

test/basic/struct_scope.sv

@@ -0,0 +1,87 @@
+module top;
+    typedef struct packed {
+        logic x;
+        logic [1:0] y;
+    } A;
+    typedef struct packed {
+        logic [2:0] x;
+        logic [3:0] y;
+    } B;
+    typedef struct packed {
+        logic [4:0] x;
+        logic [5:0] y;
+        B z;
+    } C;
+
+    A a;
+    B b;
+    C c;
+
+    generate
+        begin : foo
+            typedef struct packed {
+                logic [6:0] x;
+                logic [7:0] y;
+            } B;
+            typedef struct packed {
+                logic [8:0] x;
+                logic [9:0] y;
+                B z;
+            } D;
+
+            A a;
+            B b;
+            C c;
+            D d;
+        end
+    endgenerate
+
+`define INSPECT_SIZE(expr) $display(`"expr -> %0d`", $bits(expr));
+`define INSPECT_DATA(expr) $display(`"expr -> %b`", expr);
+    initial begin
+        `INSPECT_SIZE(a);
+        `INSPECT_SIZE(a.x);
+        `INSPECT_SIZE(a.y);
+
+        `INSPECT_SIZE(b);
+        `INSPECT_SIZE(b.x);
+        `INSPECT_SIZE(b.y);
+
+        `INSPECT_SIZE(c);
+        `INSPECT_SIZE(c.x);
+        `INSPECT_SIZE(c.y);
+        `INSPECT_SIZE(c.z);
+        `INSPECT_SIZE(c.z.x);
+        `INSPECT_SIZE(c.z.y);
+
+        `INSPECT_SIZE(foo.a);
+        `INSPECT_SIZE(foo.a.x);
+        `INSPECT_SIZE(foo.a.y);
+
+        `INSPECT_SIZE(foo.b);
+        `INSPECT_SIZE(foo.b.x);
+        `INSPECT_SIZE(foo.b.y);
+
+        `INSPECT_SIZE(foo.c);
+        `INSPECT_SIZE(foo.c.x);
+        `INSPECT_SIZE(foo.c.y);
+        `INSPECT_SIZE(foo.c.z);
+        `INSPECT_SIZE(foo.c.z.x);
+        `INSPECT_SIZE(foo.c.z.y);
+
+        `INSPECT_SIZE(foo.d);
+        `INSPECT_SIZE(foo.d.x);
+        `INSPECT_SIZE(foo.d.y);
+        `INSPECT_SIZE(foo.d.z);
+        `INSPECT_SIZE(foo.d.z.x);
+        `INSPECT_SIZE(foo.d.z.y);
+
+        `INSPECT_DATA(a);
+        `INSPECT_DATA(b);
+        `INSPECT_DATA(c);
+        `INSPECT_DATA(foo.a);
+        `INSPECT_DATA(foo.b);
+        `INSPECT_DATA(foo.c);
+        `INSPECT_DATA(foo.d);
+    end
+endmodule