Added some struct tests, and implemented a wrong struct assignment It assumes 8 bytes for all struct, we have no DType available at that point Slight improvement to an error message (Member access to unknown members)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/code/struct_3.d	Mon Apr 21 22:47:12 2008 +0200
@@ -0,0 +1,11 @@
+
+struct S
+{
+    int a;
+}
+
+void main()
+{
+    S s;
+    S s2 = s;
+}