[svn r328] Fixed an issue with interfaces where the vtable type of a interface implemented could be invalid. Fixes several tango modules like, FileStream, ServerSocket and most tina cluster modules :)

module complex3;

void main()
{
    cfloat c1 = 1f + 0i;
    cfloat c2 = 0f + 0i;
    c2 += 1f + 0i;
    //assert(c1 == c2);
}