private static boolean setDefinition(Exprent expr, Integer index) {
    if (expr.type == Exprent.EXPRENT_ASSIGNMENT) {
      Exprent left = ((AssignmentExprent)expr).getLeft();
      if (left.type == Exprent.EXPRENT_VAR) {
        VarExprent var = (VarExprent)left;
        if (var.getIndex() == index) {
          var.setDefinition(true);
          return true;
        }
      }
    }
    return false;
  }
private static boolean setDefinition(Exprent expr, Integer index)