code: private JCExpression makeOp(int pos,
                                      TokenKind topOp,
                                      JCExpression od1,
                                      JCExpression od2)
          {
              if (topOp == INSTANCEOF) {
                  return F.at(pos).TypeTest(od1, od2);
              } else {
                  return F.at(pos).Binary(optag(topOp), od1, od2);
              }
          }
docs: Construct a binary or type test node.