code: JCExpression term1Rest(JCExpression t) {
          if (token.kind == QUES) {
              int pos = token.pos;
              nextToken();
              JCExpression t1 = term();
              accept(COLON);
              JCExpression t2 = term1();
              return F.at(pos).Conditional(t, t1, t2);
          } else {
              return t;
          }
      }
docs: Expression1Rest = ["?" Expression ":" Expression1]