code: JCExpression term1() {
          JCExpression t = term2();
          if ((mode & EXPR) != 0 && token.kind == QUES) {
              mode = EXPR;
              return term1Rest(t);
          } else {
              return t;
          }
      }
docs: Expression1   = Expression2 [Expression1Rest]
  Type1         = Type2
  TypeNoParams1 = TypeNoParams2