code: public static <E> int linearSearchFwd(AbstractCounterexample<E> acex, int low, int high) {
          assert !acex.testEffects(low, high);
  
          E effPrev = acex.effect(low);
          for (int i = low + 1; i <= high; i++) {
              E eff = acex.effect(i);
              if (!acex.checkEffects(effPrev, eff)) {
                  return i - 1;
              }
              effPrev = eff;
          }
          throw new IllegalArgumentException();
      }
docs: Scan linearly through the counterexample in ascending order.
  
  @param acex
  the abstract counterexample
  @param low
  the lower bound of the search range
  @param high
  the upper bound of the search range
  
  @return an index <code>i</code> such that <code>acex.testEffect(i) != acex.testEffect(i+1)</code>