Reports method references mapped to the Comparator interface that don't fulfill its contract.

Some method references, like Integer::max, can be mapped to the Comparator interface. However, using them as Comparator is meaningless and the result might be unpredictable.

Example:


  ArrayList<Integer> ints = foo();
  ints.sort(Math::min);

After the quick-fix is applied:


  ArrayList<Integer> ints = foo();
  ints.sort(Comparator.reverseOrder());