anchor.diff:          checkNonNull "set1" set1
           checkNonNull "set2" set2
   
  -        set1.IsSubset set2
  +        IntSet.IsSubset (set1, set2)
   
       /// <summary>
       /// Evaluates to &quot;true&quot; if all elements of the first set are in the second,
  
positive.code:         checkNonNull "set1" set1
          checkNonNull "set2" set2
  
          set2.IsSubset set1
  
      /// <summary>
      /// Evaluates to &quot;true&quot; if all elements of the second set are in the first,
  
negative.code:         checkNonNull "set1" set1
          checkNonNull "set2" set2
  
          IntSet.IsProperSubset (set1, set2)
  
      /// <summary>
      /// Evaluates to &quot;true&quot; if all elements of the second set are in the first.
  