anchor.diff:    for (var i = 1; i < 4; i++) {
       set4exp.add(() => i);
     }
  -  Expect.isTrue(set4exp is Set<Function>);
  -
  -  var set4expRes = <int>[];
  -  for (var v in set4exp.toList()) {
  -    set4expRes.add(v());
  -  }
   
     var set4 = <Function>{for (var i = 1; i < 4; i++) () => i};
  -  // set4exp {Closure: () => int, Closure: () => int, Closure: () => int}
     Expect.isTrue(set4 is Set<Function>);
  -  var set4res = <int>[];
  -  for (var v in set4.toList()) {
  -    set4res.add(v());
  -  }
  -  Expect.listEquals(set4expRes, set4res);
  +  Expect.setEquals(set4exp, set4);
   }
  
positive.code:   Expect.isTrue(set1exp is Set<int>);
  
    var set1 = <int>{for (var i = 1; i < 10; i += 3) i};
    // set1exp {1, 4, 7}
    Expect.isTrue(set1 is Set<int>);
    Expect.setEquals(set1exp, set1);
  
  
negative.code:   Expect.isTrue(set2exp is Set<double>);
  
    var set2 = <double>{for (var i = 1.1; i < 10; i += 5) i + 2};
    Expect.isTrue(set2 is Set<double>);
    Expect.setEquals(set2exp, set2);
  
  