anchor.diff:    // expect___Of<...>({for (; false;) ...dyn});
     expectSetOf<int>({for (; false;) ...iterable});
     expectSetOf<int>({for (; false;) ...customSet});
  -  expectMapOf<int, int>({for (; false;) ...customMap});
  +  expectMapOf<int, String>({for (; false;) ...customMap});
   
     expectMapOf<int, int>({for (; false;) ...map, for (; false;) ...map});
     // expect___Of<...>({for (; false;) ...map, for (; false;) ...set});
     expectMapOf<dynamic, dynamic>(
  -      {for (; false;) ...map, for (; false;) ...dyn});
  +      {for (; false;) ...map, for (; false;) ...dynMap});
     // expect___Of<...>({for (; false;) ...map, for (; false;) ...iterable});
     // expect___Of<...>({for (; false;) ...map, for (; false;) ...customSet});
  -  expectMapOf<int, int>(
  +  expectMapOf<int, Object>(
         {for (; false;) ...map, for (; false;) ...customMap});
   
     expectSetOf<int>({for (; false;) ...set, for (; false;) ...set});
  -  expectSetOf<dynamic>({for (; false;) ...set, for (; false;) ...dyn});
  +  expectSetOf<dynamic>({for (; false;) ...set, for (; false;) ...dynSet});
     expectSetOf<int>({for (; false;) ...set, for (; false;) ...iterable});
     expectSetOf<int>({for (; false;) ...set, for (; false;) ...customSet});
     // expect___Of<...>({for (; false;) ...set, for (; false;) ...customMap});
   
     // expect___Of<...>({for (; false;) ...dyn, for (; false;) ...dyn});
     expectSetOf<dynamic>(
  -      {for (; false;) ...dyn, for (; false;) ...iterable});
  +      {for (; false;) ...dynSet, for (; false;) ...iterable});
     expectSetOf<dynamic>(
  -      {for (; false;) ...dyn, for (; false;) ...customSet});
  +      {for (; false;) ...dynSet, for (; false;) ...customSet});
     expectMapOf<dynamic, dynamic>(
  -      {for (; false;) ...dyn, for (; false;) ...customMap});
  +      {for (; false;) ...dynMap, for (; false;) ...customMap});
   
     expectSetOf<int>(
         {for (; false;) ...iterable, for (; false;) ...iterable});
  
positive.code: void testBottomUpInference() {
    Map<int, int> map = {};
    Set<int> set = Set();
    dynamic dyn = map;
    Iterable<int> iterable = [];
    CustomSet customSet = CustomSet();
    CustomMap customMap = CustomMap();
  
negative.code:   expectSetOf<int>({if (true) ...customSet else ...customSet});
    // expect___Of<...>({if (true) ...customSet else ...customMap});
  
    expectMapOf<int, String>({if (true) ...customMap else ...customMap});
  
    // Note: The commented out cases are the error cases. They are shown here for
    // completeness and tested in map_set_ambiguity_error_test.dart.
  