anchor.diff:    void forEachMember(
         KernelToElementMap elementMap, void f(MemberEntity member)) {
       _ensureMaps(elementMap);
  -    _memberMap.values.forEach((ir.Member member) {
  +    _members.forEach((ir.Member member) {
         f(elementMap.getMember(member));
       });
  -    for (ir.Member member in _setterMap.values) {
  -      if (member is ir.Procedure) {
  -        f(elementMap.getMember(member));
  -      } else {
  -        // Skip fields; these are also in _memberMap.
  -      }
  -    }
     }
   
     /// Return the [ConstructorEntity] for the constructor [name] in [cls].
  
positive.code:   Map<String, ir.Member> _constructorMap;
    Map<String, ir.Member> _memberMap;
    Map<String, ir.Member> _setterMap;
  
    /// Constructor bodies created for this class.
    List<ConstructorBodyEntity> _constructorBodyList;
  
negative.code:   void forEachConstructorBody(void f(ConstructorBodyEntity constructor));
  }
  
  int orderByFileOffset(ir.TreeNode a, ir.TreeNode b) {
    return a.fileOffset.compareTo(b.fileOffset);
  }
  
  /// Environment for fast lookup of class members.
  class ClassEnvImpl implements ClassEnv {
    final ir.Class cls;
  