anchor.diff:    Map<String, ir.Member> _constructorMap;
     Map<String, ir.Member> _memberMap;
     Map<String, ir.Member> _setterMap;
  +  List<ir.Member> _members; // in declarartion order.
   
     /// Constructor bodies created for this class.
     List<ConstructorBodyEntity> _constructorBodyList;
  
positive.code:   void forEachMember(
        KernelToElementMap elementMap, void f(MemberEntity member)) {
      _ensureMaps(elementMap);
      _memberMap.values.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].
  
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;
  