[Vala] error in generics: Foreach: Cannot convert from `G' to `Info.ContactTypeInfo'

[Alexey Lubimov <avl l14 ru>]

base generic class

namespace Info {
 public class GenericList  <G> : GLib.Object,Gee.Iterable<G> {

   //ArrayList
   public Gee.ArrayList <G> items;
   
   construct {
      this.items = new Gee.ArrayList<G>();
   }
    
   public Type get_element_type () {
     return typeof (G);
   }

   public Gee.Iterator<G> iterator () {
     return items.iterator();
   }
 }
}

derrived class


namespace Info{

 public class ContactTypeList :  GenericList <ContactTypeInfo> {

 

   public void refresh()
   {
     foreach (ContactTypeInfo item in items)
       {}
   }

 }
}

but vala cannot resolve  Gee.ArrayList <G> items to Gee.ArrayList 
<ContactTypeInfo> items

Error:
ContactTypeList.vala:49.7-49.45: error: Foreach: Cannot convert from `G' 
to `Info.ContactTypeInfo'
namespace Info {

  public class ContactTypeInfo: GenericInfo {
  }
}


namespace Info{

  public static enum CONTACT_TYPE_COLS{  
  ID = 0,
  NAME,
  DESCRIPTION,
  ICON,
  NUM_COLS
  }


  public class ContactTypeList :  GenericList <ContactTypeInfo> {
 
    public Gtk.ListStore list_store_items;
    
    
    construct {
      list_store_items = new Gtk.ListStore (CONTACT_TYPE_COLS.NUM_COLS,
                                            typeof(int64),  //0.id
                                            typeof(string), //1.name
                                            typeof(string), //2.Description
                                            typeof(string)); // 3.icon stock-id

    
    } 
    
     public Gtk.TreeIter add_to_store (ContactTypeInfo item) {
      Gtk.TreeIter retval;
      list_store_items.append(out retval);
      set(retval,item);
      return retval;
    }

    public void set (Gtk.TreeIter iter,ContactTypeInfo item)
    {
      
      list_store_items.set (iter,
                            CONTACT_TYPE_COLS.NAME,item.name,
                            CONTACT_TYPE_COLS.DESCRIPTION,item.description,
                            CONTACT_TYPE_COLS.ICON,item.stock_id,
                            CONTACT_TYPE_COLS.ID,item.id); 
    }
    
    public void refresh()
    {
      Gtk.TreeIter node;
      list_store_items.clear();      
      foreach (ContactTypeInfo item in items)
        node = add_to_store(item);
    }

  }

 
  
  }
}

namespace Info {

  public class GenericInfo:GLib.Object {
    public int64 id=ID_NOT_DEFINED;
    public string name="";
    public string description="";
    public string stock_id = "";
    
    private static const string info_str_pattern ="id: %lld, name: %s, description: %s";
    
    construct { 
      id=ID_NOT_DEFINED;
      name="";
      description="";
      stock_id = "gtk-new";
    }
      
    public virtual string to_string ()
    {
      return info_str_pattern.printf(id,name,description);
    }

    
  }
}


namespace Info {
  public class GenericList  <G> : GLib.Object,Gee.Iterable<G> {
    public Gee.ArrayList <G> items;
    
    construct {
       this.items = new Gee.ArrayList<G>();
    } 
    public void append(G item) {
      items.add(item);
    }
    
    public void remove_at (int index){ 
      items.remove_at(index);
    }
    
    public void add (G item){ 
      items.add (item);
    }
    
    public Type get_element_type () {
      return typeof (G);
    }
    public Gee.Iterator<G> iterator () {
      return items.iterator();
    }
  }
}