protected override ITransientMap DoAssoc(object key, object val)
{
var found = new Box(null);
var t = SortedMap.Add(this._comp, this._tree, key, val, found);
if (t is null)
{
var foundNode = found.Value as RedBlackNode;
if (foundNode.Value == val)
{
return(this);
}
this._tree = SortedMap.Replace(this._comp, this._tree, key, val);
return(this);
}
this._tree = t.Blacken();
this._count++;
return(this);
}