public void Visit(TypedNameNode node)
 {
     SourceLocation? existing;
     if (_names.TryGetValue(node.Identifier, out existing))
     {
         _errors.DuplicateSymbolError(node.SourceSpan.GetValueOrDefault(), node.Identifier, existing.GetValueOrDefault());
     }
     else
     {
         _names.Add(node.Identifier, node.SourceSpan);
     }
 }            
 public override void Visit(TypedNameNode node, Context context)
 {
     context._sb.Append(CharacterUtils.EscapeName(node.Identifier));
     context._sb.Append(" As ");
     node.Kind.Accept(this, context);
 }