Elements. Migrate DemotionVisitor.

Change-Id: I4a869708a1e73897ecf0fc568363e5fca1986169
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/405605
Reviewed-by: Phil Quitslund <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

pkg/analyzer/lib/src/dart/element/type_demotion.dart

@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// ignore_for_file: analyzer_use_new_elements
-
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/replacement_visitor.dart';
 import 'package:analyzer/src/dart/element/type.dart';
@@ -22,8 +20,8 @@ class DemotionVisitor extends ReplacementVisitor {
       return null;
     }
 
-    return TypeParameterTypeImpl(
-      element: type.element,
+    return TypeParameterTypeImpl.v2(
+      element: type.element3,
       nullabilitySuffix: type.nullabilitySuffix,
       alias: type.alias,
     );