Rewrite ImplicitConstructorBuilder to use only element model.

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

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.element;
 
 import 'dart:collection';
@@ skipping 493 matching lines @@
    */
   InterfaceType type;
 
   /**
    * A list containing all of the type parameters defined for this class.
    */
   List<TypeParameterElement> _typeParameters =
       TypeParameterElementImpl.EMPTY_ARRAY;
 
   /**
+   * The [SourceRange] of the `with` clause, `null` if there is no one.
+   */
+  SourceRange withClauseRange;
+
+  /**
    * Initialize a newly created class element to have the given [name] at the
    * given [offset] in the file that contains the declaration of this element.
    */
   ClassElementImpl(String name, int offset) : super(name, offset);
 
   /**
    * Initialize a newly created class element to have the given [name].
    */
   ClassElementImpl.forNode(Identifier name) : super.forNode(name);
 
@@ skipping 9934 matching lines @@
     // void <: void (by reflexivity)
     // bottom <: void (as bottom is a subtype of all types).
     // void <: dynamic (as dynamic is a supertype of all types)
     return identical(type, this) || type.isDynamic;
   }
 
   @override
   VoidTypeImpl substitute2(
       List<DartType> argumentTypes, List<DartType> parameterTypes) => this;
 }