Issue 22962. Adding/removing method/accessor body is a declartion mismatch.

pkg/analyzer/lib/src/generated/element_handle.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_handle;
 
 import 'ast.dart';
@@ skipping 484 matching lines @@
   ExecutableElementHandle(ExecutableElement element) : super(element);
 
   @override
   ExecutableElement get actualElement =>
       super.actualElement as ExecutableElement;
 
   @override
   List<FunctionElement> get functions => actualElement.functions;
 
   @override
+  bool get isAbstract => actualElement.isAbstract;
+
+  @override
   bool get isAsynchronous => actualElement.isAsynchronous;
 
   @override
   bool get isGenerator => actualElement.isGenerator;
 
   @override
   bool get isOperator => actualElement.isOperator;
 
   @override
   bool get isStatic => actualElement.isStatic;
@@ skipping 331 matching lines @@
    */
   MethodElementHandle(MethodElement element) : super(element);
 
   @override
   MethodElement get actualElement => super.actualElement as MethodElement;
 
   @override
   ClassElement get enclosingElement => super.enclosingElement as ClassElement;
 
   @override
-  bool get isAbstract => actualElement.isAbstract;
-
-  @override
   bool get isStatic => actualElement.isStatic;
 
   @override
   ElementKind get kind => ElementKind.METHOD;
 
   @override
   MethodDeclaration get node => actualElement.node;
 }
 
 /**
@@ skipping 76 matching lines @@
 
   @override
   PropertyAccessorElement get correspondingGetter =>
       actualElement.correspondingGetter;
 
   @override
   PropertyAccessorElement get correspondingSetter =>
       actualElement.correspondingSetter;
 
   @override
-  bool get isAbstract => actualElement.isAbstract;
-
-  @override
   bool get isGetter => actualElement.isGetter;
 
   @override
   bool get isSetter => actualElement.isSetter;
 
   @override
   ElementKind get kind {
     if (isGetter) {
       return ElementKind.GETTER;
     } else {
@@ skipping 113 matching lines @@
   DartType get type => actualElement.type;
 }
 /**
  * TODO(scheglov) invalid implementation
  */
 class WeakReference<T> {
   final T value;
   WeakReference(this.value);
   T get() => value;
 }