Don't serialize elements of top-level function/constructor/method bodies.

pkg/analyzer/test/src/context/context_test.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.
 
 library analyzer.test.src.context.context_test;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 5377 matching lines @@
    */
   void expectNoDifferences() {
     if (overwrittenCount > 0) {
       fail('Found $overwrittenCount overwritten elements.$buffer');
     }
   }
 
   @override
   void visitElement(Element element) {
     Element previousElement = previousElements[element];
-    bool expectIdentical = element is! LocalVariableElement;
-    bool ok = expectIdentical
+    bool ok = _expectedIdentical(element)
         ? identical(previousElement, element)
         : previousElement == element;
     if (!ok) {
       if (overwrittenCount == 0) {
         buffer.writeln();
       }
       overwrittenCount++;
       buffer.writeln('Overwritten element:');
       Element currentElement = element;
       while (currentElement != null) {
         buffer.write('  ');
         buffer.writeln(currentElement.toString());
         currentElement = currentElement.enclosingElement;
       }
     }
     super.visitElement(element);
   }
+
+  /**
+   * Return `true` if the given [element] should be the same as the previous
+   * element at the same position in the element model.
+   */
+  static bool _expectedIdentical(Element element) {
+    while (element != null) {
+      if (element is ConstructorElement ||
+          element is MethodElement ||
+          element is FunctionElement &&
+              element.enclosingElement is CompilationUnitElement) {
+        return false;
+      }
+      element = element.enclosingElement;
+    }
+    return true;
+  }
 }
 
 /**
  * A visitor that can be used to collect all of the elements in an element
  * model.
  */
 class _ElementGatherer extends GeneralizingElementVisitor {
   /**
    * The map in which the elements are collected. The value of each key is the
    * key itself.
    */
   Map<Element, Element> elements = new HashMap<Element, Element>();
 
   /**
    * Initialize the visitor.
    */
   _ElementGatherer();
 
   @override
   void visitElement(Element element) {
     elements[element] = element;
     super.visitElement(element);
   }
 }