Fix summarization of inferred types which are function-typed params of typedefs.

pkg/analyzer/lib/src/summary/summarize_elements.dart

 // Copyright (c) 2015, 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 serialization.elements;
 
 import 'dart:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ skipping 1033 matching lines @@
     } else {
       if (type is FunctionType &&
           typeElement.enclosingElement is ParameterElement) {
         // Code cannot refer to function types implicitly defined by parameters
         // directly, so if we get here, we must be serializing a linked
         // reference from type inference.
         assert(buildingLinkedReferences);
         ParameterElement parameterElement = typeElement.enclosingElement;
         while (true) {
           Element parent = parameterElement.enclosingElement;
-          if (parent is ExecutableElement) {
+          if (parent is FunctionTypedElement) {
             Element grandParent = parent.enclosingElement;
             b.implicitFunctionTypeIndices
                 .insert(0, parent.parameters.indexOf(parameterElement));
             if (grandParent is ParameterElement) {
               // Function-typed parameter inside a function-typed parameter.
               parameterElement = grandParent;
               continue;
             } else {
               // Function-typed parameter inside a top level function or method.
               b.reference = _getElementReferenceId(parent);
@@ skipping 603 matching lines @@
       exportNames.add(new LinkedExportNameBuilder(
           name: name,
           dependency: serializeDependency(dependentLibrary),
           unit: unit,
           kind: kind));
     }
     pb.exportNames = exportNames;
     return pb;
   }
 }