Resynthesize local variables lazily.

pkg/analyzer/test/src/summary/resynthesize_test.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 test.src.serialization.elements_test;
 
 import 'dart:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/constant/value.dart';
@@ skipping 1015 matching lines @@
       if (original.element.enclosingElement == null &&
           original.element is FunctionElement) {
         expect(resynthesized.element, new isInstanceOf<FunctionElement>());
         expect(resynthesized.element.enclosingElement, isNull, reason: desc);
         compareFunctionElements(
             resynthesized.element, original.element, '$desc element',
             shallow: true);
         expect(resynthesized.element.type, same(resynthesized));
       }
       expect(resynthesized.typeArguments.length, original.typeArguments.length,
-          reason: desc);
+          reason: '$desc typeArguments.length');
       for (int i = 0; i < resynthesized.typeArguments.length; i++) {
         if (resynthesized.typeArguments[i].isDynamic &&
             original.typeArguments[i] is TypeParameterType) {
           // It's ok for type arguments to get converted to `dynamic` if they
           // are not used.
           expect(
               isTypeParameterUsed(
                   original.typeArguments[i], original.element.type),
               isFalse);
         } else {
@@ skipping 3556 matching lines @@
       fail('Unexpectedly tried to get unlinked summary for $uri');
     }
     return serializedUnit;
   }
 
   @override
   bool hasLibrarySummary(String uri) {
     return true;
   }
 }