Fix recently introduced strong-mode errors

pkg/analyzer/test/src/dart/sdk/sdk_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.generated.sdk_test;
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/src/context/builder.dart' show EmbedderYamlLocator;
 import 'package:analyzer/src/dart/sdk/sdk.dart';
@@ skipping 15 matching lines @@
   defineReflectiveTests(EmbedderSdkTest);
   defineReflectiveTests(FolderBasedDartSdkTest);
   defineReflectiveTests(SdkExtensionFinderTest);
   defineReflectiveTests(SDKLibrariesReaderTest);
 }
 
 @reflectiveTest
 class EmbedderSdkTest extends EmbedderRelatedTest {
   void test_creation() {
     EmbedderYamlLocator locator = new EmbedderYamlLocator({
-      'fox': [pathTranslator.getResource(foxLib)]
+      'fox': <Folder>[pathTranslator.getResource(foxLib)]
     });
     EmbedderSdk sdk = new EmbedderSdk(resourceProvider, locator.embedderYamls);
 
     expect(sdk.urlMappings, hasLength(5));
   }
 
   void test_fromFileUri() {
     EmbedderYamlLocator locator = new EmbedderYamlLocator({
-      'fox': [pathTranslator.getResource(foxLib)]
+      'fox': <Folder>[pathTranslator.getResource(foxLib)]
     });
     EmbedderSdk sdk = new EmbedderSdk(resourceProvider, locator.embedderYamls);
 
     expectSource(String posixPath, String dartUri) {
       Uri uri = Uri.parse(posixToOSFileUri(posixPath));
       Source source = sdk.fromFileUri(uri);
       expect(source, isNotNull, reason: posixPath);
       expect(source.uri.toString(), dartUri);
       expect(source.fullName, posixToOSPath(posixPath));
     }
 
     expectSource('$foxLib/slippy.dart', 'dart:fox');
     expectSource('$foxLib/deep/directory/file.dart', 'dart:deep');
     expectSource('$foxLib/deep/directory/part.dart', 'dart:deep/part.dart');
   }
 
   void test_getLinkedBundle_hasBundle() {
     pathTranslator.newFileWithBytes(
         '$foxPath/sdk.ds', new PackageBundleAssembler().assemble().toBuffer());
     EmbedderYamlLocator locator = new EmbedderYamlLocator({
-      'fox': [pathTranslator.getResource(foxLib)]
+      'fox': <Folder>[pathTranslator.getResource(foxLib)]
     });
     // No bundle for spec mode.
     {
       EmbedderSdk sdk =
           new EmbedderSdk(resourceProvider, locator.embedderYamls);
       sdk.analysisOptions = new AnalysisOptionsImpl()..strongMode = false;
       expect(sdk.getLinkedBundle(), isNull);
     }
     // Has bundle for strong mode.
     {
       EmbedderSdk sdk =
           new EmbedderSdk(resourceProvider, locator.embedderYamls);
       sdk.analysisOptions = new AnalysisOptionsImpl()..strongMode = true;
       expect(sdk.getLinkedBundle(), isNotNull);
     }
   }
 
   void test_getLinkedBundle_noBundle() {
     EmbedderYamlLocator locator = new EmbedderYamlLocator({
-      'fox': [pathTranslator.getResource(foxLib)]
+      'fox': <Folder>[pathTranslator.getResource(foxLib)]
     });
     EmbedderSdk sdk = new EmbedderSdk(resourceProvider, locator.embedderYamls);
     expect(sdk.getLinkedBundle(), isNull);
   }
 
   void test_getSdkLibrary() {
     EmbedderYamlLocator locator = new EmbedderYamlLocator({
-      'fox': [pathTranslator.getResource(foxLib)]
+      'fox': <Folder>[pathTranslator.getResource(foxLib)]
     });
     EmbedderSdk sdk = new EmbedderSdk(resourceProvider, locator.embedderYamls);
 
     SdkLibrary lib = sdk.getSdkLibrary('dart:fox');
     expect(lib, isNotNull);
     expect(lib.path, posixToOSPath('$foxLib/slippy.dart'));
     expect(lib.shortName, 'dart:fox');
   }
 
   void test_mapDartUri() {
     EmbedderYamlLocator locator = new EmbedderYamlLocator({
-      'fox': [pathTranslator.getResource(foxLib)]
+      'fox': <Folder>[pathTranslator.getResource(foxLib)]
     });
     EmbedderSdk sdk = new EmbedderSdk(resourceProvider, locator.embedderYamls);
 
     void expectSource(String dartUri, String posixPath) {
       Source source = sdk.mapDartUri(dartUri);
       expect(source, isNotNull, reason: posixPath);
       expect(source.uri.toString(), dartUri);
       expect(source.fullName, posixToOSPath(posixPath));
     }
 
@@ skipping 222 matching lines @@
   "dart:fox": "slippy.dart",
   "dart:bear": "grizzly.dart",
   "dart:relative": "../relative.dart",
   "dart:deep": "deep/directory/file.dart",
   "fart:loudly": "nomatter.dart"
 }''');
   }
 
   test_create_noSdkExtPackageMap() {
     var resolver = new SdkExtensionFinder({
-      'fox': [resourceProvider.getResource('/empty')]
+      'fox': <Folder>[resourceProvider.getResource('/empty')]
     });
     expect(resolver.urlMappings.length, equals(0));
   }
 
   test_create_nullPackageMap() {
     var resolver = new SdkExtensionFinder(null);
     expect(resolver.urlMappings.length, equals(0));
   }
 
   test_create_sdkExtPackageMap() {
     var resolver = new SdkExtensionFinder({
-      'fox': [resourceProvider.getResource('/tmp')]
+      'fox': <Folder>[resourceProvider.getResource('/tmp')]
     });
     // We have four mappings.
     Map<String, String> urlMappings = resolver.urlMappings;
     expect(urlMappings.length, equals(4));
     // Check that they map to the correct paths.
     expect(urlMappings['dart:fox'], equals("/tmp/slippy.dart"));
     expect(urlMappings['dart:bear'], equals("/tmp/grizzly.dart"));
     expect(urlMappings['dart:relative'], equals("/relative.dart"));
     expect(urlMappings['dart:deep'], equals("/tmp/deep/directory/file.dart"));
   }
@@ skipping 76 matching lines @@
     expect(second, isNotNull);
     expect(second.category, "Server");
     expect(second.path, "second/second.dart");
     expect(second.shortName, "dart:second");
     expect(second.isDart2JsLibrary, false);
     expect(second.isDocumented, false);
     expect(second.isImplementation, true);
     expect(second.isVmLibrary, false);
   }
 }