fix #28008, fix #28009 implement FutureOr<T>

pkg/analyzer/test/generated/resolver_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.resolver_test;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 2407 matching lines @@
     // We cannot use either ElementFactory or TestTypeProvider (which uses
     // ElementFactory) because we side-effect the elements in ways that would
     // break other tests.
     //
     InterfaceType objectType = _classElement("Object", null).type;
     InterfaceType boolType = _classElement("bool", objectType).type;
     InterfaceType numType = _classElement("num", objectType).type;
     InterfaceType doubleType = _classElement("double", numType).type;
     InterfaceType functionType = _classElement("Function", objectType).type;
     InterfaceType futureType = _classElement("Future", objectType, ["T"]).type;
+    InterfaceType futureOrType = _classElement("FutureOr", objectType, ["T"]).type;
     InterfaceType intType = _classElement("int", numType).type;
     InterfaceType iterableType =
         _classElement("Iterable", objectType, ["T"]).type;
     InterfaceType listType = _classElement("List", objectType, ["E"]).type;
     InterfaceType mapType = _classElement("Map", objectType, ["K", "V"]).type;
     InterfaceType stackTraceType = _classElement("StackTrace", objectType).type;
     InterfaceType streamType = _classElement("Stream", objectType, ["T"]).type;
     InterfaceType stringType = _classElement("String", objectType).type;
     InterfaceType symbolType = _classElement("Symbol", objectType).type;
     InterfaceType typeType = _classElement("Type", objectType).type;
     CompilationUnitElementImpl coreUnit =
         new CompilationUnitElementImpl("core.dart");
     coreUnit.types = <ClassElement>[
       boolType.element,
       doubleType.element,
       functionType.element,
       intType.element,
       iterableType.element,
       listType.element,
       mapType.element,
       objectType.element,
       stackTraceType.element,
       stringType.element,
       symbolType.element,
       typeType.element
     ];
     CompilationUnitElementImpl asyncUnit =
         new CompilationUnitElementImpl("async.dart");
-    asyncUnit.types = <ClassElement>[futureType.element, streamType.element];
+    asyncUnit.types = <ClassElement>[futureType.element, futureOrType.element, streamType.element];
     AnalysisContext context = AnalysisEngine.instance.createAnalysisContext();
     LibraryElementImpl coreLibrary = new LibraryElementImpl.forNode(
         context, AstTestFactory.libraryIdentifier2(["dart.core"]));
     coreLibrary.definingCompilationUnit = coreUnit;
     LibraryElementImpl asyncLibrary = new LibraryElementImpl.forNode(
         context, AstTestFactory.libraryIdentifier2(["dart.async"]));
     asyncLibrary.definingCompilationUnit = asyncUnit;
     //
     // Create a type provider and ensure that it can return the expected types.
     //
     TypeProviderImpl provider = new TypeProviderImpl(coreLibrary, asyncLibrary);
     expect(provider.boolType, same(boolType));
     expect(provider.bottomType, isNotNull);
     expect(provider.doubleType, same(doubleType));
     expect(provider.dynamicType, isNotNull);
     expect(provider.functionType, same(functionType));
     expect(provider.futureType, same(futureType));
+    expect(provider.futureOrType, same(futureOrType));
     expect(provider.intType, same(intType));
     expect(provider.listType, same(listType));
     expect(provider.mapType, same(mapType));
     expect(provider.objectType, same(objectType));
     expect(provider.stackTraceType, same(stackTraceType));
     expect(provider.streamType, same(streamType));
     expect(provider.stringType, same(stringType));
     expect(provider.symbolType, same(symbolType));
     expect(provider.typeType, same(typeType));
   }
@@ skipping 1130 matching lines @@
  */
 class _StaleElement extends ElementImpl {
   _StaleElement() : super("_StaleElement", -1);
 
   @override
   get kind => throw "_StaleElement's kind shouldn't be accessed";
 
   @override
   /*=T*/ accept/*<T>*/(_) => throw "_StaleElement shouldn't be visited";
 }