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

pkg/analyzer/test/src/dart/element/element_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.dart.element.element_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/constant/value.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
@@ skipping 1801 matching lines @@
     expect(VoidTypeImpl.instance == s.returnType, isTrue);
     expect(t.isSubtypeOf(s), isTrue);
   }
 
   void test_isSubtypeOf_returnType_tAssignableToS() {
     // B extends A
     // () -> A <: () -> B
     // () -> B <: () -> A
     ClassElement a = ElementFactory.classElement2("A");
     ClassElement b = ElementFactory.classElement("B", a.type);
-    FunctionType t = ElementFactory.functionElement2("t", a).type;
-    FunctionType s = ElementFactory.functionElement2("s", b).type;
+    FunctionType t = ElementFactory.functionElement2("t", a.type).type;
+    FunctionType s = ElementFactory.functionElement2("s", b.type).type;
     expect(t.isSubtypeOf(s), isTrue);
     expect(s.isSubtypeOf(t), isTrue);
   }
 
   void test_isSubtypeOf_returnType_tNotAssignableToS() {
     // ! () -> A <: () -> B
     FunctionType t = ElementFactory
-        .functionElement2("t", ElementFactory.classElement2("A"))
+        .functionElement2("t", ElementFactory.classElement2("A").type)
         .type;
     FunctionType s = ElementFactory
-        .functionElement2("s", ElementFactory.classElement2("B"))
+        .functionElement2("s", ElementFactory.classElement2("B").type)
         .type;
     expect(t.isSubtypeOf(s), isFalse);
   }
 
   void test_isSubtypeOf_typeParameters_matchesBounds() {
     TestTypeProvider provider = new TestTypeProvider();
     InterfaceType boolType = provider.boolType;
     InterfaceType stringType = provider.stringType;
     TypeParameterElementImpl parameterB =
         new TypeParameterElementImpl.forNode(AstTestFactory.identifier3("B"));
@@ skipping 2599 matching lines @@
 }
 
 class _FunctionTypeImplTest_isSubtypeOf_baseCase_classFunction
     extends InterfaceTypeImpl {
   _FunctionTypeImplTest_isSubtypeOf_baseCase_classFunction(ClassElement arg0)
       : super(arg0);
 
   @override
   bool get isDartCoreFunction => true;
 }