Cherry-pick r44410 and r44412

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 engine.resolver_test;
 
 import 'dart:collection';
 
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
@@ skipping 12582 matching lines @@
     c = true;
     break L;
   }
   x; // marker
 }''';
     DartType t = _findMarkedIdentifier(code, "; // marker").propagatedType;
     expect(typeProvider.intType.isSubtypeOf(t), isTrue);
     expect(typeProvider.stringType.isSubtypeOf(t), isTrue);
   }
 
+  void test_mutatedOutsideScope() {
+    // https://code.google.com/p/dart/issues/detail?id=22732
+    Source source = addSource(r'''
+class Base {
+}
+
+class Derived extends Base {
+  get y => null;
+}
+
+class C {
+  void f() {
+    Base x = null;
+    if (x is Derived) {
+      print(x.y); // BAD
+    }
+    x = null;
+  }
+}
+
+void g() {
+  Base x = null;
+  if (x is Derived) {
+    print(x.y); // GOOD
+  }
+  x = null;
+}''');
+    resolve(source);
+    assertNoErrors(source);
+  }
+
   void test_objectMethodOnDynamicExpression_doubleEquals() {
     // https://code.google.com/p/dart/issues/detail?id=20342
     //
     // This was not actually part of Issue 20342, since the spec specifies a
     // static type of [bool] for [==] comparison and the implementation
     // was already consistent with the spec there. But, it's another
     // [Object] method, so it's included here.
     _assertTypeOfMarkedExpression(r'''
 f1(x) {
   var v = (x == x);
@@ skipping 851 matching lines @@
         // check propagated type
         FunctionType propagatedType = node.propagatedType as FunctionType;
         expect(propagatedType.returnType, test.typeProvider.stringType);
       } on AnalysisException catch (e, stackTrace) {
         thrownException[0] = new CaughtException(e, stackTrace);
       }
     }
     return null;
   }
 }