Don't call dinvoke on Object methods

test/checker/checker_test.dart

Index: test/checker/checker_test.dart
diff --git a/test/checker/checker_test.dart b/test/checker/checker_test.dart
index fa98ddb4eb7893a558ca14439fe710f47349f4d2..84d317d44500725a2059a45697f0d5175d523afb 100644
--- a/test/checker/checker_test.dart
+++ b/test/checker/checker_test.dart
@@ -16,7 +16,13 @@ void main() {
 
   test('conversion and dynamic invoke', () {
     testChecker({
+      '/helper.dart': '''
+      dynamic toString = (int x) => x + 42;
+      dynamic hashCode = "hello";
+      ''',
       '/main.dart': '''
+      import 'helper.dart' as helper;
+
       class A {
         String x = "hello world";
 
@@ -58,6 +64,17 @@ void main() {
         A.baz2("hello");
         var b2 = A.baz2;
         (/*warning:DynamicInvoke*/b2("hello"));
+
+        dynamic a1 = new A();
+        (/*warning:DynamicInvoke*/a1.x);
+        a1.toString();
+        a1.hashCode;
+
+        dynamic toString = () => null;
+        (/*warning:DynamicInvoke*/toString());
+
+        (/*warning:DynamicInvoke*/helper.toString());
+        int hashCode = /*info:DynamicCast*/helper.hashCode;
     '''
     });
   });