Duplicate of https://chromiumcodereview.appspot.com/11567018/

pkg/serialization/lib/src/reader_writer.dart

Index: pkg/serialization/lib/src/reader_writer.dart
diff --git a/pkg/serialization/lib/src/reader_writer.dart b/pkg/serialization/lib/src/reader_writer.dart
index 5109c5221faa0e3b7ba6a2f0f775a0de6e4ae964..586e115a15431d971ab3483fe69b94bc16b1abc3 100644
--- a/pkg/serialization/lib/src/reader_writer.dart
+++ b/pkg/serialization/lib/src/reader_writer.dart
@@ -38,7 +38,7 @@ class Writer {
    * but also serves to record which objects we have already seen.
    */
   final Map<dynamic, Reference> references =
-      new IdentityMapPlus<dynamic, Reference>();
+      new IdentityMap<Object, Reference>();
 
   /**
    * The state of objects that need to be serialized is stored here.
@@ -647,4 +647,4 @@ class DesignatedRuleForObject {
   DesignatedRuleForObject(this.target, this.rulePredicate);
 
   possibleRules(List rules) => rules.filter(rulePredicate);
-}
+}