diff --git a/lib/binary_serialization.dart b/lib/binary_serialization.dart
index a19689f..382c37e 100644
--- a/lib/binary_serialization.dart
+++ b/lib/binary_serialization.dart
@@ -435,6 +435,7 @@
         TypedefInfo info = new TypedefInfo.internal();
         _readBasicInfo(info);
         info.type = source.readString();
+        return info;
       });
 
   OutputUnitInfo _readOutputOrNull() {
diff --git a/lib/json_info_codec.dart b/lib/json_info_codec.dart
index 1732a2b..1c4c2e1 100644
--- a/lib/json_info_codec.dart
+++ b/lib/json_info_codec.dart
@@ -306,6 +306,7 @@
         return new OutputUnitInfo.internal();
       }
       assert(false);
+      return null;
     });
   }