Remove support for String operator + from dart2js.

dart/lib/isolate/frog/messages.dart

 // Copyright (c) 2012, 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.
 
 // Defines message visitors, serialization, and deserialization.
 
 /** Serialize [message] (or simulate serialization). */
 _serializeMessage(message) {
   if (_globalState.needSerialization) {
     return new _Serializer().traverse(message);
@@ skipping 132 matching lines @@
   SendPort visitWorkerSendPort(_WorkerSendPort port) {
     return new _WorkerSendPort(
         port._workerId, port._isolateId, port._receivePortId);
   }
 
   SendPort visitBufferingSendPort(_BufferingSendPort port) {
     if (port._port != null) {
       return _visitNativeOrWorkerPort(port._port);
     } else {
       // TODO(floitsch): Use real exception (which one?).
-      throw "internal error: must call _waitForPendingPorts to ensure all"
-          + " ports are resolved at this point.";
+      throw

[Lasse Reichstein Nielsen, 2012/06/18 09:25:32]

I liked the original indentation better. Just remove the '+' but keep the
indentation.
It tricks an old JS programmer to see a newline between "throw" and it's operand
- that's not allowed in JS.

[ahe, 2012/06/18 10:39:16]

I don't follow the logic of your argument.

+          "internal error: must call _waitForPendingPorts to ensure all"
+          " ports are resolved at this point.";
     }
   }
 }
 
 /** Visitor that serializes a message as a JSON array. */
 class _Serializer extends _MessageTraverser {
   int _nextFreeRefId = 0;
 
   _Serializer() : super();
 
@@ skipping 29 matching lines @@
 
   visitWorkerSendPort(_WorkerSendPort port) {
     return ['sendport', port._workerId, port._isolateId, port._receivePortId];
   }
 
   visitBufferingSendPort(_BufferingSendPort port) {
     if (port._port != null) {
       return _visitNativeOrWorkerPort(port._port);
     } else {
       // TODO(floitsch): Use real exception (which one?).
-      throw "internal error: must call _waitForPendingPorts to ensure all"
-          + " ports are resolved at this point.";
+      throw
+          "internal error: must call _waitForPendingPorts to ensure all"
+          " ports are resolved at this point.";

[Lasse Reichstein Nielsen, 2012/06/18 09:25:32]

Ditto.

[ahe, 2012/06/18 10:39:16]

Ditto.

     }
   }
 
   _serializeList(List list) {
     int len = list.length;
     var result = new List(len);
     for (int i = 0; i < len; i++) {
       result[i] = _dispatch(list[i]);
     }
     return result;
@@ skipping 89 matching lines @@
     return new _Copier().traverse(x);
   }
 
   // only visible for testing purposes
   static serialize(x) {
     _Serializer serializer = new _Serializer();
     _Deserializer deserializer = new _Deserializer();
     return deserializer.deserialize(serializer.traverse(x));
   }
 }