diff --git a/ipc/ipdl/ipdl/lower.py b/ipc/ipdl/ipdl/lower.py
index f4a65413e29..36073e9c6b6 100644
--- a/ipc/ipdl/ipdl/lower.py
+++ b/ipc/ipdl/ipdl/lower.py
@@ -4,6 +4,7 @@
 
 import os, re, sys
 from copy import deepcopy
+from collections import OrderedDict
 
 import ipdl.ast
 import ipdl.builtin
@@ -2780,7 +2781,7 @@ class _GenerateProtocolActorCode(ipdl.ast.Visitor):
 
         bridgeActorsCreated = ProcessGraph.bridgeEndpointsOf(ptype, self.side)
         opensActorsCreated = ProcessGraph.opensEndpointsOf(ptype, self.side)
-        channelOpenedActors = bridgeActorsCreated + opensActorsCreated
+        channelOpenedActors = OrderedDict.fromkeys(bridgeActorsCreated + opensActorsCreated, None)
 
         friends = _FindFriends().findFriends(ptype)
         if ptype.isManaged():
diff --git a/ipc/ipdl/test/cxx/PTestBridgeMain.ipdl b/ipc/ipdl/test/cxx/PTestBridgeMain.ipdl
index 93e905dd4dc..77b9024bf1e 100644
--- a/ipc/ipdl/test/cxx/PTestBridgeMain.ipdl
+++ b/ipc/ipdl/test/cxx/PTestBridgeMain.ipdl
@@ -7,6 +7,7 @@ namespace _ipdltest {
 
 protocol PTestBridgeMain {
     child spawns PTestBridgeSub;
+    child opens PTestBridgeMainSub;
 
 child:
     Start();
diff --git a/ipc/ipdl/test/cxx/TestBridgeMain.h b/ipc/ipdl/test/cxx/TestBridgeMain.h
index 170f2127359..43d01fb90e6 100644
--- a/ipc/ipdl/test/cxx/TestBridgeMain.h
+++ b/ipc/ipdl/test/cxx/TestBridgeMain.h
@@ -72,6 +72,16 @@ public:
 protected:
     virtual bool RecvStart() MOZ_OVERRIDE;
 
+    virtual PTestBridgeMainSubChild*
+    AllocPTestBridgeMainSubChild(Transport* transport,
+                                 ProcessId otherProcess) MOZ_OVERRIDE
+    {
+        // This shouldn't be called. It's just a byproduct of testing that
+        // the right code is generated for a bridged protocol that's also
+        // opened, but we only test bridging here.
+        MOZ_CRASH();
+    }
+
     virtual void ActorDestroy(ActorDestroyReason why) MOZ_OVERRIDE;
 
     IPDLUnitTestSubprocess* mSubprocess;