diff --git a/lib/Analysis/UndefinedArgChecker.cpp b/lib/Analysis/UndefinedArgChecker.cpp
index 923a7e1..a0c0d48 100644
--- a/lib/Analysis/UndefinedArgChecker.cpp
+++ b/lib/Analysis/UndefinedArgChecker.cpp
@@ -21,14 +21,16 @@
 namespace {
 class VISIBILITY_HIDDEN UndefinedArgChecker
   : public CheckerVisitor<UndefinedArgChecker> {
-  BugType *BT;
+  BugType *BT_call;
+  BugType *BT_msg;
 public:
-  UndefinedArgChecker() : BT(0) {}
+  UndefinedArgChecker() : BT_call(0), BT_msg(0) {}
   static void *getTag() {
     static int x = 0;
     return &x;
   }
   void PreVisitCallExpr(CheckerContext &C, const CallExpr *CE);
+  void PreVisitObjCMessageExpr(CheckerContext &C, const ObjCMessageExpr *ME);
 };
 } // end anonymous namespace
 
@@ -42,14 +44,40 @@
        I != E; ++I) {
     if (C.getState()->getSVal(*I).isUndef()) {
       if (ExplodedNode *N = C.GenerateNode(CE, true)) {
-        if (!BT)
-          BT = new BuiltinBug("Pass-by-value argument in function call is "
-                              "undefined");
+        if (!BT_call)
+          BT_call = new BuiltinBug("Pass-by-value argument in function call is "
+                                   "undefined");
         // Generate a report for this bug.
-        EnhancedBugReport *R = new EnhancedBugReport(*BT, BT->getName(), N);
+        EnhancedBugReport *R = new EnhancedBugReport(*BT_call,
+                                                     BT_call->getName(), N);
         R->addRange((*I)->getSourceRange());
         R->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, *I);
         C.EmitReport(R);
+        return;
+      }
+    }
+  }
+}
+
+void UndefinedArgChecker::PreVisitObjCMessageExpr(CheckerContext &C,
+                                                  const ObjCMessageExpr *ME) {
+
+  // Check for any arguments that are uninitialized/undefined.
+  const GRState *state = C.getState();
+  for (ObjCMessageExpr::const_arg_iterator I = ME->arg_begin(), E = ME->arg_end();
+       I != E; ++I) {
+    if (state->getSVal(*I).isUndef()) {
+      if (ExplodedNode *N = C.GenerateNode(ME, true)) {
+        if (!BT_msg)
+          BT_msg = new BuiltinBug("Pass-by-value argument in message expression"
+                                  " is undefined");      
+        // Generate a report for this bug.
+        EnhancedBugReport *R = new EnhancedBugReport(*BT_msg, BT_msg->getName(),
+                                                     N);
+        R->addRange((*I)->getSourceRange());
+        R->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, *I);
+        C.EmitReport(R);
+        return;
       }
     }
   }