diff --git a/clang/lib/CodeGen/Mangle.cpp b/clang/lib/CodeGen/Mangle.cpp
index 0aa9f40..834ef4e 100644
--- a/clang/lib/CodeGen/Mangle.cpp
+++ b/clang/lib/CodeGen/Mangle.cpp
@@ -2137,8 +2137,9 @@
   //                ::= I <template-arg>* E # argument pack
   //                ::= sp <expression>     # pack expansion of (C++0x)
   switch (A.getKind()) {
-  default:
-    assert(0 && "Unknown template argument kind!");
+  case TemplateArgument::Null:
+    llvm_unreachable("Cannot mangle NULL template argument");
+      
   case TemplateArgument::Type:
     mangleType(A.getAsType());
     break;
@@ -2187,6 +2188,16 @@
 
     break;
   }
+      
+  case TemplateArgument::Pack: {
+    // Note: proposal by Mike Herrick on 12/20/10
+    Out << 'J';
+    for (TemplateArgument::pack_iterator PA = A.pack_begin(), 
+                                      PAEnd = A.pack_end();
+         PA != PAEnd; ++PA)
+      mangleTemplateArg(P, *PA);
+    Out << 'E';
+  }
   }
 }