From 0da4a99ad36c11ee18d36c353eb4256945dfdf7b Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Fri, 24 Dec 2010 00:20:52 +0000
Subject: [PATCH] Non-type template parameter packs cannot have default
 arguments.

llvm-svn: 122533
---
 clang/lib/Sema/SemaTemplate.cpp          |  8 ++++++++
 clang/test/CXX/temp/temp.param/p9-0x.cpp | 10 ++++++++++
 2 files changed, 18 insertions(+)
 create mode 100644 clang/test/CXX/temp/temp.param/p9-0x.cpp

diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index a487825bb37c..ce0132ee8141 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -649,6 +649,14 @@ Decl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
   
   // Check the well-formedness of the default template argument, if provided.
   if (Default) {
+    // C++0x [temp.param]p9:
+    //   A default template-argument may be specified for any kind of
+    //   template-parameter that is not a template parameter pack.
+    if (IsParameterPack) {
+      Diag(EqualLoc, diag::err_template_param_pack_default_arg);
+      return Param;
+    }
+
     // Check for unexpanded parameter packs.
     if (DiagnoseUnexpandedParameterPack(Default, UPPC_DefaultArgument))
       return Param;
diff --git a/clang/test/CXX/temp/temp.param/p9-0x.cpp b/clang/test/CXX/temp/temp.param/p9-0x.cpp
new file mode 100644
index 000000000000..42d1adf29729
--- /dev/null
+++ b/clang/test/CXX/temp/temp.param/p9-0x.cpp
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -std=c++0x -fsyntax-only -verify %s
+
+// A default template-argument may be specified for any kind of
+// template-parameter that is not a template parameter pack.
+template<typename ...Types = int> // expected-error{{template parameter pack cannot have a default argument}}
+struct X0;
+
+template<int ...Values = 0> // expected-error{{template parameter pack cannot have a default argument}}
+struct X1;
+