commit 8494bec4e85a987375b3e1044574ddb89fa6e120
Author: Jason Merrill <jason@redhat.com>
Date:   Wed Jan 29 15:37:41 2014 -0500

    	PR c++/58466
    	* pt.c (unify_pack_expansion): Call expand_template_argument_pack.

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 943255d..9be9171 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -16897,6 +16897,9 @@ unify_pack_expansion (tree tparms, tree targs, tree packed_parms,
   tree pattern = PACK_EXPANSION_PATTERN (parm);
   tree pack, packs = NULL_TREE;
   int i, start = TREE_VEC_LENGTH (packed_parms) - 1;
+
+  packed_args = expand_template_argument_pack (packed_args);
+
   int len = TREE_VEC_LENGTH (packed_args);
 
   /* Determine the parameter packs we will be deducing from the
diff --git a/gcc/testsuite/g++.dg/cpp0x/variadic147.C b/gcc/testsuite/g++.dg/cpp0x/variadic147.C
new file mode 100644
index 0000000..7f606d8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/variadic147.C
@@ -0,0 +1,10 @@
+// PR c++/58466
+// { dg-require-effective-target c++11 }
+
+template<char, char...> struct A;
+
+template<typename> struct B;
+
+template<char... C> struct B<A<C...>> {};
+
+B<A<'X'>> b;