re PR c++/50303 ([C++0x] Segfault with variadic template template parameters)

	PR c++/50303
	* pt.c (tsubst_pack_expansion): Use tsubst_expr for template
	template parameters.

From-SVN: r186519

gcc/cp/ChangeLog

+2012-04-16  Jason Merrill  <jason@redhat.com>
+
+	PR c++/50303
+	* pt.c (tsubst_pack_expansion): Use tsubst_expr for template
+	template parameters.
+
 2012-04-16  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/49152

gcc/cp/pt.c

@@ -9518,7 +9518,7 @@ tsubst_pack_expansion (tree t, tree args, tsubst_flags_t complain,
         }
 
       /* Substitute into the PATTERN with the altered arguments.  */
-      if (TREE_CODE (t) == EXPR_PACK_EXPANSION)
+      if (!TYPE_P (pattern))
         TREE_VEC_ELT (result, i) = 
           tsubst_expr (pattern, args, complain, in_decl,
                        /*integral_constant_expression_p=*/false);

gcc/testsuite/ChangeLog

+2012-04-16  Jason Merrill  <jason@redhat.com>
+
+	PR c++/50303
+	* g++.dg/cpp0x/variadic128.C: New.
+
 2012-04-16  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/52864

gcc/testsuite/g++.dg/cpp0x/variadic128.C

+// PR c++/50303
+// { dg-do compile { target c++11 } }
+
+template<typename Interface>
+struct A1 {
+};
+
+template<template<class I> class... Actions>
+void g2() {
+  g2<Actions...>();
+}
+
+int main()
+{
+  g2<A1>();
+}