PR c++/71833 - member template with two parameter packs

	PR c++/54440
	* pt.c (coerce_template_parameter_pack): Fix logic for
	pack index.

From-SVN: r238731

gcc/cp/ChangeLog

 2016-07-25  Jason Merrill  <jason@redhat.com>
 
+	PR c++/71833
+	PR c++/54440
+	* pt.c (coerce_template_parameter_pack): Fix logic for
+	pack index.
+
 	PR c++/65970
 	* constexpr.c (cxx_eval_loop_expr): Count iterations.
 	* cp-gimplify.c (genericize_cp_loop): Use start_locus even for

gcc/cp/pt.c

@@ -7403,11 +7403,12 @@ coerce_template_parameter_pack (tree parms,
 
   /* Convert the remaining arguments, which will be a part of the
      parameter pack "parm".  */
+  int first_pack_arg = arg_idx;
   for (; arg_idx < nargs; ++arg_idx)
     {
       tree arg = TREE_VEC_ELT (inner_args, arg_idx);
       tree actual_parm = TREE_VALUE (parm);
-      int pack_idx = arg_idx - parm_idx;
+      int pack_idx = arg_idx - first_pack_arg;
 
       if (packed_parms)
         {
@@ -7436,12 +7437,12 @@ coerce_template_parameter_pack (tree parms,
       TREE_VEC_ELT (packed_args, pack_idx) = arg;
     }
 
-  if (arg_idx - parm_idx < TREE_VEC_LENGTH (packed_args)
+  if (arg_idx - first_pack_arg < TREE_VEC_LENGTH (packed_args)
       && TREE_VEC_LENGTH (packed_args) > 0)
     {
       if (complain & tf_error)
 	error ("wrong number of template arguments (%d, should be %d)",
-	       arg_idx - parm_idx, TREE_VEC_LENGTH (packed_args));
+	       arg_idx - first_pack_arg, TREE_VEC_LENGTH (packed_args));
       return error_mark_node;
     }
 

gcc/testsuite/g++.dg/cpp0x/variadic-nested1.C

+// PR c++/71833
+// { dg-do compile { target c++11 } }
+
+template < typename ... Ts > struct A 
+{
+  template < Ts ..., typename ... Us > struct B {};
+};
+
+A <>::B < int > e;