re PR c++/54859 (constexpr in template alias rejected as non-constant)

	PR c++/54859
	* pt.c (check_instantiated_arg): Don't complain about dependent args.

From-SVN: r193368

gcc/cp/ChangeLog

 2012-11-09  Jason Merrill  <jason@redhat.com>
 
+	PR c++/54859
+	* pt.c (check_instantiated_arg): Don't complain about dependent args.
+
 	* tree.c (cxx_attribute_table): Add abi_tag attribute.
 	(check_abi_tag_redeclaration, handle_abi_tag_attribute): New.
 	* class.c (find_abi_tags_r, check_abi_tags): New.

gcc/cp/pt.c

@@ -14362,6 +14362,8 @@ tsubst_copy_and_build (tree t,
 static bool
 check_instantiated_arg (tree tmpl, tree t, tsubst_flags_t complain)
 {
+  if (dependent_template_arg_p (t))
+    return false;
   if (ARGUMENT_PACK_P (t))
     {
       tree vec = ARGUMENT_PACK_ARGS (t);

gcc/testsuite/ChangeLog

 2012-11-09  Jason Merrill  <jason@redhat.com>
 
+	PR c++/54859
+	* g++.dg/cpp0x/alias-decl-25.C: New.
+
 	* g++.dg/abi/abi-tag1.C: New.
 	* g++.dg/abi/abi-tag2.C: New.
 

gcc/testsuite/g++.dg/cpp0x/alias-decl-25.C

+// PR c++/54859
+// { dg-options -std=c++11 }
+
+template<unsigned N>
+  using Num = int;
+
+template<typename... Types>
+  using Count = Num<sizeof...(Types)>;
+
+Count<int, char, void> i;