re PR c++/63362 (The c++11 triviality-traits need front-end help)

	PR c++/63362
	* method.c (constructible_expr): Handle value-init of non-class.
	* parser.c (cp_parser_trait_expr): Allow pack expansion.
	* pt.c (tsubst_copy_and_build): Handle pack expansion.

From-SVN: r215772

gcc/cp/ChangeLog

 2014-10-01  Jason Merrill  <jason@redhat.com>
 
 	PR c++/63362
+	* method.c (constructible_expr): Handle value-init of non-class.
+	* parser.c (cp_parser_trait_expr): Allow pack expansion.
+	* pt.c (tsubst_copy_and_build): Handle pack expansion.
+
+	PR c++/63362
 	* class.c (type_has_non_user_provided_default_constructor): Rename
 	from type_has_user_provided_default_constructor, reverse sense.
 	(default_init_uninitialized_part, explain_non_literal_class): Adjust.

gcc/cp/method.c

@@ -1077,7 +1077,9 @@ constructible_expr (tree to, tree from)
     }
   else
     {
-      if (TREE_CHAIN (from))
+      if (from == NULL_TREE)
+	return build_value_init (to, tf_none);
+      else if (TREE_CHAIN (from))
 	return error_mark_node; // too many initializers
       from = build_stub_object (TREE_VALUE (from));
       expr = perform_direct_initialization_if_possible (to, from,

gcc/cp/parser.c

@@ -8780,6 +8780,11 @@ cp_parser_trait_expr (cp_parser* parser, enum rid keyword)
 	{
 	  cp_lexer_consume_token (parser->lexer);
 	  tree elt = cp_parser_type_id (parser);
+	  if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS))
+	    {
+	      cp_lexer_consume_token (parser->lexer);
+	      elt = make_pack_expansion (elt);
+	    }
 	  if (elt == error_mark_node)
 	    return error_mark_node;
 	  type2 = tree_cons (NULL_TREE, elt, type2);

gcc/cp/pt.c

@@ -15487,7 +15487,9 @@ tsubst_copy_and_build (tree t,
 			     complain, in_decl);
 
 	tree type2 = TRAIT_EXPR_TYPE2 (t);
-	if (type2)
+	if (type2 && TREE_CODE (type2) == TREE_LIST)
+	  type2 = RECUR (type2);
+	else if (type2)
 	  type2 = tsubst (type2, args, complain, in_decl);
 	
 	RETURN (finish_trait_expr (TRAIT_EXPR_KIND (t), type1, type2));

gcc/testsuite/g++.dg/ext/is_trivially_constructible3.C

+// { dg-do compile { target c++11 } }
+
+template <class T, class... Args> void bar() {
+  static_assert(__is_trivially_constructible(T, Args...), "");
+}
+
+template void bar<int>();
+template void bar<int,int>();