Hi,
On 06/18/2013 04:15 PM, Jason Merrill wrote:
On 06/17/2013 08:21 PM, Paolo Carlini wrote:
I see... There is a little difficulty in that 56794 involves a non-type
variadic parameter and in that case type_dependent_expression_p returns
false. If I use value_dependent_expression_p things work, but I'm not
sure it's 100% correct.
I don't think we need to consider whether the initializer is dependent
here; if the array has no length and has an initializer, it must be
that we couldn't determine its length in cp_complete_array_type
because it is dependent.
Ah, fantastic. I really hoped we could say something like that but
seemed "too easy" ;) I'm finishing testing the below then.
Eventually, we'll have to decide where we want to commit this: 56794 is
fixed in 4.7 and 4.8 too, but it's true that the issue with the specific
testcase attached by Jon isn't a regression.
I think apply it to 4.8 as well.
Agreed.
Paolo.
////////////////////
Index: cp/parser.c
===================================================================
--- cp/parser.c (revision 200169)
+++ cp/parser.c (working copy)
@@ -9750,10 +9750,7 @@ cp_parser_range_for (cp_parser *parser, tree scope
range_expr = error_mark_node;
stmt = begin_range_for_stmt (scope, init);
finish_range_for_decl (stmt, range_decl, range_expr);
- if (range_expr != error_mark_node
- && !type_dependent_expression_p (range_expr)
- /* The length of an array might be dependent. */
- && COMPLETE_TYPE_P (complete_type (TREE_TYPE (range_expr)))
+ if (!type_dependent_expression_p (range_expr)
/* do_auto_deduction doesn't mess with template init-lists. */
&& !BRACE_ENCLOSED_INITIALIZER_P (range_expr))
do_range_for_auto_deduction (range_decl, range_expr);
Index: cp/pt.c
===================================================================
--- cp/pt.c (revision 200169)
+++ cp/pt.c (working copy)
@@ -20079,6 +20079,29 @@ type_dependent_expression_p (tree expression)
&& VAR_HAD_UNKNOWN_BOUND (expression))
return true;
+ /* An array of unknown bound depending on a variadic parameter, eg:
+
+ template<typename... Args>
+ void foo (Args... args)
+ {
+ int arr[] = { args... };
+ }
+
+ template<int... vals>
+ void bar ()
+ {
+ int arr[] = { vals... };
+ }
+
+ If the array has no length and has an initializer, it must be that
+ we couldn't determine its length in cp_complete_array_type because
+ it is dependent. */
+ if (VAR_P (expression)
+ && TREE_CODE (TREE_TYPE (expression)) == ARRAY_TYPE
+ && !TYPE_DOMAIN (TREE_TYPE (expression))
+ && DECL_INITIAL (expression))
+ return true;
+
if (TREE_TYPE (expression) == unknown_type_node)
{
if (TREE_CODE (expression) == ADDR_EXPR)
Index: testsuite/g++.dg/cpp0x/decltype55.C
===================================================================
--- testsuite/g++.dg/cpp0x/decltype55.C (revision 0)
+++ testsuite/g++.dg/cpp0x/decltype55.C (working copy)
@@ -0,0 +1,20 @@
+// PR c++/53211
+// { dg-do compile { target c++11 } }
+
+template<typename A, typename B>
+ struct is_same { static const bool value = false; };
+
+template<typename A>
+ struct is_same<A, A> { static const bool value = true; };
+
+template<typename... Args>
+void func(Args... args)
+{
+ int arr[] = { args... };
+ static_assert (is_same<decltype(arr), int[sizeof...(Args)]>::value, "");
+}
+
+int main()
+{
+ func(1, 2, 3, 4);
+}
