Several parts of the variadic template code have had trouble dealing
with partial instantiation; this is another one.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit 0bbe297555a3e6585f1668266d965745df352ba4
Author: Jason Merrill <ja...@redhat.com>
Date: Tue May 24 23:20:29 2011 -0400
PR c++/48292
* pt.c (tsubst_decl) [PARM_DECL]: Handle partial instantiation of
function parameter pack.
(tsubst_pack_expansion): Likewise.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index bd9aeba..fc84314 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -8711,7 +8711,12 @@ tsubst_pack_expansion (tree t, tree args, tsubst_flags_t complain,
have the wrong value for a recursive call. Just make a
dummy decl, since it's only used for its type. */
arg_pack = tsubst_decl (parm_pack, args, complain);
- arg_pack = make_fnparm_pack (arg_pack);
+ if (arg_pack && FUNCTION_PARAMETER_PACK_P (arg_pack))
+ /* Partial instantiation of the parm_pack, we can't build
+ up an argument pack yet. */
+ arg_pack = NULL_TREE;
+ else
+ arg_pack = make_fnparm_pack (arg_pack);
}
}
else
@@ -9801,14 +9806,14 @@ tsubst_decl (tree t, tree args, tsubst_flags_t complain)
if (DECL_TEMPLATE_PARM_P (t))
SET_DECL_TEMPLATE_PARM_P (r);
- /* An argument of a function parameter pack is not a parameter
- pack. */
- FUNCTION_PARAMETER_PACK_P (r) = false;
-
if (expanded_types)
/* We're on the Ith parameter of the function parameter
pack. */
{
+ /* An argument of a function parameter pack is not a parameter
+ pack. */
+ FUNCTION_PARAMETER_PACK_P (r) = false;
+
/* Get the Ith type. */
type = TREE_VEC_ELT (expanded_types, i);
diff --git a/gcc/testsuite/g++.dg/cpp0x/variadic109.C b/gcc/testsuite/g++.dg/cpp0x/variadic109.C
new file mode 100644
index 0000000..0ec69af
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/variadic109.C
@@ -0,0 +1,17 @@
+// PR c++/48292
+// { dg-options -std=c++0x }
+
+template <typename... Args> int g(Args...);
+
+template <int N = 0>
+struct A
+{
+ template <typename... Args>
+ static auto f(Args... args) -> decltype(g(args...));
+};
+
+int main()
+{
+ A<>::f();
+ return 0;
+}