* C++ PATCH for c++/48424 (function parameter packs not at the end of the list)
@ 2011-05-26 13:44 Jason Merrill
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From: Jason Merrill @ 2011-05-26 13:44 UTC (permalink / raw)
To: gcc-patches List
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The initial specification of variadic templates required function
parameter packs to be at the end of the parameter list, but that
restriction was soon found to be undesirable; this patch updates G++ to
support packs earlier in the parameter list as specified in the FDIS.
Tested x86_64-pc-linux-gnu, applying to trunk.
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commit 4903fd6cbf099822f15e6af2708ab5d54e7eae18
Author: Jason Merrill <jason@redhat.com>
Date: Wed May 25 23:15:19 2011 -0400
PR c++/48424
* decl.c (grokparms): Function parameter packs don't need to
go at the end.
* pt.c (type_unification_real): But they aren't deduced otherwise.
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 8ab0c8a..a956dbb 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -10551,12 +10551,6 @@ grokparms (tree parmlist, tree *parms)
init = check_default_argument (decl, init);
}
- if (TREE_CODE (decl) == PARM_DECL
- && FUNCTION_PARAMETER_PACK_P (decl)
- && TREE_CHAIN (parm)
- && TREE_CHAIN (parm) != void_list_node)
- error ("parameter packs must be at the end of the parameter list");
-
DECL_CHAIN (decl) = decls;
decls = decl;
result = tree_cons (init, type, result);
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index c9c25cd..ab48c8f 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -14262,11 +14262,24 @@ type_unification_real (tree tparms,
while (parms && parms != void_list_node
&& ia < nargs)
{
- if (TREE_CODE (TREE_VALUE (parms)) == TYPE_PACK_EXPANSION)
- break;
-
parm = TREE_VALUE (parms);
+
+ if (TREE_CODE (parm) == TYPE_PACK_EXPANSION
+ && (!TREE_CHAIN (parms) || TREE_CHAIN (parms) == void_list_node))
+ /* For a function parameter pack that occurs at the end of the
+ parameter-declaration-list, the type A of each remaining
+ argument of the call is compared with the type P of the
+ declarator-id of the function parameter pack. */
+ break;
+
parms = TREE_CHAIN (parms);
+
+ if (TREE_CODE (parm) == TYPE_PACK_EXPANSION)
+ /* For a function parameter pack that does not occur at the
+ end of the parameter-declaration-list, the type of the
+ parameter pack is a non-deduced context. */
+ continue;
+
arg = args[ia];
++ia;
arg_expr = NULL;
diff --git a/gcc/testsuite/g++.dg/cpp0x/variadic111.C b/gcc/testsuite/g++.dg/cpp0x/variadic111.C
new file mode 100644
index 0000000..378162e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/variadic111.C
@@ -0,0 +1,19 @@
+// PR c++/48424
+// { dg-options -std=c++0x }
+
+template<typename... Args1>
+struct S
+{
+ template<typename... Args2>
+ void f(Args1... args1, Args2&&... args2)
+ {
+ }
+};
+
+int main()
+{
+ S<int, double> s;
+ s.f(1,2.0,false,'a');
+}
+
+// { dg-final { scan-assembler "_ZN1SIIidEE1fIIbcEEEvidDpOT_" } }
diff --git a/gcc/testsuite/g++.dg/cpp0x/variadic41.C b/gcc/testsuite/g++.dg/cpp0x/variadic41.C
index d209766..9cfd847 100644
--- a/gcc/testsuite/g++.dg/cpp0x/variadic41.C
+++ b/gcc/testsuite/g++.dg/cpp0x/variadic41.C
@@ -1,3 +1,14 @@
+// A function parameter pack is only deduced if it's at the end
// { dg-options "-std=gnu++0x" }
template<typename... Args>
-void f(const Args&... args, int oops); // { dg-error "end" }
+void f(const Args&... args, int oops);
+
+int main()
+{
+ f<>(1);
+ f(1);
+ f<int>(1,2);
+ f(1,2); // { dg-error "no match" }
+}
+
+// { dg-prune-output "note" }
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