From 80390766bd24c78c10fe3a328a82a233ef46c7cb Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Thu, 16 Jun 2011 18:08:57 -0400
Subject: [PATCH] re PR c++/49251 ([C++0x][parameter pack expanding] unused
 parameter warning with unpacking empty tuples)

	PR c++/49251
	* semantics.c (finish_id_expression): Mark even dependent
	variables as used.

From-SVN: r175119
---
 gcc/cp/ChangeLog                         |  4 ++++
 gcc/cp/semantics.c                       |  5 ++++-
 gcc/testsuite/ChangeLog                  |  3 +++
 gcc/testsuite/g++.dg/cpp0x/variadic113.C | 20 ++++++++++++++++++++
 4 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/variadic113.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 6523c940623..a8baca2eb65 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 2011-06-16  Jason Merrill  <jason@redhat.com>
 
+	PR c++/49251
+	* semantics.c (finish_id_expression): Mark even dependent
+	variables as used.
+
 	PR c++/49420
 	* error.c (dump_template_argument): Don't try to omit default
 	template args from an argument pack.
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 55f9519c43b..bad7acbb671 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -3196,7 +3196,10 @@ finish_id_expression (tree id_expression,
 	     (or an instantiation thereof).  */
 	  if (TREE_CODE (decl) == VAR_DECL
 	      || TREE_CODE (decl) == PARM_DECL)
-	    return convert_from_reference (decl);
+	    {
+	      mark_used (decl);
+	      return convert_from_reference (decl);
+	    }
 	  /* The same is true for FIELD_DECL, but we also need to
 	     make sure that the syntax is correct.  */
 	  else if (TREE_CODE (decl) == FIELD_DECL)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6622a60311d..cc12e7bf279 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2011-06-16  Jason Merrill  <jason@redhat.com>
 
+	PR c++/49251
+	* g++.dg/cpp0x/variadic113.C: New.
+
 	PR c++/49420
 	* g++.dg/cpp0x/variadic112.C: New.
 
diff --git a/gcc/testsuite/g++.dg/cpp0x/variadic113.C b/gcc/testsuite/g++.dg/cpp0x/variadic113.C
new file mode 100644
index 00000000000..3f1bb2ad04a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/variadic113.C
@@ -0,0 +1,20 @@
+// PR c++/49251
+// { dg-options "-std=c++0x -Wunused-parameter" }
+
+struct A {};
+template <int> int f(A);
+
+template< int... Indices >
+struct indices {};
+
+template< class... Args >
+void sink( Args&&... ) {}
+
+template< class T, int... Indices >
+void unpack_test( T && t, indices<Indices...> ) {
+  sink( f<Indices>(t)... );
+}
+
+int main() {
+  unpack_test( A(), indices<>() );
+}
-- 
2.30.2