From fcf98edc2a993e33981f6924c8f573a8fb35a5dc Mon Sep 17 00:00:00 2001
From: jason <jason@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Sun, 18 Jun 2017 04:25:15 +0000
Subject: [PATCH] 	PR c++/70844 - -Wuseless-cast and inheriting
 constructor.

	* method.c (forward_parm): Suppress warn_useless_cast.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@249344 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/cp/ChangeLog                        |  5 +++++
 gcc/cp/method.c                         |  1 +
 gcc/testsuite/g++.dg/cpp0x/inh-ctor27.C | 13 +++++++++++++
 3 files changed, 19 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/inh-ctor27.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index dba5e4d0ddb..d0825743e45 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2017-06-17  Jason Merrill  <jason@redhat.com>
+
+	PR c++/70844 - -Wuseless-cast and inheriting constructor.
+	* method.c (forward_parm): Suppress warn_useless_cast.
+
 2017-06-16  Jason Merrill  <jason@redhat.com>
 
 	PR c++/81045 - Wrong type-dependence with auto return type.
diff --git a/gcc/cp/method.c b/gcc/cp/method.c
index 9541fcb9161..fe4b2afe7db 100644
--- a/gcc/cp/method.c
+++ b/gcc/cp/method.c
@@ -486,6 +486,7 @@ forward_parm (tree parm)
     type = PACK_EXPANSION_PATTERN (type);
   if (TREE_CODE (type) != REFERENCE_TYPE)
     type = cp_build_reference_type (type, /*rval=*/true);
+  warning_sentinel w (warn_useless_cast);
   exp = build_static_cast (type, exp, tf_warning_or_error);
   if (DECL_PACK_P (parm))
     exp = make_pack_expansion (exp);
diff --git a/gcc/testsuite/g++.dg/cpp0x/inh-ctor27.C b/gcc/testsuite/g++.dg/cpp0x/inh-ctor27.C
new file mode 100644
index 00000000000..ef2ada17d51
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/inh-ctor27.C
@@ -0,0 +1,13 @@
+// PR c++/70844
+// { dg-options -Wuseless-cast }
+// { dg-do compile { target c++11 } }
+
+struct base {
+    base (int const &);
+};
+
+struct derived : public base {
+    using base::base;
+};
+
+derived d(0);
-- 
2.11.4.GIT