From ae6af5239b96722e4db164a311956c263a7def86 Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Wed, 20 Sep 2017 23:26:19 +0100
Subject: [PATCH] PR libstdc++/79162 Fix std::string regression due to LWG 2946
 (old ABI)

	PR libstdc++/79162
	* include/bits/basic_string.h [!_GLIBCXX_USE_CXX11_ABI]
	(basic_string::_If_sv): Remove from the overload set when the
	argument is derived from basic_string.

From-SVN: r253038
---
 libstdc++-v3/ChangeLog                   | 5 +++++
 libstdc++-v3/include/bits/basic_string.h | 1 +
 2 files changed, 6 insertions(+)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index f97af8ffe7c..8f8da2fccb3 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,10 @@
 2017-09-20  Jonathan Wakely  <jwakely@redhat.com>
 
+	PR libstdc++/79162
+	* include/bits/basic_string.h [!_GLIBCXX_USE_CXX11_ABI]
+	(basic_string::_If_sv): Remove from the overload set when the
+	argument is derived from basic_string.
+
 	PR libstdc++/79162
 	* include/bits/basic_string.h (basic_string::_If_sv): Remove from the
 	overload set when the argument is derived from basic_string.
diff --git a/libstdc++-v3/include/bits/basic_string.h b/libstdc++-v3/include/bits/basic_string.h
index e7ab40f6131..7df39685ad3 100644
--- a/libstdc++-v3/include/bits/basic_string.h
+++ b/libstdc++-v3/include/bits/basic_string.h
@@ -3439,6 +3439,7 @@ _GLIBCXX_END_NAMESPACE_CXX11
       template<typename _Tp, typename _Res>
 	using _If_sv = enable_if_t<
 	  __and_<is_convertible<const _Tp&, __sv_type>,
+		 __not_<is_convertible<const _Tp*, const basic_string*>>,
 		 __not_<is_convertible<const _Tp&, const _CharT*>>>::value,
 	  _Res>;