From 3e8f909a069d36528b4cfd404db8d857f9a9d95b Mon Sep 17 00:00:00 2001
From: Paolo Carlini <paolo.carlini@oracle.com>
Date: Tue, 8 May 2018 08:55:30 +0000
Subject: [PATCH] re PR c++/80691 (Narrowing conversion in {} allowed in a
 SFINAE context)

2018-05-08  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/80691
	* g++.dg/cpp0x/narrowing1.C: New.

From-SVN: r260027
---
 gcc/testsuite/ChangeLog                 |  5 +++++
 gcc/testsuite/g++.dg/cpp0x/narrowing1.C | 24 ++++++++++++++++++++++++
 2 files changed, 29 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/narrowing1.C

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 795af52dcdc..000dc689f53 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-05-08  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/80691
+	* g++.dg/cpp0x/narrowing1.C: New.
+
 2018-05-08  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/85588
diff --git a/gcc/testsuite/g++.dg/cpp0x/narrowing1.C b/gcc/testsuite/g++.dg/cpp0x/narrowing1.C
new file mode 100644
index 00000000000..ba4bb4e9f0d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/narrowing1.C
@@ -0,0 +1,24 @@
+// PR c++/80691
+// { dg-do compile { target c++11 } }
+
+struct true_type { static constexpr bool value = true; };
+struct false_type { static constexpr bool value = false; };
+template<typename...> using void_t = void;
+template<typename T> T&& declval();
+
+template<typename T, typename U, typename = void>
+struct is_nonnarrowing_conversion : false_type {};
+
+template<typename T, typename U>
+struct is_nonnarrowing_conversion<T, U,
+    void_t<decltype(T{ declval<U>() })>> : true_type {};
+
+template<typename T>
+class wrapper
+{
+public:
+    wrapper(T) {}
+};
+
+static_assert(!is_nonnarrowing_conversion<int, float>::value, "");
+static_assert(!is_nonnarrowing_conversion<wrapper<int>, float>::value, "");
-- 
2.30.2