From a5996e8dc96c57bbd34334387fc9ea26091d22e9 Mon Sep 17 00:00:00 2001
From: Marshall Clow <mclow.lists@gmail.com>
Date: Thu, 26 Apr 2018 16:16:45 +0000
Subject: [PATCH] Move old test into test/libcxx, and implement new version of
 test for ostreambuf_iterator::failed. Fixes PR#37245. Thanks to Billy O'Neill
 for the bug report.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@330955 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/libcxx/iterators/failed.pass.cpp         | 32 +++++++++++++++++++
 .../ostreambuf.iter.ops/failed.pass.cpp       | 17 ++++++++--
 2 files changed, 47 insertions(+), 2 deletions(-)
 create mode 100644 test/libcxx/iterators/failed.pass.cpp

diff --git a/test/libcxx/iterators/failed.pass.cpp b/test/libcxx/iterators/failed.pass.cpp
new file mode 100644
index 000000000..2e4717b38
--- /dev/null
+++ b/test/libcxx/iterators/failed.pass.cpp
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <iterator>
+
+// class ostreambuf_iterator
+
+// bool failed() const throw();
+//
+//	Extension: constructing from NULL is UB; we just make it a failed iterator
+
+#include <iterator>
+#include <sstream>
+#include <cassert>
+
+int main()
+{
+    {
+        std::ostreambuf_iterator<char> i(nullptr);
+        assert(i.failed());
+    }
+    {
+        std::ostreambuf_iterator<wchar_t> i(nullptr);
+        assert(i.failed());
+    }
+}
diff --git a/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/failed.pass.cpp b/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/failed.pass.cpp
index 9d93bad37..5cc9cf928 100644
--- a/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/failed.pass.cpp
+++ b/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/failed.pass.cpp
@@ -17,14 +17,27 @@
 #include <sstream>
 #include <cassert>
 
+template <typename Char, typename Traits = std::char_traits<Char> >
+struct my_streambuf : public std::basic_streambuf<Char,Traits> {
+	typedef typename std::basic_streambuf<Char,Traits>::int_type  int_type;
+	typedef typename std::basic_streambuf<Char,Traits>::char_type char_type;
+	
+	my_streambuf() {}
+	int_type sputc(char_type) { return Traits::eof(); }
+	};
+
 int main()
 {
     {
-        std::ostreambuf_iterator<char> i(nullptr);
+    	my_streambuf<char> buf;
+        std::ostreambuf_iterator<char> i(&buf);
+        i = 'a';
         assert(i.failed());
     }
     {
-        std::ostreambuf_iterator<wchar_t> i(nullptr);
+    	my_streambuf<wchar_t> buf;
+        std::ostreambuf_iterator<wchar_t> i(&buf);
+        i = L'a';
         assert(i.failed());
     }
 }