From e376809717dc6e08eb572343f858b549e0623425 Mon Sep 17 00:00:00 2001
From: jzmaddock <john@johnmaddock.co.uk>
Date: Sat, 9 Dec 2017 12:44:38 +0000
Subject: [PATCH] Config.msvc-15.5: enable some initial C++17 features.

---
 include/boost/config/compiler/visualc.hpp  | 4 ++++
 include/boost/config/stdlib/dinkumware.hpp | 7 ++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/boost/config/compiler/visualc.hpp b/include/boost/config/compiler/visualc.hpp
index 49bb1a48..40adff94 100644
--- a/include/boost/config/compiler/visualc.hpp
+++ b/include/boost/config/compiler/visualc.hpp
@@ -223,12 +223,16 @@
 //
 #define BOOST_NO_TWO_PHASE_NAME_LOOKUP
 #if (_MSC_VER < 1912) || (_MSVC_LANG < 201402)
+// Supported from msvc-15.5 onwards:
 #define BOOST_NO_CXX11_SFINAE_EXPR
 #endif
 // C++ 14:
+// Still gives internal compiler error for msvc-15.5:
 #  define BOOST_NO_CXX14_CONSTEXPR
 // C++ 17:
+#if (_MSC_VER < 1912) || (_MSVC_LANG < 201703)
 #define BOOST_NO_CXX17_INLINE_VARIABLES
+#endif
 #define BOOST_NO_CXX17_FOLD_EXPRESSIONS
 
 //
diff --git a/include/boost/config/stdlib/dinkumware.hpp b/include/boost/config/stdlib/dinkumware.hpp
index 0fd97a41..641c2ae2 100644
--- a/include/boost/config/stdlib/dinkumware.hpp
+++ b/include/boost/config/stdlib/dinkumware.hpp
@@ -173,10 +173,15 @@
 // C++17 features
 #if !defined(_CPPLIB_VER) || (_CPPLIB_VER < 650) || !defined(BOOST_MSVC) || (BOOST_MSVC < 1910) || !defined(_HAS_CXX17) || (_HAS_CXX17 == 0)
 #  define BOOST_NO_CXX17_STD_APPLY
+#  define BOOST_NO_CXX17_ITERATOR_TRAITS
 #endif
 #if !defined(_CPPLIB_VER) || (_CPPLIB_VER < 650)
 #  define BOOST_NO_CXX17_STD_INVOKE
-#  define BOOST_NO_CXX17_ITERATOR_TRAITS
+#endif
+
+#if !(!defined(_CPPLIB_VER) || (_CPPLIB_VER < 650) || !defined(BOOST_MSVC) || (BOOST_MSVC < 1912) || !defined(_HAS_CXX17) || (_HAS_CXX17 == 0))
+// Deprecated std::iterator:
+#  define BOOST_NO_STD_ITERATOR
 #endif
 
 #if defined(BOOST_INTEL) && (BOOST_INTEL <= 1400)