From 199195ee1b156da58d2a54384b79aeb7eb04b0ce Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ion=20Gazta=C3=B1aga?= <igaztanaga@gmail.com>
Date: Thu, 31 Dec 2020 17:13:42 +0100
Subject: [PATCH] Some workarounds for older compilers to see if #36 is fixed.

---
 include/boost/move/detail/type_traits.hpp | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/include/boost/move/detail/type_traits.hpp b/include/boost/move/detail/type_traits.hpp
index bb7fa0f..6ca6c5f 100644
--- a/include/boost/move/detail/type_traits.hpp
+++ b/include/boost/move/detail/type_traits.hpp
@@ -112,9 +112,9 @@
 
 #if defined(BOOST_CLANG)
 //    BOOST_MOVE_HAS_TRAIT
-#   ifdef __is_identifier
+#   if defined __is_identifier
 #       define BOOST_MOVE_HAS_TRAIT(T) (__has_extension(T) || !__is_identifier(__##T))
-#   elif __has_extension
+#   elif defined(__has_extension)
 #     define BOOST_MOVE_HAS_TRAIT(T) __has_extension(T)
 #   else
 #     define BOOST_MOVE_HAS_TRAIT(T) 0
@@ -197,7 +197,7 @@
 #   endif
 
 //    BOOST_MOVE_HAS_TRIVIAL_MOVE_ASSIGN
-#   if BOOST_MOVE_HAS_TRAIT(is_assignable) && BOOST_MOVE_HAS_TRAIT(is_trivially_assignable)
+#   if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && BOOST_MOVE_HAS_TRAIT(is_assignable) && BOOST_MOVE_HAS_TRAIT(is_trivially_assignable)
 #     define BOOST_MOVE_HAS_TRIVIAL_MOVE_ASSIGN(T) (__is_assignable(T, T&&) && __is_trivially_assignable(T, T&&))
 #   elif BOOST_MOVE_HAS_TRAIT(has_trivial_move_assign)
 #     define BOOST_MOVE_HAS_TRIVIAL_MOVE_ASSIGN(T) __has_trivial_move_assign(T)
@@ -211,7 +211,7 @@
 #   endif
 
 //    BOOST_MOVE_HAS_NOTHROW_MOVE_ASSIGN
-#   if BOOST_MOVE_HAS_TRAIT(is_assignable) && BOOST_MOVE_HAS_TRAIT(is_nothrow_assignable)
+#   if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && BOOST_MOVE_HAS_TRAIT(is_assignable) && BOOST_MOVE_HAS_TRAIT(is_nothrow_assignable)
 #     define BOOST_MOVE_HAS_NOTHROW_MOVE_ASSIGN(T) (__is_assignable(T, T&&) && __is_nothrow_assignable(T, T&&))
 #   elif BOOST_MOVE_HAS_TRAIT(has_nothrow_move_assign)
 #     define BOOST_MOVE_HAS_NOTHROW_MOVE_ASSIGN(T) __has_nothrow_move_assign(T)
@@ -248,7 +248,7 @@
 #   define BOOST_MOVE_HAS_NOTHROW_COPY(T) ((__has_nothrow_copy(T) BOOST_MOVE_INTEL_TT_OPTS))
 #   define BOOST_MOVE_HAS_NOTHROW_ASSIGN(T) ((__has_nothrow_assign(T) BOOST_MOVE_INTEL_TT_OPTS))
 
-#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && !defined(BOOST_NO_SFINAE_EXPR)
 
    template <typename T>
    T && boost_move_tt_declval() BOOST_NOEXCEPT;
@@ -303,7 +303,11 @@
    template <typename T, typename U>
    struct boost_move_tt_is_nothrow_assignable<T, U, true>
    {
+      #if !defined(BOOST_NO_CXX11_NOEXCEPT)
       static const bool value = noexcept(boost_move_tt_declval<T>() = boost_move_tt_declval<U>());
+      #else
+      static const bool value = false;
+      #endif
    };
 
    template <typename T, typename U, bool = BOOST_MOVE_IS_CONSTRUCTIBLE(T, U)>
@@ -315,7 +319,11 @@
    template <typename T, typename U>
    struct boost_move_tt_is_nothrow_constructible<T, U, true>
    {
+      #if !defined(BOOST_NO_CXX11_NOEXCEPT)
       static const bool value = noexcept(T(boost_move_tt_declval<U>()));
+      #else
+      static const bool value = false;
+      #endif
    };
 
 #     define BOOST_MOVE_HAS_NOTHROW_MOVE_ASSIGN(T)       boost_move_tt_is_nothrow_assignable<T, T&&>::value