From ae76223babe2e088ef444f8d39494d99e3fa3f28 Mon Sep 17 00:00:00 2001
From: jzmaddock <john@johnmaddock.co.uk>
Date: Thu, 11 Jun 2015 11:26:33 +0100
Subject: [PATCH] Move trivial/nothrow construct traits closer into line with
 the standard.

---
 .../type_traits/has_trivial_move_constructor.hpp    |  8 ++++++++
 .../type_traits/is_nothrow_move_constructible.hpp   | 13 +++++--------
 test/has_trivial_move_constructor_test.cpp          | 12 ++++++------
 test/is_nothrow_move_constructible_test.cpp         |  6 +++---
 4 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/include/boost/type_traits/has_trivial_move_constructor.hpp b/include/boost/type_traits/has_trivial_move_constructor.hpp
index 1a032a9..e37dfe3 100644
--- a/include/boost/type_traits/has_trivial_move_constructor.hpp
+++ b/include/boost/type_traits/has_trivial_move_constructor.hpp
@@ -48,6 +48,14 @@ template <> struct has_trivial_move_constructor<void const> : public false_type{
 template <> struct has_trivial_move_constructor<void volatile> : public false_type{};
 template <> struct has_trivial_move_constructor<void const volatile> : public false_type{};
 #endif
+// What should we do with reference types??? The standard seems to suggest these are trivial, even if the thing they reference is not:
+template <class T> struct has_trivial_move_constructor<T&> : public true_type{};
+#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
+template <class T> struct has_trivial_move_constructor<T&&> : public true_type{};
+#endif
+// Arrays can not be explicitly copied:
+template <class T, std::size_t N> struct has_trivial_move_constructor<T[N]> : public false_type{};
+template <class T> struct has_trivial_move_constructor<T[]> : public false_type{};
 
 } // namespace boost
 
diff --git a/include/boost/type_traits/is_nothrow_move_constructible.hpp b/include/boost/type_traits/is_nothrow_move_constructible.hpp
index 323f443..4b7a71b 100644
--- a/include/boost/type_traits/is_nothrow_move_constructible.hpp
+++ b/include/boost/type_traits/is_nothrow_move_constructible.hpp
@@ -24,10 +24,6 @@ struct is_nothrow_move_constructible : public integral_constant<bool, BOOST_IS_N
 
 template <class T> struct is_nothrow_move_constructible<volatile T> : public ::boost::false_type {};
 template <class T> struct is_nothrow_move_constructible<const volatile T> : public ::boost::false_type{};
-template <class T> struct is_nothrow_move_constructible<T&> : public ::boost::false_type{};
-#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
-template <class T> struct is_nothrow_move_constructible<T&&> : public ::boost::false_type{};
-#endif
 
 #elif !defined(BOOST_NO_CXX11_NOEXCEPT) && !defined(BOOST_NO_SFINAE_EXPR)
 
@@ -53,10 +49,6 @@ template <class T> struct is_nothrow_move_constructible
 
 template <class T> struct is_nothrow_move_constructible<volatile T> : public ::boost::false_type {};
 template <class T> struct is_nothrow_move_constructible<const volatile T> : public ::boost::false_type{};
-template <class T> struct is_nothrow_move_constructible<T&> : public ::boost::false_type{};
-#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
-template <class T> struct is_nothrow_move_constructible<T&&> : public ::boost::false_type{};
-#endif
 
 #else
 
@@ -80,6 +72,11 @@ template <> struct is_nothrow_move_constructible<void const> : false_type{};
 template <> struct is_nothrow_move_constructible<void volatile> : false_type{};
 template <> struct is_nothrow_move_constructible<void const volatile> : false_type{};
 #endif
+// References are always trivially constructible, even if the thing they reference is not:
+template <class T> struct is_nothrow_move_constructible<T&> : public ::boost::true_type{};
+#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
+template <class T> struct is_nothrow_move_constructible<T&&> : public ::boost::true_type{};
+#endif
 
 } // namespace boost
 
diff --git a/test/has_trivial_move_constructor_test.cpp b/test/has_trivial_move_constructor_test.cpp
index 1071f1b..c34c834 100644
--- a/test/has_trivial_move_constructor_test.cpp
+++ b/test/has_trivial_move_constructor_test.cpp
@@ -210,14 +210,14 @@ BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<mp>::value, tru
 BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<cmf>::value, true);
 BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<enum_UDT>::value, true);
 
-BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<int&>::value, false);
+BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<int&>::value, true);
 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
-BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<int&&>::value, false);
+BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<int&&>::value, true);
 #endif
-BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<const int&>::value, false);
-BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<int[2]>::value, true);
-BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<int[3][2]>::value, true);
-BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<int[2][4][5][6][3]>::value, true);
+BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<const int&>::value, true);
+BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<int[2]>::value, false);
+BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<int[3][2]>::value, false);
+BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<int[2][4][5][6][3]>::value, false);
 BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<UDT>::value, false);
 BOOST_CHECK_INTEGRAL_CONSTANT(::tt::has_trivial_move_constructor<void>::value, false);
 // cases we would like to succeed but can't implement in the language:
diff --git a/test/is_nothrow_move_constructible_test.cpp b/test/is_nothrow_move_constructible_test.cpp
index a15cacf..7a196ed 100644
--- a/test/is_nothrow_move_constructible_test.cpp
+++ b/test/is_nothrow_move_constructible_test.cpp
@@ -182,11 +182,11 @@ BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_move_constructible<mp>::value, tr
 BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_move_constructible<cmf>::value, true);
 BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_move_constructible<enum_UDT>::value, true);
 
-BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_move_constructible<int&>::value, false);
+BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_move_constructible<int&>::value, true);
 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
-BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_move_constructible<int&&>::value, false);
+BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_move_constructible<int&&>::value, true);
 #endif
-BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_move_constructible<const int&>::value, false);
+BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_move_constructible<const int&>::value, true);
 BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_move_constructible<int[2]>::value, false);
 BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_move_constructible<int[3][2]>::value, false);
 BOOST_CHECK_INTEGRAL_CONSTANT(::tt::is_nothrow_move_constructible<int[2][4][5][6][3]>::value, false);