Do not trivially copy/move assign when not trivially copy/move constructible

include/boost/variant2/variant.hpp

@@ -1201,7 +1201,7 @@ public:
 
     // assignment
     template<class E1 = void,
-        class E2 = mp11::mp_if<mp11::mp_all<std::is_trivially_destructible<T>..., detail::is_trivially_copy_assignable<T>...>, E1>
+        class E2 = mp11::mp_if<mp11::mp_all<std::is_trivially_destructible<T>..., detail::is_trivially_copy_constructible<T>..., detail::is_trivially_copy_assignable<T>...>, E1>
     >
     BOOST_CXX14_CONSTEXPR variant& operator=( variant const & r ) noexcept
     {
@@ -1232,7 +1232,7 @@ private:
 public:
 
     template<class E1 = void,
-        class E2 = mp11::mp_if<mp11::mp_not<mp11::mp_all<std::is_trivially_destructible<T>..., detail::is_trivially_copy_assignable<T>...>>, E1>,
+        class E2 = mp11::mp_if<mp11::mp_not<mp11::mp_all<std::is_trivially_destructible<T>..., detail::is_trivially_copy_constructible<T>..., detail::is_trivially_copy_assignable<T>...>>, E1>,
         class E3 = mp11::mp_if<mp11::mp_all<std::is_copy_constructible<T>..., std::is_copy_assignable<T>...>, E1>
     >
     BOOST_CXX14_CONSTEXPR variant& operator=( variant const & r )
@@ -1243,7 +1243,7 @@ public:
     }
 
     template<class E1 = void,
-        class E2 = mp11::mp_if<mp11::mp_all<std::is_trivially_destructible<T>..., detail::is_trivially_move_assignable<T>...>, E1>
+        class E2 = mp11::mp_if<mp11::mp_all<std::is_trivially_destructible<T>..., detail::is_trivially_move_constructible<T>..., detail::is_trivially_move_assignable<T>...>, E1>
     >
     BOOST_CXX14_CONSTEXPR variant& operator=( variant && r ) noexcept
     {
@@ -1274,7 +1274,7 @@ private:
 public:
 
     template<class E1 = void,
-        class E2 = mp11::mp_if<mp11::mp_not<mp11::mp_all<std::is_trivially_destructible<T>..., detail::is_trivially_move_assignable<T>...>>, E1>,
+        class E2 = mp11::mp_if<mp11::mp_not<mp11::mp_all<std::is_trivially_destructible<T>..., detail::is_trivially_move_constructible<T>..., detail::is_trivially_move_assignable<T>...>>, E1>,
         class E3 = mp11::mp_if<mp11::mp_all<std::is_move_constructible<T>..., std::is_move_assignable<T>...>, E1>
     >
     variant& operator=( variant && r )

test/Jamfile

@@ -68,3 +68,6 @@ run variant_valueless.cpp ;
 run variant_copy_construct_throw.cpp ;
 run variant_move_construct_throw.cpp ;
 run variant_convert_construct_throw.cpp ;
+
+run variant_copy_assign_throw.cpp ;
+run variant_move_assign_throw.cpp ;

test/variant_copy_assign_throw.cpp

@@ -0,0 +1,51 @@
+
+// Copyright 2019 Peter Dimov
+//
+// Distributed under the Boost Software License, Version 1.0.
+//
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/variant2/variant.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <stdexcept>
+
+using namespace boost::variant2;
+
+struct Y1
+{
+    Y1(){} // =default fails on msvc-14.0
+
+    Y1(Y1 const&)
+    {
+        throw std::runtime_error( "Y1(Y1 const&)" );
+    }
+
+    Y1& operator=(Y1 const&) = default;
+};
+
+struct Y2
+{
+    Y2(){}
+
+    Y2(Y2 const&)
+    {
+        throw std::runtime_error( "Y2(Y2 const&)" );
+    }
+
+    Y2& operator=(Y2 const&) = default;
+};
+
+void test()
+{
+    variant<Y1, Y2> v1( in_place_type_t<Y1>{} );
+    variant<Y1, Y2> v2( in_place_type_t<Y2>{} );
+
+    BOOST_TEST_THROWS( v1 = v2, std::runtime_error )
+}
+
+int main()
+{
+    test();
+    return boost::report_errors();
+}

test/variant_move_assign_throw.cpp

@@ -0,0 +1,51 @@
+
+// Copyright 2019 Peter Dimov
+//
+// Distributed under the Boost Software License, Version 1.0.
+//
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/variant2/variant.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <stdexcept>
+
+using namespace boost::variant2;
+
+struct Y1
+{
+    Y1(){} // =default fails on msvc-14.0
+
+    Y1(Y1&&)
+    {
+        throw std::runtime_error( "Y1(Y1&&)" );
+    }
+
+    Y1& operator=(Y1&&) = default;
+};
+
+struct Y2
+{
+    Y2(){}
+
+    Y2(Y2&&)
+    {
+        throw std::runtime_error( "Y2(Y2&&)" );
+    }
+
+    Y2& operator=(Y2&&) = default;
+};
+
+void test()
+{
+    variant<Y1, Y2> v1( in_place_type_t<Y1>{} );
+    variant<Y1, Y2> v2( in_place_type_t<Y2>{} );
+
+    BOOST_TEST_THROWS( v1 = std::move( v2 ), std::runtime_error )
+}
+
+int main()
+{
+    test();
+    return boost::report_errors();
+}