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File variant.patch of Package boost

commit 33784034b70a6607c9413633375e84912213a123
Author: Pawel Dac <pawel.dac@gmail.com>
Date:   Tue Nov 7 17:49:15 2017 +0100

Perfect forwarding for passing visitor in apply_visitor.
    
    Allows to catch Visitor&&, Visitor& and const Visitor&.
    
    Removed apply_visitor with const Visitor& since it was catching inlined Visitors&&.
    Passing const Visitor to result_wrapper resulted in compilation error when Visitor was mutable.

commit 03035b2f6b5d48d82270725f6eb52968180a2c64
Author: Antony Polukhin <antoshkka@gmail.com>
Date:   Thu Jul 23 15:28:07 2020 +0300

Fix wrong usage of boost::move (fixes #53, #82)

Index: boost_1_66_0/boost/variant/detail/apply_visitor_unary.hpp
===================================================================
--- boost_1_66_0.orig/boost/variant/detail/apply_visitor_unary.hpp
+++ boost_1_66_0/boost/variant/detail/apply_visitor_unary.hpp
@@ -155,9 +155,9 @@ struct result_wrapper1
 {
     typedef decltype(result_multideduce1<Visitor, Variant>::deduce()) result_type;
 
-    Visitor& visitor_;
-    explicit result_wrapper1(Visitor& visitor) BOOST_NOEXCEPT
-        : visitor_(visitor)
+    Visitor&& visitor_;
+    explicit result_wrapper1(Visitor&& visitor) BOOST_NOEXCEPT
+        : visitor_(::boost::forward<Visitor>(visitor))
     {}
 
     template <class T>
@@ -169,26 +169,15 @@ struct result_wrapper1
 }} // namespace detail::variant
 
 template <typename Visitor, typename Visitable>
-inline decltype(auto) apply_visitor(Visitor& visitor, Visitable&& visitable,
+inline decltype(auto) apply_visitor(Visitor&& visitor, Visitable&& visitable,
     typename boost::disable_if<
         boost::detail::variant::has_result_type<Visitor>
     >::type* = 0)
 {
-    boost::detail::variant::result_wrapper1<Visitor, typename remove_reference<Visitable>::type> cpp14_vis(visitor);
+    boost::detail::variant::result_wrapper1<Visitor, typename remove_reference<Visitable>::type> cpp14_vis(::boost::forward<Visitor>(visitor));
     return ::boost::forward<Visitable>(visitable).apply_visitor(cpp14_vis);
 }
 
-template <typename Visitor, typename Visitable>
-inline decltype(auto) apply_visitor(const Visitor& visitor, Visitable&& visitable,
-    typename boost::disable_if<
-        boost::detail::variant::has_result_type<Visitor>
-    >::type* = 0)
-{
-    boost::detail::variant::result_wrapper1<const Visitor, typename remove_reference<Visitable>::type> cpp14_vis(visitor);
-    return ::boost::forward<Visitable>(visitable).apply_visitor(cpp14_vis);
-}
-
-
 #endif // !defined(BOOST_NO_CXX14_DECLTYPE_AUTO) && !defined(BOOST_NO_CXX11_DECLTYPE_N3276)
 
 } // namespace boost
Index: boost_1_66_0/libs/variant/test/const_ref_apply_visitor.cpp
===================================================================
--- boost_1_66_0.orig/libs/variant/test/const_ref_apply_visitor.cpp
+++ boost_1_66_0/libs/variant/test/const_ref_apply_visitor.cpp
@@ -190,6 +190,13 @@ void test_cpp14_visitor(const variant_ty
     BOOST_CHECK(boost::apply_visitor([](auto&& v) { return lvalue_rvalue_detector()(FORWARD(v)); }, test_var) == "lvalue reference");
 }
 
+void test_cpp14_mutable_visitor(const variant_type& test_var)
+{
+    std::cout << "Testing const lvalue visitable for c++14 with inline mutable lambda\n";
+
+    BOOST_CHECK(boost::apply_visitor([](auto&& v) mutable -> auto { return lvalue_rvalue_detector()(FORWARD(v)); }, test_var) == "lvalue reference");
+}
+
 void test_cpp14_visitor(const variant_type& test_var, const variant_type& test_var2)
 {
     std::cout << "Testing const lvalue visitable for c++14\n";
@@ -329,6 +336,7 @@ void run_cpp14_tests()
     variant_type v1(10), v2(20), v3(30);
 
     test_cpp14_visitor(v1);
+    test_cpp14_mutable_visitor(v1);
     test_cpp14_visitor(v2, v3);
     test_cpp14_visitor(v1, v2, v3);
 
Index: boost_1_66_0/boost/variant/variant.hpp
===================================================================
--- boost_1_66_0.orig/boost/variant/variant.hpp
+++ boost_1_66_0/boost/variant/variant.hpp
@@ -1048,7 +1048,7 @@ public: // internal visitor interfaces
     template <typename T>
     typename enable_if_c<MoveSemantics && is_same<T, T>::value, result_type>::type internal_visit(T&& operand, int)
     {
-        return visitor_(::boost::move<T>(operand));
+        return visitor_(::boost::move(operand));
     }
 
     //using workaround with is_same<T, T> to prenvent compilation error, because we need to use T in enable_if to make SFINAE work

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File variant.patch of Package boost

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