From a5d68e52e6d65b4942a6cdfefeac61517f4fc67b Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Thu, 3 Feb 2022 18:35:42 +0200
Subject: [PATCH] Add throw_exception_from_error overload for std::error_code

---
 include/boost/system/result.hpp |  6 ++++++
 test/result_value_access.cpp    | 35 ++++++++++++++++++++++++++++++++-
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/include/boost/system/result.hpp b/include/boost/system/result.hpp
index 4e809b1..4872c7e 100644
--- a/include/boost/system/result.hpp
+++ b/include/boost/system/result.hpp
@@ -16,6 +16,7 @@
 #include <type_traits>
 #include <utility>
 #include <iosfwd>
+#include <system_error>
 
 //
 
@@ -31,6 +32,11 @@ BOOST_NORETURN BOOST_NOINLINE inline void throw_exception_from_error( error_code
     boost::throw_exception( system_error( e ) );
 }
 
+BOOST_NORETURN BOOST_NOINLINE inline void throw_exception_from_error( std::error_code const & e )
+{
+    boost::throw_exception( std::system_error( e ) );
+}
+
 // in_place_*
 
 using in_place_value_t = variant2::in_place_index_t<0>;
diff --git a/test/result_value_access.cpp b/test/result_value_access.cpp
index fdd92ac..02eccb7 100644
--- a/test/result_value_access.cpp
+++ b/test/result_value_access.cpp
@@ -1,10 +1,11 @@
-// Copyright 2017, 2021 Peter Dimov.
+// Copyright 2017, 2021, 2022 Peter Dimov.
 // Distributed under the Boost Software License, Version 1.0.
 // https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/system/result.hpp>
 #include <boost/core/lightweight_test.hpp>
 #include <boost/core/lightweight_test_trait.hpp>
+#include <system_error>
 
 using namespace boost::system;
 
@@ -165,6 +166,22 @@ int main()
         BOOST_TEST_EQ( result<int>( ec ).operator->(), static_cast<int*>(0) );
     }
 
+    {
+        auto ec = make_error_code( std::errc::invalid_argument );
+
+        result<int, std::error_code> const r( ec );
+
+        BOOST_TEST( !r.has_value() );
+        BOOST_TEST( r.has_error() );
+
+        BOOST_TEST_NOT( r );
+        BOOST_TEST( !r );
+
+        BOOST_TEST_THROWS( r.value(), std::system_error );
+
+        BOOST_TEST_EQ( r.operator->(), static_cast<int*>(0) );
+    }
+
     {
         result<X> r( 1 );
 
@@ -341,5 +358,21 @@ int main()
         BOOST_TEST_EQ( result<void>( ec ).operator->(), static_cast<void*>(0) );
     }
 
+    {
+        auto ec = make_error_code( std::errc::invalid_argument );
+
+        result<void, std::error_code> const r( ec );
+
+        BOOST_TEST( !r.has_value() );
+        BOOST_TEST( r.has_error() );
+
+        BOOST_TEST_NOT( r );
+        BOOST_TEST( !r );
+
+        BOOST_TEST_THROWS( r.value(), std::system_error );
+
+        BOOST_TEST_EQ( r.operator->(), static_cast<void*>(0) );
+    }
+
     return boost::report_errors();
 }