Add missing include

.github/workflows/ci.yml

@@ -110,7 +110,7 @@ jobs:
             install: clang-14
           - toolset: clang
             cxxstd: "03,11,14,17,2a"
-            os: macos-10.15
+            os: macos-11
 
     runs-on: ${{matrix.os}}
 
@@ -220,7 +220,7 @@ jobs:
           - os: ubuntu-18.04
           - os: ubuntu-20.04
           - os: ubuntu-22.04
-          - os: macos-10.15
+          - os: macos-11
 
     runs-on: ${{matrix.os}}
 
@@ -267,7 +267,7 @@ jobs:
           - os: ubuntu-18.04
           - os: ubuntu-20.04
           - os: ubuntu-22.04
-          - os: macos-10.15
+          - os: macos-11
 
     runs-on: ${{matrix.os}}
 
@@ -324,7 +324,7 @@ jobs:
           - os: ubuntu-18.04
           - os: ubuntu-20.04
           - os: ubuntu-22.04
-          - os: macos-10.15
+          - os: macos-11
 
     runs-on: ${{matrix.os}}
 

include/boost/system/detail/error_code.hpp

@@ -29,6 +29,7 @@
 #include <boost/assert/source_location.hpp>
 #include <boost/cstdint.hpp>
 #include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
 #include <ostream>
 #include <new>
 #include <cstdio>
@@ -114,7 +115,10 @@ public:
 
     // constructors:
 
-    BOOST_SYSTEM_CONSTEXPR error_code() BOOST_NOEXCEPT:
+#if !BOOST_WORKAROUND(BOOST_GCC, < 40800)
+    BOOST_CONSTEXPR
+#endif
+    error_code() BOOST_NOEXCEPT:
         d1_(), lc_flags_( 0 )
     {
     }

include/boost/system/result.hpp

@@ -135,7 +135,8 @@ public:
     template<class... A, class En = typename std::enable_if<
         std::is_constructible<T, A...>::value &&
         !(detail::is_errc_t<A...>::value && std::is_arithmetic<T>::value) &&
-        !std::is_constructible<E, A...>::value
+        !std::is_constructible<E, A...>::value &&
+        sizeof...(A) >= 1
         >::type>
     explicit constexpr result( A&&... a )
         noexcept( std::is_nothrow_constructible<T, A...>::value )
@@ -146,7 +147,8 @@ public:
     // explicit, error
     template<class... A, class En2 = void, class En = typename std::enable_if<
         !std::is_constructible<T, A...>::value &&
-        std::is_constructible<E, A...>::value
+        std::is_constructible<E, A...>::value &&
+        sizeof...(A) >= 1
         >::type>
     explicit constexpr result( A&&... a )
         noexcept( std::is_nothrow_constructible<E, A...>::value )
@@ -220,7 +222,7 @@ public:
 
     constexpr bool has_error() const noexcept
     {
-        return v_.index() != 0;
+        return v_.index() == 1;
     }
 
     constexpr explicit operator bool() const noexcept
@@ -509,7 +511,7 @@ public:
 
     constexpr bool has_error() const noexcept
     {
-        return v_.index() != 0;
+        return v_.index() == 1;
     }
 
     constexpr explicit operator bool() const noexcept

test/CMakeLists.txt

@@ -124,6 +124,8 @@ boost_test(TYPE run SOURCES std_interop_test14.cpp)
 boost_test(TYPE run SOURCES ec_location_test3.cpp)
 boost_test(TYPE run SOURCES ec_location_test4.cpp)
 
+boost_test(TYPE compile SOURCES constexpr_test2.cpp)
+
 # result
 
 set(BOOST_TEST_COMPILE_FEATURES cxx_std_11)

test/Jamfile.v2

@@ -152,6 +152,8 @@ run std_interop_test14.cpp ;
 run ec_location_test3.cpp ;
 run ec_location_test4.cpp ;
 
+compile constexpr_test2.cpp ;
+
 # result
 
 import ../../config/checks/config : requires ;

test/constexpr_test2.cpp

@@ -0,0 +1,26 @@
+// Copyright 2022 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/system/error_code.hpp>
+#include <boost/config.hpp>
+#include <boost/config/pragma_message.hpp>
+
+#if defined(BOOST_GCC) && BOOST_GCC >= 40700 && BOOST_GCC < 40800
+
+BOOST_PRAGMA_MESSAGE("Skipping test, BOOST_GCC is 407xx")
+
+#else
+
+struct X
+{
+    boost::system::error_code ec;
+};
+
+X const& f()
+{
+    BOOST_STATIC_CONSTEXPR X x;
+    return x;
+}
+
+#endif

test/result_default_construct.cpp

@@ -12,6 +12,11 @@ struct X
 {
 };
 
+struct Y
+{
+    Y( int );
+};
+
 int main()
 {
     {
@@ -37,5 +42,17 @@ int main()
         BOOST_TEST( !r.has_error() );
     }
 
+    {
+        BOOST_TEST_TRAIT_TRUE((std::is_default_constructible<result<int>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_default_constructible<result<int, int>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_default_constructible<result<X>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_default_constructible<result<X, int>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_default_constructible<result<void>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_default_constructible<result<void, int>>));
+
+        BOOST_TEST_TRAIT_FALSE((std::is_default_constructible<result<Y>>));
+        BOOST_TEST_TRAIT_FALSE((std::is_default_constructible<result<Y, int>>));
+    }
+
     return boost::report_errors();
 }