Extend g++-10 workarounds to 11

.github/workflows/ci.yml

@@ -19,18 +19,15 @@ jobs:
         include:
           - toolset: gcc-4.8
             cxxstd: "03,11"
-            os: ubuntu-16.04
+            os: ubuntu-18.04
             install: g++-4.8
-          - toolset: gcc-4.9
-            cxxstd: "03,11"
-            os: ubuntu-16.04
-            install: g++-4.9
           - toolset: gcc-5
             cxxstd: "03,11,14,1z"
-            os: ubuntu-16.04
+            os: ubuntu-18.04
+            install: g++-5
           - toolset: gcc-6
             cxxstd: "03,11,14,1z"
-            os: ubuntu-16.04
+            os: ubuntu-18.04
             install: g++-6
           - toolset: gcc-7
             cxxstd: "03,11,14,17"
@@ -38,51 +35,38 @@ jobs:
           - toolset: gcc-8
             cxxstd: "03,11,14,17,2a"
             os: ubuntu-18.04
+            install: g++-8
           - toolset: gcc-9
             cxxstd: "03,11,14,17,2a"
-            os: ubuntu-18.04
+            os: ubuntu-20.04
           - toolset: gcc-10
             cxxstd: "03,11,14,17,2a"
-            os: ubuntu-18.04
-          - toolset: clang
-            compiler: clang++-3.5
-            cxxstd: "03,11,14"
-            os: ubuntu-16.04
-            install: clang-3.5
-          - toolset: clang
-            compiler: clang++-3.6
-            cxxstd: "03,11,14"
-            os: ubuntu-16.04
-            install: clang-3.6
-          - toolset: clang
-            compiler: clang++-3.7
-            cxxstd: "03,11,14"
-            os: ubuntu-16.04
-            install: clang-3.7
-          - toolset: clang
-            compiler: clang++-3.8
-            cxxstd: "03,11,14"
-            os: ubuntu-16.04
-            install: clang-3.8
+            os: ubuntu-20.04
+            install: g++-10
+          - toolset: gcc-11
+            cxxstd: "03,11,14,17,2a"
+            os: ubuntu-20.04
+            install: g++-11
           - toolset: clang
             compiler: clang++-3.9
             cxxstd: "03,11,14"
-            os: ubuntu-16.04
+            os: ubuntu-18.04
             install: clang-3.9
           - toolset: clang
             compiler: clang++-4.0
             cxxstd: "03,11,14"
-            os: ubuntu-16.04
+            os: ubuntu-18.04
             install: clang-4.0
           - toolset: clang
             compiler: clang++-5.0
             cxxstd: "03,11,14,1z"
-            os: ubuntu-16.04
+            os: ubuntu-18.04
             install: clang-5.0
           - toolset: clang
             compiler: clang++-6.0
             cxxstd: "03,11,14,17"
             os: ubuntu-18.04
+            install: clang-6.0
           - toolset: clang
             compiler: clang++-7
             cxxstd: "03,11,14,17"
@@ -90,16 +74,29 @@ jobs:
             install: clang-7
           - toolset: clang
             compiler: clang++-8
-            cxxstd: "03,11,14,17,2a"
+            cxxstd: "03,11,14,17"
             os: ubuntu-20.04
+            install: clang-8
           - toolset: clang
             compiler: clang++-9
             cxxstd: "03,11,14,17,2a"
             os: ubuntu-20.04
+            install: clang-9
           - toolset: clang
             compiler: clang++-10
             cxxstd: "03,11,14,17,2a"
             os: ubuntu-20.04
+            install: clang-10
+          - toolset: clang
+            compiler: clang++-11
+            cxxstd: "03,11,14,17,2a"
+            os: ubuntu-20.04
+            install: clang-11
+          - toolset: clang
+            compiler: clang++-12
+            cxxstd: "03,11,14,17,2a"
+            os: ubuntu-20.04
+            install: clang-12
           - toolset: clang
             cxxstd: "03,11,14,17,2a"
             os: macos-10.15

.travis.yml

@@ -288,7 +288,7 @@ matrix:
       env: CMAKE_TEST=1
       script:
         - mkdir __build__ && cd __build__
-        - cmake -DBOOST_ENABLE_CMAKE=1 -DBoost_VERBOSE=1 -DBOOST_INCLUDE_LIBRARIES=variant2 ..
+        - cmake -DBOOST_ENABLE_CMAKE=1 -DBUILD_TESTING=ON -DBoost_VERBOSE=1 -DBOOST_INCLUDE_LIBRARIES=variant2 ..
         - ctest --output-on-failure -R boost_variant2
 
     - os: linux

README.md

@@ -1,20 +1,17 @@
-# variant2
+# Boost.Variant2
 
 This repository contains a never-valueless, strong guarantee, C++11/14/17
 implementation of [std::variant](http://en.cppreference.com/w/cpp/utility/variant).
 See [the documentation](https://www.boost.org/libs/variant2)
 for more information.
 
-The code requires [Boost.Mp11](https://github.com/boostorg/mp11) and
-Boost.Config.
-
-The library is part of Boost, starting from release 1.71, but the header
-`variant.hpp` will also work [standalone](https://godbolt.org/z/nVUNKX).
+The library is part of Boost, starting from release 1.71. It depends on
+Boost.Mp11, Boost.Config, and Boost.Assert.
 
 Supported compilers:
 
 * g++ 4.8 or later with `-std=c++11` or above
-* clang++ 3.5 or later with `-std=c++11` or above
+* clang++ 3.9 or later with `-std=c++11` or above
 * Visual Studio 2015, 2017, 2019
 
 Tested on [Travis](https://travis-ci.org/boostorg/variant2/) and

doc/variant2/changelog.adoc

@@ -1,16 +1,18 @@
 ////
 Copyright 2019-2021 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
+https://www.boost.org/LICENSE_1_0.txt
 ////
 
 [#changelog]
 # Revision History
 :idprefix: changelog_
 
+## Changes in 1.78.0
+
+* Added `<boost/variant2.hpp>`.
+* Added `unsafe_get<I>`.
+
 ## Changes in 1.76.0
 
 * Improved generated code for the double buffered case.

doc/variant2/implementation.adoc

@@ -1,10 +1,7 @@
 ////
 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
+https://www.boost.org/LICENSE_1_0.txt
 ////
 
 [#implementation]
@@ -13,13 +10,13 @@ http://www.boost.org/LICENSE_1_0.txt
 
 ## Dependencies
 
-This implementation only depends on Boost.Config and Boost.Mp11.
+This implementation only depends on Boost.Config, Boost.Assert, and Boost.Mp11.
 
 ## Supported Compilers
 
 * GCC 4.8 or later with `-std=c++11` or above
-* Clang 3.5 or later with `-std=c++11` or above
+* Clang 3.9 or later with `-std=c++11` or above
 * Visual Studio 2015, 2017, 2019
 
-Tested on https://travis-ci.org/boostorg/variant2/[Travis] and
+Tested on https://github.com/boostorg/variant2/actions[Github Actions] and
 https://ci.appveyor.com/project/pdimov/variant2-fkab9[Appveyor].

doc/variant2/reference.adoc

@@ -1,10 +1,7 @@
 ////
-Copyright 2018, 2019 Peter Dimov
-
+Copyright 2018-2021 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
+https://www.boost.org/LICENSE_1_0.txt
 ////
 
 [#reference]
@@ -117,6 +114,21 @@ template<class U, class... T>
   constexpr add_pointer_t<const U>
     get_if(const variant<T...>* v) noexcept;
 
+// unsafe_get (extension)
+
+template<size_t I, class... T>
+  constexpr variant_alternative_t<I, variant<T...>>&
+    unsafe_get(variant<T...>& v);
+template<size_t I, class... T>
+  constexpr variant_alternative_t<I, variant<T...>>&&
+    unsafe_get(variant<T...>&& v);
+template<size_t I, class... T>
+  constexpr const variant_alternative_t<I, variant<T...>>&
+    unsafe_get(const variant<T...>& v);
+template<size_t I, class... T>
+  constexpr const variant_alternative_t<I, variant<T...>>&&
+    unsafe_get(const variant<T...>&& v);
+
 // relational operators
 
 template<class... T>
@@ -775,6 +787,34 @@ Requires: :: The type `U` occurs exactly once in `T...`. Otherwise, the
 Effects:  :: Equivalent to: `return get_if<I>(v);` with `I` being
   the zero-based index of `U` in `T...`.
 
+### unsafe_get (extension)
+
+```
+template<size_t I, class... T>
+  constexpr variant_alternative_t<I, variant<T...>>&
+    unsafe_get(variant<T...>& v);
+```
+```
+template<size_t I, class... T>
+  constexpr variant_alternative_t<I, variant<T...>>&&
+    unsafe_get(variant<T...>&& v);
+```
+```
+template<size_t I, class... T>
+  constexpr const variant_alternative_t<I, variant<T...>>&
+    unsafe_get(const variant<T...>& v);
+```
+```
+template<size_t I, class... T>
+  constexpr const variant_alternative_t<I, variant<T...>>&&
+    unsafe_get(const variant<T...>&& v);
+```
+[none]
+* {blank}
++
+Requires: :: `v.index() == I`.
+Returns: :: a reference to the object stored in the variant.
+
 ### Relational Operators
 
 ```
@@ -878,3 +918,7 @@ public:
     }
 };
 ```
+
+## <boost/variant2.hpp>
+
+This convenience header includes `<boost/variant2/variant.hpp>`.

include/boost/variant2.hpp

@@ -0,0 +1,10 @@
+#ifndef BOOST_VARIANT2_HPP_INCLUDED
+#define BOOST_VARIANT2_HPP_INCLUDED
+
+// Copyright 2021 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/variant2/variant.hpp>
+
+#endif // #ifndef BOOST_VARIANT2_HPP_INCLUDED

include/boost/variant2/variant.hpp

@@ -13,19 +13,18 @@
 # pragma warning( disable: 4521 4522 ) // multiple copy operators
 #endif
 
-#ifndef BOOST_MP11_HPP_INCLUDED
 #include <boost/mp11.hpp>
-#endif
+#include <boost/assert.hpp>
 #include <boost/config.hpp>
 #include <boost/detail/workaround.hpp>
 #include <boost/cstdint.hpp>
 #include <cstddef>
 #include <type_traits>
 #include <exception>
-#include <cassert>
 #include <initializer_list>
 #include <utility>
 #include <functional> // std::hash
+#include <cstdint>
 
 //
 
@@ -38,6 +37,8 @@ BOOST_NORETURN void throw_exception( std::exception const & e ); // user defined
 
 #endif
 
+template<class T> struct hash;
+
 namespace variant2
 {
 
@@ -364,37 +365,50 @@ template<std::size_t I, class... T> constexpr variant_alternative_t<I, variant<T
 #endif
 }
 
-// detail::unsafe_get (for visit)
+// unsafe_get
 
-namespace detail
-{
+#if !defined(BOOST_NO_CXX14_CONSTEXPR)
+# define BOOST_VARIANT2_CX14_ASSERT(expr) BOOST_ASSERT(expr);
+#else
+# define BOOST_VARIANT2_CX14_ASSERT(expr)
+#endif
 
 template<std::size_t I, class... T> constexpr variant_alternative_t<I, variant<T...>>& unsafe_get(variant<T...>& v)
 {
     static_assert( I < sizeof...(T), "Index out of bounds" );
+
+    BOOST_VARIANT2_CX14_ASSERT( v.index() == I )
+
     return v._get_impl( mp11::mp_size_t<I>() );
 }
 
 template<std::size_t I, class... T> constexpr variant_alternative_t<I, variant<T...>>&& unsafe_get(variant<T...>&& v)
 {
     static_assert( I < sizeof...(T), "Index out of bounds" );
+
+    BOOST_VARIANT2_CX14_ASSERT( v.index() == I )
+
     return std::move( v._get_impl( mp11::mp_size_t<I>() ) );
 }
 
 template<std::size_t I, class... T> constexpr variant_alternative_t<I, variant<T...>> const& unsafe_get(variant<T...> const& v)
 {
     static_assert( I < sizeof...(T), "Index out of bounds" );
+
+    BOOST_VARIANT2_CX14_ASSERT( v.index() == I )
+
     return v._get_impl( mp11::mp_size_t<I>() );
 }
 
 template<std::size_t I, class... T> constexpr variant_alternative_t<I, variant<T...>> const&& unsafe_get(variant<T...> const&& v)
 {
     static_assert( I < sizeof...(T), "Index out of bounds" );
+
+    BOOST_VARIANT2_CX14_ASSERT( v.index() == I )
+
     return std::move( v._get_impl( mp11::mp_size_t<I>() ) );
 }
 
-} // namespace detail
-
 // get (type)
 
 template<class U, class... T> constexpr U& get(variant<T...>& v)
@@ -854,7 +868,7 @@ template<class... T> struct variant_base_impl<true, true, T...>
     {
         size_t const J = I+1;
 
-        assert( ix_ == J );
+        BOOST_ASSERT( ix_ == J );
 
         return st_.get( mp11::mp_size_t<J>() );
     }
@@ -862,7 +876,8 @@ template<class... T> struct variant_base_impl<true, true, T...>
     template<std::size_t I> constexpr mp11::mp_at_c<variant<T...>, I> const& _get_impl( mp11::mp_size_t<I> ) const noexcept
     {
         // size_t const J = I+1;
-        // assert( ix_ == I+1 );
+
+        BOOST_VARIANT2_CX14_ASSERT( ix_ == I+1 )
 
         return st_.get( mp11::mp_size_t<I+1>() );
     }
@@ -922,7 +937,7 @@ template<class... T> struct variant_base_impl<true, false, T...>
 
     template<std::size_t I> BOOST_CXX14_CONSTEXPR mp11::mp_at_c<variant<T...>, I>& _get_impl( mp11::mp_size_t<I> ) noexcept
     {
-        assert( index() == I );
+        BOOST_ASSERT( index() == I );
 
         size_t const J = I+1;
 
@@ -932,7 +947,8 @@ template<class... T> struct variant_base_impl<true, false, T...>
 
     template<std::size_t I> constexpr mp11::mp_at_c<variant<T...>, I> const& _get_impl( mp11::mp_size_t<I> ) const noexcept
     {
-        // assert( index() == I );
+        BOOST_VARIANT2_CX14_ASSERT( index() == I )
+
         // size_t const J = I+1;
         // constexpr mp_size_t<J> j{};
 
@@ -1010,7 +1026,7 @@ template<class... T> struct variant_base_impl<false, true, T...>
     {
         size_t const J = I+1;
 
-        assert( ix_ == J );
+        BOOST_ASSERT( ix_ == J );
 
         return st_.get( mp11::mp_size_t<J>() );
     }
@@ -1018,7 +1034,8 @@ template<class... T> struct variant_base_impl<false, true, T...>
     template<std::size_t I> constexpr mp11::mp_at_c<variant<T...>, I> const& _get_impl( mp11::mp_size_t<I> ) const noexcept
     {
         // size_t const J = I+1;
-        // assert( ix_ == J );
+
+        BOOST_VARIANT2_CX14_ASSERT( ix_ == I+1 )
 
         return st_.get( mp11::mp_size_t<I+1>() );
     }
@@ -1134,7 +1151,7 @@ template<class... T> struct variant_base_impl<false, false, T...>
 
     template<std::size_t I> BOOST_CXX14_CONSTEXPR mp11::mp_at_c<variant<T...>, I>& _get_impl( mp11::mp_size_t<I> ) noexcept
     {
-        assert( index() == I );
+        BOOST_ASSERT( index() == I );
 
         size_t const J = I+1;
 
@@ -1144,7 +1161,8 @@ template<class... T> struct variant_base_impl<false, false, T...>
 
     template<std::size_t I> constexpr mp11::mp_at_c<variant<T...>, I> const& _get_impl( mp11::mp_size_t<I> ) const noexcept
     {
-        // assert( index() == I );
+        BOOST_VARIANT2_CX14_ASSERT( index() == I )
+
         // size_t const J = I+1;
         // constexpr mp_size_t<J> j{};
 
@@ -2173,7 +2191,7 @@ template<class R = detail::deduced, class F, class V1, class V2, class... V> con
 {
     return mp11::mp_with_index<detail::variant_base_size<V1>>( v1.index(), [&]( auto I ){
 
-        auto f2 = [&]( auto&&... a ){ return std::forward<F>(f)( detail::unsafe_get<I.value>( std::forward<V1>(v1) ), std::forward<decltype(a)>(a)... ); };
+        auto f2 = [&]( auto&&... a ){ return std::forward<F>(f)( unsafe_get<I.value>( std::forward<V1>(v1) ), std::forward<decltype(a)>(a)... ); };
         return visit<R>( f2, std::forward<V2>(v2), std::forward<V>(v)... );
 
     });
@@ -2195,31 +2213,59 @@ void swap( variant<T...> & v, variant<T...> & w )
 namespace detail
 {
 
-template<class V> struct hash_value_L
+inline std::size_t hash_value_impl_( mp11::mp_true, std::size_t index, std::size_t value )
+{
+    boost::ulong_long_type hv = ( boost::ulong_long_type( 0xCBF29CE4 ) << 32 ) + 0x84222325;
+    boost::ulong_long_type const prime = ( boost::ulong_long_type( 0x00000100 ) << 32 ) + 0x000001B3;
+
+    hv ^= index;
+    hv *= prime;
+
+    hv ^= value;
+    hv *= prime;
+
+    return static_cast<std::size_t>( hv );
+}
+
+inline std::size_t hash_value_impl_( mp11::mp_false, std::size_t index, std::size_t value )
+{
+    std::size_t hv = 0x811C9DC5;
+    std::size_t const prime = 0x01000193;
+
+    hv ^= index;
+    hv *= prime;
+
+    hv ^= value;
+    hv *= prime;
+
+    return hv;
+}
+
+inline std::size_t hash_value_impl( std::size_t index, std::size_t value )
+{
+    return hash_value_impl_( mp11::mp_bool< (SIZE_MAX > UINT32_MAX) >(), index, value );
+}
+
+template<template<class> class H, class V> struct hash_value_L
 {
     V const & v;
 
     template<class I> std::size_t operator()( I ) const
     {
-        boost::ulong_long_type hv = ( boost::ulong_long_type( 0xCBF29CE4 ) << 32 ) + 0x84222325;
-        boost::ulong_long_type const prime = ( boost::ulong_long_type( 0x00000100 ) << 32 ) + 0x000001B3;
-
-        // index
-
-        hv ^= I::value;
-        hv *= prime;
-
-        // value
-
         auto const & t = unsafe_get<I::value>( v );
 
-        hv ^= std::hash<remove_cv_ref_t<decltype(t)>>()( t );
-        hv *= prime;
+        std::size_t index = I::value;
+        std::size_t value = H<remove_cv_ref_t<decltype(t)>>()( t );
 
-        return static_cast<std::size_t>( hv );
+        return hash_value_impl( index, value );
     }
 };
 
+template<class... T> std::size_t hash_value_std( variant<T...> const & v )
+{
+    return mp11::mp_with_index<sizeof...(T)>( v.index(), detail::hash_value_L< std::hash, variant<T...> >{ v } );
+}
+
 } // namespace detail
 
 inline std::size_t hash_value( monostate const & )
@@ -2229,7 +2275,7 @@ inline std::size_t hash_value( monostate const & )
 
 template<class... T> std::size_t hash_value( variant<T...> const & v )
 {
-    return mp11::mp_with_index<sizeof...(T)>( v.index(), detail::hash_value_L< variant<T...> >{ v } );
+    return mp11::mp_with_index<sizeof...(T)>( v.index(), detail::hash_value_L< boost::hash, variant<T...> >{ v } );
 }
 
 namespace detail
@@ -2250,7 +2296,7 @@ template<class V> struct std_hash_impl<V, true>
 {
     std::size_t operator()( V const & v ) const
     {
-        return hash_value( v );
+        return detail::hash_value_std( v );
     }
 };
 
@@ -2276,6 +2322,8 @@ template<> struct hash< ::boost::variant2::monostate >
 
 } // namespace std
 
+#undef BOOST_VARIANT2_CX14_ASSERT
+
 #if defined(_MSC_VER) && _MSC_VER < 1910
 # pragma warning( pop )
 #endif

test/quick.cpp

@@ -1,10 +1,8 @@
-
 // Copyright 2019 Peter Dimov.
-//
 // Distributed under the Boost Software License, Version 1.0.
-// http://www.boost.org/LICENSE_1_0.txt
+// https://www.boost.org/LICENSE_1_0.txt
 
-#include <boost/variant2/variant.hpp>
+#include <boost/variant2.hpp>
 
 using namespace boost::variant2;
 

test/variant_hash.cpp

@@ -12,6 +12,7 @@
 #include <boost/core/lightweight_test_trait.hpp>
 #include <boost/container_hash/hash.hpp>
 #include <boost/config/workaround.hpp>
+#include <vector>
 
 using namespace boost::variant2;
 
@@ -47,7 +48,17 @@ template<template<class...> class Hash, class T> void test2()
     BOOST_TEST_NE( h2, h3 );
 }
 
-struct X {};
+struct X
+{
+    int m = 0;
+};
+
+std::size_t hash_value( X const& x )
+{
+    return boost::hash<int>()( x.m );
+}
+
+struct Y {}; // no hash support
 
 int main()
 {
@@ -57,6 +68,8 @@ int main()
     test<boost::hash, monostate, monostate, monostate>();
     test<boost::hash, int, int, float>();
 
+    test<boost::hash, monostate, X, std::vector<X>>();
+
     test2<std::hash, int>();
     test2<std::hash, float>();
 
@@ -65,7 +78,7 @@ int main()
 
 #if !BOOST_WORKAROUND(BOOST_MSVC, < 1910) && ( !defined(_LIBCPP_STD_VER) || _LIBCPP_STD_VER > 11 )
 
-    BOOST_TEST_TRAIT_FALSE(( detail::is_hash_enabled<X> ));
+    BOOST_TEST_TRAIT_FALSE(( detail::is_hash_enabled<Y> ));
 
 #endif
 

test/variant_in_place_index_construct_cx.cpp

@@ -105,9 +105,9 @@ int main()
         STATIC_ASSERT( v.index() == 4 );
     }
 
-#if BOOST_WORKAROUND(BOOST_GCC, >= 100000 && BOOST_GCC < 110000)
+#if BOOST_WORKAROUND(BOOST_GCC, >= 100000 && BOOST_GCC < 120000)
 
-    // no idea why this fails on g++ 10
+    // no idea why this fails on g++ 10/11
 
 #else
 

test/variant_in_place_type_construct_cx.cpp

@@ -102,9 +102,9 @@ int main()
         STATIC_ASSERT( holds_alternative<X>(v) );
     }
 
-#if BOOST_WORKAROUND(BOOST_GCC, >= 100000 && BOOST_GCC < 110000)
+#if BOOST_WORKAROUND(BOOST_GCC, >= 100000 && BOOST_GCC < 120000)
 
-    // no idea why this fails on g++ 10
+    // no idea why this fails on g++ 10/11
 
 #else