Add clang 7 to Travis, test c++2a

.travis.yml

@@ -1,4 +1,4 @@
-# Copyright 2016-2018 Peter Dimov
+# Copyright 2016-2019 Peter Dimov
 # Distributed under the Boost Software License, Version 1.0.
 # (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
 
@@ -70,7 +70,7 @@ matrix:
 
     - os: linux
       compiler: g++-8
-      env: TOOLSET=gcc COMPILER=g++-8 CXXSTD=11,14,17
+      env: TOOLSET=gcc COMPILER=g++-8 CXXSTD=11,14,17,2a
       addons:
         apt:
           packages:
@@ -80,7 +80,7 @@ matrix:
 
     - os: linux
       compiler: g++-8
-      env: UBSAN=1 TOOLSET=gcc COMPILER=g++-8 CXXSTD=11,14,17 UBSAN_OPTIONS=print_stacktrace=1 LINKFLAGS=-fuse-ld=gold
+      env: UBSAN=1 TOOLSET=gcc COMPILER=g++-8 CXXSTD=11,14,17,2a UBSAN_OPTIONS=print_stacktrace=1 LINKFLAGS=-fuse-ld=gold
       addons:
         apt:
           packages:
@@ -177,9 +177,20 @@ matrix:
             - ubuntu-toolchain-r-test
             - llvm-toolchain-trusty-6.0
 
+    - os: linux
+      compiler: clang++-7
+      env: TOOLSET=clang COMPILER=clang++-7 CXXSTD=11,14,17,2a
+      addons:
+        apt:
+          packages:
+            - clang-7
+          sources:
+            - ubuntu-toolchain-r-test
+            - llvm-toolchain-trusty-7
+
     - os: linux
       compiler: clang++-6.0
-      env: UBSAN=1 TOOLSET=clang COMPILER=clang++-6.0 CXXSTD=11,14,1z UBSAN_OPTIONS=print_stacktrace=1
+      env: UBSAN=1 TOOLSET=clang COMPILER=clang++-6.0 CXXSTD=11,14,17,2a UBSAN_OPTIONS=print_stacktrace=1
       addons:
         apt:
           packages:

doc/variant/reference.adoc

@@ -41,6 +41,9 @@ template<class T> struct variant_size<T const>: variant_size<T> {};
 template<class T> struct variant_size<T volatile>: variant_size<T> {};
 template<class T> struct variant_size<T const volatile>: variant_size<T> {};
 
+template<class T> struct variant_size<T&>: variant_size<T> {}; // extension
+template<class T> struct variant_size<T&&>: variant_size<T> {}; // extension
+
 template<class T>
   inline constexpr size_t variant_size_v = variant_size<T>::value;
 
@@ -56,6 +59,9 @@ template<size_t I, class T> struct variant_alternative<I, T const>;
 template<size_t I, class T> struct variant_alternative<I, T volatile>;
 template<size_t I, class T> struct variant_alternative<I, T const volatile>;
 
+template<size_t I, class T> struct variant_alternative<I, T&>; // extension
+template<size_t I, class T> struct variant_alternative<I, T&&>; // extension
+
 template<size_t I, class T>
   using variant_alternative_t = typename variant_alternative<I, T>::type;
 
@@ -630,6 +636,12 @@ template<size_t I, class T> struct variant_alternative<I, T volatile>;
 ```
 template<size_t I, class T> struct variant_alternative<I, T const volatile>;
 ```
+```
+template<size_t I, class T> struct variant_alternative<I, T&>; // extension
+```
+```
+template<size_t I, class T> struct variant_alternative<I, T&&>; // extension
+```
 [none]
 * {blank}
 +
@@ -639,8 +651,10 @@ If `typename variant_alternative<I, T>::type` exists and is `U`,
 * `variant_alternative<I, T const>::type` is `U const`;
 * `variant_alternative<I, T volatile>::type` is `U volatile`;
 * `variant_alternative<I, T const volatile>::type` is `U const volatile`.
+* `variant_alternative<I, T&>::type` is `U&`.
+* `variant_alternative<I, T&&>::type` is `U&&`.
 
-Otherwise, the three structs have no `type` member.
+Otherwise, these structs have no member `type`.
 --
 
 ```
@@ -651,7 +665,7 @@ template<size_t I, class... T>
 * {blank}
 +
 When `I < sizeof...(T)`, the nested type `type` is an alias for the `I`-th
-(zero-based) type in `T...`. Otherwise, there is no `type` member.
+(zero-based) type in `T...`. Otherwise, there is no member `type`.
 
 ### holds_alternative
 

test/variant_alternative.cpp

@@ -25,65 +25,130 @@ int main()
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void> volatile>, void volatile>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void> const volatile>, void const volatile>));
 
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char>&>, char&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char> const&>, char const&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char>&&>, char&&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char> const&&>, char const&&>));
+
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int>>, void>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int> const>, void const>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int> volatile>, void volatile>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int> const volatile>, void const volatile>));
 
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int>&>, char&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int> const&>, char const&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int>&&>, char&&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int> const&&>, char const&&>));
+
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int>>, int>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int> const>, int const>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int> volatile>, int volatile>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int> const volatile>, int const volatile>));
 
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int>&>, int&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int> const&>, int const&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int>&&>, int&&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int> const&&>, int const&&>));
+
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int, float>>, void>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int, float> const>, void const>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int, float> volatile>, void volatile>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int, float> const volatile>, void const volatile>));
 
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int, float>&>, char&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int, float> const&>, char const&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int, float>&&>, char&&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int, float> const&&>, char const&&>));
+
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float>>, int>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float> const>, int const>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float> volatile>, int volatile>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float> const volatile>, int const volatile>));
 
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float>&>, int&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float> const&>, int const&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float>&&>, int&&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float> const&&>, int const&&>));
+
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float>>, float>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float> const>, float const>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float> volatile>, float volatile>));
     BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float> const volatile>, float const volatile>));
 
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float>&>, float&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float> const&>, float const&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float>&&>, float&&>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float> const&&>, float const&&>));
+
     variant_alternative<0, void>();
     variant_alternative<0, void const>();
     variant_alternative<0, void volatile>();
     variant_alternative<0, void const volatile>();
 
+    variant_alternative<0, int&>();
+    variant_alternative<0, int const&>();
+    variant_alternative<0, int&&>();
+    variant_alternative<0, int const&&>();
+
     variant_alternative<0, variant<>>();
     variant_alternative<0, variant<> const>();
     variant_alternative<0, variant<> volatile>();
     variant_alternative<0, variant<> const volatile>();
 
+    variant_alternative<0, variant<>&>();
+    variant_alternative<0, variant<> const&>();
+    variant_alternative<0, variant<>&&>();
+    variant_alternative<0, variant<> const&&>();
+
     variant_alternative<1, variant<int>>();
     variant_alternative<1, variant<int> const>();
     variant_alternative<1, variant<int> volatile>();
     variant_alternative<1, variant<int> const volatile>();
 
+    variant_alternative<1, variant<int>&>();
+    variant_alternative<1, variant<int> const&>();
+    variant_alternative<1, variant<int>&&>();
+    variant_alternative<1, variant<int> const&&>();
+
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, void>));
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, void const>));
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, void volatile>));
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, void const volatile>));
 
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, int&>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, int const&>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, int&&>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, int const&&>));
+
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<>>));
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<> const>));
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<> volatile>));
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<> const volatile>));
 
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<>&>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<> const&>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<>&&>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<> const&&>));
+
     BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int>>));
     BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int> const>));
     BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int> volatile>));
     BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int> const volatile>));
 
+    BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int>&>));
+    BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int> const&>));
+    BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int>&&>));
+    BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int> const&&>));
+
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int>>));
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int> const>));
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int> volatile>));
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int> const volatile>));
 
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int>&>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int> const&>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int>&&>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int> const&&>));
+
     return boost::report_errors();
 }

test/variant_size.cpp

@@ -25,40 +25,80 @@ int main()
     BOOST_TEST_EQ( (variant_size<variant<> volatile>::value), 0 );
     BOOST_TEST_EQ( (variant_size<variant<> const volatile>::value), 0 );
 
+    BOOST_TEST_EQ( (variant_size<variant<>&>::value), 0 );
+    BOOST_TEST_EQ( (variant_size<variant<> const&>::value), 0 );
+    BOOST_TEST_EQ( (variant_size<variant<>&&>::value), 0 );
+    BOOST_TEST_EQ( (variant_size<variant<> const&&>::value), 0 );
+
     BOOST_TEST_EQ( (variant_size<variant<void>>::value), 1 );
     BOOST_TEST_EQ( (variant_size<variant<void> const>::value), 1 );
     BOOST_TEST_EQ( (variant_size<variant<void> volatile>::value), 1 );
     BOOST_TEST_EQ( (variant_size<variant<void> const volatile>::value), 1 );
 
+    BOOST_TEST_EQ( (variant_size<variant<void>&>::value), 1 );
+    BOOST_TEST_EQ( (variant_size<variant<void> const&>::value), 1 );
+    BOOST_TEST_EQ( (variant_size<variant<void>&&>::value), 1 );
+    BOOST_TEST_EQ( (variant_size<variant<void> const&&>::value), 1 );
+
     BOOST_TEST_EQ( (variant_size<variant<void, void>>::value), 2 );
     BOOST_TEST_EQ( (variant_size<variant<void, void> const>::value), 2 );
     BOOST_TEST_EQ( (variant_size<variant<void, void> volatile>::value), 2 );
     BOOST_TEST_EQ( (variant_size<variant<void, void> const volatile>::value), 2 );
 
+    BOOST_TEST_EQ( (variant_size<variant<void, void>&>::value), 2 );
+    BOOST_TEST_EQ( (variant_size<variant<void, void> const&>::value), 2 );
+    BOOST_TEST_EQ( (variant_size<variant<void, void>&&>::value), 2 );
+    BOOST_TEST_EQ( (variant_size<variant<void, void> const&&>::value), 2 );
+
     BOOST_TEST_EQ( (variant_size<variant<void, void, void>>::value), 3 );
     BOOST_TEST_EQ( (variant_size<variant<void, void, void> const>::value), 3 );
     BOOST_TEST_EQ( (variant_size<variant<void, void, void> volatile>::value), 3 );
     BOOST_TEST_EQ( (variant_size<variant<void, void, void> const volatile>::value), 3 );
 
+    BOOST_TEST_EQ( (variant_size<variant<void, void, void>&>::value), 3 );
+    BOOST_TEST_EQ( (variant_size<variant<void, void, void> const&>::value), 3 );
+    BOOST_TEST_EQ( (variant_size<variant<void, void, void>&&>::value), 3 );
+    BOOST_TEST_EQ( (variant_size<variant<void, void, void> const&&>::value), 3 );
+
     BOOST_TEST_EQ( (variant_size<variant<void, void, void, void>>::value), 4 );
     BOOST_TEST_EQ( (variant_size<variant<void, void, void, void> const>::value), 4 );
     BOOST_TEST_EQ( (variant_size<variant<void, void, void, void> volatile>::value), 4 );
     BOOST_TEST_EQ( (variant_size<variant<void, void, void, void> const volatile>::value), 4 );
 
+    BOOST_TEST_EQ( (variant_size<variant<void, void, void, void>&>::value), 4 );
+    BOOST_TEST_EQ( (variant_size<variant<void, void, void, void> const&>::value), 4 );
+    BOOST_TEST_EQ( (variant_size<variant<void, void, void, void>&&>::value), 4 );
+    BOOST_TEST_EQ( (variant_size<variant<void, void, void, void> const&&>::value), 4 );
+
     variant_size<void>();
     variant_size<void const>();
     variant_size<void volatile>();
     variant_size<void const volatile>();
 
+    variant_size<int&>();
+    variant_size<int const&>();
+    variant_size<int&&>();
+    variant_size<int const&&>();
+
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_size_t, void>));
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_size_t, void const>));
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_size_t, void volatile>));
     BOOST_TEST_TRAIT_FALSE((mp_valid<var_size_t, void const volatile>));
 
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_size_t, int&>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_size_t, int const&>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_size_t, int&&>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<var_size_t, int const&&>));
+
     BOOST_TEST_TRAIT_TRUE((mp_valid<var_size_t, variant<>>));
     BOOST_TEST_TRAIT_TRUE((mp_valid<var_size_t, variant<> const>));
     BOOST_TEST_TRAIT_TRUE((mp_valid<var_size_t, variant<> volatile>));
     BOOST_TEST_TRAIT_TRUE((mp_valid<var_size_t, variant<> const volatile>));
 
+    BOOST_TEST_TRAIT_TRUE((mp_valid<var_size_t, variant<>&>));
+    BOOST_TEST_TRAIT_TRUE((mp_valid<var_size_t, variant<> const&>));
+    BOOST_TEST_TRAIT_TRUE((mp_valid<var_size_t, variant<>&&>));
+    BOOST_TEST_TRAIT_TRUE((mp_valid<var_size_t, variant<> const&&>));
+
     return boost::report_errors();
 }