From 2357f4d2f4511b41a7f868d19295555da1d4f930 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@pdimov.com>
Date: Tue, 30 May 2017 16:57:48 +0300
Subject: [PATCH] Add test/variant_in_place_index_construct(_cx)

---
 include/boost/variant2/variant.hpp           |  23 +++-
 test/Jamfile                                 |   2 +
 test/variant_in_place_index_construct.cpp    | 124 +++++++++++++++++++
 test/variant_in_place_index_construct_cx.cpp | 116 +++++++++++++++++
 4 files changed, 264 insertions(+), 1 deletion(-)
 create mode 100644 test/variant_in_place_index_construct.cpp
 create mode 100644 test/variant_in_place_index_construct_cx.cpp

diff --git a/include/boost/variant2/variant.hpp b/include/boost/variant2/variant.hpp
index bb44f3d..7b62e81 100644
--- a/include/boost/variant2/variant.hpp
+++ b/include/boost/variant2/variant.hpp
@@ -592,12 +592,32 @@ template<class T> struct in_place_type_t
 {
 };
 
+template<class T> constexpr in_place_type_t<T> in_place_type{};
+
+namespace detail
+{
+
+template<class T> struct is_in_place_type: std::false_type {};
+template<class T> struct is_in_place_type<in_place_type_t<T>>: std::true_type {};
+
+} // namespace detail
+
 // in_place_index_t
 
 template<std::size_t I> struct in_place_index_t
 {
 };
 
+template<std::size_t I> constexpr in_place_index_t<I> in_place_index{};
+
+namespace detail
+{
+
+template<class T> struct is_in_place_index: std::false_type {};
+template<std::size_t I> struct is_in_place_index<in_place_index_t<I>>: std::true_type {};
+
+} // namespace detail
+
 // variant
 
 template<class... T> class variant: private variant2::detail::variant_base<T...>
@@ -643,7 +663,8 @@ public:
     }
 
     template<class U,
-        class E1 = std::enable_if_t<!std::is_same<std::decay_t<U>, variant>::value>,
+        class Ud = std::decay_t<U>,
+        class E1 = std::enable_if_t< !std::is_same<Ud, variant>::value && !variant2::detail::is_in_place_index<Ud>::value && !variant2::detail::is_in_place_type<Ud>::value >,
         class V = variant2::detail::resolve_overload_type<U&&, T...>,
         class E2 = std::enable_if_t<std::is_constructible<V, U>::value>
         >
diff --git a/test/Jamfile b/test/Jamfile
index 9495081..2c89a2f 100644
--- a/test/Jamfile
+++ b/test/Jamfile
@@ -25,3 +25,5 @@ run variant_copy_construct.cpp : : : $(REQ) ;
 run variant_move_construct.cpp : : : $(REQ) ;
 run variant_value_construct.cpp : : : $(REQ) ;
 compile variant_value_construct_cx.cpp : : : $(REQ) ;
+run variant_in_place_index_construct.cpp : : : $(REQ) ;
+compile variant_in_place_index_construct_cx.cpp : : : $(REQ) ;
diff --git a/test/variant_in_place_index_construct.cpp b/test/variant_in_place_index_construct.cpp
new file mode 100644
index 0000000..8f6c58f
--- /dev/null
+++ b/test/variant_in_place_index_construct.cpp
@@ -0,0 +1,124 @@
+
+// Copyright 2017 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
+
+#include <boost/variant2/variant.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <type_traits>
+#include <utility>
+#include <string>
+
+using namespace boost::variant2;
+
+struct X
+{
+	X() = default;
+	X( in_place_index_t<0> ) = delete;
+};
+
+int main()
+{
+    {
+        variant<int> v( in_place_index<0> );
+
+        BOOST_TEST_EQ( v.index(), 0 );
+        BOOST_TEST_EQ( get<0>(v), 0 );
+    }
+
+    {
+        variant<X> v( in_place_index<0> );
+
+        BOOST_TEST_EQ( v.index(), 0 );
+    }
+
+    {
+        variant<int> v( in_place_index<0>, 1 );
+
+        BOOST_TEST_EQ( v.index(), 0 );
+        BOOST_TEST_EQ( get<0>(v), 1 );
+    }
+
+    {
+        variant<int, float> v( in_place_index<0> );
+
+        BOOST_TEST_EQ( v.index(), 0 );
+        BOOST_TEST_EQ( get<0>(v), 0 );
+    }
+
+    {
+        variant<int, float> v( in_place_index<0>, 1 );
+
+        BOOST_TEST_EQ( v.index(), 0 );
+        BOOST_TEST_EQ( get<0>(v), 1 );
+    }
+
+    {
+        variant<int, float> v( in_place_index<1> );
+
+        BOOST_TEST_EQ( v.index(), 1 );
+        BOOST_TEST_EQ( get<1>(v), 0 );
+    }
+
+    {
+        variant<int, float> v( in_place_index<1>, 3.14f );
+
+        BOOST_TEST_EQ( v.index(), 1 );
+        BOOST_TEST_EQ( get<1>(v), 3.14f );
+    }
+
+    {
+        variant<int, int, float, float, std::string, std::string> v( in_place_index<0>, 1 );
+
+        BOOST_TEST_EQ( v.index(), 0 );
+        BOOST_TEST_EQ( get<0>(v), 1 );
+    }
+
+    {
+        variant<int, int, float, float, std::string, std::string> v( in_place_index<1>, 1 );
+
+        BOOST_TEST_EQ( v.index(), 1 );
+        BOOST_TEST_EQ( get<1>(v), 1 );
+    }
+
+    {
+        variant<int, int, float, float, std::string, std::string> v( in_place_index<2>, 3.14f );
+
+        BOOST_TEST_EQ( v.index(), 2 );
+        BOOST_TEST_EQ( get<2>(v), 3.14f );
+    }
+
+    {
+        variant<int, int, float, float, std::string, std::string> v( in_place_index<3>, 3.14f );
+
+        BOOST_TEST_EQ( v.index(), 3 );
+        BOOST_TEST_EQ( get<3>(v), 3.14f );
+    }
+
+    {
+        variant<int, int, float, float, std::string, std::string> v( in_place_index<4>, "text" );
+
+        BOOST_TEST_EQ( v.index(), 4 );
+        BOOST_TEST_EQ( get<4>(v), std::string("text") );
+    }
+
+    {
+        variant<int, int, float, float, std::string, std::string> v( in_place_index<5>, "text" );
+
+        BOOST_TEST_EQ( v.index(), 5 );
+        BOOST_TEST_EQ( get<5>(v), std::string("text") );
+    }
+
+    {
+        variant<int, int, float, float, std::string, std::string> v( in_place_index<5>, 4, 'a' );
+
+        BOOST_TEST_EQ( v.index(), 5 );
+        BOOST_TEST_EQ( get<5>(v), std::string( 4, 'a' ) );
+    }
+
+    return boost::report_errors();
+}
diff --git a/test/variant_in_place_index_construct_cx.cpp b/test/variant_in_place_index_construct_cx.cpp
new file mode 100644
index 0000000..e9c771f
--- /dev/null
+++ b/test/variant_in_place_index_construct_cx.cpp
@@ -0,0 +1,116 @@
+
+// Copyright 2017 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
+
+#include <boost/variant2/variant.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <type_traits>
+#include <utility>
+#include <string>
+
+using namespace boost::variant2;
+
+struct X
+{
+    constexpr X() = default;
+    constexpr explicit X(int, int) {}
+    X( in_place_index_t<0> ) = delete;
+};
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+
+int main()
+{
+    {
+        constexpr variant<int> v( in_place_index<0> );
+
+        STATIC_ASSERT( v.index() == 0 );
+        STATIC_ASSERT( get<0>(v) == 0 );
+    }
+
+    {
+        constexpr variant<X> v( in_place_index<0> );
+
+        STATIC_ASSERT( v.index() == 0 );
+    }
+
+    {
+        constexpr variant<int> v( in_place_index<0>, 1 );
+
+        STATIC_ASSERT( v.index() == 0 );
+        STATIC_ASSERT( get<0>(v) == 1 );
+    }
+
+    {
+        constexpr variant<int, float> v( in_place_index<0> );
+
+        STATIC_ASSERT( v.index() == 0 );
+        STATIC_ASSERT( get<0>(v) == 0 );
+    }
+
+    {
+        constexpr variant<int, float> v( in_place_index<0>, 1 );
+
+        STATIC_ASSERT( v.index() == 0 );
+        STATIC_ASSERT( get<0>(v) == 1 );
+    }
+
+    {
+        constexpr variant<int, float> v( in_place_index<1> );
+
+        STATIC_ASSERT( v.index() == 1 );
+        STATIC_ASSERT( get<1>(v) == 0 );
+    }
+
+    {
+        constexpr variant<int, float> v( in_place_index<1>, 3.14f );
+
+        STATIC_ASSERT( v.index() == 1 );
+        STATIC_ASSERT( get<1>(v) == 3.14f );
+    }
+
+    {
+        constexpr variant<int, int, float, float, X, X> v( in_place_index<0>, 1 );
+
+        STATIC_ASSERT( v.index() == 0 );
+        STATIC_ASSERT( get<0>(v) == 1 );
+    }
+
+    {
+        constexpr variant<int, int, float, float, X, X> v( in_place_index<1>, 1 );
+
+        STATIC_ASSERT( v.index() == 1 );
+        STATIC_ASSERT( get<1>(v) == 1 );
+    }
+
+    {
+        constexpr variant<int, int, float, float, X, X> v( in_place_index<2>, 3.14f );
+
+        STATIC_ASSERT( v.index() == 2 );
+        STATIC_ASSERT( get<2>(v) == 3.14f );
+    }
+
+    {
+        constexpr variant<int, int, float, float, X, X> v( in_place_index<3>, 3.14f );
+
+        STATIC_ASSERT( v.index() == 3 );
+        STATIC_ASSERT( get<3>(v) == 3.14f );
+    }
+
+    {
+        constexpr variant<int, int, float, float, X, X> v( in_place_index<4> );
+
+        STATIC_ASSERT( v.index() == 4 );
+    }
+
+    {
+        constexpr variant<int, int, float, float, X, X> v( in_place_index<5>, 0, 0 );
+
+        STATIC_ASSERT( v.index() == 5 );
+    }
+}