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- // 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>
- using namespace boost::variant2;
- struct X
- {
- int v;
- X() = default;
- constexpr X( int v ): v( v ) {}
- constexpr operator int() const { return v; }
- };
- struct Y
- {
- int v;
- constexpr Y(): v() {}
- constexpr Y( int v ): v( v ) {}
- constexpr operator int() const { return v; }
- };
- enum E
- {
- v
- };
- #define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
- template<class V, class T, class A> constexpr T test( A const& a )
- {
- V v;
- v = a;
- return get<T>(v);
- }
- int main()
- {
- {
- constexpr variant<int> v( 1 );
- constexpr auto w = test<variant<int>, int>( v );
- STATIC_ASSERT( w == 1 );
- }
- {
- constexpr variant<X> v( 1 );
- constexpr auto w = test<variant<X>, X>( v );
- STATIC_ASSERT( w == 1 );
- }
- #if defined( BOOST_LIBSTDCXX_VERSION ) && BOOST_LIBSTDCXX_VERSION < 50000
- #else
- {
- constexpr variant<Y> v( 1 );
- constexpr auto w = test<variant<Y>, Y>( v );
- STATIC_ASSERT( w == 1 );
- }
- #endif
- {
- constexpr variant<int, float> v( 1 );
- constexpr auto w = test<variant<int, float>, int>( v );
- STATIC_ASSERT( w == 1 );
- }
- {
- constexpr variant<int, float> v( 3.0f );
- constexpr auto w = test<variant<int, float>, float>( v );
- STATIC_ASSERT( w == 3.0f );
- }
- {
- constexpr variant<int, int, float> v( 3.0f );
- constexpr auto w = test<variant<int, int, float>, float>( v );
- STATIC_ASSERT( w == 3.0f );
- }
- {
- constexpr variant<E, E, X> v( 1 );
- constexpr auto w = test<variant<E, E, X>, X>( v );
- STATIC_ASSERT( w == 1 );
- }
- {
- constexpr variant<int, int, float, float, X> v( X(1) );
- constexpr auto w = test<variant<int, int, float, float, X>, X>( v );
- STATIC_ASSERT( w == 1 );
- }
- #if defined( BOOST_LIBSTDCXX_VERSION ) && BOOST_LIBSTDCXX_VERSION < 50000
- #else
- {
- constexpr variant<E, E, Y> v( 1 );
- constexpr auto w = test<variant<E, E, Y>, Y>( v );
- STATIC_ASSERT( w == 1 );
- }
- {
- constexpr variant<int, int, float, float, Y> v( Y(1) );
- constexpr auto w = test<variant<int, int, float, float, Y>, Y>( v );
- STATIC_ASSERT( w == 1 );
- }
- #endif
- }
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