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#include <iostream>
#include <vector>

///
// expected - An implementation of std::expected with extensions
// Written in 2017 by Sy Brand (tartanllama@gmail.com, @TartanLlama)
//
// Documentation available at http://tl.tartanllama.xyz/
//
// To the extent possible under law, the author(s) have dedicated all
// copyright and related and neighboring rights to this software to the
// public domain worldwide. This software is distributed without any warranty.
//
// You should have received a copy of the CC0 Public Domain Dedication
// along with this software. If not, see
// <http://creativecommons.org/publicdomain/zero/1.0/>.
///

#ifndef TL_EXPECTED_HPP
#define TL_EXPECTED_HPP

#define TL_EXPECTED_VERSION_MAJOR 1
#define TL_EXPECTED_VERSION_MINOR 1
#define TL_EXPECTED_VERSION_PATCH 0

#include <exception>
#include <functional>
#include <type_traits>
#include <utility>

#if defined(__EXCEPTIONS) || defined(_CPPUNWIND)
#define TL_EXPECTED_EXCEPTIONS_ENABLED
#endif

#if (defined(_MSC_VER) && _MSC_VER == 1900)
#define TL_EXPECTED_MSVC2015
#define TL_EXPECTED_MSVC2015_CONSTEXPR
#else
#define TL_EXPECTED_MSVC2015_CONSTEXPR constexpr
#endif

#if (defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ <= 9 && \
 !defined(__clang__))
#define TL_EXPECTED_GCC49
#endif

#if (defined(__GNUC__) && __GNUC__ == 5 && __GNUC_MINOR__ <= 4 && \
 !defined(__clang__))
#define TL_EXPECTED_GCC54
#endif

#if (defined(__GNUC__) && __GNUC__ == 5 && __GNUC_MINOR__ <= 5 && \
 !defined(__clang__))
#define TL_EXPECTED_GCC55
#endif

#if !defined(TL_ASSERT)
//can't have assert in constexpr in C++11 and GCC 4.9 has a compiler bug
#if (__cplusplus > 201103L) && !defined(TL_EXPECTED_GCC49)
#include <cassert>
#define TL_ASSERT(x) assert(x)
#else 
#define TL_ASSERT(x)
#endif
#endif

#if (defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ <= 9 && \
 !defined(__clang__))
// GCC < 5 doesn't support overloading on const&& for member functions

#define TL_EXPECTED_NO_CONSTRR
// GCC < 5 doesn't support some standard C++11 type traits
#define TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T) \
 std::has_trivial_copy_constructor<T>
#define TL_EXPECTED_IS_TRIVIALLY_COPY_ASSIGNABLE(T) \
 std::has_trivial_copy_assign<T>

// This one will be different for GCC 5.7 if it's ever supported
#define TL_EXPECTED_IS_TRIVIALLY_DESTRUCTIBLE(T) \
 std::is_trivially_destructible<T>

// GCC 5 < v < 8 has a bug in is_trivially_copy_constructible which breaks
// std::vector for non-copyable types
#elif (defined(__GNUC__) && __GNUC__ < 8 && !defined(__clang__))
#ifndef TL_GCC_LESS_8_TRIVIALLY_COPY_CONSTRUCTIBLE_MUTEX
#define TL_GCC_LESS_8_TRIVIALLY_COPY_CONSTRUCTIBLE_MUTEX
namespace tl {
namespace detail {
template <class T>
struct is_trivially_copy_constructible
 : std::is_trivially_copy_constructible<T> {};
#ifdef _GLIBCXX_VECTOR
template <class T, class A>
struct is_trivially_copy_constructible<std::vector<T, A>> : std::false_type {};
#endif
} // namespace detail
} // namespace tl
#endif

#define TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T) \
 tl::detail::is_trivially_copy_constructible<T>
#define TL_EXPECTED_IS_TRIVIALLY_COPY_ASSIGNABLE(T) \
 std::is_trivially_copy_assignable<T>
#define TL_EXPECTED_IS_TRIVIALLY_DESTRUCTIBLE(T) \
 std::is_trivially_destructible<T>
#else
#define TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T) \
 std::is_trivially_copy_constructible<T>
#define TL_EXPECTED_IS_TRIVIALLY_COPY_ASSIGNABLE(T) \
 std::is_trivially_copy_assignable<T>
#define TL_EXPECTED_IS_TRIVIALLY_DESTRUCTIBLE(T) \
 std::is_trivially_destructible<T>
#endif

#if __cplusplus > 201103L
#define TL_EXPECTED_CXX14
#endif

#ifdef TL_EXPECTED_GCC49
#define TL_EXPECTED_GCC49_CONSTEXPR
#else
#define TL_EXPECTED_GCC49_CONSTEXPR constexpr
#endif

#if (__cplusplus == 201103L || defined(TL_EXPECTED_MSVC2015) ||                \
     defined(TL_EXPECTED_GCC49))
#define TL_EXPECTED_11_CONSTEXPR
#else
#define TL_EXPECTED_11_CONSTEXPR constexpr
#endif

namespace tl {
template <class T, class E> class expected;

#ifndef TL_MONOSTATE_INPLACE_MUTEX
#define TL_MONOSTATE_INPLACE_MUTEX
class monostate {};

struct in_place_t {
  explicit in_place_t() = default;
};
static constexpr in_place_t in_place{};
#endif

template <class E> class unexpected {
public:
 static_assert(!std::is_same<E, void>::value, "E must not be void");

unexpected() = delete;
  constexpr explicit unexpected(const E &e) : m_val(e) {}

constexpr explicit unexpected(E &&e) : m_val(std::move(e)) {}

template <class... Args, typename std::enable_if<std::is_constructible<
 E, Args &&...>::value>::type * = nullptr>
 constexpr explicit unexpected(Args &&...args)
 : m_val(std::forward<Args>(args)...) {}
 template <
 class U, class... Args,
 typename std::enable_if<std::is_constructible<
 E, std::initializer_list &, Args &&...>::value>::type * = nullptr>
 constexpr explicit unexpected(std::initializer_list l, Args &&...args)
 : m_val(l, std::forward<Args>(args)...) {}

constexpr const E &value() const & { return m_val; }
  TL_EXPECTED_11_CONSTEXPR E &value() & { return m_val; }
  TL_EXPECTED_11_CONSTEXPR E &&value() && { return std::move(m_val); }
  constexpr const E &&value() const && { return std::move(m_val); }

private:
  E m_val;
};

#ifdef __cpp_deduction_guides
template <class E> unexpected(E) -> unexpected<E>;
#endif

template <class E>
constexpr bool operator==(const unexpected<E> &lhs, const unexpected<E> &rhs) {
 return lhs.value() == rhs.value();
}
template <class E>
constexpr bool operator!=(const unexpected<E> &lhs, const unexpected<E> &rhs) {
 return lhs.value() != rhs.value();
}
template <class E>
constexpr bool operator<(const unexpected<E> &lhs, const unexpected<E> &rhs) {
 return lhs.value() < rhs.value();
}
template <class E>
constexpr bool operator<=(const unexpected<E> &lhs, const unexpected<E> &rhs) {
 return lhs.value() <= rhs.value();
}
template <class E>
constexpr bool operator>(const unexpected<E> &lhs, const unexpected<E> &rhs) {
 return lhs.value() > rhs.value();
}
template <class E>
constexpr bool operator>=(const unexpected<E> &lhs, const unexpected<E> &rhs) {
 return lhs.value() >= rhs.value();
}

template <class E>
unexpected<typename std::decay<E>::type> make_unexpected(E &&e) {
 return unexpected<typename std::decay<E>::type>(std::forward<E>(e));
}

struct unexpect_t {
  unexpect_t() = default;
};
static constexpr unexpect_t unexpect{};

namespace detail {
template <typename E>
[[noreturn]] TL_EXPECTED_11_CONSTEXPR void throw_exception(E &&e) {
#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
 throw std::forward<E>(e);
#else
 (void)e;
#ifdef _MSC_VER
 __assume(0);
#else
 __builtin_unreachable();
#endif
#endif
}

#ifndef TL_TRAITS_MUTEX
#define TL_TRAITS_MUTEX
// C++14-style aliases for brevity
template <class T> using remove_const_t = typename std::remove_const<T>::type;
template <class T>
using remove_reference_t = typename std::remove_reference<T>::type;
template <class T> using decay_t = typename std::decay<T>::type;
template <bool E, class T = void>
using enable_if_t = typename std::enable_if<E, T>::type;
template <bool B, class T, class F>
using conditional_t = typename std::conditional<B, T, F>::type;

// std::conjunction from C++17
template <class...> struct conjunction : std::true_type {};
template <class B> struct conjunction : B {};
template <class B, class... Bs>
struct conjunction<B, Bs...>
 : std::conditional<bool(B::value), conjunction<Bs...>, B>::type {};

#if defined(_LIBCPP_VERSION) && __cplusplus == 201103L
#define TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND
#endif

// In C++11 mode, there's an issue in libc++'s std::mem_fn
// which results in a hard-error when using it in a noexcept expression
// in some cases. This is a check to workaround the common failing case.
#ifdef TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND
template <class T>
struct is_pointer_to_non_const_member_func : std::false_type {};
template <class T, class Ret, class... Args>
struct is_pointer_to_non_const_member_func<Ret (T::*)(Args...)>
 : std::true_type {};
template <class T, class Ret, class... Args>
struct is_pointer_to_non_const_member_func<Ret (T::*)(Args...) &>
 : std::true_type {};
template <class T, class Ret, class... Args>
struct is_pointer_to_non_const_member_func<Ret (T::*)(Args...) &&>
 : std::true_type {};
template <class T, class Ret, class... Args>
struct is_pointer_to_non_const_member_func<Ret (T::*)(Args...) volatile>
 : std::true_type {};
template <class T, class Ret, class... Args>
struct is_pointer_to_non_const_member_func<Ret (T::*)(Args...) volatile &>
 : std::true_type {};
template <class T, class Ret, class... Args>
struct is_pointer_to_non_const_member_func<Ret (T::*)(Args...) volatile &&>
 : std::true_type {};

template <class T> struct is_const_or_const_ref : std::false_type {};
template <class T> struct is_const_or_const_ref<T const &> : std::true_type {};
template <class T> struct is_const_or_const_ref<T const> : std::true_type {};
#endif

// std::invoke from C++17
// https://stackoverflow.com/questions/38288042/c11-14-invoke-workaround
template <
 typename Fn, typename... Args,
#ifdef TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND
 typename = enable_if_t<!(is_pointer_to_non_const_member_func<Fn>::value &&
 is_const_or_const_ref<Args...>::value)>,
#endif
 typename = enable_if_t<std::is_member_pointer<decay_t<Fn>>::value>, int = 0>
constexpr auto invoke(Fn &&f, Args &&...args) noexcept(
 noexcept(std::mem_fn(f)(std::forward<Args>(args)...)))
 -> decltype(std::mem_fn(f)(std::forward<Args>(args)...)) {
 return std::mem_fn(f)(std::forward<Args>(args)...);
}

template <typename Fn, typename... Args,
 typename = enable_if_t<!std::is_member_pointer<decay_t<Fn>>::value>>
constexpr auto invoke(Fn &&f, Args &&...args) noexcept(
 noexcept(std::forward<Fn>(f)(std::forward<Args>(args)...)))
 -> decltype(std::forward<Fn>(f)(std::forward<Args>(args)...)) {
 return std::forward<Fn>(f)(std::forward<Args>(args)...);
}

// std::invoke_result from C++17
template <class F, class, class... Us> struct invoke_result_impl;

template <class F, class... Us>
struct invoke_result_impl<
 F,
 decltype(detail::invoke(std::declval<F>(), std::declval<Us>()...), void()),
 Us...> {
 using type =
 decltype(detail::invoke(std::declval<F>(), std::declval<Us>()...));
};

template <class F, class... Us>
using invoke_result = invoke_result_impl<F, void, Us...>;

template <class F, class... Us>
using invoke_result_t = typename invoke_result<F, Us...>::type;

#if defined(_MSC_VER) && _MSC_VER <= 1900
// TODO make a version which works with MSVC 2015
template <class T, class U = T> struct is_swappable : std::true_type {};

template <class T, class U = T> struct is_nothrow_swappable : std::true_type {};
#else
// https://stackoverflow.com/questions/26744589/what-is-a-proper-way-to-implement-is-swappable-to-test-for-the-swappable-concept
namespace swap_adl_tests {
// if swap ADL finds this then it would call std::swap otherwise (same
// signature)
struct tag {};

template <class T> tag swap(T &, T &);
template <class T, std::size_t N> tag swap(T (&a)[N], T (&b)[N]);

// helper functions to test if an unqualified swap is possible, and if it
// becomes std::swap
template <class, class> std::false_type can_swap(...) noexcept(false);
template <class T, class U,
 class = decltype(swap(std::declval<T &>(), std::declval()))>
std::true_type can_swap(int) noexcept(noexcept(swap(std::declval<T &>(),
 std::declval())));

template <class, class> std::false_type uses_std(...);
template <class T, class U>
std::is_same<decltype(swap(std::declval<T &>(), std::declval())), tag>
uses_std(int);

template <class T>
struct is_std_swap_noexcept
 : std::integral_constant<bool,
 std::is_nothrow_move_constructible<T>::value &&
 std::is_nothrow_move_assignable<T>::value> {};

template <class T, std::size_t N>
struct is_std_swap_noexcept<T[N]> : is_std_swap_noexcept<T> {};

template <class T, class U>
struct is_adl_swap_noexcept
 : std::integral_constant<bool, noexcept(can_swap<T, U>(0))> {};
} // namespace swap_adl_tests

template <class T, class U = T>
struct is_swappable
 : std::integral_constant<
 bool,
 decltype(detail::swap_adl_tests::can_swap<T, U>(0))::value &&
 (!decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value ||
 (std::is_move_assignable<T>::value &&
 std::is_move_constructible<T>::value))> {};

template <class T, std::size_t N>
struct is_swappable<T[N], T[N]>
 : std::integral_constant<
 bool,
 decltype(detail::swap_adl_tests::can_swap<T[N], T[N]>(0))::value &&
 (!decltype(detail::swap_adl_tests::uses_std<T[N], T[N]>(
 0))::value ||
 is_swappable<T, T>::value)> {};

template <class T, class U = T>
struct is_nothrow_swappable
 : std::integral_constant<
 bool,
 is_swappable<T, U>::value &&
 ((decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value &&
 detail::swap_adl_tests::is_std_swap_noexcept<T>::value) ||
 (!decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value &&
 detail::swap_adl_tests::is_adl_swap_noexcept<T, U>::value))> {};
#endif
#endif

// Trait for checking if a type is a tl::expected
template <class T> struct is_expected_impl : std::false_type {};
template <class T, class E>
struct is_expected_impl<expected<T, E>> : std::true_type {};
template <class T> using is_expected = is_expected_impl<decay_t<T>>;

template <class T, class E, class U>
using expected_enable_forward_value = detail::enable_if_t<
 std::is_constructible<T, U &&>::value &&
 !std::is_same<detail::decay_t, in_place_t>::value &&
 !std::is_same<expected<T, E>, detail::decay_t>::value &&
 !std::is_same<unexpected<E>, detail::decay_t>::value>;

template <class T, class E, class U, class G, class UR, class GR>
using expected_enable_from_other = detail::enable_if_t<
 std::is_constructible<T, UR>::value &&
 std::is_constructible<E, GR>::value &&
 !std::is_constructible<T, expected<U, G> &>::value &&
 !std::is_constructible<T, expected<U, G> &&>::value &&
 !std::is_constructible<T, const expected<U, G> &>::value &&
 !std::is_constructible<T, const expected<U, G> &&>::value &&
 !std::is_convertible<expected<U, G> &, T>::value &&
 !std::is_convertible<expected<U, G> &&, T>::value &&
 !std::is_convertible<const expected<U, G> &, T>::value &&
 !std::is_convertible<const expected<U, G> &&, T>::value>;

template <class T, class U>
using is_void_or = conditional_t<std::is_void<T>::value, std::true_type, U>;

template <class T>
using is_copy_constructible_or_void =
 is_void_or<T, std::is_copy_constructible<T>>;

template <class T>
using is_move_constructible_or_void =
 is_void_or<T, std::is_move_constructible<T>>;

template <class T>
using is_copy_assignable_or_void = is_void_or<T, std::is_copy_assignable<T>>;

template <class T>
using is_move_assignable_or_void = is_void_or<T, std::is_move_assignable<T>>;

} // namespace detail

namespace detail {
struct no_init_t {};
static constexpr no_init_t no_init{};

// Implements the storage of the values, and ensures that the destructor is
// trivial if it can be.
//
// This specialization is for where neither `T` or `E` is trivially
// destructible, so the destructors must be called on destruction of the
// `expected`
template <class T, class E, bool = std::is_trivially_destructible<T>::value,
 bool = std::is_trivially_destructible<E>::value>
struct expected_storage_base {
 constexpr expected_storage_base() : m_val(T{}), m_has_val(true) {}
 constexpr expected_storage_base(no_init_t) : m_no_init(), m_has_val(false) {}

template <class... Args,
 detail::enable_if_t<std::is_constructible<T, Args &&...>::value> * =
 nullptr>
 constexpr expected_storage_base(in_place_t, Args &&...args)
 : m_val(std::forward<Args>(args)...), m_has_val(true) {}

template <class U, class... Args,
 detail::enable_if_t<std::is_constructible<
 T, std::initializer_list &, Args &&...>::value> * = nullptr>
 constexpr expected_storage_base(in_place_t, std::initializer_list il,
 Args &&...args)
 : m_val(il, std::forward<Args>(args)...), m_has_val(true) {}
 template <class... Args,
 detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
 nullptr>
 constexpr explicit expected_storage_base(unexpect_t, Args &&...args)
 : m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}

template <class U, class... Args,
 detail::enable_if_t<std::is_constructible<
 E, std::initializer_list &, Args &&...>::value> * = nullptr>
 constexpr explicit expected_storage_base(unexpect_t,
 std::initializer_list il,
 Args &&...args)
 : m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}

~expected_storage_base() {
 if (m_has_val) {
 m_val.~T();
 } else {
 m_unexpect.~unexpected<E>();
 }
 }
 union {
 T m_val;
 unexpected<E> m_unexpect;
 char m_no_init;
 };
 bool m_has_val;
};

// This specialization is for when both `T` and `E` are trivially-destructible,
// so the destructor of the `expected` can be trivial.
template <class T, class E> struct expected_storage_base<T, E, true, true> {
 constexpr expected_storage_base() : m_val(T{}), m_has_val(true) {}
 constexpr expected_storage_base(no_init_t) : m_no_init(), m_has_val(false) {}

~expected_storage_base() = default;
 union {
 T m_val;
 unexpected<E> m_unexpect;
 char m_no_init;
 };
 bool m_has_val;
};

// T is trivial, E is not.
template <class T, class E> struct expected_storage_base<T, E, true, false> {
 constexpr expected_storage_base() : m_val(T{}), m_has_val(true) {}
 TL_EXPECTED_MSVC2015_CONSTEXPR expected_storage_base(no_init_t)
 : m_no_init(), m_has_val(false) {}

~expected_storage_base() {
 if (!m_has_val) {
 m_unexpect.~unexpected<E>();
 }
 }

union {
 T m_val;
 unexpected<E> m_unexpect;
 char m_no_init;
 };
 bool m_has_val;
};

// E is trivial, T is not.
template <class T, class E> struct expected_storage_base<T, E, false, true> {
 constexpr expected_storage_base() : m_val(T{}), m_has_val(true) {}
 constexpr expected_storage_base(no_init_t) : m_no_init(), m_has_val(false) {}

~expected_storage_base() {
 if (m_has_val) {
 m_val.~T();
 }
 }
 union {
 T m_val;
 unexpected<E> m_unexpect;
 char m_no_init;
 };
 bool m_has_val;
};

// `T` is `void`, `E` is trivially-destructible
template <class E> struct expected_storage_base<void, E, false, true> {
 #if __GNUC__ <= 5
 //no constexpr for GCC 4/5 bug
 #else
 TL_EXPECTED_MSVC2015_CONSTEXPR
 #endif 
 expected_storage_base() : m_has_val(true) {}
 
 constexpr expected_storage_base(no_init_t) : m_val(), m_has_val(false) {}

constexpr expected_storage_base(in_place_t) : m_has_val(true) {}

template <class... Args,
 detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
 nullptr>
 constexpr explicit expected_storage_base(unexpect_t, Args &&...args)
 : m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}

~expected_storage_base() = default;
 struct dummy {};
 union {
 unexpected<E> m_unexpect;
 dummy m_val;
 };
 bool m_has_val;
};

// `T` is `void`, `E` is not trivially-destructible
template <class E> struct expected_storage_base<void, E, false, false> {
 constexpr expected_storage_base() : m_dummy(), m_has_val(true) {}
 constexpr expected_storage_base(no_init_t) : m_dummy(), m_has_val(false) {}

constexpr expected_storage_base(in_place_t) : m_dummy(), m_has_val(true) {}

~expected_storage_base() {
 if (!m_has_val) {
 m_unexpect.~unexpected<E>();
 }
 }

union {
 unexpected<E> m_unexpect;
 char m_dummy;
 };
 bool m_has_val;
};

// This base class provides some handy member functions which can be used in
// further derived classes
template <class T, class E>
struct expected_operations_base : expected_storage_base<T, E> {
 using expected_storage_base<T, E>::expected_storage_base;

template <class... Args> void construct(Args &&...args) noexcept {
 new (std::addressof(this->m_val)) T(std::forward<Args>(args)...);
 this->m_has_val = true;
 }

template <class Rhs> void construct_with(Rhs &&rhs) noexcept {
 new (std::addressof(this->m_val)) T(std::forward<Rhs>(rhs).get());
 this->m_has_val = true;
 }

template <class... Args> void construct_error(Args &&...args) noexcept {
 new (std::addressof(this->m_unexpect))
 unexpected<E>(std::forward<Args>(args)...);
 this->m_has_val = false;
 }

#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED

// These assign overloads ensure that the most efficient assignment
 // implementation is used while maintaining the strong exception guarantee.
 // The problematic case is where rhs has a value, but *this does not.
 //
 // This overload handles the case where we can just copy-construct `T`
 // directly into place without throwing.
 template <class U = T,
 detail::enable_if_t<std::is_nothrow_copy_constructible::value>
 * = nullptr>
 void assign(const expected_operations_base &rhs) noexcept {
 if (!this->m_has_val && rhs.m_has_val) {
 geterr().~unexpected<E>();
 construct(rhs.get());
 } else {
 assign_common(rhs);
 }
 }

// This overload handles the case where we can attempt to create a copy of
 // `T`, then no-throw move it into place if the copy was successful.
 template <class U = T,
 detail::enable_if_t<!std::is_nothrow_copy_constructible::value &&
 std::is_nothrow_move_constructible::value>
 * = nullptr>
 void assign(const expected_operations_base &rhs) noexcept {
 if (!this->m_has_val && rhs.m_has_val) {
 T tmp = rhs.get();
 geterr().~unexpected<E>();
 construct(std::move(tmp));
 } else {
 assign_common(rhs);
 }
 }

// This overload is the worst-case, where we have to move-construct the
 // unexpected value into temporary storage, then try to copy the T into place.
 // If the construction succeeds, then everything is fine, but if it throws,
 // then we move the old unexpected value back into place before rethrowing the
 // exception.
 template <class U = T,
 detail::enable_if_t<!std::is_nothrow_copy_constructible::value &&
 !std::is_nothrow_move_constructible::value>
 * = nullptr>
 void assign(const expected_operations_base &rhs) {
 if (!this->m_has_val && rhs.m_has_val) {
 auto tmp = std::move(geterr());
 geterr().~unexpected<E>();

#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
      try {
        construct(rhs.get());
      } catch (...) {
        geterr() = std::move(tmp);
        throw;
      }
#else
      construct(rhs.get());
#endif
    } else {
      assign_common(rhs);
    }
  }

// These overloads do the same as above, but for rvalues
 template <class U = T,
 detail::enable_if_t<std::is_nothrow_move_constructible::value>
 * = nullptr>
 void assign(expected_operations_base &&rhs) noexcept {
 if (!this->m_has_val && rhs.m_has_val) {
 geterr().~unexpected<E>();
 construct(std::move(rhs).get());
 } else {
 assign_common(std::move(rhs));
 }
 }

template <class U = T,
 detail::enable_if_t<!std::is_nothrow_move_constructible::value>
 * = nullptr>
 void assign(expected_operations_base &&rhs) {
 if (!this->m_has_val && rhs.m_has_val) {
 auto tmp = std::move(geterr());
 geterr().~unexpected<E>();
#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
 try {
 construct(std::move(rhs).get());
 } catch (...) {
 geterr() = std::move(tmp);
 throw;
 }
#else
 construct(std::move(rhs).get());
#endif
 } else {
 assign_common(std::move(rhs));
 }
 }

#else

// If exceptions are disabled then we can just copy-construct
 void assign(const expected_operations_base &rhs) noexcept {
 if (!this->m_has_val && rhs.m_has_val) {
 geterr().~unexpected<E>();
 construct(rhs.get());
 } else {
 assign_common(rhs);
 }
 }

void assign(expected_operations_base &&rhs) noexcept {
 if (!this->m_has_val && rhs.m_has_val) {
 geterr().~unexpected<E>();
 construct(std::move(rhs).get());
 } else {
 assign_common(std::move(rhs));
 }
 }

#endif

// The common part of move/copy assigning
 template <class Rhs> void assign_common(Rhs &&rhs) {
 if (this->m_has_val) {
 if (rhs.m_has_val) {
 get() = std::forward<Rhs>(rhs).get();
 } else {
 destroy_val();
 construct_error(std::forward<Rhs>(rhs).geterr());
 }
 } else {
 if (!rhs.m_has_val) {
 geterr() = std::forward<Rhs>(rhs).geterr();
 }
 }
 }

bool has_value() const { return this->m_has_val; }

TL_EXPECTED_11_CONSTEXPR T &get() & { return this->m_val; }
  constexpr const T &get() const & { return this->m_val; }
  TL_EXPECTED_11_CONSTEXPR T &&get() && { return std::move(this->m_val); }
#ifndef TL_EXPECTED_NO_CONSTRR
  constexpr const T &&get() const && { return std::move(this->m_val); }
#endif

TL_EXPECTED_11_CONSTEXPR unexpected<E> &geterr() & {
 return this->m_unexpect;
 }
 constexpr const unexpected<E> &geterr() const & { return this->m_unexpect; }
 TL_EXPECTED_11_CONSTEXPR unexpected<E> &&geterr() && {
 return std::move(this->m_unexpect);
 }
#ifndef TL_EXPECTED_NO_CONSTRR
 constexpr const unexpected<E> &&geterr() const && {
 return std::move(this->m_unexpect);
 }
#endif

TL_EXPECTED_11_CONSTEXPR void destroy_val() { get().~T(); }
};

// This base class provides some handy member functions which can be used in
// further derived classes
template <class E>
struct expected_operations_base<void, E> : expected_storage_base<void, E> {
 using expected_storage_base<void, E>::expected_storage_base;

template <class... Args> void construct() noexcept { this->m_has_val = true; }

// This function doesn't use its argument, but needs it so that code in
 // levels above this can work independently of whether T is void
 template <class Rhs> void construct_with(Rhs &&) noexcept {
 this->m_has_val = true;
 }

template <class Rhs> void assign(Rhs &&rhs) noexcept {
 if (!this->m_has_val) {
 if (rhs.m_has_val) {
 geterr().~unexpected<E>();
 construct();
 } else {
 geterr() = std::forward<Rhs>(rhs).geterr();
 }
 } else {
 if (!rhs.m_has_val) {
 construct_error(std::forward<Rhs>(rhs).geterr());
 }
 }
 }

bool has_value() const { return this->m_has_val; }

TL_EXPECTED_11_CONSTEXPR void destroy_val() {
    // no-op
  }
};

// This class manages conditionally having a trivial copy constructor
// This specialization is for when T and E are trivially copy constructible
template <class T, class E,
 bool = is_void_or<T, TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T)>::
 value &&TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(E)::value>
struct expected_copy_base : expected_operations_base<T, E> {
 using expected_operations_base<T, E>::expected_operations_base;
};

// This specialization is for when T or E are not trivially copy constructible
template <class T, class E>
struct expected_copy_base<T, E, false> : expected_operations_base<T, E> {
 using expected_operations_base<T, E>::expected_operations_base;

expected_copy_base() = default;
 expected_copy_base(const expected_copy_base &rhs)
 : expected_operations_base<T, E>(no_init) {
 if (rhs.has_value()) {
 this->construct_with(rhs);
 } else {
 this->construct_error(rhs.geterr());
 }
 }

expected_copy_base(expected_copy_base &&rhs) = default;
  expected_copy_base &operator=(const expected_copy_base &rhs) = default;
  expected_copy_base &operator=(expected_copy_base &&rhs) = default;
};

// This class manages conditionally having a trivial move constructor
// Unfortunately there's no way to achieve this in GCC < 5 AFAIK, since it
// doesn't implement an analogue to std::is_trivially_move_constructible. We
// have to make do with a non-trivial move constructor even if T is trivially
// move constructible
#ifndef TL_EXPECTED_GCC49
template <class T, class E,
 bool = is_void_or<T, std::is_trivially_move_constructible<T>>::value
 &&std::is_trivially_move_constructible<E>::value>
struct expected_move_base : expected_copy_base<T, E> {
 using expected_copy_base<T, E>::expected_copy_base;
};
#else
template <class T, class E, bool = false> struct expected_move_base;
#endif
template <class T, class E>
struct expected_move_base<T, E, false> : expected_copy_base<T, E> {
 using expected_copy_base<T, E>::expected_copy_base;

expected_move_base() = default;
  expected_move_base(const expected_move_base &rhs) = default;

expected_move_base(expected_move_base &&rhs) noexcept(
 std::is_nothrow_move_constructible<T>::value)
 : expected_copy_base<T, E>(no_init) {
 if (rhs.has_value()) {
 this->construct_with(std::move(rhs));
 } else {
 this->construct_error(std::move(rhs.geterr()));
 }
 }
 expected_move_base &operator=(const expected_move_base &rhs) = default;
 expected_move_base &operator=(expected_move_base &&rhs) = default;
};

// This class manages conditionally having a trivial copy assignment operator
template <class T, class E,
 bool = is_void_or<
 T, conjunction<TL_EXPECTED_IS_TRIVIALLY_COPY_ASSIGNABLE(T),
 TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T),
 TL_EXPECTED_IS_TRIVIALLY_DESTRUCTIBLE(T)>>::value
 &&TL_EXPECTED_IS_TRIVIALLY_COPY_ASSIGNABLE(E)::value
 &&TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(E)::value
 &&TL_EXPECTED_IS_TRIVIALLY_DESTRUCTIBLE(E)::value>
struct expected_copy_assign_base : expected_move_base<T, E> {
 using expected_move_base<T, E>::expected_move_base;
};

template <class T, class E>
struct expected_copy_assign_base<T, E, false> : expected_move_base<T, E> {
 using expected_move_base<T, E>::expected_move_base;

expected_copy_assign_base() = default;
  expected_copy_assign_base(const expected_copy_assign_base &rhs) = default;

expected_copy_assign_base(expected_copy_assign_base &&rhs) = default;
  expected_copy_assign_base &operator=(const expected_copy_assign_base &rhs) {
    this->assign(rhs);
    return *this;
  }
  expected_copy_assign_base &
  operator=(expected_copy_assign_base &&rhs) = default;
};

// This class manages conditionally having a trivial move assignment operator
// Unfortunately there's no way to achieve this in GCC < 5 AFAIK, since it
// doesn't implement an analogue to std::is_trivially_move_assignable. We have
// to make do with a non-trivial move assignment operator even if T is trivially
// move assignable
#ifndef TL_EXPECTED_GCC49
template <class T, class E,
 bool =
 is_void_or<T, conjunction<std::is_trivially_destructible<T>,
 std::is_trivially_move_constructible<T>,
 std::is_trivially_move_assignable<T>>>::
 value &&std::is_trivially_destructible<E>::value
 &&std::is_trivially_move_constructible<E>::value
 &&std::is_trivially_move_assignable<E>::value>
struct expected_move_assign_base : expected_copy_assign_base<T, E> {
 using expected_copy_assign_base<T, E>::expected_copy_assign_base;
};
#else
template <class T, class E, bool = false> struct expected_move_assign_base;
#endif

template <class T, class E>
struct expected_move_assign_base<T, E, false>
 : expected_copy_assign_base<T, E> {
 using expected_copy_assign_base<T, E>::expected_copy_assign_base;

expected_move_assign_base() = default;
  expected_move_assign_base(const expected_move_assign_base &rhs) = default;

expected_move_assign_base(expected_move_assign_base &&rhs) = default;

expected_move_assign_base &
  operator=(const expected_move_assign_base &rhs) = default;

expected_move_assign_base &
 operator=(expected_move_assign_base &&rhs) noexcept(
 std::is_nothrow_move_constructible<T>::value
 &&std::is_nothrow_move_assignable<T>::value) {
 this->assign(std::move(rhs));
 return *this;
 }
};

// expected_delete_ctor_base will conditionally delete copy and move
// constructors depending on whether T is copy/move constructible
template <class T, class E,
 bool EnableCopy = (is_copy_constructible_or_void<T>::value &&
 std::is_copy_constructible<E>::value),
 bool EnableMove = (is_move_constructible_or_void<T>::value &&
 std::is_move_constructible<E>::value)>
struct expected_delete_ctor_base {
 expected_delete_ctor_base() = default;
 expected_delete_ctor_base(const expected_delete_ctor_base &) = default;
 expected_delete_ctor_base(expected_delete_ctor_base &&) noexcept = default;
 expected_delete_ctor_base &
 operator=(const expected_delete_ctor_base &) = default;
 expected_delete_ctor_base &
 operator=(expected_delete_ctor_base &&) noexcept = default;
};

template <class T, class E>
struct expected_delete_ctor_base<T, E, true, false> {
 expected_delete_ctor_base() = default;
 expected_delete_ctor_base(const expected_delete_ctor_base &) = default;
 expected_delete_ctor_base(expected_delete_ctor_base &&) noexcept = delete;
 expected_delete_ctor_base &
 operator=(const expected_delete_ctor_base &) = default;
 expected_delete_ctor_base &
 operator=(expected_delete_ctor_base &&) noexcept = default;
};

template <class T, class E>
struct expected_delete_ctor_base<T, E, false, true> {
 expected_delete_ctor_base() = default;
 expected_delete_ctor_base(const expected_delete_ctor_base &) = delete;
 expected_delete_ctor_base(expected_delete_ctor_base &&) noexcept = default;
 expected_delete_ctor_base &
 operator=(const expected_delete_ctor_base &) = default;
 expected_delete_ctor_base &
 operator=(expected_delete_ctor_base &&) noexcept = default;
};

template <class T, class E>
struct expected_delete_ctor_base<T, E, false, false> {
 expected_delete_ctor_base() = default;
 expected_delete_ctor_base(const expected_delete_ctor_base &) = delete;
 expected_delete_ctor_base(expected_delete_ctor_base &&) noexcept = delete;
 expected_delete_ctor_base &
 operator=(const expected_delete_ctor_base &) = default;
 expected_delete_ctor_base &
 operator=(expected_delete_ctor_base &&) noexcept = default;
};

// expected_delete_assign_base will conditionally delete copy and move
// constructors depending on whether T and E are copy/move constructible +
// assignable
template <class T, class E,
 bool EnableCopy = (is_copy_constructible_or_void<T>::value &&
 std::is_copy_constructible<E>::value &&
 is_copy_assignable_or_void<T>::value &&
 std::is_copy_assignable<E>::value),
 bool EnableMove = (is_move_constructible_or_void<T>::value &&
 std::is_move_constructible<E>::value &&
 is_move_assignable_or_void<T>::value &&
 std::is_move_assignable<E>::value)>
struct expected_delete_assign_base {
 expected_delete_assign_base() = default;
 expected_delete_assign_base(const expected_delete_assign_base &) = default;
 expected_delete_assign_base(expected_delete_assign_base &&) noexcept =
 default;
 expected_delete_assign_base &
 operator=(const expected_delete_assign_base &) = default;
 expected_delete_assign_base &
 operator=(expected_delete_assign_base &&) noexcept = default;
};

template <class T, class E>
struct expected_delete_assign_base<T, E, true, false> {
 expected_delete_assign_base() = default;
 expected_delete_assign_base(const expected_delete_assign_base &) = default;
 expected_delete_assign_base(expected_delete_assign_base &&) noexcept =
 default;
 expected_delete_assign_base &
 operator=(const expected_delete_assign_base &) = default;
 expected_delete_assign_base &
 operator=(expected_delete_assign_base &&) noexcept = delete;
};

template <class T, class E>
struct expected_delete_assign_base<T, E, false, true> {
 expected_delete_assign_base() = default;
 expected_delete_assign_base(const expected_delete_assign_base &) = default;
 expected_delete_assign_base(expected_delete_assign_base &&) noexcept =
 default;
 expected_delete_assign_base &
 operator=(const expected_delete_assign_base &) = delete;
 expected_delete_assign_base &
 operator=(expected_delete_assign_base &&) noexcept = default;
};

template <class T, class E>
struct expected_delete_assign_base<T, E, false, false> {
 expected_delete_assign_base() = default;
 expected_delete_assign_base(const expected_delete_assign_base &) = default;
 expected_delete_assign_base(expected_delete_assign_base &&) noexcept =
 default;
 expected_delete_assign_base &
 operator=(const expected_delete_assign_base &) = delete;
 expected_delete_assign_base &
 operator=(expected_delete_assign_base &&) noexcept = delete;
};

// This is needed to be able to construct the expected_default_ctor_base which
// follows, while still conditionally deleting the default constructor.
struct default_constructor_tag {
  explicit constexpr default_constructor_tag() = default;
};

// expected_default_ctor_base will ensure that expected has a deleted default
// consturctor if T is not default constructible.
// This specialization is for when T is default constructible
template <class T, class E,
 bool Enable =
 std::is_default_constructible<T>::value || std::is_void<T>::value>
struct expected_default_ctor_base {
 constexpr expected_default_ctor_base() noexcept = default;
 constexpr expected_default_ctor_base(
 expected_default_ctor_base const &) noexcept = default;
 constexpr expected_default_ctor_base(expected_default_ctor_base &&) noexcept =
 default;
 expected_default_ctor_base &
 operator=(expected_default_ctor_base const &) noexcept = default;
 expected_default_ctor_base &
 operator=(expected_default_ctor_base &&) noexcept = default;

constexpr explicit expected_default_ctor_base(default_constructor_tag) {}
};

// This specialization is for when T is not default constructible
template <class T, class E> struct expected_default_ctor_base<T, E, false> {
 constexpr expected_default_ctor_base() noexcept = delete;
 constexpr expected_default_ctor_base(
 expected_default_ctor_base const &) noexcept = default;
 constexpr expected_default_ctor_base(expected_default_ctor_base &&) noexcept =
 default;
 expected_default_ctor_base &
 operator=(expected_default_ctor_base const &) noexcept = default;
 expected_default_ctor_base &
 operator=(expected_default_ctor_base &&) noexcept = default;

constexpr explicit expected_default_ctor_base(default_constructor_tag) {}
};
} // namespace detail

template <class E> class bad_expected_access : public std::exception {
public:
 explicit bad_expected_access(E e) : m_val(std::move(e)) {}

virtual const char *what() const noexcept override {
    return "Bad expected access";
  }

const E &error() const & { return m_val; }
  E &error() & { return m_val; }
  const E &&error() const && { return std::move(m_val); }
  E &&error() && { return std::move(m_val); }

private:
  E m_val;
};

/// An `expected<T, E>` object is an object that contains the storage for
/// another object and manages the lifetime of this contained object `T`.
/// Alternatively it could contain the storage for another unexpected object
/// `E`. The contained object may not be initialized after the expected object
/// has been initialized, and may not be destroyed before the expected object
/// has been destroyed. The initialization state of the contained object is
/// tracked by the expected object.
template <class T, class E>
class expected : private detail::expected_move_assign_base<T, E>,
 private detail::expected_delete_ctor_base<T, E>,
 private detail::expected_delete_assign_base<T, E>,
 private detail::expected_default_ctor_base<T, E> {
 static_assert(!std::is_reference<T>::value, "T must not be a reference");
 static_assert(!std::is_same<T, std::remove_cv<in_place_t>::type>::value,
 "T must not be in_place_t");
 static_assert(!std::is_same<T, std::remove_cv<unexpect_t>::type>::value,
 "T must not be unexpect_t");
 static_assert(
 !std::is_same<T, typename std::remove_cv<unexpected<E>>::type>::value,
 "T must not be unexpected<E>");
 static_assert(!std::is_reference<E>::value, "E must not be a reference");

T *valptr() { return std::addressof(this->m_val); }
 const T *valptr() const { return std::addressof(this->m_val); }
 unexpected<E> *errptr() { return std::addressof(this->m_unexpect); }
 const unexpected<E> *errptr() const {
 return std::addressof(this->m_unexpect);
 }

template <class U = T,
 detail::enable_if_t<!std::is_void::value> * = nullptr>
 TL_EXPECTED_11_CONSTEXPR U &val() {
 return this->m_val;
 }
 TL_EXPECTED_11_CONSTEXPR unexpected<E> &err() { return this->m_unexpect; }

template <class U = T,
 detail::enable_if_t<!std::is_void::value> * = nullptr>
 constexpr const U &val() const {
 return this->m_val;
 }
 constexpr const unexpected<E> &err() const { return this->m_unexpect; }

using impl_base = detail::expected_move_assign_base<T, E>;
 using ctor_base = detail::expected_default_ctor_base<T, E>;

public:
 typedef T value_type;
 typedef E error_type;
 typedef unexpected<E> unexpected_type;

#ifndef TL_EXPECTED_NO_CONSTRR
 template <class F> constexpr auto and_then(F &&f) const && {
 return and_then_impl(std::move(*this), std::forward<F>(f));
 }
#endif

#else
 template <class F>
 TL_EXPECTED_11_CONSTEXPR auto
 and_then(F &&f) & -> decltype(and_then_impl(std::declval<expected &>(),
 std::forward<F>(f))) {
 return and_then_impl(*this, std::forward<F>(f));
 }
 template <class F>
 TL_EXPECTED_11_CONSTEXPR auto
 and_then(F &&f) && -> decltype(and_then_impl(std::declval<expected &&>(),
 std::forward<F>(f))) {
 return and_then_impl(std::move(*this), std::forward<F>(f));
 }
 template <class F>
 constexpr auto and_then(F &&f) const & -> decltype(and_then_impl(
 std::declval<expected const &>(), std::forward<F>(f))) {
 return and_then_impl(*this, std::forward<F>(f));
 }

#ifndef TL_EXPECTED_NO_CONSTRR
 template <class F>
 constexpr auto and_then(F &&f) const && -> decltype(and_then_impl(
 std::declval<expected const &&>(), std::forward<F>(f))) {
 return and_then_impl(std::move(*this), std::forward<F>(f));
 }
#endif
#endif

#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
 !defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
 template <class F> TL_EXPECTED_11_CONSTEXPR auto map(F &&f) & {
 return expected_map_impl(*this, std::forward<F>(f));
 }
 template <class F> TL_EXPECTED_11_CONSTEXPR auto map(F &&f) && {
 return expected_map_impl(std::move(*this), std::forward<F>(f));
 }
 template <class F> constexpr auto map(F &&f) const & {
 return expected_map_impl(*this, std::forward<F>(f));
 }
 template <class F> constexpr auto map(F &&f) const && {
 return expected_map_impl(std::move(*this), std::forward<F>(f));
 }
#else
 template <class F>
 TL_EXPECTED_11_CONSTEXPR decltype(expected_map_impl(
 std::declval<expected &>(), std::declval<F &&>()))
 map(F &&f) & {
 return expected_map_impl(*this, std::forward<F>(f));
 }
 template <class F>
 TL_EXPECTED_11_CONSTEXPR decltype(expected_map_impl(std::declval<expected>(),
 std::declval<F &&>()))
 map(F &&f) && {
 return expected_map_impl(std::move(*this), std::forward<F>(f));
 }
 template <class F>
 constexpr decltype(expected_map_impl(std::declval<const expected &>(),
 std::declval<F &&>()))
 map(F &&f) const & {
 return expected_map_impl(*this, std::forward<F>(f));
 }

#ifndef TL_EXPECTED_NO_CONSTRR
 template <class F>
 constexpr decltype(expected_map_impl(std::declval<const expected &&>(),
 std::declval<F &&>()))
 map(F &&f) const && {
 return expected_map_impl(std::move(*this), std::forward<F>(f));
 }
#endif
#endif

#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
 !defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
 template <class F> TL_EXPECTED_11_CONSTEXPR auto transform(F &&f) & {
 return expected_map_impl(*this, std::forward<F>(f));
 }
 template <class F> TL_EXPECTED_11_CONSTEXPR auto transform(F &&f) && {
 return expected_map_impl(std::move(*this), std::forward<F>(f));
 }
 template <class F> constexpr auto transform(F &&f) const & {
 return expected_map_impl(*this, std::forward<F>(f));
 }
 template <class F> constexpr auto transform(F &&f) const && {
 return expected_map_impl(std::move(*this), std::forward<F>(f));
 }
#else
 template <class F>
 TL_EXPECTED_11_CONSTEXPR decltype(expected_map_impl(
 std::declval<expected &>(), std::declval<F &&>()))
 transform(F &&f) & {
 return expected_map_impl(*this, std::forward<F>(f));
 }
 template <class F>
 TL_EXPECTED_11_CONSTEXPR decltype(expected_map_impl(std::declval<expected>(),
 std::declval<F &&>()))
 transform(F &&f) && {
 return expected_map_impl(std::move(*this), std::forward<F>(f));
 }
 template <class F>
 constexpr decltype(expected_map_impl(std::declval<const expected &>(),
 std::declval<F &&>()))
 transform(F &&f) const & {
 return expected_map_impl(*this, std::forward<F>(f));
 }

#ifndef TL_EXPECTED_NO_CONSTRR
 template <class F>
 constexpr decltype(expected_map_impl(std::declval<const expected &&>(),
 std::declval<F &&>()))
 transform(F &&f) const && {
 return expected_map_impl(std::move(*this), std::forward<F>(f));
 }
#endif
#endif

#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
 !defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
 template <class F> TL_EXPECTED_11_CONSTEXPR auto map_error(F &&f) & {
 return map_error_impl(*this, std::forward<F>(f));
 }
 template <class F> TL_EXPECTED_11_CONSTEXPR auto map_error(F &&f) && {
 return map_error_impl(std::move(*this), std::forward<F>(f));
 }
 template <class F> constexpr auto map_error(F &&f) const & {
 return map_error_impl(*this, std::forward<F>(f));
 }
 template <class F> constexpr auto map_error(F &&f) const && {
 return map_error_impl(std::move(*this), std::forward<F>(f));
 }
#else
 template <class F>
 TL_EXPECTED_11_CONSTEXPR decltype(map_error_impl(std::declval<expected &>(),
 std::declval<F &&>()))
 map_error(F &&f) & {
 return map_error_impl(*this, std::forward<F>(f));
 }
 template <class F>
 TL_EXPECTED_11_CONSTEXPR decltype(map_error_impl(std::declval<expected &&>(),
 std::declval<F &&>()))
 map_error(F &&f) && {
 return map_error_impl(std::move(*this), std::forward<F>(f));
 }
 template <class F>
 constexpr decltype(map_error_impl(std::declval<const expected &>(),
 std::declval<F &&>()))
 map_error(F &&f) const & {
 return map_error_impl(*this, std::forward<F>(f));
 }

#ifndef TL_EXPECTED_NO_CONSTRR
 template <class F>
 constexpr decltype(map_error_impl(std::declval<const expected &&>(),
 std::declval<F &&>()))
 map_error(F &&f) const && {
 return map_error_impl(std::move(*this), std::forward<F>(f));
 }
#endif
#endif
#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
 !defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
 template <class F> TL_EXPECTED_11_CONSTEXPR auto transform_error(F &&f) & {
 return map_error_impl(*this, std::forward<F>(f));
 }
 template <class F> TL_EXPECTED_11_CONSTEXPR auto transform_error(F &&f) && {
 return map_error_impl(std::move(*this), std::forward<F>(f));
 }
 template <class F> constexpr auto transform_error(F &&f) const & {
 return map_error_impl(*this, std::forward<F>(f));
 }
 template <class F> constexpr auto transform_error(F &&f) const && {
 return map_error_impl(std::move(*this), std::forward<F>(f));
 }
#else
 template <class F>
 TL_EXPECTED_11_CONSTEXPR decltype(map_error_impl(std::declval<expected &>(),
 std::declval<F &&>()))
 transform_error(F &&f) & {
 return map_error_impl(*this, std::forward<F>(f));
 }
 template <class F>
 TL_EXPECTED_11_CONSTEXPR decltype(map_error_impl(std::declval<expected &&>(),
 std::declval<F &&>()))
 transform_error(F &&f) && {
 return map_error_impl(std::move(*this), std::forward<F>(f));
 }
 template <class F>
 constexpr decltype(map_error_impl(std::declval<const expected &>(),
 std::declval<F &&>()))
 transform_error(F &&f) const & {
 return map_error_impl(*this, std::forward<F>(f));
 }

#ifndef TL_EXPECTED_NO_CONSTRR
 template <class F>
 constexpr decltype(map_error_impl(std::declval<const expected &&>(),
 std::declval<F &&>()))
 transform_error(F &&f) const && {
 return map_error_impl(std::move(*this), std::forward<F>(f));
 }
#endif
#endif
 template <class F> expected TL_EXPECTED_11_CONSTEXPR or_else(F &&f) & {
 return or_else_impl(*this, std::forward<F>(f));
 }

template <class F> expected TL_EXPECTED_11_CONSTEXPR or_else(F &&f) && {
 return or_else_impl(std::move(*this), std::forward<F>(f));
 }

template <class F> expected constexpr or_else(F &&f) const & {
 return or_else_impl(*this, std::forward<F>(f));
 }

#ifndef TL_EXPECTED_NO_CONSTRR
 template <class F> expected constexpr or_else(F &&f) const && {
 return or_else_impl(std::move(*this), std::forward<F>(f));
 }
#endif
 constexpr expected() = default;
 constexpr expected(const expected &rhs) = default;
 constexpr expected(expected &&rhs) = default;
 expected &operator=(const expected &rhs) = default;
 expected &operator=(expected &&rhs) = default;

template <class... Args,
 detail::enable_if_t<std::is_constructible<T, Args &&...>::value> * =
 nullptr>
 constexpr expected(in_place_t, Args &&...args)
 : impl_base(in_place, std::forward<Args>(args)...),
 ctor_base(detail::default_constructor_tag{}) {}

template <class U, class... Args,
 detail::enable_if_t<std::is_constructible<
 T, std::initializer_list &, Args &&...>::value> * = nullptr>
 constexpr expected(in_place_t, std::initializer_list il, Args &&...args)
 : impl_base(in_place, il, std::forward<Args>(args)...),
 ctor_base(detail::default_constructor_tag{}) {}

template <class G = E,
 detail::enable_if_t<std::is_constructible<E, const G &>::value> * =
 nullptr,
 detail::enable_if_t<!std::is_convertible<const G &, E>::value> * =
 nullptr>
 explicit constexpr expected(const unexpected<G> &e)
 : impl_base(unexpect, e.value()),
 ctor_base(detail::default_constructor_tag{}) {}

template <
 class G = E,
 detail::enable_if_t<std::is_constructible<E, const G &>::value> * =
 nullptr,
 detail::enable_if_t<std::is_convertible<const G &, E>::value> * = nullptr>
 constexpr expected(unexpected<G> const &e)
 : impl_base(unexpect, e.value()),
 ctor_base(detail::default_constructor_tag{}) {}

template <
 class G = E,
 detail::enable_if_t<std::is_constructible<E, G &&>::value> * = nullptr,
 detail::enable_if_t<!std::is_convertible<G &&, E>::value> * = nullptr>
 explicit constexpr expected(unexpected<G> &&e) noexcept(
 std::is_nothrow_constructible<E, G &&>::value)
 : impl_base(unexpect, std::move(e.value())),
 ctor_base(detail::default_constructor_tag{}) {}

template <
 class G = E,
 detail::enable_if_t<std::is_constructible<E, G &&>::value> * = nullptr,
 detail::enable_if_t<std::is_convertible<G &&, E>::value> * = nullptr>
 constexpr expected(unexpected<G> &&e) noexcept(
 std::is_nothrow_constructible<E, G &&>::value)
 : impl_base(unexpect, std::move(e.value())),
 ctor_base(detail::default_constructor_tag{}) {}

template <class... Args,
 detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
 nullptr>
 constexpr explicit expected(unexpect_t, Args &&...args)
 : impl_base(unexpect, std::forward<Args>(args)...),
 ctor_base(detail::default_constructor_tag{}) {}

template <class U, class... Args,
 detail::enable_if_t<std::is_constructible<
 E, std::initializer_list &, Args &&...>::value> * = nullptr>
 constexpr explicit expected(unexpect_t, std::initializer_list il,
 Args &&...args)
 : impl_base(unexpect, il, std::forward<Args>(args)...),
 ctor_base(detail::default_constructor_tag{}) {}

template <class U, class G,
 detail::enable_if_t<!(std::is_convertible::value &&
 std::is_convertible<G const &, E>::value)> * =
 nullptr,
 detail::expected_enable_from_other<T, E, U, G, const U &, const G &>
 * = nullptr>
 explicit TL_EXPECTED_11_CONSTEXPR expected(const expected<U, G> &rhs)
 : ctor_base(detail::default_constructor_tag{}) {
 if (rhs.has_value()) {
 this->construct(*rhs);
 } else {
 this->construct_error(rhs.error());
 }
 }

template <class U, class G,
 detail::enable_if_t<(std::is_convertible::value &&
 std::is_convertible<G const &, E>::value)> * =
 nullptr,
 detail::expected_enable_from_other<T, E, U, G, const U &, const G &>
 * = nullptr>
 TL_EXPECTED_11_CONSTEXPR expected(const expected<U, G> &rhs)
 : ctor_base(detail::default_constructor_tag{}) {
 if (rhs.has_value()) {
 this->construct(*rhs);
 } else {
 this->construct_error(rhs.error());
 }
 }

template <
 class U, class G,
 detail::enable_if_t<!(std::is_convertible::value &&
 std::is_convertible<G &&, E>::value)> * = nullptr,
 detail::expected_enable_from_other<T, E, U, G, U &&, G &&> * = nullptr>
 explicit TL_EXPECTED_11_CONSTEXPR expected(expected<U, G> &&rhs)
 : ctor_base(detail::default_constructor_tag{}) {
 if (rhs.has_value()) {
 this->construct(std::move(*rhs));
 } else {
 this->construct_error(std::move(rhs.error()));
 }
 }

template <
 class U, class G,
 detail::enable_if_t<(std::is_convertible::value &&
 std::is_convertible<G &&, E>::value)> * = nullptr,
 detail::expected_enable_from_other<T, E, U, G, U &&, G &&> * = nullptr>
 TL_EXPECTED_11_CONSTEXPR expected(expected<U, G> &&rhs)
 : ctor_base(detail::default_constructor_tag{}) {
 if (rhs.has_value()) {
 this->construct(std::move(*rhs));
 } else {
 this->construct_error(std::move(rhs.error()));
 }
 }

template <
 class U = T,
 detail::enable_if_t<!std::is_convertible::value> * = nullptr,
 detail::expected_enable_forward_value<T, E, U> * = nullptr>
 explicit TL_EXPECTED_MSVC2015_CONSTEXPR expected(U &&v)
 : expected(in_place, std::forward(v)) {}

template <
 class U = T,
 detail::enable_if_t<std::is_convertible::value> * = nullptr,
 detail::expected_enable_forward_value<T, E, U> * = nullptr>
 TL_EXPECTED_MSVC2015_CONSTEXPR expected(U &&v)
 : expected(in_place, std::forward(v)) {}

template <
 class U = T, class G = T,
 detail::enable_if_t<std::is_nothrow_constructible<T, U &&>::value> * =
 nullptr,
 detail::enable_if_t<!std::is_void<G>::value> * = nullptr,
 detail::enable_if_t<
 (!std::is_same<expected<T, E>, detail::decay_t>::value &&
 !detail::conjunction<std::is_scalar<T>,
 std::is_same<T, detail::decay_t>>::value &&
 std::is_constructible<T, U>::value &&
 std::is_assignable<G &, U>::value &&
 std::is_nothrow_move_constructible<E>::value)> * = nullptr>
 expected &operator=(U &&v) {
 if (has_value()) {
 val() = std::forward(v);
 } else {
 err().~unexpected<E>();
 ::new (valptr()) T(std::forward(v));
 this->m_has_val = true;
 }

return *this;
  }

template <
 class U = T, class G = T,
 detail::enable_if_t<!std::is_nothrow_constructible<T, U &&>::value> * =
 nullptr,
 detail::enable_if_t<!std::is_void::value> * = nullptr,
 detail::enable_if_t<
 (!std::is_same<expected<T, E>, detail::decay_t>::value &&
 !detail::conjunction<std::is_scalar<T>,
 std::is_same<T, detail::decay_t>>::value &&
 std::is_constructible<T, U>::value &&
 std::is_assignable<G &, U>::value &&
 std::is_nothrow_move_constructible<E>::value)> * = nullptr>
 expected &operator=(U &&v) {
 if (has_value()) {
 val() = std::forward(v);
 } else {
 auto tmp = std::move(err());
 err().~unexpected<E>();

#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
 try {
 ::new (valptr()) T(std::forward(v));
 this->m_has_val = true;
 } catch (...) {
 err() = std::move(tmp);
 throw;
 }
#else
 ::new (valptr()) T(std::forward(v));
 this->m_has_val = true;
#endif
 }

return *this;
  }

template <class G = E,
 detail::enable_if_t<std::is_nothrow_copy_constructible<G>::value &&
 std::is_assignable<G &, G>::value> * = nullptr>
 expected &operator=(const unexpected<G> &rhs) {
 if (!has_value()) {
 err() = rhs;
 } else {
 this->destroy_val();
 ::new (errptr()) unexpected<E>(rhs);
 this->m_has_val = false;
 }

return *this;
  }

template <class G = E,
 detail::enable_if_t<std::is_nothrow_move_constructible<G>::value &&
 std::is_move_assignable<G>::value> * = nullptr>
 expected &operator=(unexpected<G> &&rhs) noexcept {
 if (!has_value()) {
 err() = std::move(rhs);
 } else {
 this->destroy_val();
 ::new (errptr()) unexpected<E>(std::move(rhs));
 this->m_has_val = false;
 }

return *this;
  }

template <class... Args, detail::enable_if_t<std::is_nothrow_constructible<
 T, Args &&...>::value> * = nullptr>
 void emplace(Args &&...args) {
 if (has_value()) {
 val().~T();
 } else {
 err().~unexpected<E>();
 this->m_has_val = true;
 }
 ::new (valptr()) T(std::forward<Args>(args)...);
 }

template <class... Args, detail::enable_if_t<!std::is_nothrow_constructible<
 T, Args &&...>::value> * = nullptr>
 void emplace(Args &&...args) {
 if (has_value()) {
 val().~T();
 ::new (valptr()) T(std::forward<Args>(args)...);
 } else {
 auto tmp = std::move(err());
 err().~unexpected<E>();

#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
 try {
 ::new (valptr()) T(std::forward<Args>(args)...);
 this->m_has_val = true;
 } catch (...) {
 err() = std::move(tmp);
 throw;
 }
#else
 ::new (valptr()) T(std::forward<Args>(args)...);
 this->m_has_val = true;
#endif
 }
 }

template <class U, class... Args,
 detail::enable_if_t<std::is_nothrow_constructible<
 T, std::initializer_list &, Args &&...>::value> * = nullptr>
 void emplace(std::initializer_list il, Args &&...args) {
 if (has_value()) {
 T t(il, std::forward<Args>(args)...);
 val() = std::move(t);
 } else {
 err().~unexpected<E>();
 ::new (valptr()) T(il, std::forward<Args>(args)...);
 this->m_has_val = true;
 }
 }

template <class U, class... Args,
 detail::enable_if_t<!std::is_nothrow_constructible<
 T, std::initializer_list &, Args &&...>::value> * = nullptr>
 void emplace(std::initializer_list il, Args &&...args) {
 if (has_value()) {
 T t(il, std::forward<Args>(args)...);
 val() = std::move(t);
 } else {
 auto tmp = std::move(err());
 err().~unexpected<E>();

#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
 try {
 ::new (valptr()) T(il, std::forward<Args>(args)...);
 this->m_has_val = true;
 } catch (...) {
 err() = std::move(tmp);
 throw;
 }
#else
 ::new (valptr()) T(il, std::forward<Args>(args)...);
 this->m_has_val = true;
#endif
 }
 }

private:
  using t_is_void = std::true_type;
  using t_is_not_void = std::false_type;
  using t_is_nothrow_move_constructible = std::true_type;
  using move_constructing_t_can_throw = std::false_type;
  using e_is_nothrow_move_constructible = std::true_type;
  using move_constructing_e_can_throw = std::false_type;

void swap_where_both_have_value(expected & /*rhs*/, t_is_void) noexcept {
    // swapping void is a no-op
  }

void swap_where_both_have_value(expected &rhs, t_is_not_void) {
    using std::swap;
    swap(val(), rhs.val());
  }

void swap_where_only_one_has_value(expected &rhs, t_is_void) noexcept(
 std::is_nothrow_move_constructible<E>::value) {
 ::new (errptr()) unexpected_type(std::move(rhs.err()));
 rhs.err().~unexpected_type();
 std::swap(this->m_has_val, rhs.m_has_val);
 }

void swap_where_only_one_has_value(expected &rhs, t_is_not_void) {
 swap_where_only_one_has_value_and_t_is_not_void(
 rhs, typename std::is_nothrow_move_constructible<T>::type{},
 typename std::is_nothrow_move_constructible<E>::type{});
 }

void swap_where_only_one_has_value_and_t_is_not_void(
      expected &rhs, t_is_nothrow_move_constructible,
      e_is_nothrow_move_constructible) noexcept {
    auto temp = std::move(val());
    val().~T();
    ::new (errptr()) unexpected_type(std::move(rhs.err()));
    rhs.err().~unexpected_type();
    ::new (rhs.valptr()) T(std::move(temp));
    std::swap(this->m_has_val, rhs.m_has_val);
  }

void swap_where_only_one_has_value_and_t_is_not_void(
      expected &rhs, t_is_nothrow_move_constructible,
      move_constructing_e_can_throw) {
    auto temp = std::move(val());
    val().~T();
#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
    try {
      ::new (errptr()) unexpected_type(std::move(rhs.err()));
      rhs.err().~unexpected_type();
      ::new (rhs.valptr()) T(std::move(temp));
      std::swap(this->m_has_val, rhs.m_has_val);
    } catch (...) {
      val() = std::move(temp);
      throw;
    }
#else
    ::new (errptr()) unexpected_type(std::move(rhs.err()));
    rhs.err().~unexpected_type();
    ::new (rhs.valptr()) T(std::move(temp));
    std::swap(this->m_has_val, rhs.m_has_val);
#endif
  }

void swap_where_only_one_has_value_and_t_is_not_void(
      expected &rhs, move_constructing_t_can_throw,
      e_is_nothrow_move_constructible) {
    auto temp = std::move(rhs.err());
    rhs.err().~unexpected_type();
#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
    try {
      ::new (rhs.valptr()) T(std::move(val()));
      val().~T();
      ::new (errptr()) unexpected_type(std::move(temp));
      std::swap(this->m_has_val, rhs.m_has_val);
    } catch (...) {
      rhs.err() = std::move(temp);
      throw;
    }
#else
    ::new (rhs.valptr()) T(std::move(val()));
    val().~T();
    ::new (errptr()) unexpected_type(std::move(temp));
    std::swap(this->m_has_val, rhs.m_has_val);
#endif
  }

public:
 template <class OT = T, class OE = E>
 detail::enable_if_t<detail::is_swappable<OT>::value &&
 detail::is_swappable<OE>::value &&
 (std::is_nothrow_move_constructible<OT>::value ||
 std::is_nothrow_move_constructible<OE>::value)>
 swap(expected &rhs) noexcept(
 std::is_nothrow_move_constructible<T>::value
 &&detail::is_nothrow_swappable<T>::value
 &&std::is_nothrow_move_constructible<E>::value
 &&detail::is_nothrow_swappable<E>::value) {
 if (has_value() && rhs.has_value()) {
 swap_where_both_have_value(rhs, typename std::is_void<T>::type{});
 } else if (!has_value() && rhs.has_value()) {
 rhs.swap(*this);
 } else if (has_value()) {
 swap_where_only_one_has_value(rhs, typename std::is_void<T>::type{});
 } else {
 using std::swap;
 swap(err(), rhs.err());
 }
 }

constexpr const T *operator->() const {
    TL_ASSERT(has_value());
    return valptr();
  }
  TL_EXPECTED_11_CONSTEXPR T *operator->() {
    TL_ASSERT(has_value());
    return valptr();
  }

template <class U = T,
 detail::enable_if_t<!std::is_void::value> * = nullptr>
 constexpr const U &operator*() const & {
 TL_ASSERT(has_value());
 return val();
 }
 template <class U = T,
 detail::enable_if_t<!std::is_void::value> * = nullptr>
 TL_EXPECTED_11_CONSTEXPR U &operator*() & {
 TL_ASSERT(has_value());
 return val();
 }
 template <class U = T,
 detail::enable_if_t<!std::is_void::value> * = nullptr>
 constexpr const U &&operator*() const && {
 TL_ASSERT(has_value());
 return std::move(val());
 }
 template <class U = T,
 detail::enable_if_t<!std::is_void::value> * = nullptr>
 TL_EXPECTED_11_CONSTEXPR U &&operator*() && {
 TL_ASSERT(has_value());
 return std::move(val());
 }

constexpr bool has_value() const noexcept { return this->m_has_val; }
  constexpr explicit operator bool() const noexcept { return this->m_has_val; }

template <class U = T,
 detail::enable_if_t<!std::is_void::value> * = nullptr>
 TL_EXPECTED_11_CONSTEXPR const U &value() const & {
 if (!has_value())
 detail::throw_exception(bad_expected_access<E>(err().value()));
 return val();
 }
 template <class U = T,
 detail::enable_if_t<!std::is_void::value> * = nullptr>
 TL_EXPECTED_11_CONSTEXPR U &value() & {
 if (!has_value())
 detail::throw_exception(bad_expected_access<E>(err().value()));
 return val();
 }
 template <class U = T,
 detail::enable_if_t<!std::is_void::value> * = nullptr>
 TL_EXPECTED_11_CONSTEXPR const U &&value() const && {
 if (!has_value())
 detail::throw_exception(bad_expected_access<E>(std::move(err()).value()));
 return std::move(val());
 }
 template <class U = T,
 detail::enable_if_t<!std::is_void::value> * = nullptr>
 TL_EXPECTED_11_CONSTEXPR U &&value() && {
 if (!has_value())
 detail::throw_exception(bad_expected_access<E>(std::move(err()).value()));
 return std::move(val());
 }

constexpr const E &error() const & {
    TL_ASSERT(!has_value());
    return err().value();
  }
  TL_EXPECTED_11_CONSTEXPR E &error() & {
    TL_ASSERT(!has_value());
    return err().value();
  }
  constexpr const E &&error() const && {
    TL_ASSERT(!has_value());
    return std::move(err().value());
  }
  TL_EXPECTED_11_CONSTEXPR E &&error() && {
    TL_ASSERT(!has_value());
    return std::move(err().value());
  }

template <class U> constexpr T value_or(U &&v) const & {
 static_assert(std::is_copy_constructible<T>::value &&
 std::is_convertible::value,
 "T must be copy-constructible and convertible to from U&&");
 return bool(*this) ? **this : static_cast<T>(std::forward(v));
 }
 template <class U> TL_EXPECTED_11_CONSTEXPR T value_or(U &&v) && {
 static_assert(std::is_move_constructible<T>::value &&
 std::is_convertible::value,
 "T must be move-constructible and convertible to from U&&");
 return bool(*this) ? std::move(**this) : static_cast<T>(std::forward(v));
 }
};

namespace detail {
template <class Exp> using exp_t = typename detail::decay_t<Exp>::value_type;
template <class Exp> using err_t = typename detail::decay_t<Exp>::error_type;
template <class Exp, class Ret> using ret_t = expected<Ret, err_t<Exp>>;

#ifdef TL_EXPECTED_CXX14
template <class Exp, class F,
 detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 *std::declval<Exp>()))>
constexpr auto and_then_impl(Exp &&exp, F &&f) {
 static_assert(detail::is_expected<Ret>::value, "F must return an expected");

return exp.has_value()
 ? detail::invoke(std::forward<F>(f), *std::forward<Exp>(exp))
 : Ret(unexpect, std::forward<Exp>(exp).error());
}

template <class Exp, class F,
 detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>()))>
constexpr auto and_then_impl(Exp &&exp, F &&f) {
 static_assert(detail::is_expected<Ret>::value, "F must return an expected");

return exp.has_value() ? detail::invoke(std::forward<F>(f))
 : Ret(unexpect, std::forward<Exp>(exp).error());
}
#else
template <class> struct TC;
template <class Exp, class F,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 *std::declval<Exp>())),
 detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr>
auto and_then_impl(Exp &&exp, F &&f) -> Ret {
 static_assert(detail::is_expected<Ret>::value, "F must return an expected");

return exp.has_value()
 ? detail::invoke(std::forward<F>(f), *std::forward<Exp>(exp))
 : Ret(unexpect, std::forward<Exp>(exp).error());
}

template <class Exp, class F,
 class Ret = decltype(detail::invoke(std::declval<F>())),
 detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr>
constexpr auto and_then_impl(Exp &&exp, F &&f) -> Ret {
 static_assert(detail::is_expected<Ret>::value, "F must return an expected");

return exp.has_value() ? detail::invoke(std::forward<F>(f))
 : Ret(unexpect, std::forward<Exp>(exp).error());
}
#endif

#ifdef TL_EXPECTED_CXX14
template <class Exp, class F,
 detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 *std::declval<Exp>())),
 detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
constexpr auto expected_map_impl(Exp &&exp, F &&f) {
 using result = ret_t<Exp, detail::decay_t<Ret>>;
 return exp.has_value() ? result(detail::invoke(std::forward<F>(f),
 *std::forward<Exp>(exp)))
 : result(unexpect, std::forward<Exp>(exp).error());
}

template <class Exp, class F,
 detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 *std::declval<Exp>())),
 detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
auto expected_map_impl(Exp &&exp, F &&f) {
 using result = expected<void, err_t<Exp>>;
 if (exp.has_value()) {
 detail::invoke(std::forward<F>(f), *std::forward<Exp>(exp));
 return result();
 }

return result(unexpect, std::forward<Exp>(exp).error());
}

template <class Exp, class F,
 detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>())),
 detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
constexpr auto expected_map_impl(Exp &&exp, F &&f) {
 using result = ret_t<Exp, detail::decay_t<Ret>>;
 return exp.has_value() ? result(detail::invoke(std::forward<F>(f)))
 : result(unexpect, std::forward<Exp>(exp).error());
}

template <class Exp, class F,
 detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>())),
 detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
auto expected_map_impl(Exp &&exp, F &&f) {
 using result = expected<void, err_t<Exp>>;
 if (exp.has_value()) {
 detail::invoke(std::forward<F>(f));
 return result();
 }

return result(unexpect, std::forward<Exp>(exp).error());
}
#else
template <class Exp, class F,
 detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 *std::declval<Exp>())),
 detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>

constexpr auto expected_map_impl(Exp &&exp, F &&f)
 -> ret_t<Exp, detail::decay_t<Ret>> {
 using result = ret_t<Exp, detail::decay_t<Ret>>;

return exp.has_value() ? result(detail::invoke(std::forward<F>(f),
 *std::forward<Exp>(exp)))
 : result(unexpect, std::forward<Exp>(exp).error());
}

auto expected_map_impl(Exp &&exp, F &&f) -> expected<void, err_t<Exp>> {
 if (exp.has_value()) {
 detail::invoke(std::forward<F>(f), *std::forward<Exp>(exp));
 return {};
 }

return unexpected<err_t<Exp>>(std::forward<Exp>(exp).error());
}

constexpr auto expected_map_impl(Exp &&exp, F &&f)
 -> ret_t<Exp, detail::decay_t<Ret>> {
 using result = ret_t<Exp, detail::decay_t<Ret>>;

return exp.has_value() ? result(detail::invoke(std::forward<F>(f)))
 : result(unexpect, std::forward<Exp>(exp).error());
}

auto expected_map_impl(Exp &&exp, F &&f) -> expected<void, err_t<Exp>> {
 if (exp.has_value()) {
 detail::invoke(std::forward<F>(f));
 return {};
 }

return unexpected<err_t<Exp>>(std::forward<Exp>(exp).error());
}
#endif

#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
 !defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
template <class Exp, class F,
 detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 std::declval<Exp>().error())),
 detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
constexpr auto map_error_impl(Exp &&exp, F &&f) {
 using result = expected<exp_t<Exp>, detail::decay_t<Ret>>;
 return exp.has_value()
 ? result(*std::forward<Exp>(exp))
 : result(unexpect, detail::invoke(std::forward<F>(f),
 std::forward<Exp>(exp).error()));
}
template <class Exp, class F,
 detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 std::declval<Exp>().error())),
 detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
auto map_error_impl(Exp &&exp, F &&f) {
 using result = expected<exp_t<Exp>, monostate>;
 if (exp.has_value()) {
 return result(*std::forward<Exp>(exp));
 }

detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error());
 return result(unexpect, monostate{});
}
template <class Exp, class F,
 detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 std::declval<Exp>().error())),
 detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
constexpr auto map_error_impl(Exp &&exp, F &&f) {
 using result = expected<exp_t<Exp>, detail::decay_t<Ret>>;
 return exp.has_value()
 ? result()
 : result(unexpect, detail::invoke(std::forward<F>(f),
 std::forward<Exp>(exp).error()));
}
template <class Exp, class F,
 detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 std::declval<Exp>().error())),
 detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
auto map_error_impl(Exp &&exp, F &&f) {
 using result = expected<exp_t<Exp>, monostate>;
 if (exp.has_value()) {
 return result();
 }

detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error());
 return result(unexpect, monostate{});
}
#else
template <class Exp, class F,
 detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 std::declval<Exp>().error())),
 detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
constexpr auto map_error_impl(Exp &&exp, F &&f)
 -> expected<exp_t<Exp>, detail::decay_t<Ret>> {
 using result = expected<exp_t<Exp>, detail::decay_t<Ret>>;

return exp.has_value()
 ? result(*std::forward<Exp>(exp))
 : result(unexpect, detail::invoke(std::forward<F>(f),
 std::forward<Exp>(exp).error()));
}

template <class Exp, class F,
 detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 std::declval<Exp>().error())),
 detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
auto map_error_impl(Exp &&exp, F &&f) -> expected<exp_t<Exp>, monostate> {
 using result = expected<exp_t<Exp>, monostate>;
 if (exp.has_value()) {
 return result(*std::forward<Exp>(exp));
 }

detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error());
 return result(unexpect, monostate{});
}

template <class Exp, class F,
 detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 std::declval<Exp>().error())),
 detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
constexpr auto map_error_impl(Exp &&exp, F &&f)
 -> expected<exp_t<Exp>, detail::decay_t<Ret>> {
 using result = expected<exp_t<Exp>, detail::decay_t<Ret>>;

return exp.has_value()
 ? result()
 : result(unexpect, detail::invoke(std::forward<F>(f),
 std::forward<Exp>(exp).error()));
}

template <class Exp, class F,
 detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 std::declval<Exp>().error())),
 detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
auto map_error_impl(Exp &&exp, F &&f) -> expected<exp_t<Exp>, monostate> {
 using result = expected<exp_t<Exp>, monostate>;
 if (exp.has_value()) {
 return result();
 }

detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error());
 return result(unexpect, monostate{});
}
#endif

#ifdef TL_EXPECTED_CXX14
template <class Exp, class F,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 std::declval<Exp>().error())),
 detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
constexpr auto or_else_impl(Exp &&exp, F &&f) {
 static_assert(detail::is_expected<Ret>::value, "F must return an expected");
 return exp.has_value() ? std::forward<Exp>(exp)
 : detail::invoke(std::forward<F>(f),
 std::forward<Exp>(exp).error());
}

template <class Exp, class F,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 std::declval<Exp>().error())),
 detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
detail::decay_t<Exp> or_else_impl(Exp &&exp, F &&f) {
 return exp.has_value() ? std::forward<Exp>(exp)
 : (detail::invoke(std::forward<F>(f),
 std::forward<Exp>(exp).error()),
 std::forward<Exp>(exp));
}
#else
template <class Exp, class F,
 class Ret = decltype(detail::invoke(std::declval<F>(),
 std::declval<Exp>().error())),
 detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
auto or_else_impl(Exp &&exp, F &&f) -> Ret {
 static_assert(detail::is_expected<Ret>::value, "F must return an expected");
 return exp.has_value() ? std::forward<Exp>(exp)
 : detail::invoke(std::forward<F>(f),
 std::forward<Exp>(exp).error());
}

template <class T, class E, class U, class F>
constexpr bool operator==(const expected<T, E> &lhs,
 const expected<U, F> &rhs) {
 return (lhs.has_value() != rhs.has_value())
 ? false
 : (!lhs.has_value() ? lhs.error() == rhs.error() : *lhs == *rhs);
}
template <class T, class E, class U, class F>
constexpr bool operator!=(const expected<T, E> &lhs,
 const expected<U, F> &rhs) {
 return (lhs.has_value() != rhs.has_value())
 ? true
 : (!lhs.has_value() ? lhs.error() != rhs.error() : *lhs != *rhs);
}
template <class E, class F>
constexpr bool operator==(const expected<void, E> &lhs,
 const expected<void, F> &rhs) {
 return (lhs.has_value() != rhs.has_value())
 ? false
 : (!lhs.has_value() ? lhs.error() == rhs.error() : true);
}
template <class E, class F>
constexpr bool operator!=(const expected<void, E> &lhs,
 const expected<void, F> &rhs) {
 return (lhs.has_value() != rhs.has_value())
 ? true
 : (!lhs.has_value() ? lhs.error() == rhs.error() : false);
}

template <class T, class E, class U>
constexpr bool operator==(const expected<T, E> &x, const U &v) {
 return x.has_value() ? *x == v : false;
}
template <class T, class E, class U>
constexpr bool operator==(const U &v, const expected<T, E> &x) {
 return x.has_value() ? *x == v : false;
}
template <class T, class E, class U>
constexpr bool operator!=(const expected<T, E> &x, const U &v) {
 return x.has_value() ? *x != v : true;
}
template <class T, class E, class U>
constexpr bool operator!=(const U &v, const expected<T, E> &x) {
 return x.has_value() ? *x != v : true;
}

template <class T, class E>
constexpr bool operator==(const expected<T, E> &x, const unexpected<E> &e) {
 return x.has_value() ? false : x.error() == e.value();
}
template <class T, class E>
constexpr bool operator==(const unexpected<E> &e, const expected<T, E> &x) {
 return x.has_value() ? false : x.error() == e.value();
}
template <class T, class E>
constexpr bool operator!=(const expected<T, E> &x, const unexpected<E> &e) {
 return x.has_value() ? true : x.error() != e.value();
}
template <class T, class E>
constexpr bool operator!=(const unexpected<E> &e, const expected<T, E> &x) {
 return x.has_value() ? true : x.error() != e.value();
}

template <class T, class E,
 detail::enable_if_t<(std::is_void<T>::value ||
 std::is_move_constructible<T>::value) &&
 detail::is_swappable<T>::value &&
 std::is_move_constructible<E>::value &&
 detail::is_swappable<E>::value> * = nullptr>
void swap(expected<T, E> &lhs,
 expected<T, E> &rhs) noexcept(noexcept(lhs.swap(rhs))) {
 lhs.swap(rhs);
}
} // namespace tl

#endif

template<typename T1, typename T2>
class C 
{
 private:
 T1 a;
 T2 b;
};

template<typename T>
C (int, const T&)->C<int, const T&>;

class MyError {
public:
        enum ErrorType : int {
            none,
            type1,
            type2
        };

MyError (ErrorType type, const std::string& description)
        {

}
};

namespace tl {

template<typename T>
unexpected(MyError::ErrorType, const T&) -> unexpected<MyError>;

} // namespace tl

int main() 
{
    return 0;
}