ydb/contrib/libs/cxxsupp/libcxx/patches/00-future-2023-11-30-fix-std-expected-DEVTOOLSSUPPORT-54349.patch

diff --git a/include/__expected/expected.h b/include/__expected/expected.h
index 045370a..bf16c8f 100644
--- a/include/__expected/expected.h
+++ b/include/__expected/expected.h
@@ -119,9 +119,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI constexpr expected()
     noexcept(is_nothrow_default_constructible_v<_Tp>) // strengthened
     requires is_default_constructible_v<_Tp>
-      : __has_val_(true) {
-    std::construct_at(std::addressof(__union_.__val_));
-  }
+      : __union_(std::in_place), __has_val_(true) {}
 
   _LIBCPP_HIDE_FROM_ABI constexpr expected(const expected&) = delete;
 
@@ -136,14 +134,7 @@ public:
     noexcept(is_nothrow_copy_constructible_v<_Tp> && is_nothrow_copy_constructible_v<_Err>) // strengthened
     requires(is_copy_constructible_v<_Tp> && is_copy_constructible_v<_Err> &&
              !(is_trivially_copy_constructible_v<_Tp> && is_trivially_copy_constructible_v<_Err>))
-      : __has_val_(__other.__has_val_) {
-    if (__has_val_) {
-      std::construct_at(std::addressof(__union_.__val_), __other.__union_.__val_);
-    } else {
-      std::construct_at(std::addressof(__union_.__unex_), __other.__union_.__unex_);
-    }
-  }
-
+      : __union_(__other.__has_val_, __other.__union_), __has_val_(__other.__has_val_) { }
 
   _LIBCPP_HIDE_FROM_ABI constexpr expected(expected&&)
     requires(is_move_constructible_v<_Tp> && is_move_constructible_v<_Err>
@@ -154,13 +145,7 @@ public:
     noexcept(is_nothrow_move_constructible_v<_Tp> && is_nothrow_move_constructible_v<_Err>)
     requires(is_move_constructible_v<_Tp> && is_move_constructible_v<_Err> &&
              !(is_trivially_move_constructible_v<_Tp> && is_trivially_move_constructible_v<_Err>))
-      : __has_val_(__other.__has_val_) {
-    if (__has_val_) {
-      std::construct_at(std::addressof(__union_.__val_), std::move(__other.__union_.__val_));
-    } else {
-      std::construct_at(std::addressof(__union_.__unex_), std::move(__other.__union_.__unex_));
-    }
-  }
+      : __union_(__other.__has_val_, std::move(__other.__union_)), __has_val_(__other.__has_val_) { }
 
 private:
   template <class _Up, class _OtherErr, class _UfQual, class _OtherErrQual>
@@ -200,26 +185,14 @@ public:
   expected(const expected<_Up, _OtherErr>& __other)
     noexcept(is_nothrow_constructible_v<_Tp, const _Up&> &&
              is_nothrow_constructible_v<_Err, const _OtherErr&>) // strengthened
-      : __has_val_(__other.__has_val_) {
-    if (__has_val_) {
-      std::construct_at(std::addressof(__union_.__val_), __other.__union_.__val_);
-    } else {
-      std::construct_at(std::addressof(__union_.__unex_), __other.__union_.__unex_);
-    }
-  }
+      : __union_(__other.__has_val_, __other.__union_), __has_val_(__other.__has_val_) {}
 
   template <class _Up, class _OtherErr>
     requires __can_convert<_Up, _OtherErr, _Up, _OtherErr>::value
   _LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_Up, _Tp> || !is_convertible_v<_OtherErr, _Err>)
   expected(expected<_Up, _OtherErr>&& __other)
     noexcept(is_nothrow_constructible_v<_Tp, _Up> && is_nothrow_constructible_v<_Err, _OtherErr>) // strengthened
-      : __has_val_(__other.__has_val_) {
-    if (__has_val_) {
-      std::construct_at(std::addressof(__union_.__val_), std::move(__other.__union_.__val_));
-    } else {
-      std::construct_at(std::addressof(__union_.__unex_), std::move(__other.__union_.__unex_));
-    }
-  }
+      : __union_(__other.__has_val_, std::move(__other.__union_)), __has_val_(__other.__has_val_) {}
 
   template <class _Up = _Tp>
     requires(!is_same_v<remove_cvref_t<_Up>, in_place_t> && !is_same_v<expected, remove_cvref_t<_Up>> &&
@@ -227,61 +200,47 @@ public:
              (!is_same_v<remove_cv_t<_Tp>, bool> || !__is_std_expected<remove_cvref_t<_Up>>::value))
   _LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_Up, _Tp>)
       expected(_Up&& __u) noexcept(is_nothrow_constructible_v<_Tp, _Up>) // strengthened
-      : __has_val_(true) {
-    std::construct_at(std::addressof(__union_.__val_), std::forward<_Up>(__u));
-  }
+      : __union_(std::in_place, std::forward<_Up>(__u)), __has_val_(true) {}
 
   template <class _OtherErr>
     requires is_constructible_v<_Err, const _OtherErr&>
   _LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<const _OtherErr&, _Err>)
   expected(const unexpected<_OtherErr>& __unex)
     noexcept(is_nothrow_constructible_v<_Err, const _OtherErr&>) // strengthened
-      : __has_val_(false) {
-    std::construct_at(std::addressof(__union_.__unex_), __unex.error());
-  }
+      : __union_(std::unexpect, __unex.error()), __has_val_(false) {}
 
   template <class _OtherErr>
     requires is_constructible_v<_Err, _OtherErr>
   _LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_OtherErr, _Err>)
   expected(unexpected<_OtherErr>&& __unex)
     noexcept(is_nothrow_constructible_v<_Err, _OtherErr>) // strengthened
-      : __has_val_(false) {
-    std::construct_at(std::addressof(__union_.__unex_), std::move(__unex.error()));
-  }
+      : __union_(std::unexpect, std::move(__unex.error())), __has_val_(false) {}
 
   template <class... _Args>
     requires is_constructible_v<_Tp, _Args...>
   _LIBCPP_HIDE_FROM_ABI constexpr explicit expected(in_place_t, _Args&&... __args)
     noexcept(is_nothrow_constructible_v<_Tp, _Args...>) // strengthened
-      : __has_val_(true) {
-    std::construct_at(std::addressof(__union_.__val_), std::forward<_Args>(__args)...);
-  }
+      : __union_(std::in_place, std::forward<_Args>(__args)...), __has_val_(true) {}
 
   template <class _Up, class... _Args>
     requires is_constructible_v< _Tp, initializer_list<_Up>&, _Args... >
   _LIBCPP_HIDE_FROM_ABI constexpr explicit
   expected(in_place_t, initializer_list<_Up> __il, _Args&&... __args)
     noexcept(is_nothrow_constructible_v<_Tp, initializer_list<_Up>&, _Args...>) // strengthened
-      : __has_val_(true) {
-    std::construct_at(std::addressof(__union_.__val_), __il, std::forward<_Args>(__args)...);
-  }
+      : __union_(std::in_place, __il, std::forward<_Args>(__args)...), __has_val_(true) {}
 
   template <class... _Args>
     requires is_constructible_v<_Err, _Args...>
   _LIBCPP_HIDE_FROM_ABI constexpr explicit expected(unexpect_t, _Args&&... __args)
-    noexcept(is_nothrow_constructible_v<_Err, _Args...>)  // strengthened
-      : __has_val_(false) {
-    std::construct_at(std::addressof(__union_.__unex_), std::forward<_Args>(__args)...);
-  }
+    noexcept(is_nothrow_constructible_v<_Err, _Args...>) // strengthened
+      : __union_(std::unexpect, std::forward<_Args>(__args)...), __has_val_(false) {}
 
   template <class _Up, class... _Args>
     requires is_constructible_v< _Err, initializer_list<_Up>&, _Args... >
   _LIBCPP_HIDE_FROM_ABI constexpr explicit
   expected(unexpect_t, initializer_list<_Up> __il, _Args&&... __args)
     noexcept(is_nothrow_constructible_v<_Err, initializer_list<_Up>&, _Args...>) // strengthened
-      : __has_val_(false) {
-    std::construct_at(std::addressof(__union_.__unex_), __il, std::forward<_Args>(__args)...);
-  }
+      : __union_(std::unexpect, __il, std::forward<_Args>(__args)...), __has_val_(false) {}
 
   // [expected.object.dtor], destructor
 
@@ -440,9 +399,10 @@ public:
       std::destroy_at(std::addressof(__union_.__val_));
     } else {
       std::destroy_at(std::addressof(__union_.__unex_));
-      __has_val_ = true;
     }
-    return *std::construct_at(std::addressof(__union_.__val_), std::forward<_Args>(__args)...);
+    std::construct_at(std::addressof(__union_.__val_), std::forward<_Args>(__args)...);
+    __has_val_ = true;
+    return __union_.__val_;
   }
 
   template <class _Up, class... _Args>
@@ -452,9 +412,10 @@ public:
       std::destroy_at(std::addressof(__union_.__val_));
     } else {
       std::destroy_at(std::addressof(__union_.__unex_));
-      __has_val_ = true;
     }
-    return *std::construct_at(std::addressof(__union_.__val_), __il, std::forward<_Args>(__args)...);
+    std::construct_at(std::addressof(__union_.__val_), __il, std::forward<_Args>(__args)...);
+    __has_val_ = true;
+    return __union_.__val_;
   }
 
 
@@ -893,11 +854,15 @@ public:
   }
 
 private:
-  struct __empty_t {};
-
   template <class _ValueType, class _ErrorType>
   union __union_t {
-    _LIBCPP_HIDE_FROM_ABI constexpr __union_t() {}
+    template <class... _Args>
+    _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(std::in_place_t, _Args&&... __args)
+        : __val_(std::forward<_Args>(__args)...) {}
+
+    template <class... _Args>
+    _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(std::unexpect_t, _Args&&... __args)
+        : __unex_(std::forward<_Args>(__args)...) {}
 
     template <class _Func, class... _Args>
     _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(
@@ -909,6 +874,14 @@ private:
         std::__expected_construct_unexpected_from_invoke_tag, _Func&& __f, _Args&&... __args)
         : __unex_(std::invoke(std::forward<_Func>(__f), std::forward<_Args>(__args)...)) {}
 
+    template <class _Union>
+    _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(bool __has_val, _Union&& __other) {
+      if (__has_val)
+        std::construct_at(std::addressof(__val_), std::forward<_Union>(__other).__val_);
+      else
+        std::construct_at(std::addressof(__unex_), std::forward<_Union>(__other).__unex_);
+    }
+
     _LIBCPP_HIDE_FROM_ABI constexpr ~__union_t()
       requires(is_trivially_destructible_v<_ValueType> && is_trivially_destructible_v<_ErrorType>)
     = default;
@@ -927,10 +900,17 @@ private:
   template <class _ValueType, class _ErrorType>
     requires(is_trivially_move_constructible_v<_ValueType> && is_trivially_move_constructible_v<_ErrorType>)
   union __union_t<_ValueType, _ErrorType> {
-    _LIBCPP_HIDE_FROM_ABI constexpr __union_t() : __empty_() {}
     _LIBCPP_HIDE_FROM_ABI constexpr __union_t(const __union_t&) = default;
     _LIBCPP_HIDE_FROM_ABI constexpr __union_t& operator=(const __union_t&) = default;
 
+    template <class... _Args>
+    _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(std::in_place_t, _Args&&... __args)
+        : __val_(std::forward<_Args>(__args)...) {}
+
+    template <class... _Args>
+    _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(std::unexpect_t, _Args&&... __args)
+        : __unex_(std::forward<_Args>(__args)...) {}
+
     template <class _Func, class... _Args>
     _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(
         std::__expected_construct_in_place_from_invoke_tag, _Func&& __f, _Args&&... __args)
@@ -941,6 +921,14 @@ private:
         std::__expected_construct_unexpected_from_invoke_tag, _Func&& __f, _Args&&... __args)
         : __unex_(std::invoke(std::forward<_Func>(__f), std::forward<_Args>(__args)...)) {}
 
+    template <class _Union>
+    _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(bool __has_val, _Union&& __other) {
+      if (__has_val)
+        std::construct_at(std::addressof(__val_), std::forward<_Union>(__other).__val_);
+      else
+        std::construct_at(std::addressof(__unex_), std::forward<_Union>(__other).__unex_);
+    }
+
     _LIBCPP_HIDE_FROM_ABI constexpr ~__union_t()
       requires(is_trivially_destructible_v<_ValueType> && is_trivially_destructible_v<_ErrorType>)
     = default;
@@ -950,7 +938,6 @@ private:
       requires(!is_trivially_destructible_v<_ValueType> || !is_trivially_destructible_v<_ErrorType>)
     {}
 
-    _LIBCPP_NO_UNIQUE_ADDRESS __empty_t __empty_;
     _LIBCPP_NO_UNIQUE_ADDRESS _ValueType __val_;
     _LIBCPP_NO_UNIQUE_ADDRESS _ErrorType __unex_;
   };
@@ -998,11 +985,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI constexpr expected(const expected& __rhs)
     noexcept(is_nothrow_copy_constructible_v<_Err>) // strengthened
     requires(is_copy_constructible_v<_Err> && !is_trivially_copy_constructible_v<_Err>)
-      : __has_val_(__rhs.__has_val_) {
-    if (!__rhs.__has_val_) {
-      std::construct_at(std::addressof(__union_.__unex_), __rhs.__union_.__unex_);
-    }
-  }
+      : __union_(__rhs.__has_val_, __rhs.__union_), __has_val_(__rhs.__has_val_) {}
 
   _LIBCPP_HIDE_FROM_ABI constexpr expected(expected&&)
     requires(is_move_constructible_v<_Err> && is_trivially_move_constructible_v<_Err>)
@@ -1011,51 +994,35 @@ public:
   _LIBCPP_HIDE_FROM_ABI constexpr expected(expected&& __rhs)
     noexcept(is_nothrow_move_constructible_v<_Err>)
     requires(is_move_constructible_v<_Err> && !is_trivially_move_constructible_v<_Err>)
-      : __has_val_(__rhs.__has_val_) {
-    if (!__rhs.__has_val_) {
-      std::construct_at(std::addressof(__union_.__unex_), std::move(__rhs.__union_.__unex_));
-    }
-  }
+      : __union_(__rhs.__has_val_, std::move(__rhs.__union_)), __has_val_(__rhs.__has_val_) {}
 
   template <class _Up, class _OtherErr>
     requires __can_convert<_Up, _OtherErr, const _OtherErr&>::value
   _LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<const _OtherErr&, _Err>)
   expected(const expected<_Up, _OtherErr>& __rhs)
     noexcept(is_nothrow_constructible_v<_Err, const _OtherErr&>) // strengthened
-      : __has_val_(__rhs.__has_val_) {
-    if (!__rhs.__has_val_) {
-      std::construct_at(std::addressof(__union_.__unex_), __rhs.__union_.__unex_);
-    }
-  }
+      : __union_(__rhs.__has_val_, __rhs.__union_), __has_val_(__rhs.__has_val_) {}
 
   template <class _Up, class _OtherErr>
     requires __can_convert<_Up, _OtherErr, _OtherErr>::value
   _LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_OtherErr, _Err>)
   expected(expected<_Up, _OtherErr>&& __rhs)
     noexcept(is_nothrow_constructible_v<_Err, _OtherErr>) // strengthened
-      : __has_val_(__rhs.__has_val_) {
-    if (!__rhs.__has_val_) {
-      std::construct_at(std::addressof(__union_.__unex_), std::move(__rhs.__union_.__unex_));
-    }
-  }
+      : __union_(__rhs.__has_val_, std::move(__rhs.__union_)), __has_val_(__rhs.__has_val_) {}
 
   template <class _OtherErr>
     requires is_constructible_v<_Err, const _OtherErr&>
   _LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<const _OtherErr&, _Err>)
   expected(const unexpected<_OtherErr>& __unex)
     noexcept(is_nothrow_constructible_v<_Err, const _OtherErr&>) // strengthened
-      : __has_val_(false) {
-    std::construct_at(std::addressof(__union_.__unex_), __unex.error());
-  }
+      : __union_(std::unexpect, __unex.error()), __has_val_(false) {}
 
   template <class _OtherErr>
     requires is_constructible_v<_Err, _OtherErr>
   _LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_OtherErr, _Err>)
   expected(unexpected<_OtherErr>&& __unex)
     noexcept(is_nothrow_constructible_v<_Err, _OtherErr>) // strengthened
-      : __has_val_(false) {
-    std::construct_at(std::addressof(__union_.__unex_), std::move(__unex.error()));
-  }
+      : __union_(std::unexpect, std::move(__unex.error())), __has_val_(false) {}
 
   _LIBCPP_HIDE_FROM_ABI constexpr explicit expected(in_place_t) noexcept : __has_val_(true) {}
 
@@ -1063,17 +1030,13 @@ public:
     requires is_constructible_v<_Err, _Args...>
   _LIBCPP_HIDE_FROM_ABI constexpr explicit expected(unexpect_t, _Args&&... __args)
     noexcept(is_nothrow_constructible_v<_Err, _Args...>) // strengthened
-      : __has_val_(false) {
-    std::construct_at(std::addressof(__union_.__unex_), std::forward<_Args>(__args)...);
-  }
+      : __union_(std::unexpect, std::forward<_Args>(__args)...), __has_val_(false) {}
 
   template <class _Up, class... _Args>
     requires is_constructible_v< _Err, initializer_list<_Up>&, _Args... >
   _LIBCPP_HIDE_FROM_ABI constexpr explicit expected(unexpect_t, initializer_list<_Up> __il, _Args&&... __args)
     noexcept(is_nothrow_constructible_v<_Err, initializer_list<_Up>&, _Args...>) // strengthened
-      : __has_val_(false) {
-    std::construct_at(std::addressof(__union_.__unex_), __il, std::forward<_Args>(__args)...);
-  }
+      : __union_(std::unexpect, __il, std::forward<_Args>(__args)...), __has_val_(false) {}
 
 private:
   template <class _Func>
@@ -1507,11 +1470,23 @@ private:
   union __union_t {
     _LIBCPP_HIDE_FROM_ABI constexpr __union_t() : __empty_() {}
 
+    template <class... _Args>
+    _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(std::unexpect_t, _Args&&... __args)
+        : __unex_(std::forward<_Args>(__args)...) {}
+
     template <class _Func, class... _Args>
     _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(
         __expected_construct_unexpected_from_invoke_tag, _Func&& __f, _Args&&... __args)
         : __unex_(std::invoke(std::forward<_Func>(__f), std::forward<_Args>(__args)...)) {}
 
+    template <class _Union>
+    _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(bool __has_val, _Union&& __other) {
+      if (__has_val)
+        std::construct_at(std::addressof(__empty_));
+      else
+        std::construct_at(std::addressof(__unex_), std::forward<_Union>(__other).__unex_);
+    }
+
     _LIBCPP_HIDE_FROM_ABI constexpr ~__union_t()
       requires(is_trivially_destructible_v<_ErrorType>)
     = default;
@@ -1534,11 +1509,23 @@ private:
     _LIBCPP_HIDE_FROM_ABI constexpr __union_t(const __union_t&) = default;
     _LIBCPP_HIDE_FROM_ABI constexpr __union_t& operator=(const __union_t&) = default;
 
+    template <class... _Args>
+    _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(std::unexpect_t, _Args&&... __args)
+        : __unex_(std::forward<_Args>(__args)...) {}
+
     template <class _Func, class... _Args>
     _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(
         __expected_construct_unexpected_from_invoke_tag, _Func&& __f, _Args&&... __args)
         : __unex_(std::invoke(std::forward<_Func>(__f), std::forward<_Args>(__args)...)) {}
 
+    template <class _Union>
+    _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(bool __has_val, _Union&& __other) {
+      if (__has_val)
+        std::construct_at(std::addressof(__empty_));
+      else
+        std::construct_at(std::addressof(__unex_), std::forward<_Union>(__other).__unex_);
+    }
+
     _LIBCPP_HIDE_FROM_ABI constexpr ~__union_t()
       requires(is_trivially_destructible_v<_ErrorType>)
     = default;